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Although stakeholders' participation in forest management helps overcome problems and conflicts that prevent sustainable solutions, different approaches and nomenclature for similar contents in the literature hinder theoretical progress on the topic. This study organises existing information through a bibliometric analysis of scientific papers from the last 30 years (1991–2021) on sustainable forest management, focusing on the stakeholders' participation. Results demonstrate that stakeholders' participation in sustainable forest management gained relevance from 2017 onwards. Case studies are predominant (66%) and six major trends were identified. The first emphasises a systemic approach to participation. The second updates the community management discussion. The third studies historical problems related to the use of resources, rights, and services. The fourth focuses on regional assessments and studies. The fifth concerns assessment, decision-making, and planning, including issues related to certifications and policies. The sixth discusses innovation related to adaptation, climate change, equity, and resilience. The studies included in this last classification are problem-solving-oriented and seek new forest management. Although important, the role of innovation in stakeholders' participation in sustainable forest management is overlooked, which constitutes an avenue for future research. [ABSTRACT FROM AUTHOR]

Tree detection and canopy area measurement are important and difficult tasks in forest inventory, which are important for understanding forest stand structure. This study utilized remotely piloted aircraft (RPA) aerial photography technology to collect remote sensing images of forests in Xiong County, China, creating a dataset comprising 1200 images of six tree species. Based on this dataset, the paper proposes an optimized model, Att-Mask R-CNN, for canopy detection and segmentation. Att-Mask R-CNN outperforms the original models (Mask R-CNN and MS R-CNN) by achieving 65.29% mean average precision for detection, 80.44% mean intersection over union for segmentation, and 90.67% overall recognition rate for the six tree species. In addition, a pixel statistics method based on segmentation masks is introduced for estimating the vertical projected area of individual tree crowns, and comparisons between the measured and predicted vertical projected area of the crowns of six tree species (100 trees of each class) show an overall goodness-of-fit R2 of 85% and a relative root-mean-square error rRMSE of 12.81%. By using remote sensing images from RPAs and optimizing existing deep learning models, the detection and segmentation of individual tree canopies can be achieved, resulting in a more accurate understanding of forest structure, which provides scientific support for forest management and resource monitoring. [ABSTRACT FROM AUTHOR]

This paper reviews and discusses the main features of biological invasion by plants and the assisted migration theory referencing a critical common factor—belowground ecology. The risk of a plant becoming invasive and the potential failure of assisted migration programs depend on the presence or absence of soil microorganisms that regulate key ecosystem processes and mitigate adverse environmental conditions. This biotic interaction should be considered in the selection of sites for afforestation programs since it is as important as temperature and precipitation regarding conservation decisions, and assisted migration practices in response to climate change. Fungal species should be determined and included in climate change mitigation programs to avoid disease outbreaks and ensure the presence of beneficial mutualistic species in sites selected for assisted migration. Plants considered for assisted migration should pose a low risk of becoming invasive for having establishment difficulties per se. However, the real threat is that they may displace other species, introduce pathogens, or trigger disease outbreaks in introduction sites that nullify assisted migration efforts. [ABSTRACT FROM AUTHOR]

Planted forests are in the utilisation phase in Japan, contributing to the increased use of timber and the realisation of carbon neutrality. We simulated and compared the carbon emission reduction effects of three forest management scenarios, including a no final cutting scenario at two geographical scales, in the context of a privately owned Cryptomeria japonica planted forest in Tsuruoka City, Yamagata Prefecture, Japan. We adopted two substitution approaches: the status quo approach and the dynamic approach in line with Japan's nationally determined contribution. We used hypothetical stands over three rotation periods of 150 years at the stand level, and a harvest schedule of 120 years at the regional level. The harvesting scenarios based on the status quo substitution approach reduced carbon emissions more than the no final cutting scenario for current wood usage at the study site, although those based on the dynamic substitution approach reduced carbon emissions as much as the no final cutting scenario during the first 30 years. Sustainable timber production from forests may reduce carbon emissions as much as unharvested forests until 2050, indicating that the substitution effects of harvested wood products could have a significant impact on the climate change mitigation effect arising from timber. [ABSTRACT FROM AUTHOR]

North American conifers exhibit three radial specific gravity (SG) patterns (Type 1, 2, and 3), which balance hydraulic and mechanical requirements. Type 1 and 2 patterns (Pinaceae) have low SG and high microfibril angle (MFA) corewood ensuring compliance, whereas in outerwood high SG/low MFA provide stiffness and strength resisting bending. Hydraulically, corewood, especially in Type 2 species, is resistant to embolism, whereas outerwood has higher specific conductivity. Cupressaceae (Type 3) have hydraulically very efficient, low SG outerwood, facilitating rapid growth. Corewood is flexible, whereas outerwood is mechanically weak and compensated for by more conical stems and durable heartwood (which prevents Brazier buckling). Radially earlywood (EW) decreases, and latewood (LW) increases for all types, whereas %latewood (%LW) increases (Type 1), decreases, then increases (Type 2) and decreases (Type 3). Ring SG increases when increasing LW SG and %LW are sufficient to counteract decreasing EW SG. Shade tolerance, crown recession, hormone gradients, and environmental variation affect patterns. Auxin concentration decreases with increasing distance from juvenile foliage slowing cell division, concomitantly gibberellin concentration (lignification) and carbohydrates (cell wall thickening) increase, producing higher %LW. Across a species range regions receiving relatively high summer rainfall have trees with higher %LW (by ring). [ABSTRACT FROM AUTHOR]

Spatially explicit global estimates of forest carbon storage are typically coarsely scaled. While useful, these estimates do not account for the variability and distribution of carbon at management scales. We asked how climate, topography, and disturbance regimes interact across and within geopolitical boundaries to influence tree biomass carbon, using the perhumid region of the Pacific Coastal Temperate Rainforest, an infrequently disturbed carbon dense landscape, as a test case. We leveraged permanent sample plots in southeast Alaska and coastal British Columbia and used multiple quantile regression forests and generalized linear models to estimate tree biomass carbon stocks and the effects of topography, climate, and disturbance regimes. We estimate tree biomass carbon stocks are either 211 (SD = 163) Mg C ha−1 or 218 (SD = 169) Mg C ha−1. Natural disturbance regimes had no correlation with tree biomass but logging decreased tree biomass carbon and the effect diminished with increasing time since logging. Despite accounting for 0.3% of global forest area, this forest stores between 0.63% and 1.07% of global aboveground forest carbon as aboveground live tree biomass. The disparate impact of logging and natural disturbance regimes on tree biomass carbon suggests a mismatch between current forest management and disturbance history. [ABSTRACT FROM AUTHOR]

