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Made available in DSpace on 2020-12-10T19:36:21Z (GMT). No. of bitstreams: 0 Previous issue date: 2019-09-15 Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) University of Sao Paulo Sao Paulo State University Federal University of Lavras Federal University of Rio Grande do Norte Colorado State University North Carolina State University USDA Forest Service Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Anglo American Arauco Arborgen ArcelorMittal Cenibra CMPC Comigo Copener Duratex Eldorado Fazenda Campo Bom Fibria Florestal Itaquari Forestal Oriental Gerdau GMR International Paper Jari Klabin Lwarcel Montes del Plata Plantar Rigesa Suzano Vallourec Veracel Growth and yield (G &Y) model systems aim at forecasting forest productivity. The lack of environmental variables to account for how water availability constrains eucalyptus production in Brazil, however, is argued to be a major drawback of these model systems. Thus, this study aimed to develop a stand-level G & Y model system that accounts for water availability (G & Y with SWD), highlighting its usefulness when applied for clonal eucalypt stands under drier climatic conditions. The dataset is composed of remeasurement information of sixteen research sites that span all climatic regions in Brazil. A total of eleven eucalypt clones were planted in single block plots at each site, and extra replications under the rainfall exclusion system were also installed for these eleven clones in fourteen sites. Linear algebra techniques were used to simultaneously fit a compatible set of prediction and projection basal area equations. A stand-level volume equation was also developed. These equations were validated through the use of an independent dataset composed of the rainfall exclusion plots. Finally, the accuracy and usefulness of a conventional G & Y model system applied to clonal eucalypt stands in Brazil was compared to the new proposed G & Y model system, which accounts for the impact of water availability in eucalyptus productivity. The prediction and projection basal area equations accounting for water availability displayed estimates in the order of 5% more accurate compared to the conventional basal area modeling. Stand-level volume estimates were 40% and 74% less biased through the use of the new G & Y model system. This result highlighted how useful and powerful the newly developed approach is, since the model system was capable to provide accurate estimates through the use of the rainfall exclusion plots. The new G & Y model system is a powerful alternative to estimate forest afforestation yield and is fully capable to accurately update forest inventories. The model system can also be used for projecting how forest growth may be impacted by short-term climate variation. North Carolina State Univ, Dept Forestry & Environm Resources, 2820 Faucette Dr,Campus Box 8001, Raleigh, NC 27695 USA Virginia Polytech Inst & State Univ, Dept Forest Resources & Environm Conservat, 310 W Campus Dr,Campus Box 169, Blacksburg, VA 24061 USA Forestry Sci & Res Inst, Via Comendador Pedro Morganti 3500, BR-13415000 Piracicaba, SP, Brazil State Univ Sao Paulo, Dept Forest Sci, Ave Univ 3780, BR-18610034 Botucatu, SP, Brazil Univ Sao Paulo, Dept Forest Sci, Ave Padua Dias 11, BR-13418900 Piracicaba, SP, Brazil State Univ Sao Paulo, Dept Forest Sci, Ave Univ 3780, BR-18610034 Botucatu, SP, Brazil CNPq: 249979/2013-6

Made available in DSpace on 2019-10-04T12:34:17Z (GMT). No. of bitstreams: 0 Previous issue date: 2019-01-15 Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Anglo American Arauco Arborgen ArcelorMittal Cenibra CMPC Comigo Copener Duratex Eldorado Fazenda Campo Bom Fibria Florestal Itaquari Forestal Oriental Gerdau GMR International Paper Jari Klabin Lwarcel Montes del Plata Plantar Rigesa Suzano Vallourec Veracel University of Sao Paulo Sao Paulo State University Federal University of Lavras Federal University of Rio Grande do Norte Colorado State University North Carolina State University USDA Forest Service Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Linking individual-tree and stand-level growth models is required for estimating future forest stand structure, while maintaining the desired accuracy for forest management decision making. There is a scarcity of studies addressing this issue for clonal Eucalypt stands in Brazil. Thus, this paper aims to develop a compatible individual-tree and stand-level growth and yield system for clonal Eucalypt stands in Brazil. The dataset used in this study is derived from remeasurement information of sixteen TECHS sites. At every site, eleven Eucalypt clones were planted in single block plots, while extra plots under a rainfall exclusion regime were also installed in fourteen sites. Prediction and projection diameter percentile equations were developed, as well as an individual-tree mortality equation and a generalized height-diameter equation. In addition, a detailed explanation of the structural architecture of the developed compatible growth and yield system is provided. Differences when forecasting forest afforestation and updating forest inventories were highlighted in order to provide the proper use of the developed growth and yield system. Finally, the individual-tree equations were validated through the use of the rainfall exclusion regime plots as was the growth and yield system when applied for prediction and projection purposes. The individual-tree level equations provided accurate estimates. The newly developed compatible growth and yield system also displayed unbiased and accurate estimates. The system achieved full compatibility between individual-tree and stand-level estimates and produced accurate stand table estimates. The growth and yield system presented is a powerful analytical tool that can serve to update inventory data in tropical Brazil and also to provide estimates for expected forest afforestation. The system has the capability of providing detailed outputs, which allows forest managers to consider merchandizing the clonal Eucalypt stands into multiple products. North Carolina State Univ, Dept Forestry & Environm Resources, 2820 Faucette Dr,Campus Box 8001, Raleigh, NC 27695 USA Virginia Polytech Inst & State Univ, Dept Forest Resources & Environm Conservat, 310 W Campus Dr,Campus Box 169, Blacksburg, VA 24061 USA Univ Fed Santa Catarina, Dept Forestry Agr & Biodivers, Campus Box 101,Rod Ulysses Gaboardi,Km 3, BR-89520000 Curitibanos, SC, Brazil State Univ Sao Paulo, Dept Forest Sci, Ave Univ,3780, BR-18610034 Botucatu, SP, Brazil Univ Sao Paulo, Dept Forest Sci, Ave Padua Dias,11, BR-13418900 Piracicaba, SP, Brazil State Univ Sao Paulo, Dept Forest Sci, Ave Univ,3780, BR-18610034 Botucatu, SP, Brazil CNPq: 249979/2013-6

Made available in DSpace on 2019-10-04T12:34:17Z (GMT). No. of bitstreams: 0 Previous issue date: 2019-01-15 Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Anglo American Arauco Arborgen ArcelorMittal Cenibra CMPC Comigo Copener Duratex Eldorado Fazenda Campo Born Fibria Florestal Itaquari Forestal Oriental Gerdau GMR International Paper Jani Klabin Lwarcel Montes del Plata Plantar Rigesa Suzano Vallourec Veracel University of Sao Paulo Sao Paulo State University Federal University of Lavras Federal University of Rio Grande do Norte Colorado State University North Carolina State University USDA Forest Service Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Several approaches for modeling whole-stand survival or mortality have been reported in the literature, although this component is often times neglected for clonal eucalypt stands in Brazil. In addition, the traditional form for projecting whole-stand survival appears incomplete for clonal eucalypt stands, since this tree species is highly sensitive to lack of water in the environment. Consequently, this study aimed to define the best approach to estimate whole-stand survival in clonal eucalypt stands and to develop a new approach for modeling whole-stand survival as a function of cumulative soil water deficit. Remeasurement of sixteen research sites composed the database used in this study. At each research site, the same eleven eucalypt clones were planted in single block plots, which results in a total of 176 plots distributed across Brazil. Two traditional approaches (two-step approach and direct estimation) were tested for modeling whole-stand survival. Additionally a new approach that replaces the age term by cumulative soil water deficit (cumulative SWD) was compared to the best selected traditional approach to estimate whole-stand survival in clonal eucalypt stands. The direct projection approach of whole-stand survival displayed better results when compared to the two-step approach. In addition, the replacement of age by cumulative SWD in the direct estimation approach allowed for an increase in the explanatory ability of the developed difference model. The newly developed difference model employing the direct estimation approach constrained by cumulative SWD ensures that the environmental stress effect is reflected on the survival of clonal eucalypt stands over time, and it is more biologically sound for extrapolation purposes. North Carolina State Univ, Dept Forestry & Environm Resources, 2820 Faucette Dr,Campus Box 8001, Raleigh, NC 27695 USA Virginia Polytech Inst & State Univ, Dept Forest Resources & Environm Conservat, 310 W Campus Dr,Campus Box 169, Blacksburg, VA 24061 USA Forestry Sci & Res Inst, Via Comendador Pedro Morganti, BR-13415000 Sao Paulo, Brazil State Univ Sao Paulo, Dept Forest Sci, Ave Univ,3780, BR-18610034 Botucatu, SP, Brazil Univ Sao Paulo, Dept Forest Sci, Ave Padua Dias,11, BR-13418900 Sao Paulo, Brazil State Univ Sao Paulo, Dept Forest Sci, Ave Univ,3780, BR-18610034 Botucatu, SP, Brazil CNPq: 249979/2013-6

Made available in DSpace on 2020-12-12T01:32:48Z (GMT). No. of bitstreams: 0 Previous issue date: 2020-11-01 Clonal plantations of Eucalyptus are among the most productive forests in the world, with intensification of silviculture and genetic breeding doubling the wood mean annual increments over the past four decades. The TECHS Project demonstrated that even with intensive silviculture, wood production varies by more than two-fold across environmental gradients, and growth of highly selected clones differs by more than two-fold within a site. Wood production accounts for less than half of the photosynthesis of a forest, and we tested two hypotheses about the relation between wood production and the entire carbon balance for five genotypes across four of the TECHS sites, varying in temperature and water availability. We hypothesized that the influence of the environment on carbon fluxes and partitioning related to gross primary production would be consistent across genotypes. We also hypothesized that carbon flux and partitioning would be more sensitive to water stress than temperature. Annual average temperatures ranged from 18 to 27 °C, and annual rainfall ranged from about 600 to 1500 mm yr−1. Water stress was further tested by reduction in rainfall within sites using troughs to capture about 30% of incoming rain. The geographic gradient led to a six-fold range in wood net primary production during the two years of measurement (from age 1.5 to 3.5 years, the period of maximum current annual increment). Gross primary production (GPP) differed only by two-fold, highlighting very large differences among sites in partitioning: wood net primary production (NPP) accounted for 44% of GPP on sites with higher GPP, and only 34% of GPP on lower GPP sites. The average differences for wood NPP among clones was also large, with about half of the differences among clones relating to differences in GPP, and half to differences in the partitioning to wood NPP. The clones showed similar partitioning patterns across sites, supporting our first hypothesis. Differences across sites and clones in partitioning of GPP to wood NPP related inversely to belowground allocation. Belowground partitioning of carbon increased with increasing temperature and increasing water stress. Our second hypothesis was rejected, as patterns across sites related somewhat more strongly to temperature than to water stress. Overall, this ecophysiological investigation in the TECHS Project underscored the importance of understanding how carbon budgets differ across sites (even with intensive silviculture), and why clones can largely differ in wood production. Department of Forest Sciences Federal University of Lavras (UFLA) Department of Forest Soils and Environmental Sciences São Paulo State University (UNESP) Forestry Science and Research Institute (IPEF) School of Forestry Northern Arizona University Natural Resource Ecology Laboratory Colorado State University USDA Forest Service Rocky Mountain Research Station Klabin Telêmaco Borba International Paper Suzano Department of Forest Soils and Environmental Sciences São Paulo State University (UNESP)

