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We present new climate field reconstructions (CFR) of tropical Pacific ENSO sea surface temperatures (HadISST) for the boreal winter season using a circum‐Pacific tree‐ring network from known El Niño rainfall impact regions. We use two different CFR methods: Point‐by‐Point Regression (PPR) and reduced‐space Orthogonal Spatial Regression (OSR). Both methods produce reconstructions with high validation skill, but OSR is preferred because it has less spatial noise and is more efficient. Only the leading EOF of the SST field (EOF1) can be skillfully reconstructed by either method; EOF2 does not validate. The success of EOF1 reflects its importance for ENSO rainfall impacts over land; the failure with EOF2 is from the lack of these impacts. EOF1 allows for the reconstruction of many ENSO indices, including the ENSO Longitudinal Index (ELI). We also find evidence in our reconstructions for a recent increase in ENSO activity. Plain Language Summary: Earth's climate is strongly affected by how warm the tropical Pacific Ocean "El Niño" region is. This is especially true for the delivery of rainfall over many parts of the globe. Tree growth can thus be strongly affected by El Niño impacts on rainfall. We use this relationship to reconstruct tropical Pacific sea surface temperatures associated with El Niño over most of the past millennium from a network of annual tree‐ring chronologies located in regions known to be impacted by El Niño rainfall. Only the leading mode of variability in Pacific sea surface temperatures associated with El Niño can be reconstructed well, but it reflects most of the long‐term variability of El Niño exceptionally well. The reconstruction extends back to 1500 with exceptional skill and back to 1100 with acceptable skill. We can thus compare recent El Niño variability, perhaps affected by global warming, with what happened over the previous centuries unaffected by human activity. We find evidence for an increase in El Niño activity, and for an overall warming in recent decades. Key Points: Tree‐ring series from ENSO rainfall impact regions reconstruct tropical Pacific SSTs with high degrees of skill back to 1500 CE and 1100 CETwo very different reconstruction methods produce similar results and each can only reconstruct the leading EOF mode of SST variabilityReconstructions extending back 1100 CE indicate a recent increase in El Niño variability, and overall SST warming in the equatorial Pacific [ABSTRACT FROM AUTHOR]

Iron (Fe) plays a fundamental role in the nutrition of plants, yet its role in oil palm remains understudied. This study aims to unlock the role of Fe by analyzing its cycling and export different stages of oil palm tree growth. The experiment was conducted in Thailand, Pará State (Brazil), in a dystrophic Yellow Ferralsol, in a split-block, with four replications and seven treatments (plant age; 2, 3, 4, 5, 6, 7, and 8). The concentration, accumulation, recycling, immobilization, and export of Fe were evaluated, in addition to Fe use efficiency, in all plant organs. Analysis of variance (p < 0.05) was carried out on the results and regression model adjustments. The concentration and accumulation of Fe in the stem was greatest at the eighth year of the plants, and the fruit had higher Fe export values in the eighth year of the oil palm as well. As plants aged, the Fe concentration, accumulation, export, and use efficiency increased. Oil palm accumulates and immobilizes more Fe in its organs than it exports, a fact that contributes to the cycling and nutrition of the Fe in the plant. This research paves the way for future studies to explore how Fe can be optimized in oil palm trees to unlock their full potential. [ABSTRACT FROM AUTHOR]

Studying tree growth processes helps us evaluate the success of restoration efforts in recovering ecosystem processes such as carbon accumulation. Here, we study aboveground biomass dynamics in four common‐endemic tree species from the tropical Andes (Quercus humboldtii, Retrophyllum rospigliosii, Citharexylum subflavescens, and Croton magdalenensis), established in the main water supply basins of Medellín, Colombia. We use measurements from 19 permanent plots from five censuses between 2010 and 2023 to develop biomass equations as a function of t for each species (B = f[t]) by combining tree growth models of diameter (D) as a function of time (t) and pre‐existing allometric equations of biomass (B) developed in the same site as a function of D and wood density (ρ). We found that, because of initially higher growth rates characteristic of species belonging to the fast‐growing end of the fast‐slow growth economic spectrum, C. magdalenensis and C. subflavescens were the species with higher biomass accumulation at 13 years (142 and 132 kg, respectively). However, the potential of the slow‐growing species (Q. humboldtii and R. rospigliosii) for carbon sequestration initiatives in the long term was highlighted. To our knowledge, this is the first study in the region examining the dynamics of aboveground biomass in Andean restoration programs. It combines growth models and allometric equations, which can be useful for measuring the success of the implementation of ecological restoration programs and evaluating the need to apply adaptive management strategies. [ABSTRACT FROM AUTHOR]