We studied how management intensity and climate severity affect volume growth, timber yield, carbon stocks, and the amount of deadwood in Scots pine (Pinus sylvestris (L.)), Norway spruce (Picea abies (L.) Karst.), and silver birch (Betula pendula Roth.) dominated stands in the Republic of Karelia and Arkhangelsk region of northwest Russia. Using the forest ecosystem model (SIMA) under different climates (current and representative concentration pathway scenarios, RCP4.5 and RCP8.5), no-thinning, low, medium, and high intensity thinning rotational forestry regimes were simulated. Under RCPs, the volume growth and timber yield (5%–53%), carbon stocks (1%–22%), and deadwood amounts (11%–75%) increased for all Scots pine and silver birch stands. The use of low intensity management increased volume growth and carbon stocks (3%–16%) and deadwood amount (up to 60%) under RCPs, but not timber yield (±3%) in these stands. For Norway spruce stands, the volume growth (5%–26%), timber yield (23%–75%), and carbon stocks (5%–15%) decreased under RCP8.5, but deadwood amount increased (up to 142%). Intensive management increased volume growth (4%–19%), timber yield (4%–63%), carbon stocks (up to 14%), and deadwood amounts (up to 49%). Our results highlight that effects of climate severity and management intensity are site and species-specific for Eurasian's boreal forests. [ABSTRACT FROM AUTHOR]

Measuring the chemical traits of leaf litter is important for understanding plants' influence on nutrient cycles, including through nutrient resorption and litter decomposition, but conventional leaf trait measurements are often destructive and labor-intensive. Here, we develop and evaluate the performance of partial least-squares regression models that use reflectance spectra of intact or ground leaves to estimate leaf litter traits, including carbon and nitrogen concentration, carbon fractions, and leaf mass per area (LMA). Our analyses included more than 300 samples of senesced foliage from 11 species of temperate trees, including both needleleaf and broadleaf species. Across all samples, we could predict each trait with moderate-to-high accuracy from both intact-leaf litter spectra (validation R2 = 0.543–0.941; %root mean squared error (RMSE) = 7.49–18.5) and ground-leaf litter spectra (validation R2 = 0.491–0.946; %RMSE = 7.00–19.5). Notably, intact-leaf spectra yielded better predictions of LMA. Our results support the feasibility of building models to estimate multiple chemical traits from leaf litter of a range of species. In particular, intact-leaf spectral models allow non-destructive trait estimation in a matter of seconds, which could enable researchers to measure the same leaves over time in studies of nutrient resorption. [ABSTRACT FROM AUTHOR]

Western redcedar has high economic value and has been traditionally used for cultural purposes by Indigenous communities. Second-growth redcedar is potentially growing faster due to lower planting densities, fertilization, and tree breeding. Little quantitative information is available about the impact of management practices on wood quality, particularly heartwood extractives. This study evaluated the effects of growth rate and site on heartwood extractives at two locations aged 70–90 years in British Columbia, Canada. A three-parameter sigmoid model was fit to the data using nonlinear mixed effects to analyze the relationship between heartwood extractives relative to cambial age, growth rate, and sampling site. The southern site had significantly higher cumulative extractive concentrations, while all extractive concentrations increased faster. This study shows that smaller trees will reach their peak concentrations earlier than larger trees. Results show that faster growth through active management of western redcedar may lead to increased and more uniformly distributed content of heartwood extractives. [ABSTRACT FROM AUTHOR]

Models of forest regeneration dynamics have been less widely applied in forest management than those representing growth and mortality in later stages of stand development, in spite of the critical role of regeneration in maintaining forest ecosystems. This omission is demonstrated by a review of pertinent literature and examined in the context of reforestation in the province of Alberta. Regeneration assessments in Alberta are undertaken before the regeneration phase of stand development is complete. As a result, existing growth and yield models, used to predict whether regeneration performance will meet management objectives, do not adequately represent juvenile mortality, ingress of natural regeneration, stand density, and the responses of ingress and mortality to reforestation treatments. A long-term experiment monitoring regeneration of lodgepole pine stands following harvest has over the last 20 years attempted to address some of the resulting challenges. Opportunities and needs for regeneration modelling include extension to other boreal species and ecotypes, incorporation of climatic variables, and innovations in data collection and analytical techniques. Steps are recommended for expediting the required research. [ABSTRACT FROM AUTHOR]

Our model for optimizing stand-level wood production and carbon sinks includes individual-tree models for forest growth, an advanced model for soil carbon, detailed wood production economy, and an intertemporal objective for the value of wood production and carbon sinks/emissions. Carbon stocks include aboveground biomass and carbon in forest soil and in wood products. Optimization of the management regime, rotations and thinning timing, and type and intensity are carried out by reinforcement learning. Including the social price of carbon causes a regime switch from continuous cover forestry to clear-cuts, postponed lighter thinning, and a longer rotation, and with a high carbon price, to solutions with pure clear-cuts or solutions utilizing stands as pure carbon stocks. Carbon price has profound effects on stand values, and the bare land value may well exceed the value before a clear-cut. The total average carbon stock is maximized with harvest and a long rotation instead of "no harvesting". Bioenergy, carbon capture, and storage (BECCS) always increases the value of wood production but not necessarily the value of carbon sinks. With BECCS, increasing carbon stocks in trees and forest soil remains optimal. [ABSTRACT FROM AUTHOR]