Made available in DSpace on 2020-12-12T01:29:27Z (GMT). No. of bitstreams: 0 Previous issue date: 2020-10-15 Phenotypic plasticity refers to the ability of a single genotype to express distinct phenotypes in response to the environment, a crucial feature for sessile organisms like forest trees, especially in a scenario of global climate change. Several studies show that epigenetic regulation plays an important role in this plastic adaptation response, driving the search for associations between natural epigenetic variation with environmental cues and phenotypic traits based on patterns of cytosine methylation. Clonally propagated trees across variable sites offer a robust system to control for the confounding effect of the background genetic variation among genotypes, allowing the analysis of epigenetic modifications in response to variable environments. In this study we investigated the overall patterns of epigenetic changes by the analysis of the genome-wide DNA methylation status based on high throughput MS-DArT-seq (Methyl Sensitive DArT-seq sequencing) of reduced genome complexity representations. We compared patterns of DNA methylation of biological replicates of leaf and xylem tissue samples of four commercially planted elite Eucalyptus grandis × Eucalyptus urophylla clones and one Eucalyptus urophylla in two contrasting sites in Brazil, and the association of these methylation patterns with the environments and growth traits. DNA sequence reads were mapped against the Eucalyptus grandis reference genome, counting and annotating differentially methylated sites. A total of 90,378 MS-DArT-seq sites were identified, the majority (~70%) located in genes and 10% in transposable elements. The distribution of methylation sites showed extensive variation between the five genotypes and the environments. Sets of methylation sites exclusive to each location were identified for each clone but no consistently shared epigenetic marks for all five clones were found across environments. Multiple correspondence analysis suggests a significant contribution of the genetic background on the distribution of methylation changes. We used a gene-environment association analysis to search for association of methylation patterns with growth traits. A total of 445 methylation sites across all 11 Eucalyptus chromosomes were found significantly associated with one or more of the three measured traits (total height, estimated volume and breast high diameter). The absence of clustered differentially methylated sites is consistent with the fact that complex growth traits are governed by a large number of loci of small effect across the entire genome suggesting that this same pattern will likely hold for what regards epigenetic marks. Department of Cell Biology University of Brasília Embrapa Genetic Resources and Biotechnology Department of Forest Sciences Federal University of Lavras – UFLA Department of Forest Science São Paulo State University – UNESP Department of Forestry and Environmental Resources – Suzano Universidade Católica de Brasília Department of Forest Science São Paulo State University – UNESP

Made available in DSpace on 2020-12-12T01:19:41Z (GMT). No. of bitstreams: 0 Previous issue date: 2020-06-15 Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) We examined the influence of stand density and genotype on transpiration and water use efficiency in high productivity plantations. Three widely planted Eucalyptus clones that differ in drought tolerance and productivity (E. urophylla, E. urophylla × E. grandis and E. grandis × E. camaldulensis, clones IP, B2 and C3, respectively) were measured at four densities (590, 1030, 1420, and 2950 trees ha−1). Over the 1-year study period (1.5–2.5 years after planting), individual biomass increment decreased with increasing density, from 21 kg tree−1 at 590 trees ha−1 to 6 kg tree−1 at 2950 trees ha−1. Stand increment typically follows the reverse pattern, increasing as density increases. This was the case for two clones (IP and B2), but stand increment was consistent across tree spacings for C3. Transpiration increased with density, from a low of 622 mm yr−1 to a high of 879 mm y−1. Some of the increased water use resulted from higher leaf area index at higher densities. The B2 clone transpired the most water on average, produced the greatest increment (23 Mg ha−1 yr−1 for 1030 trees ha−1), and produced the most wood L−1 transpiration (water use efficiency, 2.3 g biomass L−1). The clone C3 had the lowest increment (only 12 Mg ha−1 yr−1) because of the combination of low transpiration and low water use efficiency (only 1.5 g biomass L−1). Optimizing clone selection and silviculture for the combination of high yield and high water use efficiency may help reduce risks from drought as well as water conservation. Department of Forest Science Federal Rural University of Pernambuco USDA Forest Service Rocky Mountain Research Station Department of Forest Sciences University of São Paulo UNESP-FCA Department of Forest Sciences Federal University of Lavras UNESP-FCA

Made available in DSpace on 2020-12-12T01:16:21Z (GMT). No. of bitstreams: 0 Previous issue date: 2020-05-01 Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) Universidade de São Paulo Differences in growth rates between Eucalyptus clones depend on differences in the acquisition of resources, and the efficiency of using resources to produce carbohydrates and grow wood. We examined differences in canopy structure, light interception, and light use efficiency for the 18 TECHS clones in a common garden experiment in Brazil. The degree of clumping within canopies varied substantially among clones, leading to large differences in both leaf area and light interception per unit of leaf area. Two methods of determining plot-level leaf area index (LP-80 and LAI-2000) were moderately well correlated (R2 = 0.4), but both methods underestimated actual leaf area index (determined by destructive sampling) by about one-third. Completely overcast sky conditions increased accuracy of leaf area estimates, reducing variation among measurements within plots and lowering the number of samples needed to obtain a given level of precision. Genotypes with high leaf area clumping also had higher leaf angle inclinations than genotypes with lower clumping. The apparent light interception coefficient (k) averaged 0.56 for the LP-80, and 0.47 for the LAI-2000. The range of k estimates differed by up to 2-fold among clones, underscoring the limited generality of light extinction coefficients. Light interception ranged from about 70 to 95% of incoming light, and leaf area index accounted for only 30% of the pattern in light interception among clones. Differences in stemwood production were influenced more strongly by clonal differences in efficiency of light use (stemwood production per unit of light intercepted) than by differences in leaf area or light interception. The efficiency of producing wood per unit of light intercepted spanned a two-fold range, with higher efficiencies for more productive clones. We suggest that production ecology studies focus more on measurements of light interception than on leaf area, avoiding issues about difficult-to-measure features of crown and canopy structures. The additional step of characterizing light use efficiency would also be very important. Department of Forest Sciences University of São Paulo Geplant Forest Technology Llc. School of Forestry Northern Arizona University Universidade Federal de Lavras Department of Forest Science São Paulo State University - UNESP Department of Forest Science São Paulo State University - UNESP

Made available in DSpace on 2020-12-12T02:36:23Z (GMT). No. of bitstreams: 0 Previous issue date: 2020-04-15 Different ecophysiological models are used to predict the productivity of forest plantations worldwide. The Physiological Principles in Prediction Growth (3-PG) model has been successfully used for this purpose since 1997. In this study, the 3-PG model was parameterized and validated to predict the productivity of the most planted clonal eucalypts in Brazil (Eucalyptus urophylla) in different regions of the country and assess the attainable productivity of this same clone for a region little exploited for this plantations in the country. Through data collection carried out between 2012 and 2018, conducted in 36 sites distributed across an environmental gradient that spans over 3500 km in Brazil, it was possible to parameterize the 3-PG model using data that represent a portion of the soil and climate diversity of forest plantations in Brazil. We determined the initial biomass of the compartments (stem, leaf, and root), relationship between net and gross productivity, average wood density, maximum stem biomass for 1000 trees ha−1, maximum stomatal conductance, bark and branch fractions for the initial and mature age, specific leaf area for the initial and mature age, and allometric parameters at different ages. Considering the model initialization period, the initial age was defined at 12 months after planting and the final age was considered at 80 months. Model calibration was performed in four experimental sites (special sites for the calibration set), which correspond to the environmental diversities of the project, and model validation was performed by applying the setup of the model obtained in 10 other sites (regular sites for validation set) of the same experimental network. In all sites tested, estimates of basal area, diameter at breast height, leaf area index, and stem biomass agreed with the measured values. On average, the estimates of diameter and breast height were 4.91% higher than the observed measures, whereas the stem biomass estimates were 16.44% lower and the leaf area index was 26.22% lower; moreover, the estimates were overestimated for the first three years and underestimated in recent years. Overall, the model was able to capture the soil and climate differences for predicting E. urophylla clone productivity. Its application in a region not yet exploited for eucalypts plantations may help investors in the region select areas for acquisition, planting extensions, and extend production technologies. Department of Forest Soils and Environmental Sciences São Paulo State University-UNESP Department of Agronomy Rondônia Federal Institute, 76993-000 Colorado do Oeste Suzano SA Company Federal University of Lavras – UFLA, 37.200-000 Lavras Department of Forest Science Federal Rural University of Pernambuco – UFRPE Department of Forest Soils and Environmental Sciences São Paulo State University-UNESP

Increasing forest site productivity is a need. Land use conflicts, high land prices, or owners’ objectives, have motivated forest managers to apply more intensive silvicultural treatments to increase forest site productivity. Understanding how intensive silvicultural practices such as weed control and fertilization + weed control affect productivity will permit managers to select the best treatment to increase it. Our objectives were: (1) to estimate the gap between current and attainable productivity of Eucalyptus plantations and (2) to determine the effect of treatment on light use and light use efficiency. To estimate the gap between current and attainable productivity, we established 53 pairs of plots, which were measured for two years. Each pair consisted of a control plot, which received the management regime that is regularly applied to the stands, and a treated plot, which received intensive silvicultural treatment (fertilization + weed control) in addition to the operational management applied to the control plots. At 25% of the sites, a third plot (weed control only) was established. Stem biomass growth in the control and treated plots was 12.4 and 14.8 Mg ha−1 yr−1, respectively. We found significant differences in light use between the control and treated plots, i.e., averages of 1344 MJ m−2 yr−1 and 1406 MJ m−2 yr−1, respectively, representing a 4.6% increase. The increase in light use efficiency (LUE) was higher and reached 20%. On average, the control plots had a LUE of 0.9 g of dry mass (DM)/MJ compared with 1.10 g DM/MJ for the treated plots. There is a considerable opportunity to increase forest productivity through fertilization, and it may be possible to obtain greater gains than those observed in this study. This information is important to estimate the expected responses to intensive silviculture and will help to decide where silvicultural treatments should be applied to maximize the gains obtained from the investment.