Phyllosphere microorganisms are essential for plant growth and health. Although there are an increasing number of studies showing that the composition of phyllosphere communities varies among different plant species, it remains unclear whether and how their bacterial and fungal community composition predictably varies with plant traits and leaf age. In this study, we used high-throughput sequencing to explore the diversity and composition of phyllosphere communities in needles of different ages (originating from different cohorts) for three evergreen coniferous species (Pinus koraiensis, Picea koraiensis, and Abies nephrolepis). Our results indicated that Gammaproteobacteria (bacteria) and Dothideomycetes (fungi) were dominant in newly formed needles, whereas Actinobacteria (bacteria) and Eurotiomycetes (fungi) were dominant in perennial needles. Tree species identity and needle age were the main factors explaining the variations of the α diversity (species richness of phyllosphere communities) and β diversity (dissimilarity among phyllosphere communities). In particular, we found that leaf dry matter content, leaf mass per area, and total phosphorus content emerged as key predictors of composition and diversity of phyllosphere microbial communities, underscoring the major influence of tree species identity and needle age on phyllosphere communities through changes in plant functional traits. Finally, we found that the interaction between tree species identity and needle age also contributed significantly to explaining the diversity and composition of phyllosphere communities, probably because differences in plant functional traits or environmental conditions between new and perennial needles depend on tree growth rates and resource acquisition strategies. These findings provide new insights into the mechanisms of community assembly among different evergreen tree species and offer a better understanding of the interactions between plant traits and phyllosphere microorganisms during needle aging. [ABSTRACT FROM AUTHOR]

The Democratic Republic of the Congo (DRC) is facing a shortage of local scientists, particularly in the field of environmental research, which is hindering the study and preservation of the Congo River Basin rainforest. The lack of researchers is seen as a threat to the long-term survival of the rainforest, which is the second largest in the world. While foreign researchers contribute to the study of the rainforest, local scientists offer language skills, knowledge of local cultures, and a better understanding of the landscape. However, training and retaining researchers in the DRC is challenging due to limited funding, outdated science curricula, poor infrastructure, and low salaries. Efforts are being made to boost local scientific capacity, but more support and investment are needed to address these obstacles and ensure the preservation of the rainforest. [Extracted from the article]

The Himalayas are undergoing significant changes in temperature and moisture availability due to global climate change. Understanding how these changes affect tree growth is critical for conserving and managing this biodiverse region. To investigate the growth-limiting climatic factors, we collected tree-ring data from Abies pindrow old-growth mountain forests across 3190 to 3700 m a.s.l. in the inner valleys of the Garhwal Himalayas. This area faces significant temperature increases, reduced summer monsoon activity, and decreased winter precipitation. We found that over the past century, tree growth suffered from warm and dry springs and benefited from cool and moist springs, particularly at lower elevations (< 3400 m a.s.l.). Conversely, summer climate dynamics had minimal impact on radial growth. The sensitivity of Abies growth to spring climate can be attributed to the inner valleys' continental climate, marked by spring water deficit. Additionally, higher elevation trees (> 3400 m a.s.l.) showed positive correlations with dormant period temperatures in prior October and January, with the positive effect of October warmth strengthening over time. A dynamic analysis of the impact of spring (March–May) temperature, precipitation and Standardized Precipitation-Evapotranspiration Index revealed a recent unification (the 1980–2010s) of the climate–growth relationship across elevations. Specifically, the low-elevation trees have become less sensitive to warm springs, while the high-elevation trees have only recently become sensitive to warm and dry springs. The varying growth responses along the elevation gradient highlight the necessity of site-dependent differentiation when assessing the impacts of global climate change on species performance and geographic range shifts. [ABSTRACT FROM AUTHOR]

South American subtropical landscapes are dominated by open grasslands and mosaics of forest–grassland formations. Forests are often restricted to riverine margins with sharp forest–grassland ecotones. Understanding the mechanisms maintaining forest–grassland ecotones is important to anticipate the effects of changing climate and disturbance regimes on the extent of these biomes and the ecosystem services they provide.We used a combination of field surveys and long‐term field experiments to explore the mechanisms that explain tree cover expansion at the ecotone of riverine forests and grasslands in central Uruguay, within the South American Campos. We assessed the role of tree seed dispersal and seedling establishment limitations, and experimentally tested for the effects of cattle, nurse tree cover and grasses on the recruitment of forest and grassland tree species at the forest–grassland ecotone.We found that forest expansion depends on the interplay between cattle and nurse trees. Vachellia caven trees colonize the grassland successfully and facilitate the formation of forest patches by enhancing seed accumulation and seedling establishment of forest tree species. Surprisingly, grass cover had mostly positive effects on early seedling survival of forest tree seedlings. However, cattle limits tree seedling growth and survival, especially of forest tree species. This results in a nucleated vegetation pattern of tree patches that ultimately limits forest expansion.Synthesis and applications. Tree cover can potentially expand on the subtropical South American grasslands. Reductions in cattle densities and increases in rainfall levels associated with climate change could facilitate forest expansion in this region. [ABSTRACT FROM AUTHOR]