To facilitate the movement and processing of timber in some regions of the Pacific Northwest, logs are tied together to form large rectangular rafts (often called "booms") which are transported and stored in aquatic environments. In the lower Fraser River, British Columbia, some reaches have >50% of shoreline with adjacent log booms, yet our understanding of the effects of log booms on habitats and biota is very limited. We compared sites that have never had log booms to nearby ones with active boom storage occurring to examine differences in environmental characteristics. In contrast to reference sites, nearly all active sites had compacted sediments and little vegetation coverage, likely caused by logs "grounding" onto benthic environments due to tidally influenced water level changes. Total benthic invertebrate abundance was higher at reference sites which had relatively more Amphipoda and Trichoperta, but fewer Haplotaxida, compared to active sites whose compacted and more detrital-laden sediments should favour haplotaxids. Water quality variables generally did not differ between reference and active sites. Grounding of log booms and contact with the below substrate is in contradiction of best management practices and has clear effects on the physical habitat and biota of the area underneath booming sites. [ABSTRACT FROM AUTHOR]

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European aspen is a keystone species in boreal forests, which support numerous ecologically important and endangered species. As detection of those species by remote sensing is impossible, we instead investigated the detection of large aspen trees using airborne laser scanning and aerial image data. However, this is a challenge due to their low quantity and scattered occurrence. The performance was assessed with representative and unrepresentative (where aspens were over-represented) samples of the population. First, we detected individual trees and then the random forest (RF) classifier was used to identify large aspens. The RF classification was implemented with and without synthetic minority oversampling technique (SMOTE) to balance the training data due to the rarity of large aspens. At the tree-level, the best F1-score (0.44) was obtained when the unrepresentative plot data were used with SMOTE. However, the F1-score decreased to 0.21 when the representative data were used. The best plot-level (plots with at least one aspen tree) F1-score with the representative plot data was 0.41. We conclude that although data augmentation may improve the result, it is difficult to detect large aspen trees in genuine populations. [ABSTRACT FROM AUTHOR]

We compared three methods for estimating current-year spruce budworm (Choristoneura fumiferana (Clem.)) defoliation from 2014 to 2021 using a network of 99 permanent sample plots in central Gaspé Peninsula, Québec. Percent current-year defoliation was measured by assessing shoots from mid-crown branches, ocular ratings of all individual trees using binoculars, and provincial government aerial surveys. Ocular survey defoliation differed from branch sample defoliation in 5–6 out of 7 years, consistently underestimating defoliation, across the full range of defoliation severity observed. Nested mixed-effect models for fir–spruce combined, balsam fir, white spruce, and black spruce ocular survey defoliation bias resulted in marginal R2 of 0.40, 0.47, 0.82, and 0.86, respectively. Current defoliation severity and its interaction with previous year defoliation and weather conditions significantly affected ocular survey bias. Correspondence of aerial survey estimates and mean plot defoliation occurred in only 43% of all plot-years and ranged from 14%–58% in individual years. Differences between aerial survey defoliation and plot values mainly resulted from assigning an adjacent class (e.g., light <30% assigned as moderate 31%–70% defoliation) or misplaced defoliation polygon boundaries, suggesting that assignment of aerial survey defoliation to plots or specific ground areas needs ground truth sampling. [ABSTRACT FROM AUTHOR]

Forest fires and logging drive the structure of boreal forest landscapes. According to recent studies, stand origin is a key driver of the variation in wood properties in black spruce (Picea mariana (Mill.) BSP.), although the underlying mechanisms remain to be elucidated. By comparing post-cut, post-fire and old-growth forests, this study aimed to better distinguish the effects of stand structure from those of the seed or layer origin of the trees on wood properties. We conducted comparative analyses based on ecological characteristics of the sites and static bending tests of small, defect-free wood specimens. Black spruce stands with a regular structure established after logging or fire exhibited higher stiffness at a given cambial age than old-growth forests with irregular structures, as well as lower wood density in the first 40 rings near the pith. However, the bending strength was comparable in all three types of forests studied. Differences in wood stiffness among stand types appeared to be driven more by stand structure than by the seed or layer origin of the stems. [ABSTRACT FROM AUTHOR]

Accurate and fine-scale forest data are essential to improve natural resource management, particularly in the face of climate change. Here, we present SCANFI, the Spatialized CAnadian National Forest Inventory, which provides coherent, 30 m resolution 2020 wall-to-wall maps of forest attributes (land cover type, canopy height, crown closure, aboveground tree biomass, and main species composition). These maps were developed using the NFI photo-plot dataset, a systematic regular sample grid of photo-interpreted high-resolution imagery covering all of Canada's non-arctic landmass. SCANFI was produced using temporally harmonized summer and winter Landsat spectral imagery along with hundreds of tile-level regional models based on a multiresponse k-nearest neighbours and random forest imputation method. This tile-level approach revealed the importance of radiometric variables in predicting vegetation attributes, namely winter radiometry, as the large-scale climate gradients were controlled at the tile-level. SCANFI was validated with rigorous cross-validation analyses, which revealed robust model performance for structural attributes (biomass R2 = 0.76; crown closure R2 = 0.82; height R2 = 0.78) and tree species cover (e.g., Douglas fir R2 = 0.60). SCANFI attributes were also validated with several independent external products, ranging from ground plot-based tree species cover (e.g., black spruce R2 = 0.53) to satellite LiDAR height data products (e.g., crown closure R2 = 0.71). SCANFI total aboveground biomass trends also followed those published by other studies. The methodology presented herein can be used to map time series of these attributes, identify the original training points used to make any given prediction, as well as map additional variables associated with the NFI photo-plots that are challenging to map using traditional remote sensing approaches. [ABSTRACT FROM AUTHOR]

Eucalyptus species are cultivated for various purposes around the world, mainly because they adapt well and grow quickly. These productive matrices of planted forests are common in Brazil, added to which, areas of native vegetation are requirements of environmental legislation. Although eucalyptus plantations are widely distributed in Brazil, little is known about the soil seed bank (SSB) in the eucalyptus productive matrix (EPM). We aim to understand how the EPM made up of eucalyptus plantations and native forest remnants affect the SSB in the Brazilian Pampa. Samples of the SSB of EPM were collected and monitored for 6 months in a shade house. We evaluated seedling emergence, richness, composition, ecological characteristics of the species, diversity, and floristic similarity. We recorded a high rate of seedling emergence, species richness, and different life forms and native species in all EPM treatments; however, the similarity between native remnants and eucalyptus plantations was low. The size and level of conservation of native remnants and the position and management of eucalyptus sites in the EPM influenced the diversity and composition of species. Eucalyptus plantations contain SSBs with potential for natural regeneration when they are in a landscape that maintains conserved native forest remnants. These results expand the knowledge of the SSB in EPM and can support actions in ecological restoration projects. [ABSTRACT FROM AUTHOR]

