Search

Tall eucalypt old-growth forests are notable for their large, old (i.e. venerable) trees and have both significant conservation value and high carbon stores. We investigated whether canopy height and biomass had recovered in an oldgrowth red tingle (Eucalyptus jacksonii) forest 78 years after a high-intensity fire. We recorded species, diameter, hollow butting and height of all 596 trees .10-cm diameter at breast height, as well as fine and coarse woody debris, in a 3.55-ha plot near Nornalup, south-western Australia. Pre-fire canopy height was estimated by allometrics derived from tree height and diameter, and diameter and length of recently fallen branches. Of the basal area (75.0 m2 ha -11), 92.7% was eucalypt (chiefly E. jacksonii), with regeneration accounting for only 8.5% of the total. Although canopy species composition apparently did not change following fire, stand height and biomass had not recovered to pre-1937 levels by 2015. Canopy height remained 5.06 m (11%) less and biomass 25% less, 78 years after the fire. The combination of intense fire and a warmer, drier climate appears to have prevented recovery of forest height and structure at this site. These findings indicate that ecologically important, venerable trees are increasingly vulnerable to canopy fire and climate change. [ABSTRACT FROM AUTHOR]

Copyright of Ciência Florestal (01039954) is the property of Ciencia Florestal and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

• The parameters a s , n s , η Rx , η Rn and t c were selected to be predicted by artificial neural networks (ANN). • ANN allows relating different types of variables generating greater precision in the 3-PG parameterization. • Different alternatives in database structure can be used in the ANN training or application to predict the 3-PG parameters. • With the use of ANN, it is possible to calibrate 3-PG model for managing forests in different regions. Understanding how the physiological processes of trees are affected by the environment or silvicultural practices is important for forest management, which requires process-based models. It enables the evaluation of the growth of a forest under different scenarios. The 3-PG model has been widely used all over the world, justified by its simplicity and efficiency, as it uses a more accessible language and fewer parameters than other process-based models. It is a model of greatest interest for forest management because it enables the use of allometric equations to calculate variables of interest in this area, such as the average diameter at 1.30 m height (DBH), total height and stand volume. The 3-PG parameterization is essential to guarantee the model's good performance; however, in some cases, when observed data are not available, values from the literature is used or calibration is performed. In general, there is a mixture of these alternatives in the same parameterization, but some of the parameters generate greater sensitivity in some outputs or change according to site characteristics. In the present work, we analyzed the efficiency of artificial neural networks to predict some of the parameters pointed out in the literature as being of the greatest importance for 3-PG using climate and process variables as inputs. For this, a simulated database was generated, using 16 parameterizations of 3-PG, for different regions of Brazil. The parameters values of the DBH function (a s and n s), minimum and maximum fraction of biomass allocated to the root (η Rn and η Rx), and age at full canopy cover (t c) were associated with this database. The Artificial Neural Networks (ANNs) were trained using the database with parameter repetition over time and with the average condition of each site. In the second case, training was performed using 100% of the data, and validation was performed using a simulated database. The efficiency of neural networks has been proven in predicting the parameters a s , n s and η Rx , with validation root mean squared error (RMSE) of 6.9%, 6.9% and 4.8%, in the first training approach, respectively. For training based on sites average condition RMSE was 20.7%, 3.0% and 8.8%, for a s , n s and η Rx , respectively. The study showed the need for more scientific investigation for the other parameters, including information and input variables such as soil characteristics. As demonstrated in this study, the possibility of parameterizing 3-PG with ANNs or any machine learning technique may contribute to the broader use of this process-based model. In addition, artificial neural networks have great potential to assist in the calibration process of the 3-PG model, making this process more efficient by integrating environmental conditions and allowing the association between parameters. It is recommended to apply these ANNs for the conditions tested here. [Display omitted] [ABSTRACT FROM AUTHOR]

Mulching is an effective post-fire soil erosion mitigation treatment. Experiments with forest residue mulch have demonstrated that it increased ground cover to 70% and reduced runoff and soil loss at small spatial scales and for short post-fire periods. However, no studies have systematically assessed the joint effects of scale, time since burning, and mulching on runoff, soil loss, and organic matter loss. The objective of this study was to evaluate the effects of scale and forest residue mulch using 0.25 m 2 micro-plots and 100 m 2 slope-scale plots in a burnt eucalypt plantation in central Portugal. We assessed the underlying processes involved in the post-fire hydrologic and erosive responses, particularly the effects of soil moisture and soil water repellency. Runoff amount in the micro-plots was more than ten-fold the runoff in the larger slope-scale plots in the first year and decreased to eight-fold in the third post-fire year. Soil losses in the micro-plots were initially about twice the values in the slope-scale plots and this ratio increased over time. The mulch greatly reduced the cumulative soil loss measured in the untreated slope-scale plots (616 g m − 2 ) by 91% during the five post-fire years. The implications are that applying forest residue mulch immediately after a wildfire can reduce soil losses at spatial scales of interest to land managers throughout the expected post-fire window of disturbance, and that mulching resulted in a substantial relative gain in soil organic matter. [ABSTRACT FROM AUTHOR]

Declining forest health can affect crucial ecosystem functions, such as carbon storage in biomass and soils, the regulation of water regimes, the modulation of regional climate and conservation of biodiversity. Airborne laser scanning (ALS) and imaging spectroscopy (IS) are two potentially complementary remote sensing technologies capable of characterizing and monitoring regional forest health. However, the combined use of ALS and IS data to classify the health of individual trees has not yet been assessed. In this study we propose a new approach utilizing ALS and IS combined to characterize the health of individual trees. Firstly, we applied a recently developed bottom-up individual tree delineation algorithm across a structurally complex floodplain eucalypt forest that has experienced episodes of severe dieback over the past six decades. We further calculated ALS and IS indices for delineated tree crowns and used them as predictor variables in machine learning models. We trained and evaluated an object-oriented random forest classifier against field-measured tree crown dieback and transparency ratios, as indicators of eucalypt tree health and crown density, respectively. Our results showed that dieback levels of individual trees can be classified using ALS and IS with an overall accuracy of 81% and a kappa score of 0.66, while the classification of tree crown transparency levels had an overall accuracy of 70% and a kappa score of 0.5. Returned pulse width, intensity and density related ALS indices were the most important predictors in the tree health classification, as they accounted for > 40% of the variance in the data. At the forest level in terms of dieback, 81.5% of correctly delineated trees were classified as healthy, 12.3% as declining and 6.2% as dying or dead. Dieback occurred primarily in areas that were flooded < 5% of the time, as quantified by Landsat derived flooding frequency (1986–2011). Our results provide a novel application of ALS and IS to accurately classify the health of individual trees in a structurally complex eucalypt forest, enabling us to prioritize areas for forest health promotion and conservation of biodiversity. [ABSTRACT FROM AUTHOR]

We used genome-wide markers and an unprecedented scale of sampling to construct a phylogeny for a globally significant Eucalyptus lineage that has been impacted by hybridisation, recent radiation and morphological convergence. Our approach, using 3109 DArT markers distributed throughout the genome and 540 samples covering 185 terminal taxa in sections Maidenaria , Exsertaria , Latoangulatae and related smaller sections, with multiple geographically widespread samples per terminal taxon, produced a phylogeny that largely matched the morphological treatment of sections, though sections Exsertaria and Latoangulatae were polyphyletic. At lower levels there were numerous inconsistencies between the morphological treatment and the molecular phylogeny, and taxa within the three main sections were generally not monophyletic at the series (at least 62% polyphyly) or species (at least 52% polyphyly) level. Some of the discrepancies appear to be the result of morphological convergence or misclassifications, and we propose some taxonomic reassessments to address this. However, many inconsistencies appear to be the products of incomplete speciation and/or hybridisation. Our analysis represents a significant advance on previous phylogenies of these important eucalypt sections (which have mainly used single samples to represent each species), thus providing a robust phylogenetic framework for evolutionary and ecological studies. [ABSTRACT FROM AUTHOR]

The introduction of N2-fixing tree species in fast growing tree plantations is a sustainable management option aiming to reduce the risk of nitrogen (N) deficiency due to a large and frequent exportation of nutrients at harvest. Differences in soil mineral N preferences between Eucalyptus urophylla × grandis and Acacia mangium may, in addition to facilitation related to atmospheric N2 fixation, contribute to the success of mixed-species plantations of the two species on nutrient-poor soils of the coastal Congolese plains. We tested whether these two species differ in their preference for nitrate or ammonium by supplying either ammonium or nitrate enriched in 15N to six-month-old potted trees growing in an open-air nursery. Although the uptake of nitrate tended to be higher than that of ammonium by both species, the difference was not significant and there was no significant difference between the species regarding their preferred form of soil mineral N. Despite much lower N contents in foliage, stems, and roots of eucalypt compared to acacia, the specific rates of N uptake were up to three times higher for eucalypt than acacia, which suggests that atmospheric N2 was the major source of N in the six-month-old acacias. We conclude that N2 fixation rather than complementarity for soil mineral nitrogen alleviates the competition between species in successful mixed eucalypt and acacia plantations. [ABSTRACT FROM AUTHOR]