Wood ash fertilization remarkably increases tree growth and hence, carbon sequestration in drained boreal peatland forests, particularly in nitrogen (N)-rich Scots pine sites with limited phosphorus (P) and potassium (K). Because ash lacks N, N-deficient ombrotrophic and poor oligotrophic sites are generally considered unsuitable for ash fertilization. In this study, timber production was investigated in six field experiments in N-poor, drained Scots pine dominated peatlands in central Finland, where ash fertilization was applied 15–85 years earlier. Ash significantly increased tree growth in all the study sites. Unfertilized plots showed long-term average mean annual increment (MAI) of 2.01 m3·ha−1·a−1, whereas in fertilized plots MAI was 4.46 m3·ha−1·a−1. An analysis with nonlinear mixed effects model revealed a faster volume yield development and higher asymptote of the mean curve in fertilized plots. Higher amount of K in the ash significantly increased the response. Fertilizations were financially lucrative: on average, the break-even cost surpassed the ash fertilization cost (390 € ha−1) more than two-fold at 5% interest rate. The current nutrient status of fertilized trees was rather balanced. The results proved that the long-term growth response to ash fertilization in poor drained peatland sites is comparable to N-rich sites, but the response time is distinctively longer. [ABSTRACT FROM AUTHOR]

Leaf‐cutting ants (LCA) are one of the most important pests in the Neotropics region. To estimate the potential biomass consumption by LCA on Salicaceae plantations in the lower delta of the Paraná River, we studied the foraging activity and harvesting patterns of Acromyrmex lundii (Guérin‐Méneville, 1838) and Acromyrmex ambiguus (Emery, 1888) (Hymenoptera: Formicidae) in a 14‐year‐old poplar plantation in Argentina. Foraging activity (workers/time), harvested vegetal biomass (dry weight/time) and climatic conditions (temperature and relative humidity) were monitored daily and seasonally in nests from autumn 2016 to summer 2017. The two sympatric species harvested a similar quantity of dry biomass throughout the year (4.9–6.0 kg/colony). Although both species were active in all seasons, their foraging activity was higher in spring and summer, but they avoided extreme temperatures. The accumulated biomass harvested for both species was higher in summer (28.8 and 25.7 g/colony/day, for Ac. ambiguus and Ac. lundii, respectively). However, Ac. lundii harvested three times more biomass than Ac. ambiguus in spring (30.3 and 13.1 g/colony/day, respectively). Although the highest consumption on the vegetation occurred in summer, control tasks should be started during spring (sprouting phase), the most vulnerable period for Salicaceaes. The consumption of new leaves in spring is critical for tree growth, survival and wood production, especially by Ac. lundii, the most detrimental species during this season. [ABSTRACT FROM AUTHOR]

Growth curve models are popular tools for studying the development of a response variable within subjects over time. Heterogeneity between subjects is common in such models, and researchers are typically interested in explaining or predicting this heterogeneity. We show how generalized linear mixed-effects model (GLMM) trees can be used to identify subgroups with different trajectories in linear growth curve models. Originally developed for clustered cross-sectional data, GLMM trees are extended here to longitudinal data. The resulting extended GLMM trees are directly applicable to growth curve models as an important special case. In simulated and real-world data, we assess performance of the extensions and compare against other partitioning methods for growth curve models. Extended GLMM trees perform more accurately than the original algorithm and LongCART, and similarly accurate compared to structural equation model (SEM) trees. In addition, GLMM trees allow for modeling both discrete and continuous time series, are less sensitive to (mis-)specification of the random-effects structure and are much faster to compute. [ABSTRACT FROM AUTHOR]