Forest plantations play an increasingly important role in meeting global demand for wood. They usually have higher yield than naturally regenerated forests. Thus, plantations can support economically viable wood production, enable forest conservation elsewere, help mitigate climate change by contributing to carbon sequestration and increase forest resilience and resistance to biotic and abiotic stressors. If yield of plantations is not as high as anticipated, then their use could generate important sustainability issues. There are still major gaps in our understanding of the factors that influence yield, even with respect to black spruce, white spruce, and jack pine, three of the most commonly planted tree species in northeastern North America. Our objective was to evaluate the yield of forest plantations of these species over a 416 000 km2 region that was representative of northeastern North American forests. Contrary to our prediction, realized yield of operational plantations was consistently lower than anticipated. Site index and competition both played a significant role in determining the yield of plantations. In the context of uncertain realized yield of operational plantations, we emphasize the necessity of relying on adaptive management to determine harvest levels that are compatible with sustainable management objectives. [ABSTRACT FROM AUTHOR]

Mixed plantations are garnering increased attention due to their potential to provide a broader array of benefits compared to monocultures. Although numerous studies have indicated promising complementarity between black spruce (Picea mariana) and tamarack (Larix laricina), few have delved into individual tree growth interactions to thoroughly assess early growth complementarity. We sampled 119 planted black spruce and their immediate environment to quantify and qualify any differences between two conditions in young plantations: mixed tamarack ("mixtures") and black spruce monocultures ("monocultures") within young plantations. We investigated the effect of neighbouring under four perspectives: tree competition, microenvironment, foliar nutrients, and soil nutrients. Our results showed increased values for black spruce foliar nitrogen total concentration, soil pH, and canopy closure in mixtures compared to monocultures. Furthermore, black spruce stem volume was increased by 38.1% in mixture compared to monoculture. Black spruce stem volume was negatively affected (86% decrease) by the combined effect of shrubs and non-crop trees under high competition pressure, despite the plantation being mechanically released in 2017. Collectively, our results suggest that black spruce growing in mixtures holds a greater growth potential than black spruce in monocultures. [ABSTRACT FROM AUTHOR]

Growth and yield systems are essential tools for enhancing forest management decision-making. This study systematically evaluated three stand-level models and two data types for predicting stand survival and basal area of Chinese fir (Cunning lanceolate (Lamb.) Hook.) plantations in southern China. The first model links survival and diameter through the self-thinning concept. The second model incorporates stand diameter, the previous year's diameter, and stand survival, while the third model treats stand survival and diameter as mutually independent functions of only stand age. Model 2 was the best performer for short-term prediction (2–4 years), whereas Model 3 excelled in longer projection periods (6–10 years). Despite the independent predictions of stand survival and diameter in Model 3, it closely tracked observed self-thinning trajectories in long-term predictions. Tree-level model growth derived from Models 2 and 3 performed optimally for short-term and long-term tree-level predictions, respectively. While limited to four experimental sites, this research contributes theoretical groundwork to growth and yield modeling for Chinese fir plantations. [ABSTRACT FROM AUTHOR]

The Atlantic Forest fragments have suffered from the impacts of climate change, resulting in the increased production of coarse woody debris (CWD), which needs to be evaluated in space and time to generate accurate estimates of carbon accumulation. Thus, the goals of this study were (i) to quantify the CWD volume, necromass, carbon stock, and annual increment of carbon (AIcarb) over a period of 4 years; and (ii) to select the optimal combination of climatic, topographic, edaphic, and intrinsic forest variables to accurately predict AIcarb using machine learning and multivariate analysis. The CWD volume, necromass, and carbon stock increased between 2017 and 2020. The AIcarb was 1.09 MgC ha−1 year−1 (2017–2018), 1.24 MgC ha−1 year−1 (2018–2019), and 2.31 MgC ha−1 year−1 (2019–2020). Statistical analysis indicated that climate variables had greater weight in the CWD carbon increment in the 2018–2019 and 2019–2020 periods, while edaphic, topographical, and intrinsic forest variables were more important for the 2017–2018 period. Our findings showed that the carbon increase in CWD was linked to temporal and spatial variables within forests. These results demonstrate the importance of this parameter in the carbon cycle of forest ecosystems and highlight that there should be greater international research efforts to quantify this carbon pool. [ABSTRACT FROM AUTHOR]

We address the concerns that managed forest plantations may cause reductions of diversity of understory vegetation. We performed inventories of two mature ponderosa pine plantations in which multiple treatments were applied during plantation establishment. At stand age 35, we measured tree heights and diameters, understory plant cover and diversity, soil nutrients and chemical properties, and soil microbial biomass and diversity with phospholipid fatty acid. We found a significant, positive effect from both herbicide (H) and fertilizer (F) applications on subsequent overstory tree growth and development (P < 0.05); insecticide (I) effect was minimal. We observed negative effects on understory plant diversity decades later when herbicide was applied during stand establishment. However, lower plant diversity and ground cover appeared to have been caused primarily from overstory canopy closure, supported by the increased understory cover and diversity observed in the HI and HFI plots that had been thinned at age 12. Similarly, while fertilizer increased tree growth at both sites, it only negatively affected understory plants at the higher quality site. We did not find significant influence of treatment effects on soil nutrients and microbial communities. Therefore, to mitigate the potential loss of understory biodiversity in plantations, foresters can manage overstory trees with traditional pre-commercial thinning techniques and early tending. [ABSTRACT FROM AUTHOR]

Understory small trees and shrubs play a crucial role in the biogeochemical cycles in forest ecosystems. However, their biomass in northeastern China is still uncertain and has been heavily disregarded due to the limited number of available allometric equations. For this study, 782 plants from 33 species obtained by the destructive method were used to develop species-specific and generalized aboveground allometric biomass equations based on collar diameter (D) and height (H) using weighted nonlinear seemingly unrelated regression. Each biomass component was shown to be well predicted by D alone, with R2 adj. values mostly greater than 0.80. The majority of species performed better in the models for wood and aboveground biomass when H was included as D2H. Furthermore, generalized equations for the two components showed a comparatively large coefficient of variation but comparable Bias to species-specific equations, especially for small trees. It is recommended to estimate biomass using generalized equations for mixed species only when species-specific equations are unavailable at a given site. However, in the event when precision is not the primary concern, generalized equations are also suggested. The developed equations will help to improve the accuracy of biomass assessment of understory woody plants in northeastern China forest ecosystems. [ABSTRACT FROM AUTHOR]