Made available in DSpace on 2018-11-26T17:42:01Z (GMT). No. of bitstreams: 0 Previous issue date: 2017-12-01 Anglo American Arauco Arborgen ArcelorMittal Cenibra CMPC Comigo Copener Duratex Eldorado Fazenda Campo Born Fibria Florestal Itaquari Forestal Oriental Gerdau GMR International Paper Jari Klabin Lwarcel Montes del Plata Plantar Rigesa Suzano Vallourec Veracel University of Sao Paulo - Brazil Sao Paulo State University - Brazil Federal University of Lavras - Brazil Federal University of Rio Grande do Norte - Brazil Colorado State University - USA North Carolina State University - USA USDA Forest Service Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Intensively managed plantations account for 1.5% of the world's forests, but they meet one-third of the demand for wood products. Eucalyptus plantations are among the most productive, with rates of growth depending heavily on genetics, silviculture, and climate. The TECHS Project examines productivity at 36 locations across a 3500 km gradient from Brazil to Uruguay, testing the interacting influences of genetics, temperature and precipitation on stemwood production. Across all sites and genotypes, stemwood production in the middle of the 6 year rotation (the peak period of growth) averaged 22 Mg ha(-1) yr(-1). Production varied by fivefold across sites, and by about 2-fold among genotypes within each site. The best clones at each location grew 1.5-4 Mg ha(-1) yr(-1) more than the average for all clones, underscoring the importance of matching genotypes to local site conditions. Contrary to patterns for natural forests across geographic gradients, Eucalyptus production declined with increasing temperature, dropping by 2.5 Mg ha(-1) yr(-1) for a 1 degrees C temperature increase. The temperature effect was likely driven in part by the geographic covariance of temperature and rainfall, as rainfall tended to decline by 78 mm yr(-1) for each 1 degrees C increase in temperature. Stemwood production increased an average of 1.5 Mg ha(-1) yr(-1) for each 100 mm yr(-1) increase in precipitation, but when the covariation of temperature and precipitation were included the apparent influence of precipitation declined to 0.4 Mg ha(-1) yr(-1) for each 100 mm yr(-1) increase in precipitation. Future results will determine if within-site reductions in ambient rainfall have the same apparent influences as the rainfall pattern across the geographic gradient, as well as quantifying the importance of insects and pests in affecting growth. The supply of wood from intensively managed plantations will be strongly influenced by both temperature and precipitation at plantation locations, and with changing climates. No Arizona Univ, Sch Forestry, Flagstaff, AZ 86011 USA Swedish Univ Agr Sci, Dept Forest Ecol & Management, SE-90183 Umea, Sweden Fed Univ Santa Catarina UFSC, BR-89520000 Curitibanos, SC, Brazil Inst Pesquisas & Estudos Florestais, Via Comendador Pedro Morganti,3500 Bairro Monte A, Piracicaba, SP, Brazil Univ Sao Paulo, Dept Forest Sci, BR-13400 Piracicaba, SP, Brazil Sao Paulo State Univ, Dept Forest Sci, BR-18600 Botucatu, SP, Brazil Sao Paulo State Univ, Dept Forest Sci, BR-18600 Botucatu, SP, Brazil

The goals of this study were to identify and group three eucalyptus clones, each under coppice and clear-cut management regimes, into two or more groups based on similar growth rates; and fit a site index equation as a function of rainfall variables for each group to evaluate how different groups were impacted by climatic variation. The database came from the Continuous Forest Inventory (CFI) and weather stations. The CFI was conducted between 1994 and 2012, with climatic data also being gathered for the same period. The study area was managed by clear-cut and coppice regimes, with 126 and 72 CFI plots, respectively. The relationship between clones, management regimes and stand age with annual dominant height growth was assessed by linear mixed effects modeling. Ridge regression was applied for fitting each group as a function of the rainfall variables. Finally, ordinary Kriging was applied for each of the rainfall variables in the study area. Then, site index equations were applied to the generated maps enabling the observation of their pattern throughout the study area as well as their evaluation under a pessimistic climatic scenario. Three groups were defined, since each clone exhibited similar growth behavior under either management regimes; however, the 3 clones differ among each other. A significant reduction in the annual dominant height growth over time was observed for all 3 clones. Ridge regressions afforded good accuracy and equations with sound biological behavior. Applying the fitted site index equations to the maps of precipitation and rainy days enabled the definition of the most appropriate clone to be planted throughout the area. Site quality as a function of rainfall variables could be an important tool to better enable silvicultural planning, since it provides estimates of the site index and also enables the incorporation of short-term climate change.

Made available in DSpace on 2019-10-04T12:34:17Z (GMT). No. of bitstreams: 0 Previous issue date: 2019-01-15 Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Anglo American Arauco Arborgen ArcelorMittal Cenibra CMPC Comigo Copener Duratex Eldorado Fazenda Campo Bom Fibria Florestal Itaquari Forestal Oriental Gerdau GMR International Paper Jari Klabin Lwarcel Montes del Plata Plantar Rigesa Suzano Vallourec Veracel University of Sao Paulo Sao Paulo State University Federal University of Lavras Federal University of Rio Grande do Norte Colorado State University North Carolina State University USDA Forest Service Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) The research objective of this paper was to group eleven widely planted eucalypt clones based on their volume yield pattern by assessing how climatic variation impacts their productivity in tropical Brazil. A total of 187 plots evenly distributed across eleven clones and 17 sites (from Parana to Para State) were used. Plot measurements were carried out every six months (from 2013 to 2017) to evaluate eucalyptus growth. Since the year of plot establishment differs across the sites, volumes of all the plots and sites were standardized at a common age of 5 years. Clonal grouping analysis was performed based on the common age for volume yields using a new approach, which consisted of three steps: (1) create general groups based on testing of the slope coefficient, which was applied to every clonal-specific regression with volume yield as a function of annual water deficit index (WDI); (2) split each general group using volume yield deviation computations into subgroups of high and low productivity; (3) apply linear mixed effects models for every subgroup in order to confirm the non-existence of statistical difference among the volume yield of the clones. Statistical tests showed satisfactory yield estimates at the common age of 5 years. Clonal grouping revealed the identification of four groups (A: high productivity and non-sensitive to climate variation, B: high productivity and sensitive to climate variation, C: low productivity and sensitive to climate variation, D: low productivity and non-sensitive to climate variation). The volume yield of the Clonal group B was detected to be the most impacted by annual water deficit index variation, followed by clonal groups C, A and D. The findings of the study highlighted the utility of the proposed approach for grouping clones. Group identification and detection of the climatic impact on yield patterns was evaluated as a measure to increase site-specific productivity. North Carolina State Univ, Dept Forestry & Environm Resources, 2820 Faucette Dr,Campus Box 8001, Raleigh, NC 27695 USA Virginia Polytech Inst & State Univ, Dept Forest Resources & Environm Conservat, 310 W Campus Dr,Campus Box 169, Blacksburg, VA 24061 USA Univ Fed Santa Catarina, Dept Forestry Agr & Biodivers, Campus Box 101,Rod Ulysses Gaboardi,Km 3, BR-89520000 Curitibanos, SC, Brazil State Univ Sao Paulo, Dept Forest Sci, Ave Univ,3780, BR-18610034 Botucatu, SP, Brazil Univ Sao Paulo, Dept Forest Sci, Ave Padua Dias,11, BR-13418900 Sao Paulo, Brazil State Univ Sao Paulo, Dept Forest Sci, Ave Univ,3780, BR-18610034 Botucatu, SP, Brazil CNPq: 249979/2013-6

Made available in DSpace on 2019-10-06T16:31:57Z (GMT). No. of bitstreams: 0 Previous issue date: 2019-09-01 Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Climate changes will increase the probability of drought, which is likely to dramatically increase tree mortality. The capacity of trees to withdraw water in deep soil layers is an important trait likely to account for tree survival over prolonged droughts. Our study aimed to gain insight into the maximum distance from the trunk where Eucalyptus fine roots take up water and mobile nutrients in deep sandy soils during dry periods. NO3 −-15N was injected in the soil at the end of the rainy season in commercial Eucalyptus stands planted with the same E. urophylla × E. grandis clone. The 15N tracer was applied in the middle of the inter-row (replicated in 3 plots): at 5 depths (from 0.1 to 6 m)at age 0.6 year, at 4 depths (from 0.1 to 9 m)at age 1.2 years, at 5 depths (from 0.1 to 12 m)at age 2.2 years, and at 6 depths (from 0.1 to 15 m)at age 6.4 years. δ15N was determined in leaves sampled in dominant and suppressed trees at different distances from each injection area, 4–5 months after NO3 −-15N injection (after the dry season). While dominant trees took up NO3 −-15N down to a depth of 6 m between 7 and 12 months after planting, the maximum depth of NO3 −-15N uptake for suppressed trees was between 3 and 4.5 m. From 1.5 to 6 years after planting, a foliar enrichment in 15N was mainly detected when the NO3 −-15N tracer was injected in the upper soil layers and only for a few trees at a depth of 6 m. Most of the uptake of 15N occurred within 2 m of horizontal distance from the injection site, whatever tree age and tree social status. Low amounts of NO3 −-15N were taken up for injection sites located between 2 m and 5 m from the trunk, and 15N uptake was never detected at horizontal distances greater than 6 m from the trunk. Eucalyptus fine roots can take up nitrates at depths between 6 and 8 m the first year after planting. However, the NO3 −-15N tracer injected at a depth of 6 m was only taken up by dominant trees and a 15N foliar enrichment of suppressed trees was only detected when the tracer was injected in the upper 3 m. Fertilizers must be applied within 2 m of the trunks in Eucalyptus plantations to be taken up by all trees, regardless of their social status. When fertilizations are concentrated the first months after planting in sandy soils, nutrient leaching in deep layers might increase the heterogeneity of the stands since mobile nutrients could only be taken up by dominant trees. Universidade Estadual Paulista (Unesp) Faculdade de Ciências Agronômicas CIRAD UMR Eco&Sols Eco&Sols CIRAD INRA IRD Montpellier SupAgro University of Montpellier ESALQ Universidade de São Paulo Universidade Estadual Paulista (Unesp) Centro de Isótopos Estáveis Suzano SA Company Universidade Estadual Paulista (Unesp) Faculdade de Ciências Agronômicas Universidade Estadual Paulista (Unesp) Centro de Isótopos Estáveis FAPESP: 2015/25946-0