In mountainous tea plantations, which are the primary mode of tea cultivation in China, issues such as soil erosion and declining soil fertility are particularly severe. Although green manure cover is an effective agricultural measure for restoring soil fertility, its application in mountainous tea plantations has been relatively understudied. Methods: This study investigated the effects of continuous green manure cover using the slope-protecting plant Ophiopogon japonicus on tea plant growth and soil microbial community structure. We implemented three treatments: 1 year of green manure coverage, 2 years of coverage, and a control, to study their effects on tea plant growth, soil physicochemical properties, and soil bacterial and fungal communities. Results: Results demonstrate that green manure coverage significantly promote the growth of tea plants, enhanced organic matter and pH levels in soil, and various enzyme activities, including peroxidases and cellulases. Further functional prediction results indicate that green manure coverage markedly promoted several carbon cycling functions in soil microbes, including xylanolysis, cellulolysis, degradation of aromatic compounds, and saprotrophic processes. LEfSe analysis indicated that under green manure cover, the soil tends to enrich more beneficial microbial communities with degradation functions, such as Sphingomonas, Sinomonas, and Haliangium (bacteria), and Penicillium, Apiotrichum, and Talaromyce (fungi). In addition. Random forest and structural equation models indicated that carbon cycling, as a significant differentiating factor, has a significant promoting effect on tea plant growth. Discussion: In the management practices of mountainous tea plantations, further utilizing slope-protecting plants as green manure can significantly influence the soil microbial community structure and function, enriching microbes involved in the degradation of organic matter and aromatic compounds, thereby positively impacting tea tree growth and soil nutrient levels. [ABSTRACT FROM AUTHOR]

This article discusses a study on the growth performance of Cedrus deodara forests in the Western Nepal Himalaya in response to climate change. The study found that tree growth was influenced by temperature and moisture levels, with warmer winters and increased evapotranspiration negatively impacting growth. The researchers also observed a decline in tree growth in one location due to local disturbances. The study emphasizes the need for further research to understand the complex interactions between climate, topography, and species physiology in determining tree growth. [Extracted from the article]

China's large-scale tree planting programs are critical for achieving its carbon neutrality by 2060, but determining where and how to plant trees for maximum carbon sequestration has not been rigorously assessed. Here, we developed a comprehensive machine learning framework that integrates diverse environmental variables to quantify tree growth suitability and its relationship with tree numbers. Then, their correlations with biomass carbon stocks were robustly established. Carbon sink potentials were mapped in distinct tree-planting scenarios. Under one of them aligned with China's ecosystem management policy, 44.7 billion trees could be planted, increasing forest stock by 9.6 ± 0.8 billion m³ and sequestering 5.9 ± 0.5 PgC equivalent to double China's 2020 industrial CO2 emissions. We found that tree densification within existing forests is an economically viable and effective strategy and so it should be a priority in future large-scale planting programs. China's large-scale tree planting could sequester 5.9 ± 0.5 PgC by planting 44.7 billion trees. Tree densification in existing forests may be a more cost-effective strategy than afforestation. [ABSTRACT FROM AUTHOR]

Introduction: To investigate the differences in the response of radial growth of larch (Larix gmelinii) at varying altitude gradients to climatic factors, this study established tree-ring width chronologies of Larix gmelinii at altitudes of 900 m, 1,120 m and 1,300 m based dendroclimatology. Methods: We also employed R packages including "dplR," "static" and "moving" to determine the correlation between larch at different altitudes and climatic factors and to explore the sensitivity and stability between radial growth and the climate of larch at different altitudes in the northern part of the Greater Khingan Mountains Range in Northeast China. Results: The results revealed the radial growth of larch in high altitude areas to exhibit a downward trend due to climate warming, while the growth of trees in intermediate and low altitude areas showed an upward trend. The growth-- climate relationship exhibited a significant negative correlation between radial growth in low altitude larch (900 m) and temperatures in the current winter (February and March) and growing season (July, October of the current year, and October of the previous year) (p < 0.05). Moreover, high altitude larch (1,300 m) showed a significant negative correlation with temperature in January, March, and October of the current year (p < 0.05). However, in intermediate altitude areas (1,120 m), the radial growth of trees was significantly positively correlated with the temperature of the growing season (May, June and August). Precipitation in April was observed to promote the radial growth of low-altitude larch. Moving correlation analysis revealed that the inhibitory effect of low temperatures in winter and high temperatures in the growing season on the radial growth of larch at three altitudes gradually strengthened, transitioning from significant negative/positive correlations to significant positive/negative correlations along the altitudinal gradient. Discussion: Larch trees in high and low altitudes exhibited an increased sensitivity to winter and spring precipitation, while in the intermediate region, the inhibitory effect of growing season precipitation on larch radial growth continued to intensify. The results of the study have an important reference value for the indepth understanding of the growth dynamics of Larix gmelinii natural forests in the northern part of the Greater Khingan Mountains under climate change. [ABSTRACT FROM AUTHOR]