In northern British Columbia and southern Yukon woodland, caribou forage extensively on terrestrial lichens, predominately mat-forming Cladina species in late-successional pine-lichen woodlands. Many of these stands are now reaching a point in their development where lichen abundance declines as feather-moss mats increase. We evaluated the response of forest floor plant communities in pine-lichen woodlands from the southern Yukon Lewes Marsh partial-cutting trial 8 years after harvesting. Photoplot results documented a major decline (>60% ± 5.6% SE) in the mean surface area of existing large clumps of C. mitis in control (unharvested) treatments, whereas the mean surface area of large C. mitis clumps declined by 28% (±15% SE) in the one-third basal-area removal and showed an increase of 13.5% (±25% SE) in the two-thirds basal-area removal. Line intercept transects documented no changes in overall stand-level lichen abundance between pre-harvest (2012) and post-harvest (2021) measurements, while feather-moss mats and dwarf shrubs showed declines and increases, respectively, in partial-cutting harvest plots. Stand thinning may provide a bridging strategy to extend the period of forage lichen availability in late-seral pine-lichen woodlands, an important consideration in landscapes where increasing severity and frequency of fires are changing the seral-state distribution of caribou habitat. [ABSTRACT FROM AUTHOR]

New wood uses of Japanese white birch (Betula platyphylla var. japonica) have attracted much attention in recent years, but false heartwood has led to a decline in commercial value due to its irregular wood color. In this study, we assessed the occurrence of false heartwood and its proportion to stem cross-sectional area (PFH) in individual Japanese white birch (482 trees) in a ca. 70-year-old natural secondary forest. Specifically, we investigated the relative strength of the direct/indirect effects of individual size (BA), growth rate (GR), crown ratio (CR), number of branch scars (NBS), basal area sum of neighboring trees (BAS) and topographic wetness index (TWI) on PFH. In total, 80.3% of trees had false heartwood. CR was found to be the most important factor, acting through direct and indirect negative effects. BA and NBS had a positive effect, and TWI had a negative effect on PFH. BA had a positive correlation with tree age, indicating that PFH can be reduced in trees with faster growth. Simultaneously, BAS had an indirect positive effect on PFH. These results suggested that thinning, which reduces BAS and increases CR, can reduce false heartwood. [ABSTRACT FROM AUTHOR]

We assessed the impacts of three approaches to thinning from below with varying spatial patterns on several stand and individual tree variables for interior Douglas-fir (Pseudotsuga menziesii var. glauca (Beissn.) Franco), interior spruce (Picea glauca (Moench) Voss × Picea engelmannii Engelm.), and lodgepole pine (Pinus contorta Dougl. Ex Loud. var. latifolia Englem.) in central British Columbia, Canada. The three thinning treatments were two experimental "clumped" treatments (3 m Clumped and 5 m Clumped) and the Standard (more uniform spacing) thinning treatment that was employed operationally at that time. We used long-term data from 24 plots measured five times over 21 years. Thinning increased stand basal area increment, with the plots that received the 5 m Clumped treatment having significantly higher periodic annual relative basal area increment than the unthinned Control plots. The responses for the two clumped treatments were not any lower than the Standard. The 3 m Clumped treatment was best if one is concerned about fast recovery of the growing space; however, the 5 m Clumped spacing treatment may be preferable if higher individual tree vigour is needed for resistance and resilience to fire, insects, and disease. [ABSTRACT FROM AUTHOR]

Black locust (Robinia pseudoacacia L.) plantations on the Loess Plateau have become multigenerational sprouting forests with an obvious trend toward degradation. The species composition and vertical distribution pattern of understory woody plants were investigated in mature stands located at the top (T_GS) and bottom (B_GS) of a slope in the gully region to explore whether there may be replacement species for black locust. The species composition of T_GS and B_GS clearly differed, and species diversity indices in B_GS were significantly greater than those in T_GS. These differences in species composition were mainly attributed to elevation, leaf area index, and basal area of total canopy trees. In T_GS, Rubus corchorifolius and Rosa xanthina had an absolute advantage in terms of the number of individuals in the vertical space of (0, 100] cm and (100, 300] cm, respectively. In B_GS, Acanthopanax senticosus was dominant at (0, 200] cm, and Broussonetia papyrifera and Celtis sinensis began to dominate at >200 cm. These results suggest that shrub species (Rubus corchorifolius and Rosa xanthina) and tree species (Broussonetia papyrifera and Celtis sinensis) should be prioritized when mixed with black locust in T_GS and B_GS, respectively, to gradually replace black locust on the Loess Plateau. [ABSTRACT FROM AUTHOR]

The economic efficiency of conventional breeding strategies for forest trees based on biparental crosses is compared with that of alternative strategies based on pedigree reconstruction using molecular markers. Analyses of economic efficiency is based on comparisons of breeding scenarios corresponding to the same total investment. The first step is the description and cost evaluation of each basic operation, from crossing to genetic selection and clonal archive establishment. Breeding scenarios are then compared by stochastic sampling with a parametric genetic model (POPSIM), the comparison criteria in this case being genetic gain in the seed orchard for a given level of genetic diversity. Additionally, the economic gain resulting from the use of improved material is estimated for different levels of breeding investment. Our analysis shows that genotyping costs account for a much smaller proportion of total investment than phenotyping costs. We also show that, in comparisons of breeding scenarios corresponding to the same total investment, the three main breeding strategies (biparental crosses, polymix crosses, and open pollination) achieve similar genetic gains provided that sufficiently large numbers of parents are considered. These results open up promising perspectives for the wider integration of molecular markers into forest tree breeding strategies. [ABSTRACT FROM AUTHOR]