Made available in DSpace on 2020-12-12T01:33:53Z (GMT). No. of bitstreams: 0 Previous issue date: 2020-11-01 International Paper Cross-site patterns for multiple sites tend to be more broadly applicable and more useful for constructing and constraining models. We examined cross-site patterns of Eucalyptus plantation response to water supply (including irrigation and 1/3 precipitation removal), mean annual temperature (MAT), vapor pressure deficit during the daytime (VPD), and nutrient addition in eight sites from the Brazil Eucalyptus Productivity Project (BEPP). Mean annual increment (MAI) for all treatments and sites varied from 12.7 to 37.3 Mg ha−1 yr−1 across a 1400 km latitudinal gradient where annual precipitation varied from 940 to 1430 mm yr−1. MAI varied with water added across all sites, with a near linear increase of 1.42 Mg ha−1 yr−1 per 100 mm yr−1 between 640 and 1800 mm yr−1, a MAI plateau of 30.8 Mg ha−1 yr−1 at ~2000 mm yr−1, then decreasing to MAI of 27.2 Mg ha−1 yr−1 at 3060 mm yr−1. Including MAT with the water response showed that MAI decreased at 1.23 Mg ha−1 yr−1 per °C. For the natural precipitation treatments, MAI decreased at 2.52 Mg ha−1 yr−1 per °C, comparable to that for the much broader TECHS Project (Binkley et al., 2020). MAI was not related to temperature for the irrigation treatments, suggesting that some or all of the response of MAI to temperature is related to water supply. The difference between the biomass of the irrigation treatments and that of natural precipitation treatment slowed its increase or stopped increasing at age 30–60 months for five of the eight sites, but increased through the study duration for the other three sites. The difference in biomass between the fertilization and no fertilization treatments increased throughout the study for two sites. Three- and six-month growth was generally unrelated prior 3–12 month weather. Age-related decline was observed for all of the treatments at four of the eight sites. These cross-site comparisons affirm that water supply is the key resource determining levels of plantation productivity in Brazil and that individual site studies are inadequate for understanding many key responses. Department of Ecosystem Science & Sustainability Colorado State University USDA Forest Service Rocky Mountain Research Station Department of Forest Science São Paulo State University – UNESP Forestry Science and Research Institute (IPEF) School of Forestry Northern Arizona University Department of Forest Science São Paulo State University – UNESP

Made available in DSpace on 2020-12-10T19:58:18Z (GMT). No. of bitstreams: 0 Previous issue date: 2020-06-15 Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Anglo American Arauco Arborgen ArcelorMittal Cenibra CMPC Comigo Copener Duratex Eldorado Fazenda Campo Bom Fibria Florestal Itaquari Forestal Oriental Gerdau GMR International Paper Jari Klabin Lwarcel Montes del Plata Plantar Rigesa Suzano Vallourec Veracel University of Sao Paulo Sao Paulo State University Federal University of Lavras Federal University of Rio Grande do Norte Colorado State University North Carolina State University USDA Forest Service Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Growth models have been applied to assess the growth potential for areas without previous forest plantation records and to update forest inventory when commercial stands have been planted. However, there is a lack of growth models capable of incorporating environmental variables for updating forest inventories and recomputing site quality throughout Brazil. Consequently, this research aimed to deliver a compatible set of prediction and projection growth equations with parameters refined by environmental variables. The dataset used through this study is composed of remeasurement information of 16 research sites in Brazil. At each site, the same eleven eucalypt clones were planted in single block plots. Extra block plots were also installed in 14 sites to evaluate eucalyptus growth under drier climate scenarios. Four different competing model forms were tested. A common parameter of the best compatible set of growth equations was refined to test the magnitude of the environment effect on the prediction and projections of dominant height/site index in clonal eucalypt stands in Brazil. The compatible set of Chapman-Richards growth equations displayed the most accurate estimates of dominant height for clonal eucalypt plantations in Brazil. The common asymptote parameters between the growth models were refined as a function of annual soil water deficit (SWD), and a gain in accuracy of the projected and predicted dominant height estimates was observed. It is relevant to highlight that the developed set of growth equations possesses the ability to make short-, medium- and long-term predictions and projections with more assuredness about the biological behavior and its soundness. This feature ensures accurate estimation of site-specific growth curves. North Carolina State Univ, Dept Forestry & Environm Resources, 2820 Faucette Dr,Campus Box 8001, Raleigh, NC 27695 USA Univ Fed Lavras, LEMAF, Dept Forest Sci, Campus Univ,Campus Box 3037, BR-37200000 Lavras, MG, Brazil Virginia Polytech Inst & State Univ, Dept Forest Resources & Environm Conservat, 310 W Campus Dr,Campus Box 169, Blacksburg, VA 24061 USA Forestry Sci & Res Inst, Via Comendador Pedro Morganti 3500, BR-13415000 Piracicab, SP, Brazil State Univ Sao Paulo, Dept Forest Sci, Ave Univ 3780, BR-18610034 Botucatu, SP, Brazil Univ Sao Paulo, Dept Forest Sci, Ave Padua Dias 11, BR-13418900 Piracicaba, SP, Brazil State Univ Sao Paulo, Dept Forest Sci, Ave Univ 3780, BR-18610034 Botucatu, SP, Brazil CNPq: 249979/2013-6

Made available in DSpace on 2020-12-12T01:20:50Z (GMT). No. of bitstreams: 0 Previous issue date: 2020-06-15 High stocking short rotation plantations provide high yields for bioenergy use and have been adopted worldwide, especially in tropical areas. This silvicultural approach might alter ecosystem water balances compared with lower stocking, longer rotation practices. The sensitivity of water balance to stocking might also differ among genotypes. We evaluated the primary components of ecosystem water balance (transpiration - Et, canopy interception - Ei, soil evaporation – Es) for two hybrid clones that differ in drought tolerance and productivity (E. urophylla × E. grandis, Clone B2 and E.grandis × E.camaldulensis, Clone C3) planted in stockings ranging from 590 to 2,950 tree ha.-1 in a tropical region in Brazil. On a monthly time step, all water balance components of the two clones were largely related to the seasonality of rainfall, where the wet season represented 73% of the total rainfall, these processes corresponded on average to 76, 75, 67 and 70% of annual canopy interception, soil evaporation, transpiration and evapotranspiration (ET), respectively. For both clones, temperature (R2 = 0.32) and precipitation (R2 > 0.76) explained evapotranspiration responses while adding stocking as a second independent variable slightly improving the model for clone B2 but no improvement was detected for clone C3. When scaling up the monthly data to yearly analyses, all water balance components responded strongly to tree stocking for both clones during the two years of measurements (1.7 to 3.7 years-old). Annual transpiration rose linearly with stocking for the clone B2, rising from 550 mm yr−1 up to 1,039 mm yr−1, corresponding to 53–100% of precipitation (P). The clone C3 showed a much weaker influence of stocking on transpiration, rising only from 550 mm yr−1 at low stocking to 650 mm yr−1 at high stocking (53–63% of P). Canopy interception rose from about 230 mm yr−1 at low stocking to 300 mm yr−1 at high stocking, with little difference between the clones, ranging from 21 to 30% of P. Evaporation from the soil decreased with increased stocking for both clones and represented an average of 20–12% of P from lowest to highest stocking. Total evapotranspiration (ET – sum of Et, Ei and Es) was about 1,000 to 1,050 mm yr−1 at low-to-moderate stockings of both clones, but the less-drought tolerant clone B2 showed substantially higher total evapotranspiration at high stocking (2,900 mm yr−1) compared to the clone C3 (2300 mm yr−1). The difference between precipitation and evapotranspiration (the overall ecosystem water balance) declined with increasing stocking, dropping below 0 at stockings higher than 1,030 tree ha−1 for both clones. High stocking in highly productive Eucalyptus plantations may be less sustainable across multiple rotations, since any deficit in the ecosystem water balance would need to come from longer-term soil water storage. Our results indicate that both genetics and tree stocking can be used as silviculture tools to manage the sustainably of short rotation forest plantations in the face of climate change. Department of Forest Science Federal Rural University of Pernambuco USDA Forest Service Rocky Mountain Research Station, Fort Collins UNESP-FCA Department of Forest Sciences University of São Paulo UNESP-FCA

Made available in DSpace on 2020-12-12T01:16:20Z (GMT). No. of bitstreams: 0 Previous issue date: 2020-04-15 Colorado State University North Carolina State University Universidade Federal de Lavras Universidade Federal do Rio Grande do Norte U.S. Forest Service Universidade de São Paulo The TECHS project spanned a 3500 km gradient from the Amazon to Uruguay, examining the influence of stresses from temperature and water supply on clonal plantations of Eucalyptus, with and without rain reduction, and across a stocking gradient. The whole-rotation mean annual increment (MAI) showed a humped pattern in relation to temperature, rising from about 18 Mg ha−1 yr−1 of stemwood production when mean annual temperatures were near 16 °C, to 27 Mg ha−1 yr−1 at 20 °C, and then falling to less than 15 Mg ha−1 yr−1 above 24 °C. The age trend in growth showed a steeper initial rise in the warmer tropical sites (reaching a peak current annual increment, CAI, of 27 Mg ha−1 yr−1, at age 2–3 years), but the slower early growth in the cooler subtropical sites had a higher peak (CAI of 32 Mg ha−1 yr−1, at 4 years) and slower decline, giving 15% higher MAI for the cooler region. Whole-rotation MAI declined by about 2.2 Mg ha−1 yr−1 for each 1 °C increase in temperature (in the range between 19.5 and 23.5 °C), and MAI declined by 0.5 Mg ha−1 yr−1 for each 100 mm yr−1 decline in rain. The effect of reducing ambient rain was also a loss of 0.5 Mg ha−1 yr−1 for each 100 mm yr−1 reduction in rain, though the effect was small on low productivity sites (

We examined the change in spatial structures of Eucalyptus plantations across different types of silvicultural treatments over a full rotation. Clonal and seed-origin Eucalyptus plots applied with differing levels of fertilization (high vs. traditional) and irrigation (irrigated vs. non-irrigated) treatments were investigated. Additionally, for the clonal plots, uniform vs. heterogeneous stand structure treatments were created using staggered planting dates. The heterogeneous structure of the clonal plots aimed to mimic the seed-origin plots. Spatial structures were characterized by assessing the spatial autocorrelations of diameters, heights, and biomass. We also applied two distance-based neighborhood structures to look at the degree of change in spatial autocorrelations with different numbers of neighboring trees being defined as neighbors. The results suggest that spatial autocorrelations of diameters, heights, and biomass of Eucalyptus plantations were mostly insignificant at an alpha level of 0.05 over the rotation. However, spatial autocorrelations in most plots after the middle of the rotation were predominantly negative, indicating the occurrence of size differences among neighboring trees. In particular, general declining patterns from positive to negative spatial autocorrelations in diameters and biomass, except for plots with the heterogeneous stand structures, were noted at plots treated with high levels of fertilizer. This suggests that high fertilization may have influenced the realizations of microsite effects in the early stage of stand development. General trends in spatial autocorrelations between the two neighborhood structures considered were mostly similar except for several plots differing in intensities of spatial autocorrelations over the rotation.