Copyright of Fire Ecology is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Salinity effects on plant can often be related to mineral ion content alteration, including phosphate. Under saline conditions, phosphate levels were reported to decrease in plants. Such effects could indirectly affect intracellular phosphate levels, leading to phosphate deficiency, which in turn leads to increased activities of phosphate uptake mechanisms. This research was aimed to investigate the effects of salinity on the expression changes of phosphate transporter genes isolated from E. camaldulensis x E. globulus hybrid clones subjected to salt concentrations of 0 (control), 50, 100, and 150 mMNaCl. Fragments of genes (1164bp long and encodes 304 amino acid polypeptides) known to be involved in phosphate uptake were identified and isolated by RACE from these hybrids, encoding a Phosphate Transporter (Ecg PT). Expression studies using Northern-Blot analysis revealed that the expression of EcgPT was found to be affected by salt, suggesting a direct effect of salinity on phosphate uptake. EcgPT was expressed differently in different clones, indicating different degrees of phosphate transporter activation in order to tolerate salt stress. Molecular data are discussed in relation to measurements of ion levels in different organs of different clones and under various salt regimes during the course of the hydroponic experiment.

Pruning of live branches is a management option to enhance wood quality in plantation trees. It may also alter whole-tree water use, but little is known about the extent and duration of changes in transpiration. In this study, sap flow sensors were used to measure transpiration for 14 days prior to, and 75 days following the removal, through pruning, of the lower 50% of the live-crown length of 10–11 m tall four-year old Eucalyptus pilularis Sm. and E. cloeziana F. Muell. trees. Pruning had no effect on stem growth, sapwood water content or radial pattern of sap velocity in either species. Pruning reduced mean daily water use by 39% in E. pilularis and 59% in E. cloeziana during the first eight days after pruning. Thirty six days after pruning there were no longer any significant differences in transpiration rates between pruned and unpruned trees in either species. Our results show that pruning of live branches had only a short-term effect on whole-tree transpiration in these sub-tropical eucalypt species.

In order for a lignocellulosic bioenergy feedstock to be considered sustainable, it must possess a high rate of growth to supply biomass for conversion. Despite the desirability of a fast growth rate for industrial application, it is unclear what effect growth rate has on biomass composition or saccharification. We characterized Klason lignin, glucan, and xylan content with response to growth in Corymbia interspecific F1 hybrid families (HF) and parental species C. torelliana (CT) and C. citriodora subspecies variegata (CCV) and measured the effects on enzymatic hydrolysis from hydrothermally pretreated biomass. Analysis of biomass composition within Corymbia populations found similar amounts of Klason lignin content (19.7-21.3%) among parental and hybrid populations, whereas glucan content was clearly distinguished within CCV (52%) and HF148 (60%) as compared to other populations (28-38%). Multiple linear regression indicates that biomass composition is significantly impacted by tree size measured at the same age, with Klason lignin content increasing with diameter breast height (DBH) (+0.12% per cm DBH increase), and glucan and xylan typically decreasing per DBH cm increase (-0.7% and -0.3%, respectively). Polysaccharide content within CCV and HF-148 were not significantly affected by tree size. High-throughput enzymatic saccharification of hydrothermally pretreated biomass found significant differences among Corymbia populations for total glucose production from biomass, with parental CT and hybrids HF-148 and HF-51 generating the highest amounts of glucose (~180 mg/g biomass, respectively), with HF-51 undergoing the most efficient glucan-to-glucose conversion (74%). Based on growth rate, biomass composition, and further optimization of enzymatic saccharification yield, high production Corymbia hybrid trees are potentially suitable for fast-rotation bioenergy or biomaterial production.

The leaf area index (LAI) is a key characteristic of forest ecosystems. Estimations of LAI from satellite images generally rely on spectral vegetation indices (SVIs) or radiative transfer model (RTM) inversions. We have developed a new and precise method suitable for practical application, consisting of building a species-specific SVI that is best-suited to both sensor and vegetation characteristics. Such an SVI requires calibration on a large number of representative vegetation conditions. We developed a two-step approach: (1) estimation of LAI on a subset of satellite data through RTM inversion; and (2) the calibration of a vegetation index on these estimated LAI. We applied this methodology to Eucalyptus plantations which have highly variable LAI in time and space. Previous results showed that an RTM inversion of Moderate Resolution Imaging Spectroradiometer (MODIS) near-infrared and red reflectance allowed good retrieval performance (R2 = 0.80, RMSE = 0.41), but was computationally difficult. Here, the RTM results were used to calibrate a dedicated vegetation index (called “EucVI”) which gave similar LAI retrieval results but in a simpler way. The R2 of the regression between measured and EucVI-simulated LAI values on a validation dataset was 0.68, and the RMSE was 0.49. The additional use of stand age and day of year in the SVI equation slightly increased the performance of the index (R2 = 0.77 and RMSE = 0.41). This simple index opens the way to an easily applicable retrieval of Eucalyptus LAI from MODIS data, which could be used in an operational way.

The objective of this study was to evaluate the efficiency of use of the Frechet function for modeling the diameter structure of eucalypt. We used data from permanent plot inventory, measured at ages 28, 40, 52, 64, 76 and 84 months. Set for every occasion and share with the function Frechet 3 and 2 parameters and using the location parameter of the stand as the minimum diameter (γ = dapmin). The function was fitted by maximum likelihood method. The adhesion function to the data was verified by applying the Kolmogorov-Smirnov (K-S. The construction of the diametric distribution model based on the correlation of the pdf parameters stand characteristics. All adjustments to the data presented adherence by K-S test.The equations that comprise the model of the diameter distribution of 2P and γ = dapmin showed no bias in their estimates, and may be used to describe the diameter distribution of even-aged stands.

Native or exotic woody plants can proliferate in dry and moist eucalypt ecosystems shading out many other native species, contributing to chronic decline of eucalypts and reinforcing unnatural fire regimes and nutrient cycling processes. Whether native or exotic, they proliferate as a consequence of disturbances which impact directly on these ecosystems. The most extensive ongoing disturbance since European occupation of Australia has been the disruption of frequent mild burning by humans. This burning maintained dynamically stable nutrient cycling processes and a competitive balance in dry and moist eucalypt systems and prevented plant “invasions”.

The knowledge of breeding impacts on the genetic diversity of hybrids of Eucalyptus is crucial to the exploration of genetic resources. We estimated genetic polymorphic parameters of 112 hybrids of Eucalyptus spp. using 10 genomic simple sequence repeats (SSR) markers and 10 expressed sequence tags (EST) microsatellite markers. According to Student's t-test, there were no significant differences between genomic SSR and EST-SSR markers. Our results also revealed high polymorphism in the hybrids analyzed, indicating that both markers are appropriate for use in genetic breeding programs.

The objective of this work was to evaluate some wood properties of a clone of Eucalyptus urophylla in the radial direction and in two positions along the trunk. The studied material came from Votorantim Metais Zinco S.A., and the plantations, located in Vazante, State of Minas Gerais, Brazil, were six years old. Six trees were harvested from which were cut two logs with three meter long each. Those logs were sawed into thick diametral slabs. A one-meter sample was obtained from these planks in the radial direction. Following this,samples were taken for the evaluation of specific gravity and apparent density, shrinkage from green or from 12% moisture, fiber and vessel sizes and static bending properties. It was foundthat basic and apparent specific gravities, total longitudinal shrinkage, fiber length, vessel diameter and moduli of rupture and elasticity tended to increase in the bark-to-pith direction,while partial longitudinal shrinkage, the tangential/radial ratios and the vessel frequency were reduced. Radial and tangential shrinkages, width, lumen diameter and fiber wall thickness showed different patterns of variation. Only partial volumetric, radial shrinkages and vessel frequency showed different values between the two logs taken from the same tree. The main correlations observed were between modulus of elasticity and of rupture with either specific gravity or apparent density and between fiber lumen diameter with specific gravity, total longitudinal shrinkage and with modulus of rupture in static bending.