Individual tree diameter at breast height (DBH) distribution is an important information for forest management planning. Forest managers obtain the DBH data either by field measurements or estimations using predictive models. However, probability distribution models are still lacking or need improvement. Therefore, we aimed to construct and fit diameter distribution models that reflect forest structure and composition change. We evaluated gamma, log-normal, and Weibull probability distribution functions (PDFs) for two commercially important tree species, black spruce (Picea mariana (Mill) B.S.P.) and jack pine (Pinus banksiana Lamb), grown in natural stands across Ontario, Canada. We modelled the parameters of the distributions as a function of stand-level variables for these species. We used DBH data from 735 permanent sample plots. Our results showed that all three evaluated PDFs reflected observed DBH distribution. We demonstrated that the moment-based recovered parameters could represent the maximum likelihood-estimated parameters precisely, and parameters of the PDFs can be modelled as a function of stand-level dynamic covariates. The models unbiasedly predicted the PDF parameters DBH means and DBH classes. The R2 of the model fit ranged between 0.35 and 0.98 for the predicted parameters and 0.90 and 0.97 for the predicted DBH. [ABSTRACT FROM AUTHOR]

Construction and use of buildings is one of the highest users of global energy (34%) and one of the highest contributors to greenhouse gas emissions (37%). Using wood instead of carbon-intensive materials such as bricks reduces a building's embodied energy and is a more eco-friendly alternative. Since the quota of newly built wooden houses in Germany is still relatively low, gaining insights into the perspective of consumers is crucial. This study aims to investigate factors from a consumer perspective that influence the selection of wood as the primary building material for residential houses. Therefore, an online survey was conducted in Germany to gather data from individuals (N = 510) who either bought or built a house in the last 5 years. By conducting a logistic regression, we have identified six influencing factors for the selection of wood. Positive views on wood's eco-friendliness and emphasis on renewable materials are key factors in choosing wood. Higher age and living in rural areas also increase the likelihood of selecting wood, while concerns about value stability and durability have negative effects. We conclude that increasing information activities, raising awareness about wood's ecological benefits, and dispelling prejudices can significantly impact its selection as a preferred building material. [ABSTRACT FROM AUTHOR]

Moose are an iconic symbol of northern forests. In many jurisdictions, the management of moose has focused on regulating harvest with less emphasis on understanding moose–habitat relationships. We reviewed the literature and summarised the effects of forest harvest and management on the ecology of moose. Greater than 50 years of scientific studies document both positive and negative effects of forest harvest and associated activities such as silviculture and road building. Moose require spatially adjacent patches of younger plant communities for forage and older forests for thermal and security cover. Extensive and rapid forest harvest can result in the prevalence of young forest with a corresponding reduction in the fitness of moose populations. A warming climate likely will exacerbate the negative effects associated with the broad-scale removal of forest cover. Resource roads can create edge habitat that may serve as forage, but those features result in increased hunting and collisions with vehicles and facilitate the movement of predators. Post-harvest silviculture, including the application of herbicides, can create stand conditions that provide very little or low-quality forage. The ecological and societal benefits of moose are dependent on forest management that provides a mix of old and young forest, employs silviculture that retains adequate cover and forage plants, and minimises the development of roads. [ABSTRACT FROM AUTHOR]

The objective of this study was to evaluate the wood chemical and energetic characteristics of Eucalyptus spp. clones planted in three sites in the Midwest of Brazil. Thus, five clones from Eucalyptus spp. were planted in different sites aiming to determine the qualitative characteristics of the wood resulting from the variation in the tree growth environment and the genetic material. The same clones were planted in the three sites to determine the genotype × environment interaction. The trees were then sampled at 5 years after planting for their physical–chemical and energetic characterization. The results showed that the wood characteristics vary in different proportions according to the clone, just as the growth environment of the trees alters the behavior of the clones for the same characteristics. The edaphic variables affected the wood characteristics, inferring that the water content in the soil has more effect on the wood properties than the water content in the air, mainly on wood basic density. The results of this study indicate that using the appropriate genotype related to the environment conditions determines the wood characteristics, since the wood properties are strongly influenced by the edaphoclimatic variables. [ABSTRACT FROM AUTHOR]

Leaf area is an important ecophysiological variable for quantifying the potential production of trees, since it is closely related to tree growth. However, it is difficult to measure the leaf area completely because of the large number of leaves, so it is particularly important to develop accurate species-specific leaf area models. In this study, using 144 parse trees from 48 plots of different climate zones and ages of Chinese fir, tree leaf area models were developed based on sapwood area at breast height (SABH), diameter at breast height (DBH), and diameter at crown base (DCB), respectively. The results showed that the population-averaged levels of nonlinear mixed-effects (NLME) models were better than the plot-levels and base models, and the leaf area models based on DCB performed the best. Finally, the NLME model (16) based on DCB was used as the final model for tree leaf area of Chinese fir plantations, which was consistent with the pipe model theory. All the variables had certain biological and statistical significance and were easy to obtain in the field work (nondestructive). In addition, this study can also provide a reference for other tree species in predicting tree leaf area. [ABSTRACT FROM AUTHOR]

Non-industrial wood ash may be an effective forest soil nutrient supplement but its use in Canada is largely restricted because of unknown concentrations of trace metal contaminants. Sugar maple (Acer saccharum Marshall) is particularly sensitive to low soil calcium (Ca) levels, and though maple syrup is of great economic importance in Canada, it is unknown how wood ash could affect sap chemistry. Non-industrial wood ash (NIWA; 6 Mg·ha−1) applied to experimental plots in Muskoka, Ontario was rich in Ca (27%), while metal concentrations were well below provincial regulatory limits. One-year post-application, significant increases were observed in the treated plots in the soil pH and base cations (Ca, K, and Mg) in the surface soil horizons, and metal concentrations in the litter. Sap yield in the control plots was significantly lower in the first-year post-application than in the second year, but no other differences were found. In both tapping years, sap sweetness remained similar and differences in nutrient and metal concentrations between treatments were generally small and inconsistent. Foliar chemistry remained largely unchanged 1 year following application, except for K that was twice as high in the treated plots. Ultimately, NIWA is unlikely to significantly alter sugar maple sap chemistry, indicating that it is a viable nutrient supplement that can enhance soil fertility in sugar bushes with no impact on sap sweetness. [ABSTRACT FROM AUTHOR]