A nutrient dose and application frequency study was installed in Eucalyptus grandis stands at six sites in the Colombian Andes to examine three hypotheses: (1) individual sites have different treatment responses (there is a significant site effect); (2) the relationship between volume growth response and applied nitrogen is not linear (there is an optimal amount of applied nitrogen beyond which growth improvements would be small); and (3) application frequency does not affect response if the cumulative dose applied is equivalent (there is no frequency effect). Nitrogen, phosphorus and boron were applied at a 1.0:0.1:0.005 ratio, where nitrogen rates ranged from 0 to 250 kg ha−1 and application frequency was 6, 12, 24 or 36 months. Fertilization began when trees were 11–24 months old and we examined volume growth response three years after study initiation when the maximum cumulative nitrogen application reached 720 kg ha−1. There was a significant site effect: two sites were responsive and four were non-responsive to treatment. At the two responsive sites, the relationship between volume growth response and applied nitrogen was not linear. Three years after treatment initiation, the maximum absolute response was 142 m3 ha−1 (91% increase) and 116 m3 ha−1 (56% increase) for Sites 1 and 4, respectively. Sites 1 and 4 reached maximum volume response at cumulative nitrogen doses of 360 and 480 kg ha−1, respectively. Tests that compared different nitrogen application rates and frequencies to achieve the same cumulative dose were not significantly different except for one test at Site 4 where the volume growth response to three applications of 180 kg nitrogen ha−1 was 58% greater than the response to six applications of 90 kg ha−1.

Deforestation for urbanization and agriculture expansion drastically reduced the area of the Atlantic forest biome in Brazil. To reverse this process, rehabilitating degraded lands, restoration plantations with native tree species show significant potential to rebuild the forest habitat and promoting carbon sequestration. High input silviculture (intensive fertilization and weed control), similar to those applied in commercial production forest plantations can increase productivity, accelerating forest restoration process. We evaluated the effects of two contrasting silvicultural systems, “traditional” (based on common silviculture of forest reforestation in Brazil – low input) and “intensive” (based on commercial plantations – high input) on carbon (C) stocks of a restoration plantation. We also compared the plantations with a mature forest remnant. Six years after planting, forest C stock (coarse roots and aboveground biomass) under intensive silviculture reached 23.3 Mg C ha−1, more than 3-fold the stock under traditional silviculture (6.9 Mg C ha−1). Under both silvicultural systems, soil showed constant C stock (average of 33 Mg C ha−1). The C accumulation in biomass with intensive silviculture reached 12.8% of that stored in the mature forest (181.5 Mg C ha−1), compared with just 3.8% for traditional silviculture. Intensive silviculture provided nutrients and reduced competition with weeds, increasing growth and carbon sequestration. Forest plantations aiming at restoration and also carbon sequestration are practicable, and are highly responsive to intensive silviculture.

Wood growth in trees depends on the acquisition of resources, and can vary with tree size leading to a variety of stand dynamics. Typically, larger trees obtain more resources and grow faster than smaller trees, but while light has been addressed more often, few case studies have investigated the contributions of water use and water use efficiency (WUE) within stands to isolate the tree-size dominance effect. Our sites were located near the cities of Aracruz and Eunapolis in Northeastern Brazil. We measured tree biomass growth, water use and WUE to explore patterns of growth among dominant and non-dominant trees in rainfed (1350 mm yr−1) and irrigated experimental stands in two high productivity tropical clones of Eucalyptus grandis × urophylla growing in clayey Ultisol soils. During the study period, irrigation supplied an additional 607 mm and 171 mm at the Aracruz and Eunapolis sites respectively. We tested two hypotheses; (1) larger trees transpire more water, and produce more wood per water used (higher water use efficiency, WUE) than smaller trees of the same clone and; (2) this pattern also applies if a water surplus is added via irrigation to alleviate water stress. Across both sites, we measured stand water use using sap flow sensors from August to December, and quantified wood growth on a tree-basis and then derived WUE, in kg wood per m3 of water transpired. Dominant trees showed higher rates of tree growth, water use and WUE than dominated trees for the two sites-clones and under both water supply regimes. Using the rainfed trees at Aracruz as an example, 50-kg trees grew 1.0 kg month−1 compared with growth of 100-kg trees of 3.8 kg month−1. The smaller trees would use water in a rate of 2.1 m3 month−1, compared with 3.1 m3 month−1 for the larger trees, demonstrating a higher WUE for the larger tree (1.2 kg m−3 versus 0.5 kg m−3). Our results suggest that manipulating stand density on heterogeneous stands, e.g. thinning, has the potential to minimize the tradeoffs between wood growth and tree water use in Eucalyptus grandis × urophylla plantations, mainly in tropical regions with seasonal water deficit. However, more research is needed to discern the underlying mechanisms responsible for higher WUE exhibited by dominant trees and distinct clones.

Increased soil carbon sequestration can potentially mitigate CO2 emission and can indicate sustainable forest management. This study aims to determine the relative influence of commercial plantation tree species on soil carbon following establishment on former tropical pastures. Soil carbon (organic horizon plus mineral soil from 0 to 45 cm) and stemwood productivity were quantified from 6 to 34 year-old conifer and broadleaf plantations in a sandy Oxisol (Typic Hapludox) in southeastern Brazil. Study plots consisted of ten pastures paired with broadleaf plantations and ten additional broadleaf plantations paired with conifer plantations. Pastures primarily consisted of Brachiaria decumbens Stapf., while broadleaf plantations were primarily Eucalyptus, but also included one plot each of three other broadleaf species. Conifer stands were made up of Pinus species. Average stemwood productivity (± standard error) was 9.7 (±1.0) Mg C ha−1 yr−1 for broadleaf and 5.7 (±0.5) Mg C ha−1 yr−1 for conifer plantations, but did not correlate to soil C. The soil C in the paired Pasture–Broadleaf plots averaged 36.0 ± 1.7 Mg C ha−1 in pastures and 36.8 ± 1.9 Mg C ha−1 in broadleaf plantations. The Broadleaf–Conifer plots averaged 38.3 ± 1.9 Mg C ha−1 for broadleaf plantations and 36.0 ± 1.6 Mg C ha−1 for conifers. Our results show little difference in soil C across vegetation types, providing evidence that conifer and broadleaf plantations overall maintain similar levels of soil carbon to pasture land-use up to 34 years following land conversion. Soil C differences between Pasture–Broadleaf pairs indicated a small decline in soil C accretion early after plantation establishment, followed by recovery to slightly higher accretion rates.

Deforestation has led to ecosystem degradation in many tropical regions. Re-establishment of native tree species on degraded land presents challenges due to environmental stressors such as water and nutrient limitations, particularly from weed competition. Ecophysiological studies can help assess responses of native tree species to silvicultural practices and improve our understanding of processes that influence their establishment and growth. Silvicultural treatments borrowed from commercial tree plantations such as greater nutrient applications and complete weed control can improve best silvicultural practices in forest restoration. Two contrasting silvicultural treatments, “traditional” based on common management practices for reforestation of native trees and “intensive” based on commercial plantation silviculture, were evaluated based on tree mortality, biomass, photosynthesis, chlorophyll content, soluble proteins, and nutritional status of 20 native Brazilian species, 2.5 years after planting. Intensive silviculture increased tree survival by 20%, showed higher aboveground biomass from 13% to 7-fold and increased photosynthesis of ∼20% from 15.8 μmol m−2 s−1 to 18.7 μmol m−2 s−1, compared to traditional silviculture. Total soluble proteins were 14% higher with 6.7 μg cm−2 in intensive silviculture compared to 5.9 μg cm−2 under traditional silviculture. Eighty percent of trees showed greater N content, with a 13% higher average than under traditional silviculture (2.60 g m−2 versus 2.92 g m−2). Average values of chlorophyll A, B, and total were ∼8% higher under intensive silviculture, but not significantly different between treatments. Overall, intensive silviculture provided a positive impact on the restoration plantation. During the initial years of plantation establishment, intensive silviculture methods were effective in leading to significant increases in growth and survival.

Instituto de Pesquisas e Estudos Florestais (IPEF), Avenida Padua Dias 11, Caixa Postal 530, CEP 13400-970, Piracicaba, SP

Site-specific constraints on foliage development and leaf area duration were investigated in two-year-old Pinus radiata D. Don. plantations established under a factorial combination of soil tillage (shovel vs. subsoil + bedding + shovel), fertilization (B only vs. N, P, K, and B), and weed control (pre-plant vs. pre-plant + two-year banded) at three contrasting textural (sand, clay and ash) and climatic soil-site conditions in the Central Valley of Chile. We examined site effects and five treatments at each site to test hypotheses that soil tillage and nutrient and water limitations, would not influence foliage development or leaf area duration. Site effects were evident for foliage development and leaf area duration. Improved nutrient availability increased fascicle length at the sand and clay sites. Improved water availability increased fascicle length and leaf area duration at the sand site, and increased fascicle number at the sand and clay sites. Soil tillage reduced fascicle length at the ash site. Fascicle length may be influenced by factors including water and nutrient availability and soil and air temperature; however based on our data and indications in the literature that the largest effects on foliage length have been associated with resource availability we hypothesize that tillage may have induced nutrient and or water limitations at the ash site.