Tree planting with drought tolerant species, particularly Acacia and Eucalyptus species may be considered as a logical method for rehabilitation of marginal lands which can potentially meet the needs of local people in terms of wood, fuel wood, fodder, edible fruits, etc. These goals may be much better attained when the trees are planted in floodwater spreading (FWS) systems which drastically change the desert ecosystems through provision of more water and better rooting environments. In 1994, a pilot project was carried out in FWS systems in Gareh Baygan Plain in Fars Province of Iran to study the growth and performance of four Eucalyptus and four Acacia species which had previously been tested successfully in a preliminary adaptation experiment. A randomized complete block design with four replications was employed to establish the experiment. Each replication comprised of eight plots (species) and each plot contained 49 trees with 3m×3m spacing. The seedlings were irrigated only by rain and ephemeral floodwaters. In a ten year period, growth parameters including survival percentage, height and diameter at breast height were assessed or measured every year. The existence of pests or diseases and the viability of the trees were also monitored annually and the final evaluation was made at the age of ten. Survival and growth performance of the trees were quite satisfactory. Eucalyptus camaldulensis, E. oleosa, Acacia victoriae, A. salicina, and E. microtheca were all promising species, showing over eighty percent survival in the final year of experiment and were not significantly different from each other. The survival of E. fruticetorum was significantly different (p=0.0001) from those of the other species. Eucalyptus camaldulensis showed the highest growth in terms of height and diameter, while A. saligna ranked the lowest. It may be concluded that E. camaldulensis, E. oleosa, E. microtheca, E. fruticetorum, A. salicina, and A. victoriae were highly promising species and may be recommended for large-scale plantations in arid zones of southern Iran, using floodwater spreading systems. Moreover, further tests of cold resistant provenances of A. cyanophylla and A. saligna are recommended.

The objectives of the present work were to establish the minimal lethal dose of the selective agent to determine the type and concentration of appropriate antibiotics for the elimination of Agrobacterium tumefaciens inoculated explants, without interfering with the regenerative potential of the E. camaldulensis cotyledonary explants. Non-transformed explants were cultivated in medium supplemented with kanamycin. The results showed that the antibiotic was suitable for the selection of transformed cells in the concentration of 9 mg L-1 as it inhibited the growth of non-transformed cells. Cotyledons infected with A. tumefaciens were cultivated in MS N/2 medium supplemented with BAP, ANA, Km and cefotaxime or AugmentinÒ . The highest average of regenerated shoots by explant (5,4) was observed in the presence of 300 mg L-1 of AugmentinÒ /15 days, followed by 150 mg L-1/15 days and 100 mg L-1/30 days.O presente trabalho teve como objetivos determinar o tipo e a concentração de antibióticos adequados para a eliminação de Agrobacterium tumefaciens de explantes inoculados e estabelecer a dose letal mínima do agente seletivo canamicina (Km), sem interferir com o potencial regenerativo do explante cotiledonar de E. camaldulensis. Para a avaliação da eficiência dos antibióticos, cotilédones infectados com A. tumefaciens foram cultivados em meio MS N/2 com BAP, ANA, canamicina e cefotaxima ou AugmentinaÒ . Foi observada a maior média de brotos regenerados por explante (5,4) na presença de 300 mg.L-1 de AugmentinaÒ /15 dias, seguido por 150 mg.L-1/30 dias, e 100 mg.L-1/30 dias. Explantes cotiledonares não transformados foram cultivados em meio de cultura suplementado com antibiótico canamicina onde a concentração adequada para a seleção de células transformadas foi de 9 mg.L-1.

A considerable portion of Brazil‘s commercial eucalypt plantations is located in areas subjected to periods of water deficit and grown in soils with low natural fertility, particularly poor in potassium. Potassium is influential in controlling water relations of plants. The objective of this study was to verify the influence of potassium fertilization and soil water potential (Ψw) on the dry matter production and on water relations of eucalypt seedlings grown under greenhouse conditions. The experimental units were arranged in 4x4x2 randomized blocks factorial design, as follow: four species of Eucalyptus (Eucalyptus grandis, Eucalyptus urophylla, Eucalyptus camaldulensis and hybrid Eucalyptus grandis x Eucalyptus urophylla), four dosages of K (0, 50, 100 and 200 mg dm-3) and two soil water potentials (-0.01MPa and -0.1 MPa). Plastic containers with 15 cm diameter and 18 cm height, with Styrofoam base, containing 3.0 dm3 of soil and two plants per container were used. Soil water potential was kept at –0.01MPa for 40 days after seeding. Afterward, the experimental units were divided into two groups: in one group the potential was kept at -0.01MPa, and in the other one, at -0.10 MPa. Soil water potential was controlled gravimetrically twice a day with water replacement until the desired potential was reestablished. A week before harvesting, the leaf water potential (Ψ), the photosynthetic rate (A), the stomatal conductance (gs) and the transpiration rate were evaluated. The last week before harvesting, the mass of the containers was recorded daily before watering to determine the consumption of water by the plants. After harvesting, total dry matter and leaf area were evaluated. The data were submitted to analysis of variance, to Tukey's tests and regression analyses. The application of K influenced A, gs and the transpiration rate. Plants deficient in K showed lower A and higher gs and transpiration rates. There were no statistical differences in A, gs and transpiration rates in plants with and without water deficit. The addition of K reduced the consumption of water per unit of leaf area and, in general, plants submitted to water deficit presented a lower consumption of water.

O trabalho teve como objetivo avaliar a sobrevivência do clone H13 de Eucalyptus urograndis sob dois manejos hídricos de viveiro, plantados em dois solos, com e sem a adição de polímero hidroabsorvente (hidrogel). O plantio foi realizado em vasos mantidos em estufa, com dois tipos de solo: um arenoso e outro argiloso. Cada vaso recebeu 2,5 L de solo, um litro de água e o hidrogel na proporção de 0,4 g vaso-1 (120 mL de gel). O delineamento experimental adotado foi o inteiramente casualizado, com três repetições. Os sintomas de estresse, nos vários níveis avaliados, sempre se manifestaram primeiro nas plantas no solo argiloso, de modo mais acentuado naquelas que foram mantidas sem estresse de água na fase de viveiro. Isso garantiu que as plantas sobrevivessem por um período menor sem água, variando de 14 a 20 dias (com e sem hidrogel, respectivamente), enquanto, no solo arenoso, a sobrevivência foi maior, de 29 a 34 dias (com e sem hidrogel, respectivamente). Apesar da não significância estatística, os resultados com o hidrogel possibilitam, em ambos os solos, maior flexibilidade operacional na intervenção com novas irrigações.The research aim was to evaluate the survival of Eucalyptus urograndis clone H13 selected for water deficit, under two water management for nursery, with and without the addition of hydro absorbent polymers (hydrogel), planted in two soils. The plantation was done in vases kept in greenhouse with two different soil textures: sandy and clay. Each vase received 2.5 L of soil, one liter of water and 0.4 g (120 mL of polymer) of hydro absorbent polymers. The experimental delineation was totally randomized, with three repetitions. The water deficit symptoms at different levels always appeared first in plants of vases with clay soil, starting in those that were kept without water stress in the nursery phase. Assuring the plants survival in a period without water varying from 14 to 20 days (with and without hydrogel, respectively), while for sandy soil, plants survived from 29 to 34 days (with and without hydrogel, respectively). Despite no statistically significant results with the hydrogel, it allows great operational flexibility for intervention with new irrigation in both soils.

O conhecimento detalhado de radiação solar total que incide sobre uma região é importante para o planejamento das atividades florestais. Poucos trabalhos têm considerado a topologia da região para determinar o saldo de radiação solar (Rn), o que pode levar a erros significativos de estimativa dessa variável, dependendo do tipo de relevo predominante na região. Este estudo teve como objetivo estimar o Rn em plantios de eucalipto, levando-se em consideração a exposição do terreno em plantios florestais de eucalipto, bem como comparar essas estimativas com a estimativa em condições de topografia plana. A simulação foi realizada para os anos de 2001 e 2002, em uma microbacia do rio Doce. As encostas com orientações para o norte, nordeste e noroeste apresentaram aumentos do Rn em relação à estimativa da superfície plana, pelo fato de que, nessa época do ano, o sol, em seu movimento aparente, encontra-se ao norte da microbacia. Entretanto, as encostas com orientações para o sul, sudeste e sudoeste tiveram diminuição do Rn quando comparadas com as condições de topografia plana. A inclinação das encostas influenciou a magnitude das diferenças de ganho e perda de Rn. Quanto maiores as inclinações das encostas voltadas para o norte, noroeste e nordeste, maiores as variações, atingindo valores percentuais de aumento do Rn de até 40%, em julho. Portanto, verificou-se existir importante influência das diferentes inclinações e orientações das encostas nos totais diários do Rn.The detailed knowledge of the total solar radiation that reaches a surface is fundamental for the planning of the forest activities. A few research works cited in the literature have considered the topographic effect of the region to determine the solar radiation balance (Rn), in which, depending on the predominant topographic relief of the region, significant errors can be obtained. This study was carried out to estimate the Rn considering the slope aspect of the terrain for eucalypt forest plantation, and to compare this estimates with and flat terrain areas. The simulation was carried out for the years of 2001 and 2002 in Rio Doce watershed. The hillsides with northward, northeast and the northwest orientation presented increases in Rn in relation to the estimate for flat horizontal surface, because at this time of the year, the sun, in its apparent movement, tape place north of the watershed. However, the hillsides with south, southeast and southwest orientation, presented reduction in Rn when compared with the conditions of flat topography. The hillsides inclination influenced in the magnitude of the differences between gain of energies and loss Rn. The hillsides inclinations faced northward, the northwest and northeast, had greaters variations, witch increased Rn of up to 40%, in July. It was demonstrated that exist important influence of the different slopes and aspects of the hillsides terrain over the total daily radiation balance.