As wildfires are increasingly causing negative impacts to communities and their livelihoods, many communities are demanding more proactive and locally driven approaches to address wildfire risk. This marks a shift away from centralized governance models where decision-making is concentrated in government agencies that prioritize reactive wildfire suppression. In British Columbia (BC), Canada, Community Forests—a long-term, area-based tenure granted to Indigenous and/or local communities—are emerging as local leaders facilitating proactive wildfire management. To explore the factors that are enabling local governance approaches to managing wildfire risk, we conducted semi-structured interviews with 26 Community Forest managers across BC. Managers highlighted financial and social capacity, especially trust and relationships with both community members and government agencies, as crucial factors influencing their ability to undertake proactive management. These factors enable Community Forests to address wildfire risk not only within their own tenure area, but also at household, community, and landscape scales, while balancing diverse community values, objectives for forest management, and legal and policy obligations. Despite ongoing challenges, Community Forests emphasized the importance of scaling up their efforts to address wildfire risk and are a critical form of local wildfire governance that can help advance proactive wildfire management across BC. [ABSTRACT FROM AUTHOR]

This study verified the potential for determining the age of conifer trees using resistance microdrilling. A laboratory investigation, comparison of resistance microdrilling and counting branch whorls, and dating of old trees in a historic heritage site were conducted in this study. Two methods were proposed to determine the drilling path for resistance microdrilling. The results showed that resistance microdrilling is suitable for non-destructive testing (NDT) of living conifer trees. Moreover, the drilling path deviation must not exceed 15° to obtain reliable results. The absolute detection error of resistance microdrilling was within ± 3 years for young trees (age < 40 years old), within ± 5 years for old trees, and the relative error for all trees was less than 10%. The two methods for determining the drilling path proposed in this study are recommended for aligning the needle with the pith. For trees with a DBH exceeding the range of a resistance microdrill, the pith and age may be determined by using a "two-way drilling" in a forward and then reverse direction. [ABSTRACT FROM AUTHOR]

Climate change interacts with ecological processes leading to changes in tree and forest growth rate, biome shifts and species composition, all of which are influenced by disturbances. This study explores future overarching climate trends of eight of Canada's ecozones containing managed forests. For the 2071 to 2100 period, climate projections indicate a warming trend of up to an additional 5.5 °C and an overall increase in annual precipitation. Future trends suggest marked contrast between coastal and interior forests and polarization between western and eastern forests. Warmer temperatures, accumulating degree-days above 5 °C and frost-free days suggest longer and drier growing seasons and greater risk of drought particularly in moisture-limited areas such as montane cordillera, taiga shield and boreal shield ecozones. Warmer temperatures and rising precipitation combined with less snow suggest shorter and wetter future winters. This indicates greater risk of rain-on-snow and freeze-thaw events, flooding and landslides particularly in coastal ecozones. We discuss how these projections are likely to result in shifts in dominant species and abundance, which when coupled with the cumulative effects of future disturbances, is likely to alter future forest dynamics and impact harvestable wood volumes for Canada's forestry industry. [ABSTRACT FROM AUTHOR]

Balsam fir (Abies balsamea (L.) Mill.) is projected to decline in the Acadian Forest Region under climate change. We hypothesized that along a 700 km latitudinal gradient with increasing mean annual temperature from New Brunswick to Nova Scotia, Canada, balsam fir regeneration density and growth rates would (1) decline with warming and (2) decline more in immature than in mature stands due to greater exposure to adverse climate conditions. Regeneration density, height growth, and lateral branch growth were measured in 30 mature and 28 immature plots and related to climate and stand variables using generalized additive models. Balsam fir regeneration density was negatively affected by increased mean annual temperature and increased with summer precipitation, supporting our first hypothesis, but varied by height class. Canopy cover significantly affected seedling density, but its effect varied by substrate type (coniferous litter and dry moss litter), with seedling density being greatest under low canopy cover for large seedlings and greatest at intermediate canopy cover for small seedlings. Seedling growth rates were determined by height class, canopy cover, precipitation, and coniferous litter cover. Stand maturity did not significantly affect fir regeneration density or growth rates. Our results indicate that over time, increasing mean annual temperature may reduce balsam fir regeneration density within the Acadian Forest Region, while the marginal summer precipitation increases may lead to small gains in growth. [ABSTRACT FROM AUTHOR]

Coating seeds in taste-averting chemical defenses (e.g., capsaicin from Capsicum spp.) can reduce rodent seed predation, and thus might promote plant establishment and forest regeneration. However, the efficacy of such seed coatings remains unknown for many woody plant species, and seed coatings have not been evaluated across different habitats where forest managers might seek to promote forest regeneration. We used two complementary seed-removal experiments in closed-canopy forests (Michigan) and an old field undergoing reforestation (New York) to examine whether coating seeds of four native tree species (Acer rubrum, Fagus grandifolia, Pinus banksiana, and Pinus resinosa) with chili powder reduces seed removal by rodents. In all species and habitats, control seeds were removed more than seeds treated with capsaicin (94% more in the closed-canopy forest, 17% more in the old field). Seed coatings containing capsaicin may provide a generally effective tool to support native tree recruitment and promote restoration success. [ABSTRACT FROM AUTHOR]

Data from tree cores and disks were used to develop biomass and carbon mass taper models for five major Sierra Nevada conifer species. These taper models were used to predict masses of tree boles, tree bole portions, branch, and foliage using carbon fraction data for oven-dried and living tissues. Taper models developed using core data were well modeled to disk data with R2 values ranging from 0.98 to 0.99 by inclusion of a calibration parameter. The fit of the final models suggests our approach can be used to include large diameter trees that cannot be cut down in biomass data collection efforts that otherwise would only sample smaller diameter trees. Our results show that biomass-weighted living carbon estimates at the whole tree level ranged from 2.8% to 9% higher than estimation methods using the standard carbon fraction of 0.5 depending on the tree species. Our approach addresses the need to account for variation in carbon fraction and wood density throughout trees, as well as demonstrating a data collection and modeling approach to include large old growth trees that cannot be destructively sampled. [ABSTRACT FROM AUTHOR]