Competition is a crucial factor in determining stand structure and productivity. Competition entails complex interactions that depend on spatial arrangement of trees, resource supplies, and the efficiency of using resources. The net outcome of competition may be characterized by the sizes and distances of trees in a neighborhood around a focal tree. We tested a hypothesis that higher variability in tree sizes within the neighborhood (=low uniformity) would directly reduce growth of individual trees. Neighborhood models tested the influence of focal tree size and neighborhood competition on focal tree growth, and whether further inclusion of a uniformity measure would improve model performance. We modeled growth of 8800 focal clonal trees in a 9 ha operational, clonal plantation of Eucalyptus grandis x urophylla to test our hypothesis by estimating the effects of size, and neighborhood competition and uniformity. The growth of a focal tree was strongly related to the tree’s size and to the neighborhood competition index that combined the sizes and distances of neighboring trees (within 8 m of the focal tree). For a given size focal tree and a given level of neighborhood competition, the uniformity of neighborhood trees influenced potential growth by −2% (very uniform neighborhoods) to −10% (for heterogeneous neighborhoods), for an overall reduction in potential stand growth of 4.3%. Higher growth of larger trees did not compensate for lower growth of smaller trees, and silviculture systems that maximize stand uniformity may lead to measurable increases in stand-level growth.

Fertilization and irrigation may substantially increase productivity of forests by increasing stand leaf area index and the efficiency of converting intercepted light into wood biomass. This stand-level growth response is the summation of individual tree responses, and these tree-level responses are often non-linear, resulting from shifting in the intensity of competition and dominance. We examined tree-level responses of aboveground net primary production (ANPP), absorbed photosynthetically active radiation (APAR) and (light use efficiency) LUE in relation to tree size class to explore how stand-level outcomes depend on shifting patterns among trees. We evaluated the production ecology of a nine-year-old loblolly pine (Pinus taeda L.) plantation, 2 years after the initiation of treatments: control, irrigation, fertilization and irrigation + fertilization. We measured tree level ANPP, simulated APAR for individual tree crowns using the MAESTRA process-based model and calculated LUE (ANPP/APAR) in relation to tree size to explore the influence of tree dominance on both light capture and light use efficiency. Fertilization and irrigation + fertilization strongly increased both APAR and LUE, in contrast to little effect of irrigation alone. Tree size had a strong influence on APAR and LUE across all treatments; the largest 20% trees showed 3.4 times greater ANPP when compared to the smallest 20% trees, with 66% resulting from higher APAR, and 34% from higher LUE, than the smallest 20% of trees. Fertilization increased the growth of the largest 20% trees 2-fold (8.6 kg tree−1 year−1), with 29% of the increase resulting from higher APAR (13.7 GJ tree−1 year−1), and 71% from higher LUE (0.63 g MJ−1), relative to the largest trees in the control treatment (4.3 kg tree−1 year−1, 11 GJ tree−1 year−1 and 0.39 g MJ−1, respectively). Irrigation and fertilization tripled production (13.2 kg tree−1 year−1) of the largest trees with an even greater proportional contribution from increased LUE (15.1 GJ tree−1 year−1, 85% response contribution; APAR 0.87 g MJ−1, 15% response contribution). Overall, large trees grow faster than smaller trees because of greater light capture, whereas the greater response of large trees to treatments resulted more from increased efficiency of using light.

Made available in DSpace on 2018-11-26T16:32:51Z (GMT). No. of bitstreams: 0 Previous issue date: 2016-04-15 Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) ArcelorMittal Cenibra Bahia Specialty Cellulose Duratex Fibria International Paper Klabin Suzano Vallourec CIRAD North Carolina State University French Agence Nationale de la Recherche through the MACACC (Modelling to ACCompany stakeholders towards Adaptation of forestry and agroforestry systems to Climate changes) project Although pioneer studies showed several decades ago that deep rooting is common in tropical forests, direct measurements of fine root distributions over the entire soil profile explored by the roots are still scarce. Our study aimed to compare, 2 years after planting, fine root traits of Eucalyptus trees planted from cuttings and from seedlings in order to assess whether the propagation mode has an influence on the capacity of the trees to explore very deep soils. Soils cores were sampled down to a depth of 13.5 mat the peak of leaf area index (LAI), 2 years after planting, under three Eucalyptus clones (belonging to species E. saligna, E. grandis x E. urophylla, E. grandis x E. camaldulensis) and under E. grandis seedlings in the same Ferralsol soil. LAI was estimated using allometric equations based on destructive sampling of eight trees per genotype. All the genotypes exhibited fine root densities roughly constant between the depths of 0.25 and 6.00 m. Changes in fine root traits (diameter, specific root length and specific root area) were low between the topsoil and the root front. The ratios between mean tree height and root front depth ranged from 0.8 to 1.2 for the four genotypes. Although tree vertical extension was roughly symmetric above and below ground for all the genotypes, the depth of the root front ranged from 8.0 m for the seedlings and the E. grandis x E. urophylla clone to 11.5 m for the E. saligna clone. Soil water content profiles suggested that the four genotypes had the capacity to withdraw water down to a depth of 8-10 m over the first 2 years after planting. Total fine root length ranged from 3.3 to 6.0 km per m(2) of soil depending on the genotype. The root area/leaf area ratio ranged from 1.3 to 3.2 and was negatively correlated with LAI across the four genotypes. This pattern suggests that the genotypes more conservative for water use (with a low LAI) invest more in fine root area relative to leaf area than genotypes adapted to wet regions (with a high LAI). The velocity of downward movement of the root front might be a relevant criterion in the last stage of the breeding programs to select clones with a fast exploration of deep soil layers in drought prone regions. (C) 2016 Elsevier B.V. All rights reserved. Univ Estadual Paulista Julio de Mesquita Mho, Dept Solos & Recursos Ambientais, BR-18610300 Botucatu, SP, Brazil CIRAD, UMR Eco&Sols, 2 Pl Viala, F-34060 Montpellier, France Univ Sao Paulo, Dept Ciencias Atmosfer, BR-05508900 Sao Paulo, Brazil IPEF, Forestry Sci & Res Inst, BR-13418260 Piracicaba, SP, Brazil N Carolina State Univ, Dept Forage & Environm Resources, Raleigh, NC 27695 USA Univ Fed Sao Paulo, Ctr Ciencias & Tecnol Sustentabilidade, BR-18052780 Sorocaba, SP, Brazil Univ Estadual Paulista Julio de Mesquita Mho, Dept Solos & Recursos Ambientais, BR-18610300 Botucatu, SP, Brazil FAPESP: 2012/13380-3 French Agence Nationale de la Recherche through the MACACC (Modelling to ACCompany stakeholders towards Adaptation of forestry and agroforestry systems to Climate changes) project: ANR- 13-AGRO-0005

Wood production varies substantially with resource availability, and the variation in wood production can result from several mechanisms: increased photosynthesis, and changes in partitioning of photosynthesis to wood production, belowground flux, foliage production or respiration. An understanding of the mechanistic basis for patterns in wood production within a stand and across landscapes requires a complete annual carbon budget. We measured annual carbon flows to wood production, foliage production and total belowground carbon flux (the sum of root production, root respiration, and mycorrhizal production and respiration) from ages three to five years in clonal Eucalyptus plantations at four sites in Brazil to test if fertility, water availability and stand structure changed wood production and by what mechanism. We also quantified the patterns in light interception and the efficiency of light use to provide additional mechanistic insights into growth responses and to determine if light-use efficiency was related to changes in flux and partitioning. The routine level of forest fertilization at these four sites was high enough that further increases in nutrient supply did not increase wood growth. Irrigation increased wood net primary productivity (age three to five) from 1.45 to 1.84 kg m � 2 year � 1 of C (27%), because of increases in light interception (5%), photosynthetic efficiency (from 0.028 to 0.031 mol C/mol photons absorbed, 11%), gross primary productivity (from 3.62 to 4.28 m � 2 year � 1 of C, 18%), and partitioning to wood (from 0.397 to 0.430 of photosynthesis, 8%). These changes increased light-use efficiency by 20%. Annual flux belowground varied among sites from 0.43 to 1.0 m � 2 year � 1 of C but did not vary with water availability. Across the four sites

We examined the potential growth of clonal Eucalyptus plantations at eight locations across a 1000+ km gradient in Brazil by manipulating the supplies of nutrients and water, and altering the uniformity of tree sizes within plots. With no fertilization or irrigation, mean annual increments of stem wood were about 28% lower (16.2 Mg ha−1 yr−1, about 33 m3 ha−1 yr−1) than yields achieved with current operational rates of fertilization (22.6 Mg ha−1 yr−1, about 46 m3 ha−1 yr−1). Fertilization beyond current operational rates did not increase growth, whereas irrigation raised growth by about 30% (to 30.6 Mg ha−1 yr−1, about 62 m3 ha−1 yr−1). The potential biological productivity (current annual increment) of the plantations was about one-third greater than these values, if based only on the period after achieving full canopies. The biological potential productivity was even greater if based only on the full-canopy period during the wet season, indicating that the maximum biological productivity across the sites (with irrigation, during the wet season) would be about 42 Mg ha−1 yr−1 (83 m3 ha−1 yr−1). Stands with uniform structure (trees in plots planted in a single day) showed 13% greater growth than stands with higher heterogeneity of tree sizes (owing to a staggered planting time of up to 80 days). Higher water supply increased growth and also delayed by about 1 year the point where current annual increment and mean annual increment intersected, indicating opportunities for lengthening rotations for more productive treatments as well as the influence of year-to-year climate variations on optimal rotations periods. The growth response to treatments after canopy closure (mid-rotation) related well with full-rotation responses, offering an early opportunity for estimating whole-rotation yields. These results underscore the importance of resource supply, the efficiency of resource use, and stand uniformity in setting the bounds for productivity, and provide a baseline for evaluating the productivity achieved in operational plantations. The BEPP Project showed that water supply is the key resource determining levels of plantation productivity in Brazil. Future collaboration between scientists working on silviculture and genetics should lead to new insights on the mechanisms connecting water and growth, leading to improved matching of sites, clones, and silviculture.