This work aimed to analyze the socio-economic reorganization due to the insertion of Eucalyptusplantation (Eucalyptus grandis) in the far southern region of Bahia. In order to accomplish this analysis,it was done a diagnosis of the main social and economical changes due to the establishment of eucalyptusin the region, using literature retrieval, IBGE’s socio-economic data and the UNDP’s Atlas of HumanDevelopment. It could be noted that the insertion of Eucalyptus plantation in the region has provokeda significant growth of Bahia’s exports participation in the national scenario, making the economymore dynamic, especially in the far southern region of Bahia. This impact in the economy may beperceived through the GDP’s rising in the State level as far as in the counties that grow eucalyptusgrandis. In relation to the rural landscape, it was noted a considerable changing related to a reductionin the number of the agricultural activities and to the land concentration. It defines a reforming frameworkof the local land ownership structure. Under this new agricultural scenario, it can be noted, for instance,the reduction concerning the number of jobs generated in the rural area, and the activities developed inthe context of the family agriculture; what provokes an increasing of urban population.

Neste trabalho, estudaram-se o desenvolvimento e a reprodução de Dirphia moderata Bouvier, 1919 (Lepidoptera: Saturniidae) alimentada com Eucalyptus cloeziana F. Muell ou Psidium guajava L. Os períodos de pré-oviposição, oviposição e incubação e a viabilidade e número de ovos por fêmea foram de 6,71 ± 0,18 dia; 4,00 ± 0,66 dia; 18,14 ± 0,18 dia; 17,54 ± 3,78%; 121,71 ± 18,96% para esse inseto com E. cloeziana e de 3,86 ± 0,26 dia; 5,86 ± 0,40 dia; 17,71 ± 0,21 dia; 23,12 ± 10,81%; 112,00 ± 8,79% com P. guajava, respectivamente. A duração e viabilidade larval (%) foram de 53,00 ± 0,09 e 80,00 ± 0,99 e de 55,83 ± 0,29 e de 77,5 ± 6,60 para lagartas de D. moderata criadas nos primeiro e segundo hospedeiros, respectivamente. A duração e viabilidade das fases de pré-pupa e pupa foram de 4,84 ± 0,07 dia e 96,88 ± 3,13% e de 37,64 ± 1,20 dia e 84,37 ± 6,53% com E. cloeziana e de 3,82 ± 0,06 dia e 100% e de 49,93 ± 2,04 dias e 75,00 ± 7,79% com P. guajava, respectivamente. A razão sexual de D. moderata foi de 0,48 e 0,46 e a longevidade, de 6,78 e 8,84 dias para machos e de 10,23 e 10,07 dias para fêmeas desse inseto com E. cloeziana e P. guajava, respectivamente. D. moderata apresentou melhor desenvolvimento e reprodução em E. cloeziana, mas P. guajava pode, também, ser utilizado para a criação desse inseto em laboratório.This work studied the development and reproduction of Dirphia moderata Bouvier, 1919 (Lepidoptera: Saturniidae) fed on Eucalyptus cloeziana F. Muell or Psidium guajava L. The periods of pre-oviposition, oviposition and egg incubation as well as viability and number of eggs per female were 6.71 ± 0.18 days; 4.00 ± 0.66 days; 18.14 ± 0.18 days; 17.54 ± 3.78%; 121.71 ± 18.96 for this insect on E. cloeziana and 3.86 ± 0.26 days; 5.86 ± 0.40 days; 17.71 ± 0.21 days; 23.12 ± 10.81%; 112.00 ± 8.79 on P. guajava, respectively. Larva stage duration and viability (%) were 53.00 ± 0.09 and 80.00 ± 0.99 and 55.83 ± 0.29 and 77.5 ± 6.60 for caterpillars of D. moderata reared with the first and second hosts, respectively. Duration and viability of the pre-pupa and pupa stages were 4.84 ± 0.07 days and 96.88 ± 3.13% and 37.64 ± 1.20 days and 84.37 ± 6.53% on E. cloeziana and 3.82 ± 0.06 days and 100.00% and 49.93 ± 2.04 days and 75.00 ± 7.79% on P. guajava, respectively. Sex rate of D. moderata was 0.48 and 0.46 and longevity was 6.78 and 8.84 days for males and 10.23 and 10.07 days for females when this insect fed on E. cloeziana and P. guajava, respectively. Dirphia moderata presented better development and reproduction with E. cloeziana but P. guajava can also be used to rear this insect in the laboratory.

Este estudo teve como objetivo predizer a produção volumétrica e o estoque de carbono nos fustes das árvores em povoamentos de eucalipto, bem como avaliar economicamente a inclusão dos Certificados de Emissões Reduzidas (CERs) nos projetos florestais através de critérios quantitativos. Para isso, utilizaram-se dados de povoamentos de Eucalyptus grandis localizados no Município de Guanhães, MG, Minas Gerais. De posse das equações de volume e carbono para o fuste das árvores individuais e de 95 parcelas permanentes, ajustou-se o modelo de crescimento e produção de Clutter (1983) para projeção da produção volumétrica e do estoque de carbono. Após as análises, verificou-se que: a) o modelo de crescimento e produção proposto por Clutter (1983) propiciou idades técnicas de colheita coerentes com a capacidade produtiva dos povoamentos, tanto para a produção volumétrica quanto para o estoque de carbono; b) as idades técnicas de colheita (ITCs) foram praticamente iguais, considerando-se o estoque volumétrico e o estoque de carbono; c) as rotações econômicas foram maiores do que as idades técnicas de colheita (ITCs) em locais de baixa e média produtividades (S = 20 e S = 26), independentemente da inclusão ou não dos CERs; d) os CERs contribuem para a viabilidade financeira dos projetos florestais em locais de baixa produtividade, quando se considera que as receitas sejam auferidas no ano de implantação do projeto; e) na análise de sensibilidade, o preço da madeira foi o item que mais influenciou a viabilidade econômica dos projetos. No entanto, os Certificados de Emissões Reduzidas tiveram pouca influência.The objectives of this study were to predict volumetric yield and carbon stock in the stems of eucalypt plantation trees, as well as to economically evaluate the inclusion of the Reduced Emission Certificates (RECs) in forest projects by quantitative criteria. Thus, data from Eucalyptus grandis stands, located in Guanhães-Minas Gerais, were used. Based on the volume and carbon equations for the stems of individual trees and for 95 permanent plots, Clutter growth and production model (1983) were adjusted for volumetric production and carbon stock projection. After analysis, it was verified that: a) the growth and yield model proposed by Clutter (1983) provided technical cutting ages according to the productivity capacity of the stands, both for volumetric yield and carbon stock; b) the technical cutting ages (TCAs) were practically the same, considering the volumetric and carbon stocks; c) the economic rotations were greater than the technical cutting age in sites with low and average productivity (S = 20 and S = 26), regardless of the inclusion or not of the CERs in the analysis; d) the CERs contributed to the economic viability of the forest projects in low productivity sites, considering the budgets for the establishment of the projects; e) in the sensitivity analysis, the item wood price had the greatest influence on the economic viability of the projects. In contrast, the Reduced Emission Certificates (RECs) had little influence.