Black spruce is the most common tree species in Canada, dominating treed peatlands where they are usually stunted. We used 495 destructively sampled trees from 56 plots to develop allometric models of aboveground biomass by components (stem, branches, and needles) for small (<5 m tall) black spruce from peatlands in the Taiga Plains and Boreal Plains Ecozones of Western Canada, for which there were no specific models available of biomass by components. We used leave-one-plot-out cross-validation to assess transferability and compare our models with existing national and ecozone-specific equations. Our models predicted total tree biomass with better accuracy and less biased estimates than the national model (relative RMSE: 30% versus 35% national; relative bias: +1% versus –12% national). Similar results were obtained in other external datasets. Existing ecozone equations performed worse than either our models or the national ones. When we applied the models at the plot level to predict aboveground biomass density (Mg·ha−1), our models outperformed the national model again (relative RMSE: 15.9% versus 18.6% national, relative bias: +3.5% versus –13.6% national). These results indicate that at least for peatlands of Western Canada, our models provide better aboveground biomass estimates for small black spruce trees than existing models. [ABSTRACT FROM AUTHOR]

The recent expansion of mountain pine beetle (MPB, Dendroctonus ponderosae) from its native range in western North America into northern boreal pine forests in Alberta, Canada has resulted in conditions for tree regeneration that are dramatically different from those after wildfire, the predominant natural disturbance in these forests. We assessed natural regeneration post-MPB for northern boreal lodgepole pine sites in Alberta, Canada via intensive surveys of small plots at 33 severely attacked pine stands and using data from 205 permanent sample plots representing various site types and levels of MPB mortality. We used model selection to identify factors explaining regeneration. Overall, pine regeneration was very poor 6–9 years post-MPB; only 42% of the 33 intensively surveyed plots and only 9% of the 205 permanent plots had pine seedlings. This poor regeneration is attributed to high levels of cone serotiny in these populations, unsuitable regeneration microsites due to undisturbed litter or feathermoss layers, and competition from the residual canopy and understory vegetation. Other species (aspen, birch, poplar, and black and white spruce) were found on most sites, either as post-attack regeneration or regeneration established in advance. Without intervention, many of these stands will likely transition away from pine, to broadleaf and other conifer species. [ABSTRACT FROM AUTHOR]

Woodland caribou (Rangifer tarandus caribou (Gmelin, 1788)) use older forests that provide abundant terrestrial lichen forage and refuge from predators. However, forest structural characteristics vary widely, differing in forage availability but also, perhaps, in the ability of caribou to move freely to access forage or to escape predation. We conducted a multivariate analysis of habitat in two geographically and biophysically distinct regions to identify the independent effects of various attributes, including forest understorey stand density, defined as standing and downed biomass, on caribou habitat selection. We developed Bayesian network models to predict the probability of habitat selection based on a set of remotely sensed habitat inputs. Caribou in the Bistcho range (northwestern Alberta) selected non-forest/sparsely forested areas, while caribou in the Trout Lake region (northwestern Ontario) selected primarily forested habitats, nevertheless consistent with selection for reduced predation risk in both cases. Caribou also selected forest stands with lower understorey stand density in both regions, consistent with selection for stands that would allow greater ease of movement. The high-resolution satellite data resolved habitat characteristics more consistently and in greater detail than standard forest cover datasets that are most often used for these analyses, and led us to conclude that habitat management may require different treatments in different parts of the species' range to address what are nevertheless common pathways to decline. [ABSTRACT FROM AUTHOR]

The forest sector faces complex societal demands that require a workforce with the desired composition of competence. It is also a primary, rural, and male-dominated industry based on gendered norms and culture. There are knowledge gaps in how gender influences work-related satisfaction and experiences in the forest sector and how women manage to work in male-dominated workplaces. We fill part of these voids by studying job satisfaction and women's strategies using the Norwegian forest sector as a case study. By combining surveys and group interviews, we unveil statistical gender differences and individual experiences. We found that while most men and women are satisfied with the social aspects of the workplace, men are more satisfied than women. Women report considerably less gender equality and more use of suppression techniques than men. Thirty-two percent of the women report being sexually harassed during their most important job position. Being exposed to harassment, most women choose not to report it to management, but instead handle the situation themselves. Forestry is a gendered sector, and to change attitudes for improving the work environment and opportunities for all employees, gender-related issues must be raised and handled in a suitable manner by managers and organizations. [ABSTRACT FROM AUTHOR]

Forest fire detection towers are crucial in supporting rapid firefighting actions in conservation units and thus reducing environmental, social, and economic damages. Thus, the aim was to evaluate scenarios for optimal allocation of forest fire detection towers, according to the risk of occurrence, in the Caparaó National Park, Brazil. Thus, by geotechnological analysis, the areas most susceptible to forest fires and the optimal locations for installation of detection and monitoring for these events were delimited. To run the proposed models, biological, physical, socioeconomic, and meteorological variables were used. From the application of the methodologies, it was observed that 76.70% of the study area was covered by low, moderate, and shallow fire risk classes, while high and very high-risk classes were concentrated in the buffer zone. The scenario with 45 towers was considered the most advantageous, given that they presented viewing levels above 70% and a lower cost per hectare viewed than the scenario with 48 towers. Results showed no critical risks of fire occurrence within the conservation unit, but preventive measures are still needed to avoid fire spread, particularly near the buffer zone. The study's methodologies can be applied in other areas to improve forest fire prevention and control efforts. [ABSTRACT FROM AUTHOR]

Fungi are primary agents of coarse woody debris (CWD) decay in boreal forests, playing an essential role in nutrient cycling and carbon storage. We compared fungal community assemblages using alpha and beta diversity metrics, and physical and chemical properties of CWD across three tree species (trembling aspen [Populus tremuloides], black spruce [Picea mariana], and jack pine [Pinus banksiana]), five decay classes, and two stand development stages, differing in time since stand replacing disturbance in Ontario's boreal forest region. We sampled 180 individual CWD logs from 6 independent stands, with 3 replicates per each species × decay class combination at each site. Using high-throughput sequencing of marker DNA, we found that fungal community structure significantly differed across tree species, decay stage, and stand age. Fungal diversity was highest in decay class 4 CWD. We found that Mn and K concentrations, total carbon, C/N ratio, N/P ratio, and moisture content were important predictors of fungal composition across CWD species and/or decay stage. This study suggests that forest management guidelines that consider both deadwood quantity and quality will support a broader range of fungal species and communities through post-disturbance stand development. [ABSTRACT FROM AUTHOR]