The growth of wood in trees and forests depends on the acquisition of resources (light, water, and nutrients), the efficiency of using resources for photosynthesis, and subsequent partitioning to woody tissues. Patterns of efficiency over time for individual trees, or between trees at one time, result from changes in rates photosynthesis and shifts in the relative partitioning to wood. We measured the production ecology (stem growth, light interception, and light use efficiency) to explain patterns of growth among trees within plots through stand development, and tested three hypotheses: (1) dominant trees have higher light use efficiency than subordinate trees; (2) lower variation in the size distribution of trees within plots allows higher light use efficiency; and (3) uniform stand structure and high light use efficiency reduce the age-related decline in tree growth. The experiment used clonal plantations of Eucalyptus at four locations in eastern Brazil. Irrigation and fertilization treatments ensured the major resource limitation for tree growth would be light supply. The influence of variation in the sizes of trees within plots was tested by comparing plots with all trees planted in a single day (uniform treatment) with plots where planting was spread over 80 days (heterogeneous treatment). Light interception per tree was simulated with the MAESTRA model. Across sites, treatments and whole-rotation stand development, dominant trees showed higher rates of stem growth, light interception, and light use efficiency than subordinate trees (supporting the first hypothesis). For example, dominant trees (80th percentile rank) at the end of the rotation grew four-times faster than suppressed trees (20th percentile rank), as a result of 2.1-fold greater light interception, and 1.8-fold greater stem growth per unit of light interception. In some cases, greater variation among tree sizes within plots led to lower efficiency of light use by average-size trees, providing mixed evidence for the second hypothesis. Greater uniformity of sizes of trees within plots did not substantially mitigate the decline in stem growth from mid-rotation to the end of the rotation, refuting the third hypothesis. The high efficiency of dominant trees underscores the marginal contribution of subordinate trees to total stand growth, and should spur further work on thinning to increase growth and lengthen rotations for dominant trees.

A B S T R A C T Only 7% of the once extensive forest along the eastern coast of Brazil remains, and much of that is degraded and threatened by agricultural expansion and urbanization. We wondered if methods similar to those developedto establish fast-growing Eucalyptus plantations might also work to enhance survival and growth of rainforest species on degraded pastures composed of highly competitive C 4 grasses. An 8- factor experiment was laid out to contrast the value of different intensities of cultivation, application of fertilizerand weedcontrol on thegrowth and survivalof amixtureof20 rainforest speciesplanted attwo densities: 3 m � 1 m, and 3 m � 2 m. Intensive management increased seedling survival from 90% to 98%, stemwood production and leaf area index (LAI) by �4-fold, and stemwood production per unit of light absorbed by 30%. Annual growth in stem biomass was closely related to LAI alone ( r 2 = 0.93, p < 0.0001), and the regression improved further in combination with canopy nitrogen content (r 2 = 0.99, p < 0.0001). Intensive management resulted in a nearly closed forest canopy in less than 4 years, and offers a practical means to establish functional forests on abandoned agricultural land.

Eucalyptus plantations occupy almost 20 million ha worldwide and exceed 3.7 million ha in Brazil alone. Improved genetics and silviculture have led to as much as a three-fold increase in productivity in Eucalyptus plantations in Brazil and the large land area occupied by these highly productive ecosystems raises concern over their effect on local water supplies. As part of the Brazil Potential Productivity Project, we measured water use of Eucalyptus grandis x urophylla clones in rainfed and irrigated stands in two plantations differing in productivity. The Aracruz (lower productivity) site is located in the state of Espirito Santo and the Veracel (higher productivity) site in Bahia state. At each plantation, we measured stand water use using homemade sap flow sensors and a calibration curve using the clones and probes we utilized in the study. We also quantified changes in growth, leaf area and water use efficiency (the amount of wood produced per unit of water transpired). Measurements were conducted for 1 year during 2005 at Aracruz and from August through December 2005 at Veracel. Transpiration at both sites was high compared to other studies but annual estimates at Aracruz for the rainfed treatment compared well with a process model calibrated for the Aracruz site (within 10%). Annual water use at Aracruz was 1394 mm in rainfed treatments versus 1779 mm in irrigated treatments and accounted for approximately 67% and 58% of annual precipitation and irrigation inputs respectively. Increased water use in the irrigated stands at Aracruz was associated with higher sapwood area, leaf area index and transpiration per unit leaf area but there was no difference in the response of canopy conductance with air saturation deficit between treatments. Water use efficiency at the Aracruz site was also not influenced by irrigation and was similar to the rainfed treatment. During the period of overlapping measurements, the response to irrigation treatments at the more productive Veracel site was similar to Aracruz. Stand water use at the Veracel site totaled 975mm and 1102mm in rainfed and irrigated treatments during the 5-month measurement period respectively. Irrigated stands at Veracel also had higher leaf area with no difference in the response of canopy conductance with air saturation deficit between treatments.Water use efficiency was also unaffected by irrigation at Veracel. Results from this and other studies suggest that improved resource availability does not negatively impact water use efficiency but increased productivity of these plantations is associated with higher water use and should be given consideration during plantation management decision-making processes aimed at increasing productivity.

Patterns of stand growth and dominance among individual trees change through stand development. We tested a prediction that large, old plantations of Eucalyptus saligna (Sm.) in Hawaii and Brazil would show a pattern of “reverse” growth dominance, with the largest trees contributing more to stand biomass than to current stand increment. This pattern might develop if the largest trees accounted for a large portion of the total resource use of the stand, but were less efficient at utilizing resources to produce stemwood. The 70-year-old plantation in Hawaii had a stem mass of 610 Mg/ha, compared with 325 Mg/ha in the 66-year-old Brazil plantation. Cumulative frequency plots for both sites showed that dominant trees comprised a very large proportion of total stand mass; the largest 20% of the trees accounted for 50% and 30% of the total stand mass in Hawaii and Brazil, respectively. Contrary to expectations, the largest trees continued to produce a disproportionately large amount of total stand growth, with the largest 20% of trees accounting for 60% (Hawaii) and 40% (Brazil) of stand growth. The frequency distributions resulted in positive growth dominance coefficients (similar to Gini coefficients) of 0.14 for Hawaii and 0.09 for Brazil, rather than negative values that would indicate that reverse growth dominance. The failure of these monoculture Eucalyptus stands to develop reverse growth dominance contrasts starkly with a variety of studies with pine species, which tend to show neutral-to-reverse growth dominance. Indeed, continued dominance of large trees suggests the trees might respond well to silvicultural treatments such as thinning or fertilization. Future work that contrasts patterns of growth dominance among species will be important as a foundation for developing generalizations about trends in growth dominance with stand development.

We developed site specific component (stem, branch, and foliage) biomass functions for two sites in Sweden (64° and 57° North latitude) where four treatments (control, irrigated, fertilized, irrigated plus fertilized) were applied in the existing Norway spruce stands (Picea abies L. Karst.) for 17 years. We tested for site effects in the component biomass equations and compared site specific biomass estimates to those generated using published functions ( Lehtonen et al., 2004 , Wirth et al., 2004 ). Site effects were significant for all components and indicated it would be unlikely to generate equations that well estimate biomass across the Norway spruce range as implicitly indicated in our efforts to generate species biomass expansion factors. We rejected our hypothesis that the published functions would well estimate component biomass for control plots. The published functions did not compare well with site specific component biomass estimates for the other treatments; both published functions well estimated stem mass up to stem mass of 25 Mg ha−1, beyond which stem mass was overestimated, and both functions over and under estimated foliage and branch mass. Nor did the published functions compare well with each other, with stem, foliage and branch mass estimate differences of 12, 55, −8% and 11, 77, and 59% for the southern and northern sites, respectively, when averaged over all treatments and years. Adding limiting resources through fertilization increased stem, foliage and branch mass 57, 11, 18% and 120, 37, and 69% at the southern and northern sites, respectively, which would increase carbon sequestration and available stemwood and bioenergy materials. We recommend that more effort is spent in process-based modeling to better predict mass at a given site and ultimately provide better estimates of carbon sequestration and bioenergy material production changes.

We examined resource limitations on growth and carbon allocation in a fast-growing, clonal plantation of Eucalyptus grandis × urophylla in Brazil by characterizing responses to annual rainfall, and response to irrigation and fertililization for 2 years. Productivity measures included gross primary production (GPP), total belowground carbon allocation (TBCA), bole growth, and net ecosystem production (NEP). Replicate plots within a single plantation were established at the midpoint of the rotation (end of year 3), with treatments of no additional fertilization or irrigation, heavy fertilization (to remove any nutrient limitation), irrigation (to remove any water limitation), and irrigation plus fertilization. Rainfall was unusually high in the first year (1769 mm) of the experiment, and control plots had high rates of GPP (6.64 kg C m−2 year−1), TBCA (2.14 kg C m−2 year−1), and bole growth (1.81 kg C m−2 year−1). Irrigation increased each of these rates by 15–17%. The second year of the experiment had average rainfall (1210 mm), and lower rainfall decreased production in control plots by 46% (GPP), 52% (TBCA), and 40% (bole growth). Fertilization treatments had neglible effects. The response to irrigation was much greater in the drier year, with irrigated plots exceeding the production in control plots by 83% (GPP), 239% (TBCA), and 24% (bole growth). Even though the rate of irrigation ensured no water limitation to tree growth, the high rainfall year showed higher production in irrigated plots for both GPP (38% greater than in drier year) and bole growth (23% greater). Varying humidity and supplies of water led to a range in NEP of 0.8–2.7 kg C m−2 year−1. This difference between control and irrigated treatments, combined with differences between drier and wetter years, indicated a strong response of these Eucalyptus trees to both water supply and atmospheric humidity during the dry season. The efficiency of converting light energy into fixed carbon ranged from a low of 0.027 mol C to a high of 0.060 mol C per mol of absorbed photosynthetically active radiation (APAR), and the efficiency of bolewood production ranged from 0.78 to 1.98 g wood per MJ of APAR. Irrigation increased the efficiency of wood production per unit of water used from 2.55 kg wood m−3 in the rainfed plot to 3.51 kg m−3 in irrigated plots. Detailed information on the response of C budgets to environmental conditions and resource supplies will be necessary for accurate predictions of plantation yields across years and landscapes.