O psilídeo-de-concha, Glycaspis brimblecombei, é uma praga exótica específica de Eucalyptus, que causa desfolha, secamento de ponteiros e ramos, podendo levar as árvores à morte. O parasitóide Psyllaephagus bliteus é indicado como principal agente no controle biológico desta praga. Portanto, o monitoramento adequado de as ambas espécies por um método eficiente de amostragem facilitaria o manejo para uma futura tomada de decisão. Devido à falta de informações referentes ao seu comportamento em plantações extensivas de eucalipto no Brasil, este trabalho teve como objetivo estudar as populações de G. brimblecombei e de P. bliteus em florestas de Eucalyptus camaldulensis, utilizando armadilhas amarelas para determinação de sua flutuação populacional e correlacionado-as com variáveis meteorológicas (temperatura e precipitação). A determinação da flutuação populacional (53 pontos amostrais) foi realizada em talhão de 19ha com E. camaldulensis em Luíz Antônio, SP, em 10avaliações quinzenais, entre janeiro e junho de 2005. As populações de ambas as espécies apresentaram correlação inversamente proporcional em função da temperatura e não há correlação com a precipitação no período avaliado.Psyllids are one most widespread group of pests, causing severe damage on agricultural and forestry systems. The recently discover about occurrence of red gum lerp psyllid Glycaspis brimblecombei Moore (Hemiptera: Psyllidae), in Brazil is, nowadays a serious problem in Eucalyptus forests, mainly in E. camaldulensis. The psyllid specific parasitic wasp Psyllaephagus bliteus Riek (Hymenoptera: Encyrtidae) is the main biological control agent of this pest. Thus, the adequate monitoring of both species by efficient sampling method would facilitate a future decision making. Due to economic importance, this study aimed to evaluate G. brimblecombei and P. bliteus populations in Eucalyptus camaldulensis plantation, using yellow traps to determinate population fluctuation with weather interactions (temperature and rainfall). The study of the pest and parasitoid population (53 sampling dates) was carried out on E. camaldulensis plantations in 19ha area in Luíz Antônio municipality (SP, Brazil), with quarterly samplings, between January and June, 2005 (ten sampling dates). This research indicated that populations had an inversely proportional correlation subject according to the temperature. However, there is no correlation between both species with the rainfall in the evaluated period.

As mudanças nas distintas frações da matéria orgânica do solo (MOS) sob cultivo do eucalipto são pouco conhecidas. Assim, o presente trabalho teve como objetivo avaliar o impacto do cultivo do eucalipto nos estoques de C das diversas frações da MOS, em solos ocupados anteriormente por pastagens degradadas, bem como verificar qual fração da MOS constitui-se um indicador mais sensível à mudança de uso do solo. O estudo foi realizado em plantações comerciais de eucalipto em dois locais na região do Vale do Rio Doce-MG (Belo Oriente e Virginópolis), onde foram determinados em amostras dos solos: C orgânico total (COT), C da fração leve (leve livre - FLL e leve oclusa - FLO), da fração pesada (areia - AR, silte + argila - S + A e argila - ARG), da biomassa microbiana (BM) e das frações húmicas (ácidos fúlvicos - FAF, ácidos húmicos - FAH e huminas - FH). Os resultados indicaram que, de maneira geral, os solos sob os diferentes tipos de uso em Virginópolis, em virtude da menor temperatura média anual e maior teor de argila, apresentaram maiores estoques de C em todas as frações da MOS em relação a Belo Oriente. Assim, o seqüestro de C no solo pelo cultivo do eucalipto foi maior em Virginópolis (14,2 t ha-1) que em Belo Oriente (10,0 t ha-1), resultando numa taxa de seqüestro de C de aproximadamente 0,42 e 0,29 t ha-1 ano-1 , respectivamente. Em Belo Oriente, o cultivo do eucalipto favoreceu o aumento no estoque de C das frações ARG, S + A e FH no solo. Comportamento semelhante foi observado para o C das FLL, FAF e FAH, em Virginópolis. Dentre todas as frações da MOS analisadas, a BM e a FLO foram indicadores menos sensíveis às alterações na MOS após três décadas da mudança de uso do solo. Com isso, o COT e a fração leve livre, ácidos fúlvicos, ácidos húmicos e humina foram mais eficientes nesse sentido.Little is known about the changes in different soil organic matter (SOM) fractions under short-rotation eucalypt plantations. This study aimed to evaluate the impact of eucalypt cultivation on C stocks of several organic matter fractions in soils previously covered with degraded pasture, as well as to identify which SOM fractions are more sensitive indicators of land use change impacts. The study was conducted at two sites (Belo Oriente and Virginópolis) with commercial short-rotation eucalypt plantations in the Rio Doce Valley region, Minas Gerais state, Brazil. The soil samples were analyzed for: total organic C (TOC), light fraction C (free light - FLL and occluded light- FLO), C associated to heavy fractions (sand - AR, silt + clay - S+A and clay - ARG), microbial biomass C (BM) and humic fractions C (fulvic acids- FAF; humic acid- FAH and humin- FH). Results indicate that overall organic C stockst in all SOM fractions were higher in soils of Virginópolis than those of Belo Oriente due to the lower annual mean temperature and higher clay content. Thus, soil C sequestration by eucalypt plantations was higher in Virginópolis (14.2 t ha-1) than in Belo Oriente (10.0 t ha-1), resulting in a C sequestration rate of 0.42 t ha-1 yr-1 and 0.29 t ha-1 yr-1 , respectively. In Belo Oriente the eucalypt plantations also favored the increase in C stocks of the ARG, S + A and FH fractions. A similar pattern was observed for C of FLL, FAF and FAH in Virginópolis. Of all SOM fractions, the BM and the FLO were the least sensitive indicators of alterations in SOM three decades after land use changes. In this regard, TOC and C of FLL, FAF, FAH and FH were more efficient.

O objetivo principal deste trabalho foi ajustar equações para a estimativa da biomassa da parte aérea e sistema radicular de povoamentos de Eucalyptus grandis aos 11 anos de idade, crescendo em dois sítios com produtividades distintas. O solo argiloso (sítio mais produtivo) foi classificado como Latossolo Vermelho Distrófico (LVd) e o solo arenoso (sítio menos produtivo), como Neossolo Quartzarênico (RQ). Foi realizado um inventário de biomassa de 10 árvores-amostra em cada sítio, incluindo os componentes da parte aérea (fuste, casca, folhas e galhos) e do sistema radicular (raízes finas e grossas). Ajustaram-se dois modelos logarítmicos para estimar a biomassa das árvores, nos quais se utilizaram como variáveis independentes o diâmetro à altura do peito (DAP), a altura total das árvores (H) ou a variável combinada DAP²H. Os modelos testados foram significativos no nível de 95% de probabilidade, pelo teste t, de Student. O melhor ajuste das equações foi obtido com a variável DAP²H. A validação de equações comuns aos dois sítios foi baseada na análise conjunta do coeficiente de determinação (R²;), erro-padrão da estimativa (Sy.x) e análise gráfica dos resíduos porcentuais. As equações ajustadas tiveram maior precisão na estimativa da biomassa do fuste (R² = 0,99; Sy.x = 0,12) e da casca (R² = 0,97; Sy.x = 0,24). Apesar dos R² > 0,70, as equações para a estimativa da biomassa de folhas e galhos apresentaram baixa capacidade preditiva, caso em que se recomenda a adição de outras variáveis associadas ao tamanho da copa das árvores. Equações específicas para cada local, visando estimar a biomassa de raízes finas [LVd (R² = 0,97; Sy.x = 0,30); RQ (R² = 0,96; Sy.x = 0,15)] e grossas [LVd (R² = 0,98; Sy.x = 0,19); RQ (R² = 0,99; Sy.x = 0,15)], mostraram uma precisão melhor que as equações comuns, uma vez que houve maior alocação relativa de biomassa radicular no solo mais arenoso (RQ).The main objective of this work was to adjust equations to estimate biomass of shoot and root system in 11-year-old Eucalyptus grandis stands growing in two sites with different productivities. Loamy soil (more productivity site) was classified as a Typic Hapludox (RED) and sandy soil (less productivity site) as a Typic Quartzipsamment (QTZ). Biomass inventory was carried out using ten sample-trees in each site including shoot (stem, bark, leaves and branches) and root system (fine and coarse roots) tree components. Two logarithmic regression equations were adjusted to estimate tree biomass, with diameter at breast height (DBH) and height (H) or DBH²H being used as independent variables. The adjusted models were significant at 95 % of probability by the t Student test. The best-fit equations were found with DBH²H. Validation of common equations for the two sites was based in the combined analyses of coefficient of determination (R²), stand error of estimate (Sy.x) and graphic analysis of residues. Adjusted equations had highest precision for estimate of stem biomass (R² = 0.99; Sy.x = 0.12) and bark biomass (R² = 0.97; Sy.x = 0.24). In spite of R² > 0.70, equation for leaf and branch biomass had low accuracy. Thus, it was suggested the inclusion of other variables related to size of trees. Specific equations for biomass estimation by each site for fine [RED (R² = 0.97; Sy.x = 0.30); QTZ (R² = 0.96; Sy.x = 0.15)] and coarse roots [LVd (R² = 0.98; Sy.x = 0.19); RQ (R² = 0.99; Sy.x = 0.15)] were more accurate than common equations, since that there was more root biomass allocation in sandy soil (QTZ).

Este trabalho constitui a ultima parte do estudo que objetivou calcular o consumo de água em plantios de eucalipto. Nesta parte, modelou-se a resistência estomática em função das variáveis ambientais irradiância solar global, déficit de pressão de vapor e temperatura. Com a resistência estomática modelada a partir dos valores observados no artigo anterior, foi possível calcular a transpiração do eucalipto pelo método Penman-Monteith em alguns dias, nos períodos úmido e seco do ano. Verificou-se a existência da correlação entre a resistência estomática e as variáveis ambientais. Os modelos gerados nessa relação mostraram-se eficientes para calcular as variações diárias resistência estomática e também totais horários e diários de transpiração.This paper concludes the last part of the work aimed to calculate water consumption in eucalypt plantations. Stomatal resistance was modeled as a function of the following ambient variables: global solar irradiance, vapor pressure deficit and temperature. Based on stomatal resistance modeled from the values observed in the first part of this work, eucalypt transpiration by the Penman-Monteith method could be calculated in some days during the humid and dry periods of the year. Correlation between stomatal resistance and ambient variables was verified. The models generated by this relation proved efficient in calculating the diurnal variation of stomatal resistance as well as hourly and daily transpiration totals.

The soil attributes can affect the wood quality of eucalypt, which may result in considerable effect on cellulose production. This study evaluated the effect of different physical and chemical soil attributes on wood quality of Eucalyptus grandis for cellulose production. Five sites were selected at the Western Plateau of the State of São Paulo, planted with one clone of Eucalyptus grandis, with ages ranging between 6.5 and 7.0 years. Four soil types, with texture ranging from sandy to very clayey were found. At each site, three experimental plots were allocated with 100 trees each. Trees representative of each class frequency of diameter at breast height were harvested. Their biomass and wood components were characterized. The wood productivity and quality was affected by physical attributes of soil, mainly clay content, which is directly related to the amount of available water. Basic wood density did not changed at different soil types. Total lignin content decreased and holocellulose content exponentially increased as soil clay content increased (until about 350 to 400 g kg-1 of clay). The wood extractives content was not affected by soil attributes. Screened cellulose yield exponentially increased with soil clay content.Os atributos edáficos podem afetar a qualidade da madeira de eucalipto, o que pode resultar em considerável efeito sobre a produção de celulose. Este trabalho teve como objetivo avaliar o efeito de atributos físicos e químicos do solo na qualidade da madeira de Eucalyptus grandis usada para polpação celulósica. Foram selecionadas cinco áreas no planalto ocidental do Estado de São Paulo, Brasil, plantadas com um mesmo clone de Eucalyptus grandis, com idades variando entre 6,5 e 7,0 anos de idade. Quatro classes de solo, com textura arenosa a muito argilosa, foram encontradas. Em cada uma das cinco áreas, foram demarcadas, aleatoriamente, 3 parcelas com 100 plantas cada. Em cada parcela, foram colhidas árvores representativas das diferentes classes de diâmetro à altura do peito para avaliação de suas biomassas e para a análise de extrativos e componentes da madeira. Os atributos físicos do solo, sobretudo o teor de argila, diretamente relacionado à quantidade de água disponível, foram os que mais afetaram a produtividade e a qualidade da madeira. A densidade básica da madeira não se alterou nas diferentes classes de solo. O teor de lignina total diminuiu e o de holocelulose aumentou exponencialmente com o aumento do teor de argila do solo (até cerca de 350 a 400 g kg-1 de argila). O teor de extrativos da madeira não foi afetado pelos atributos do solo. O rendimento de celulose depurada relacionou-se exponencialmente com o teor de argila do solo.

• Increased exposure to canopy fire may threaten carbon stocks in resprouting forests. • The response of carbon to short-interval understorey and canopy fire was assessed. • Carbon decreased after one canopy fire but was resistant to repeated canopy fires. • Large trees are a fire-resistant carbon pool in forests of epicormic resprouters. • Carbon estimates need to account for the partial mortality of resprouting trees. Short-interval high severity wildfires threaten the stability of carbon stocks across forest communities, particularly those dominated by 'fire-sensitive' trees. However, there is a dearth of research on the effect of these extreme fires on forests dominated by 'fire-tolerant' tree species that can resprout from their trunk and branches i.e. epicormic resprouters. We assessed the effect of the severity of two wildfires occurring in short succession (6-year interval) on live and dead above ground carbon stocks (≥2.5 cm diameter) and carbon stability (i.e. the proportion of total carbon stored in live trees) in a temperate eucalypt forest dominated by epicormic resprouters. Four factorial combinations of low severity understorey fire and high severity canopy fire were examined across two wildfires. Carbon stocks were estimated using two approaches, a standard approach that assigns trees to the live and dead pools based on the presence of live foliage, and a novel approach that accounts for partial mortality of branches and stems. When accounting for partial tree mortality, total carbon stocks were greatest following repeated understorey fire and lowest in areas that had recently experienced canopy fire irrespective of canopy fire frequency. Trends in total carbon were driven by substantial reductions in live carbon following canopy fire, which were partially offset by gains in the standing dead carbon pool. Exposure to canopy fire reduced the proportion of carbon stored in live trees, increasing the susceptibility of carbon stocks to future losses through decomposition and consumption by fire. Relative to sites recently exposed to a single canopy fire, exposure to repeated canopy fires did not result in further reductions to carbon stocks or their stability. The standard carbon estimates substantially overestimated live carbon (+59 %) and underestimated dead carbon (-52 %) in areas recently affected by canopy fire, thus underestimating the impact of high severity fires on carbon stability. Our results suggest that carbon stocks in forests dominated by epicormic resprouters are sensitive to losses following canopy fire but are resistant to compounding effects of short-interval high severity fires, owing to the survival of large live stems. Our results highlight the need to account for partial tree mortality and feedbacks between short-interval wildfires when estimating transitions between carbon pools in fire tolerant forests. [ABSTRACT FROM AUTHOR]

Single-pass cut-and-chipping with modified foragers currently represents the most efficient technique for harvesting fuel chips from short rotation forestry (SRF). Modified foragers are designed to produce small chips, in the 25–30-mm length range. However, chip length settings can be adjusted for obtaining different commercial products. In that regard, it is important to determine the trade-offs of chip length manipulation, which may affect machine performance. This study tested the same modified forager designed for producing 30-mm chips, under variable chip length settings. In particular, chip length setting was adjusted both downwards to a minimum length of 5 mm (microchips), and upwards to a maximum length of 90 mm (billets). As expected, any setting adjustments that deviated from optimum values resulted in performance decline. Downward alterations of chip length setting resulted in a steady performance decline, which peaked at the shortest length setting (5 mm). Under that setting, productivity was 56% lower and diesel fuel consumption was 183% higher than under the optimum 30-mm setting. In contrast, upward alterations of chip length setting resulted in an immediate and moderate decay of machine performance at the very first increment, followed by the absence of further significant decline as additional increments were introduced. Reducing target chip length below 30 mm doubled or even quadrupled the proportion of fine particles (<3 mm) in the total chip mass, which detracted from chip quality. [ABSTRACT FROM AUTHOR]

Background: Climate change factors such as elevated atmospheric carbon dioxide concentrations (e[CO2]) and altered rainfall patterns can alter leaf composition and phenology. This may subsequently impact insect herbivory. In sclerophyllous forests insects have developed strategies, such as preferentially feeding on new leaf growth, to overcome physical or foliar nitrogen constraints, and this may shift under climate change. Few studies of insect herbivory at elevated [CO2] have occurred under field conditions and none on mature evergreen trees in a naturally established forest, yet estimates for leaf area loss due to herbivory are required in order to allow accurate predictions of plant productivity in future climates. Here, we assessed herbivory in the upper canopy of mature Eucalyptus tereticornis trees at the nutrient-limited Eucalyptus free-air CO2 enrichment (EucFACE) experiment during the first 19 months of CO2 enrichment. The assessment of herbivory extended over two consecutive spring--summer periods, with a first survey during four months of the [CO2] ramp-up phase after which full [CO2] operation was maintained, followed by a second survey period from months 13 to 19. Results: Throughout the first 2 years of EucFACE, young, expanding leaves sustained significantly greater damage from insect herbivory (between 25 and 32% leaf area loss) compared to old or fully expanded leaves (less than 2% leaf area loss). This preference of insect herbivores for young expanding leaves combined with discontinuous production of new foliage, which occurred in response to rainfall, resulted in monthly variations in leaf herbivory. In contrast to the significant effects of rainfall-driven leaf phenology, elevated [CO2] had no effect on leaf consumption or preference of insect herbivores for different leaf age classes. Conclusions: In the studied nutrient-limited natural Eucalyptus woodland, herbivory contributes to a significant loss of young foliage. Leaf phenology is a significant factor that determines the level of herbivory experienced in this evergreen sclerophyllous woodland system, and may therefore also influence the population dynamics of insect herbivores. Furthermore, leaf phenology appears more strongly impacted by rainfall patterns than by e[CO2]. e[CO2] responses of herbivores on mature trees may only become apparent after extensive CO2 fumigation periods. [ABSTRACT FROM AUTHOR]