Many forest experiments test for nutrient limitation in replicated fertilization trials at one or several locations, providing a poor basis for extrapolation across large landscapes. We present an experiment that paired control and treated plots at 127 locations (with similar initial wood biomass, ‘‘twin-plot’’), providing no experimental replication within sites, but strong replication within the population of stands across the landscape. This twin-plot approach, with 6-month period re-measurements, showed that forest productivity increased from 19.6 to 24.4 Mg ha � 1 yr � 1 , representing an average response to heavy application of fertilization of 4.8 Mg ha � 1 yr � 1 (10 m 3 ha � 1 yr � 1 ) for 2 years. The response in stands derived from clonal plantlets and seedlings was the same, although the fertilized clonal stands were 48% more productive than stands derived from seedlings. Older stands of both types were more responsive than younger stands, with a 0.6 Mg ha � 1 yr � 1 increase in growth for each additional year of age. Coarse-textured Entisols showed twice the response that developed in more-productive, fine-textured Entisols. The growth response was much smaller during the dry season (4.5 Mg ha � 1 yr � 1 ) than in the rainy season (9.4 Mg ha � 1 yr � 1 ). Analysis of growth by treatment and season allowed us to estimate the potential productivity of the sites, which averaged 29.1 Mg ha � 1 yr � 1 (62 m 3 ha � 1 yr � 1 ). The twin-plot design is relative simple and inexpensive, and can be used in conjunction with routine inventory designs to

The growth of forests can be described as a function of the supply of resources, the proportion of resources captured by trees, and the efficiency with which trees use resources to fix carbon dioxide. This function can be modified to explain wood production by subtracting the allocation of biomass to other tissues and to respiration. At the scale of leaves and seconds, rates of net photosynthesis typically show declining marginal gains with increasing rates of light absorption and transpiration. However, these trends may not represent those that occur at the scale of forests and years, owing to more complete biomass accounting (including costs of synthesis and maintenance of tissues), interactions among resources, and adaptation of biomass partitioning to optimize resource capture and use. Patterns in the growth of forests, across environmental gradients or silvicultural treatments, demonstrate that the efficiency of resource use at the scale of forests and years can increase with increasing rates of resource use. Case studies from Eucalyptus plantations indicate that more productive sites tend to have higher efficiency of resource use than less productive sites, and silvicultural treatments may increase both resource supplies and efficiency of resource use. The questions raised here apply to all forests, but the level of confidence in our general conclusions remains limited by the small number of studies available with complete estimates of rates of resource use and production.

The productivity of fast-growing tropical plantations depends, in part, on the ability of trees to obtain and utilize site resources, and the allocation of fixed carbon (C) to wood production. Simulation models can represent these processes and interactions, but the value of these models depends on their ability to improve predictions of stand growth relative to simpler empirical approaches. We evaluated the 3-PG process-based model for simulating the response of Eucalyptus grandisurophylla to changes in soil fertility and climate. This was done by calibrating the model with a complete C budget from an irrigated plantation, and then validating the model using independent data based on 2 years of growth from 40 pairs of fertilized and unfertilized stands. The 3-PG predictions were tested against actual production, and against a classic, empirical approach to estimating stand yield. The 3-PG parameter for site fertility was based on an objective fertilization response from the paired-plots. The 3-PG model responded well to the range of soil and climatic conditions during calibration, and was particularly sensitive to estimates of leaf area index. Actual wood production for the 40 validation stands ranged from 2 to 51 Mg ha � 1 per year, compared with model estimates of 10-42 Mg ha � 1 per year (r 2 ¼ 0:78). Both 3-PG and the empirical model provided good estimates of wood production for average conditions, but 3-PG successfully represented the wet years and dry years that were not differentiated in the empirical model. This sensitivity of 3-PG to climate may be very useful for the prediction of wood production during short rotations, where a few years of unusual weather may strongly influence yield. Process-based models can play an important role in improving the management of these almost-agricultural forests, especially in regions with high rainfall variability. # 2004 Elsevier B.V. All rights reserved.

Millions of hectares of Eucalyptus are intensively managed for wood production in the tropics, but little is known about the physiological processes that control growth and their regulation. We examined the main environmental factors controlling growth and resource use across a geographic gradient with clonal E. grandisurophylla in north-eastern Brazil. Rates of production and resource use were estimated for 14 stands that spanned a four-fold range in production. The supply of water appeared to be the most limiting resource in these fertilized plantations. Above-ground net primary production (ANPP) increased by 2.3 Mg ha � 1 per year for each 100 mm per year increase in rainfall. Higher water supply was also associated with increased use of light and nitrogen (N). The efficiency of resource use (ANPP per unit of resource used) increased with increasing productivity along the gradient. The most efficient stands produced 3.21 kg ANPP m � 3 of transpired water, 1.14 kg ANPP GJ � 1 absorbed photosynthetically active radiation (PAR), and 381 kg ANPP kg � 1 N taken up. The stands with high resource use and high efficiency also had lower mean vapor pressure deficits, less soil water stress, and smaller coarse root to above-ground biomass ratios. Our study indicates that the productivity of fertilized tropical plantations of Eucalyptus is most likely constrained by water supply, and that water supply substantially affects the efficiency of resource use as well as biomass allocation to roots, stems, and leaves. At a regional scale, our results indicate that high productivity stands could produce wood in a 6-year rotation on half the land area required for low productivity stands, using only half as much water. # 2004 Elsevier B.V. All rights reserved.

International audience; Large differences in productivity have been observed between neighboring Eucalyptus plantations in Brazil, that cannot be explained by climate and are unlikely to be due solely to altered management practices. Current ecophysiological models used by forestry companies to simulate stand development in large plantation zones rely on empirical site fertility indices (representing water and nutrient availability) to capture this spatial variability in growth rates. We propose a model that requires no empirical assessment of site fertility to simulate stand growth over entire rotations. We applied a modified version of the G'DAY model of carbon, nitrogen and water cycling at a daily time step to short-rotation plantations located in Sao Paulo State, including a simple mechanistic description of the effect of water availability on growth. The progressive and rapid root exploration of deep soil layers was modeled in a simple way, by considering that maximum plant available water increased with mean tree height. The model was parameterized using detailed measurements made over the entire rotation of an experimental stand of Eucalyptus grandis, and was subsequently applied to 16 clonal stands managed in a similar way by one company, but with different planting dates and contrasting productivity levels. Stem biomass simulations, driven by daily weather data (maximum and minimum air temperatures, global radiation and rainfall), were strongly correlated with company inventory estimates of stem biomass carried out at different ages. The temporal variation of leaf area index was also adequately simulated, as was shown by comparison with leaf area index derived from satellite data. The model was able to capture more than 95% of the variability of standing stem biomass and more than 85% of the variability of stem growth measured on these stands, provided spatial differences in soil water holding capacity were taken into account.

International audience; Local tree density may vary in young Eucalyptus plantations under the effects of environmental conditions or inadequate management, and these variations need to be mapped over large areas as they have a significant impact on the final biomass harvested. High spatial resolution optical satellite images have the potential to provide crucial information on tree density at an affordable cost for forest management. Here, we test the capacity of this promising technique to map the local density of young and small Eucalyptus trees in a large plantation in Brazil. We use three Worldview panchromatic images acquired at a 50 cm resolution on different dates corresponding to trees aged 6, 9 and 13 months and define an overall accuracy index to evaluate the quality of the detection results. The best agreement between the local densities obtained by visual detection and by marked point process modeling was found at 9 months, with only small omission and commission errors and a stable 4% underestimation of the number of trees across the density gradient. We validated the capability of the MPP approach to detect trees aged 9 months by making a comparison with local densities recorded on 112 plots of ~590 m² and ranging between 1360 and 1700 trees per hectare. We obtained a good correlation (r²=0.88) with a root mean square error of 31 trees/ha. We generalized detection by computing a consistent map over the whole plantation. Our results showed that local tree density was not uniformly distributed even in a well-controlled intensively managed Eucalyptus plantation and therefore needed to be monitored and mapped. Use of the marked point process approach is then discussed with respect to stand characteristics (canopy closure), acquisition dates and recommendations for algorithm parameterization.

Brazilian Eucalyptus plantations are some of the most productive forest plantations in the world, sustaining mean growth rates of 25 Mg ha −1 year −1 (50 m 3 ha −1 year −1 ) over the 4.7 million hectares planted across the country. To better understand forest productivity, studies at the stand scale need to be coupled with tree level evaluations of the production ecology (the assessment of wood production as a function of crown light absorption and light use efficiency). The soil clay content (≈20% to ≈40%), topography and historical land use of the experimental site generated a natural gradient in productivity. We measured (from 6 to 7 years after planting) stem wood dry biomass growth and estimated light absorption and light use efficiency at the tree level with a three-dimensional array model (MAESTRA) in 12 plots within a seed-origin Eucalyptus grandis plantation. We investigated the hypothesis that dominant trees (the 20% largest) are more productive than non-dominant trees (the 20% smallest) as a result of greater light absorption and light use efficiency; and that with increasing productivity across plots, dominant trees would show larger increases in light use and light use efficiency in comparison to non-dominant trees. The 20% smallest of the trees averaged 10.6 kg of stem wood dry biomass (1.6 kg of stem wood growth during the last year of the rotation), compared with 185 kg per stem wood in the 20% largest of trees (34 kg of stem wood growth over the same period). The smallest trees contained 7.2% of the leaf area as compared to the largest trees (3.0 m 2 versus 41.7 m 2 ), and they absorbed only 6.7% as much light (2.2 versus 32.8 GJ year −1 ). The smallest trees grew at about 4.7% of the rate of the largest trees, which is a smaller percentage than the difference in absorbed photosynthetically active radiation; therefore the light use efficiency was lower for the smallest trees (0.75 kg GJ −1 versus 1.03 kg GJ −1 ). Our results show the significant contribution of dominant trees to stand productivity and the importance of evaluating production ecology at the individual tree scale.

The productivity of most forest plantations is less than their physiological potential as defined by the prevailing climate, because the supply or capture of light, water and nutrients is less than optimal. However, maximum growth does not equate to maximum wood value. The silvicultural challenge is to design and use management regimes that achieve target growth rates and wood quality by manipulating resource supply, capture or use. It has been and remains possible to identify and ameliorate factors limiting growth, sometimes on a large scale, e.g. by soil cultivation, residue management, fertiliser, weed control, irrigation, coppice management, thinning and pruning. This review examines some of these silvicultural practices for eucalypt plantations. During the past two decades, an increase in research on silvicultural practices in relation to soil and plant processes has improved our understanding of their effects on tree growth and wood quality, and on non-wood values including the potential for adverse on- or off-site effects. Eucalypt silviculture usually targets high growth rates and short rotations. High growth rates, and to some extent low nutrient-use efficiencies of eucalypts, lead to high nutrient demand and a high potential for nutrient depletion if management does not facilitate nutrient conservation. A detailed examination of nutrient management is presented. We indicate how silvicultural information is incorporated into current empirical- and process-based systems of productivity prediction, and identify potential improvements to these models. Silvicultural options are included adequately in some empirical models, and some process-based productivity models adequately cater for pruning and thinning, but process-based predictions of other silvicultural options, e.g. cultivation, slash retention, fertiliser, weed control and pest management, remain in their infancy.