Epichrysocharis burwelli (Hymenoptera: Eulophidae) was detected in Portugal, infesting the leaves of lemon-scented gum, Corymbia citriodora (Myrtaceae), in four out of seven sampled locations, along Tagus river, between the region of Lisbon and Castelo Branco. This is the first record of this alien gall wasp in Europe and in the Palaearctic region. An unidentified species of Closterocerus, which is not known from Europe, was found parasitizing the larvae of E. burwelli. [ABSTRACT FROM AUTHOR]

Forest residues (i.e. harvest residues and litter) are important nutrient sources for trees because soils of poor fertility are used for eucalypt plantations in Brazil. Understanding the dynamics of decomposition for these residues and their effects on soil fertility are relevant for the management of forest plantations. The objectives with this study were to assess the effects of forest residue management and fertilizer, both applied in the establishment of a Eucalyptus grandis Hill ex Maiden stand, on the decomposition rate (k), nutrient release and soil fertility after harvest of this stand. The treatments were applied to a plantation (R1). After 8 yr, R1 was clear-cut and all of the treatments were reapplied to a new planting (R2). At the end of R1 (age of 8 yr), there was a reduction of 10% in the wood volume in the treatment with the forest residues removed and 36% reduction with no fertilizer application. At the end of 1 yr for plantation R2, these reductions were 30 and 57%, respectively. Residue decomposition under R2 was assessed by a new approach that involved collecting samples directly on the site without using litter bags. The k of forest residues was 3.6 for leaves, 1.2 for bark and 0.8 for branches. The application of small rates of N and P fertilizer did not influence the k of forest residues. In the first 300 days after clear-cutting, approximately 50% of N, P, Ca, Mg and S and 80% of K in the forest residues were released. Even so, this did not result in significant changes in soil fertility levels. Only small reductions in soil N and P contents over time and changes in topsoil pH resulted from forest residue removal. [ABSTRACT FROM AUTHOR]

The aim of this paper is to present approaches to optimize stand-level, short-rotation coppice management planning, taking into account uncertainty in stand growth due to climate change. The focus is on addressing growth uncertainty through a range of climate scenarios so that an adaptive capacity may be possible and the vulnerability of the stand to climate change may be reduced. The optimization encompasses finding both the harvest age in each cycle and the number of coppice cycles within a full rotation that maximize net present revenue. The innovation lies in the combination of the process-based model (Glob3PG) with two dynamic programming (DP) approaches. The former is able to project growth of eucalypt stands under climate change scenarios. The innovative approaches are thus influential to define the management policy (e.g., stool thinning, number of coppice cycles, and cycle length) that maximizes net present revenue taking into account uncertainty in forest growth due to climate change. In both approaches, the state of the system is defined by the number of years since plantation, whereas DP stages are defined by the cumulative number of harvests. The first approach proposes the optimal policy under each climate change scenario at each state. The second approach addresses further situations when the climate scenario is unknown at the beginning of the planning horizon. Both help address uncertainty in an adaptive framework, as a set of readily available options is proposed for each scenario. Results of an application to a typical Eucalyptus globulus Labill. stand in central Portugal are discussed. [ABSTRACT FROM AUTHOR]

Eucalyptus polybractea (blue mallee) is the most widely harvested species in Australia for the production of pharmaceutical grade eucalyptus oil. Its use for both oil and biomass production is set to expand because blue mallee grows vigorously on semi-arid land where agricultural crop production is unsustainable. One of the most important tools for improvement of blue mallee, and for dissection of its unique traits, is an efficient method of indirect organogenesis. Our aim was to develop such a method, which is efficient for all genotypes and applicable to adult-derived explants. We also aimed to test whether genetically modified plants could be produced using this protocol. In vitro cultures were developed from three field-grown adult clones and it was found that over 95% of the resultant leaf explants initiated callus in a medium supplemented with thidiazuron and 1-naphthaleneacetic acid. The effect of the cytokinins, 6-benzylaminopurine (BA) and N 6 -(2-isopentenyl) adenine (2iP) on plant regeneration from the initiated callus was compared. Ninety percent of callus from all three clones regenerated shoots in a medium supplemented with BA, whereas only one clone regenerated shoots at high efficiency (93%) with 2iP. Roots were successfully developed on regenerated shoots with high efficiency (>60%) via exposure to indole-3-butyric acid, and hardened plants were successfully established in soil. Leaf explants from one clone were transformed with Agrobacterium tumefaciens T-DNA containing genes for hygromycin phosphotransferase (Hpt) resistance and green fluorescent protein (GFP), both constitutively expressed using the CaMV35S promoter. Transformants showed GFP fluorescence in calli and plantlet leaves and were successfully rooted and hardened into plants. This work will enable large scale cloning of adult blue mallee plants and, after optimization of the transformation protocol, provide an important platform for further research on the biosynthesis of eucalyptus oils with the potential to dramatically improve blue mallee as a crop. [ABSTRACT FROM AUTHOR]

In South Africa, commercial eucalypt stands may be regenerated through the stepwise reduction of coppice shoots following felling. The development of secondary coppice regrowth following these reduction operations results in competition with the remaining stems, possibly resulting in a reduction in growth. Currently, secondary coppice regrowth is controlled manually, or through spraying with glyphosate at 0.6% when ca. 0.75 m in height. No research has been conducted to determine whether alternative rates and/or timing of application are possible or cost-effective. In 2006 a trial was implemented in Zululand, South Africa on a recently coppiced stand ofEucalyptus grandis×Eucalyptus urophyllaso as to optimise rates of glyphosate application (0.6%, 1.2% and 1.8%) for the control of secondary coppice regrowth at various heights (0.5, 1.0 and 1.5 m). Tree and secondary coppice regrowth variates were measured annually until rotation-end (9 years, 3 months). The volume of herbicide used, the number of occasions each treatment was sprayed and associated costs were combined to provide an indication of the most cost-effective treatment. Although there were no significant differences in final coppice yield for the various rates of glyphosate and timing of application (as assessed by the size of the secondary coppice regrowth) tested, treatment efficacy in terms of treating secondary coppice regrowth increased with an increase in the rate of glypho- sate applied (0% < 0.6% < 1.2% < 1.8%), especially when treated at either 1.0 or 1.5 m in height. The use of glypho- sate, irrespective of rate and/or timing of application (as assessed by secondary coppice regrowth height), proved to be more cost-effective compared with manual control or the spraying of the secondary coppice regrowth at 0.75 m height with 0.6% glyphosate. The most cost-effective treatment was 1.2% glyphosate applied when the secondary coppice regrowth was 1.5 m. If reduced herbicide use is a major criterion within a company portfolio, then the secondary coppice regrowth can be manually removed when 1.5 m. [ABSTRACT FROM PUBLISHER]

Este estudo teve por objetivos: quantificar o estoque de madeira para a produção de carvão e serraria em uma floresta de eucalipto; quantificar o estoque de carbono nos diferentes compartimentos da floresta; e avaliar economicamente alternativas de manejo, com vista à inserção de povoamentos florestais no mecanismo de desenvolvimento limpo e na venda de créditos de carbono. Para isso, realizou-se um inventário florestal em uma plantação de Eucalyptus grandis, com 6 anos de idade, no Município de Viçosa, Minas Gerais. Após as análises, verificou-se que: a) o fuste é o componente da árvore que mais contribui, em média, para o total de carbono da parte aérea (81,84%), seguido por casca (8,05%), galhos (7,74%) e folhas (2,57%); b) 47,7 toneladas de carbono por hectare estão estocadas na parte aérea das árvores; 14,71 nas raízes e 8,72 na manta orgânica, totalizando 71,13 toneladas de carbono por hectare; c) a produção de madeira somente para a venda de créditos de carbono, sem considerar o seu uso final, é economicamente viável, segundo critérios quantitativos de avaliação do projeto, se a tonelada de carbono for comercializada a preços maiores que US$ 10,07; e d) a venda de créditos de carbono torna o empreendimento ainda mais atrativo economicamente, sobretudo porque a receita é auferida no início do projeto.The objectives of this study were: to quantify the wood stock for coal production and for sawmill in an eucalypt stand;) to quantify the carbon stock in the various compartments of the forest; and to evaluate economically management alternatives in order to include forest stands in the Clean Development Mechanism and in the sale of the carbon credits. In order to do so, a forest inventory in a 6-year-old plantation of Eucalyptus grandis, located in Viçosa, Minas Gerais State, Brazil, was carried out. The analysis showed that: a) the stem is a tree component that contributes the most, in average, for total carbon of the aerial part (81.84%), followed by the bark (8.05%), branches (7.74%), and leaves (2.57%); b) 47.7 tons of the carbon per hectare are stocked in the aerial parts of the trees; 14.71 tons in the roots; and 8.72 tons in the organic litter; totaling 71.13 tons of carbon per hectare; c) the wood production for the sale of carbon credits only, without considering its final use, is economically feasible, according to quantitative criteria of the project evaluation, if the ton of carbon was commercialized at prices higher than US$ 10.07; d) the sale of the carbon credits makes the activity even more attractive economically, mainly because the income enters at the beginning of the project.

Soil water repellency (SWR) is a dynamic soil property that influences soil hydrology. The main goal of this work was to determine in situ spatial and temporal variations in SWR in six recently burnt eucalypt stands with different pre- and post-fire management. The severity of SWR was measured in the field using the 'molarity of an ethanol droplet test' during 1-2 years, at intervals of 1-2 weeks. Measurements were taken for the ash layer, soil surface and three different soil depths (2-3, 7-8 and 14-16 cm). The volumetric soil moisture content (SMC) was measured at the three deepest layers. The results showed that ploughing operations carried out several years before the fire did not have major impacts on the severity of SWR. The ash layer was predominately wettable, whereas the other soil layers were dominated by strong to extreme severity SWR. Furthermore, and starting at a soil depth of 3 cm, the severity of repellency decreased with increasing depth. The spatial variability within a slope was significant on half of the sampling days, indicating that wettable patches were present under median severely repellent conditions, possibly increasing hydrological connectivity within the slopes. Temporal SWR patterns were inversely related to antecedent rainfall and SMC. The SWR patterns were similar between sites, as well as for the different sampling depths within each site. Major changes in the median levels of repellency were registered in periods as short as 1-2 weeks, but measured rainfall and/or soil moisture conditions were insufficient to explain these changes. Copyright © 2015 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Increases in post-fire runoff and erosion have been reported worldwide, but little is known about the combined effect of wildfires and pre-existent ploughing operations. A previous study using simulated rainfall found a similar runoff for an unploughed and a pre-fire ploughed site, but clearly showed lower erosion for the pre-fire ploughed site. This study measured post-fire runoff and erosion at the same two sites, with the same experimental design, but under natural rainfall conditions. Four micro-plots were installed on each of two eucalypt stands, one of which was rip-ploughed 20 years before the fire. The rainfall amount was 35% lower during the first post-fire year than during the second, but the runoff coefficient was approximately 20% for both years and sites. The sediment losses were significantly higher on the unploughed than on the pre-fire ploughed site during the first year (378 vs. 112 g m−2 y−1) and especially during the second year (552 vs. 67 g m−2 y−1). Half of the eroded sediments consisted of organic matter. On the unploughed site, both the natural and the extreme-intensity simulated rainfall produced specific sediment losses of 0·35 gm−2 mm−1 rain, whereas the high-intensity simulated rainfall produced approximately half (0·16 g m−2 mm−1 rain). At the pre-fire ploughed site, the natural, high, and extreme-intensity simulated rainfall produced similarly low-specific sediment losses (0·07 g m−2 mm−1 rain). These low rates and the absence of differences between methodologies and simulated intensities suggested a depletion of soil stocks 20 years after the rip-ploughing. Copyright © 2015 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Globally, agriculture is the greatest source of threat to biodiversity, through both ongoing conversion of natural habitat and intensification of existing farmland. Land sparing and land sharing have been suggested as alternative approaches to reconcile this threat with the need for land to produce food. To examine which approach holds most promise for grassland species, we examined how bird population densities changed with farm yield (production per unit area) in the Campos of Brazil and Uruguay. We obtained information on biodiversity and crop yields from 24 sites that differed in agricultural yield. Density-yield functions were fitted for 121 bird species to describe the response of population densities to increasing farm yield, measured in terms of both food energy and profit. We categorized individual species according to how their population changed across the yield gradient as being positively or negatively affected by farming and according to whether the species' total population size was greater under land-sparing, land-sharing, or an intermediate strategy. Irrespective of the yield, most species were negatively affected by farming. Increasing yields reduced densities of approximately 80% of bird species. We estimated land sparing would result in larger populations than other sorts of strategies for 67% to 70% of negatively affected species, given current production levels, including three threatened species. This suggests that increasing yields in some areas while reducing grazing to low levels elsewhere may be the best option for bird conservation in these grasslands. Implementing such an approach would require conservation and production policies to be explicitly linked to support yield increases in farmed areas and concurrently guarantee that larger areas of lightly grazed natural grasslands are set aside for conservation. [ABSTRACT FROM AUTHOR]

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 m at the peak of leaf area index (LAI), 2 years after planting, under three Eucalyptus clones (belonging to species E. saligna , E. grandis × E. urophylla , E. grandis × 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 belowground for all the genotypes, the depth of the root front ranged from 8.0 m for the seedlings and the E. grandis × 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. [ABSTRACT FROM AUTHOR]

Adaptive strategies to improve tree water-use efficiency (WUE) are required to meet the global demand for wood in a future drier climate. A large-scale throughfall exclusion experiment was set up in Brazil to study the interaction between water status and potassium (K) or sodium (Na) availability on the ecophysiology of Eucalyptus grandis trees. This experiment focused primarily on the changes in aboveground net primary production, stand water use, phloem sap and leaf δ 13 C, net CO 2 assimilation and stomatal conductance. The correlations between these response variables were determined to gain insight into the factors controlling water-use efficiency in tropical eucalypt plantations. The intrinsic WUE in individual leaves (the ratio of net CO 2 assimilation to stomatal conductance) was estimated at a very short time scale from the leaf gas exchange. Sap flow measurements were carried out to assess the WUE for stemwood production (the ratio of wood biomass increment to stand water use). Averaged over the two water supply regimes, the stemwood biomass 3 years after planting was 173% higher in trees fertilized with K and 79% higher in trees fertilized with Na than in trees with no K and Na addition. Excluding 37% of the throughfall reduced stemwood production only for trees fertilized with K. Total canopy transpiration between 1 and 3 years after planting increased from about 750 to 1300 mm y −1 in response to K fertilization with a low influence of the water supply regime. K fertilization increased WUE for stemwood production by approx. 60% with or without throughfall exclusion. There was a strong positive correlation between phloem sap δ 13 C and short-term leaf-level intrinsic WUE. Whatever the water and nutrient supply regime, the gas exchange WUE estimates were not correlated with WUE for stemwood production. Phloem sap δ 13 C and leaf δ 13 C were therefore not valuable proxies of WUE for stemwood production. The allocation pattern in response to nutrient and water supply appeared to be a major driver of WUE for stemwood production. In areas with very deep tropical soils and annual rainfall <1500 mm, our results suggest that breeding programs selecting the eucalypt clones with the highest growth rates tend to select the genotypes with the highest water-use efficiency for wood production. [ABSTRACT FROM AUTHOR]

Understanding the consequences of changes in climatic and biological drivers on tree carbon and water fluxes is essential in forestry. Using a metamodeling approach, sensitivity and uncertainty analyses were carried out for a tree-scale model (MAESPA) to isolate the effects of climate, morphological and physiological traits, and intertree competition on the absorption of photosynthetically active radiation (APAR), gross primary production (GPP), transpiration (TR), light use efficiency (LUE), and water use efficiency (WUE) in clonal Eucalyptus plantations. The metamodel predicting daily TR was validated using one year of sap flow measurements and showed close agreement with the measurements (mean percentage error = 11%, n = 2155). Simulations showed that APAR, GPP, and TR were very sensitive to the tree morphology and to a competition index representing its local environment. LUE and WUE were, in addition, very sensitive to the natural variability of the physiological leaf and root parameters. A maximum percentage error of 10% in these parameters leads to 18%, 17%, 16%, 9%, and 18% uncertainty for APAR, GPP, TR, LUE, and WUE, respectively. The uncertainties in TR were highest for the smallest trees. This study highlighted the need to take account of the spatial and temporal variability of tree traits and environmental conditions for simulations at the tree scale. [ABSTRACT FROM AUTHOR]

Copyright of Canadian Journal of Forest Research is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)