The increasing duration of drought induced by global climate change has reduced forest productivity. Biodiversity is believed to mitigate the effects of drought, thereby enhancing the stability of tree growth. However, the effects of species richness on tree growth stability under droughts with different durations remain uncertain. Here, we used tree ring data from 4,072 sites globally, combined with climate and plant richness data, to evaluate the effects of species richness on the resistance and resilience of trees to short-term and prolonged droughts. We found that species richness enhanced resistance but weakened resilience of trees to drought globally. Compared to short-term drought, species richness further increased tree growth during prolonged drought but reduced the growth afterward, resulting in stronger effects on resistance and resilience. In addition, as the degree of drought intensified and regional aridity levels increased, the effects of richness on resistance and resilience under short-term drought were enhanced, but these trends were reduced or even reversed under prolonged drought. These results reveal the global effects of species richness on resistance and resilience of tree growth to droughts with different durations and highlight that species richness plays a crucial role in resisting prolonged drought. [ABSTRACT FROM AUTHOR]

Tree productivity is not only determined by stand structure, but also influenced by soil chemical properties, climate and topography. However, the relative importance of each indicator on larch (Larix principis-rupprechtii) productivity were uncertain. In this study, 76 pure larch forest plots were selected based on national forest inventory (NFI) data in Hebei Province, China. Structural equation model (SEM) was used to analyze the direct and indirect effects of stand structure, soil chemical properties, climate and topography on larch productivity, and to quantify the relative importance of each indicator in determining productivity. The results showed that stem volume growth (SVG) of larch was influenced by a combination of stand density, diameter at breast height (DBH), mean winter snow (PAS), annual temperature range (TD), slope, and alkali-hydrolysis nitrogen (AN). SVG tended to increase with decreasing stand density and AN content and increasing DBH. Stand density, DBH and AN were more important than PAS, TD, and slope in explaining SVG variation. The results can provide a scientific basis for adaptive management of larch forests. [ABSTRACT FROM AUTHOR]

Key message: Metabolic, physiological and inter-tree competitive processes interact to determine long-term growth behaviour of stands and individual trees of even-aged, monospecific forests. Context: Even-aged, monospecific forests go through an initial phase from seedling establishment to full canopy development, then follows a progressive decline in growth rate, leading eventually to tree senescence and death. Individual trees show a relationship between their maximum possible growth rates and their sizes (hence ages), maxima that show a progressive decline as the trees grow larger. Growth rates are further restricted by competition with their neighbours for access from the site to the light, water and mineral nutrients essential to their growth. To ensure they remain standing upright and can access the resources they need, trees must maintain a balance between the sizes of both their above- and below-ground parts. Aims: This review aimed to summarise what is known about the various biological factors that control these growth processes, both at the stand and individual tree levels. Conclusions: The principal factors determining growth behaviour are species characteristics, environmental circumstances of the site on which the forest is growing, availability from the site of the resources essential to growth, sizes (hence ages) of individual trees, competition between neighbours for growth resources and partitioning of growth between the parts of individuals to maintain an appropriate balance between their sizes. [ABSTRACT FROM AUTHOR]

This study evaluated the foliar antioxidant activity in nine Hevea brasiliensis genotypes from the ECC-1 (Élite Caquetá Colombia) selection and IAN 873 cultivar (control) in trees in the growth stage in two large-scale clonal trials in response to different climatic (semi-humid warm and humid warm sites) and seasonal (dry and rainy periods) conditions in the Colombian Amazon. The results indicated that Reactive Oxygen Species (ROS) production increased under conditions of lower water availability (dry period), leading to lipid peroxidation, high defense of photosynthetic pigments, and development of better osmotic adjustment capacity in the ECC 64, IAN 873, ECC 90, and ECC 35 genotypes due to high concentrations of carotenoids (0.40 mg g-1), reducing sugars (65.83 μg mg-1), and malondialdehyde (MDA) (2.44 nmol ml-1). In contrast, during the rainy period, a post-stress action was observed due to high contents of proline and total sugars (39.43 μg g-1 and 173.03 μg g-1, respectively). At the site level, with high Photosynthetically Active Radiation (PAR) values (1143 moles photons m-2 s-1), temperature (32.11°C), and lower precipitation (135 mm), higher antioxidant activity (chlorophylls a, b and total, carotenoids, and proline) was recorded at the humid warm site, demonstrating that the ECC 90, ECC 64, and ECC 66 genotypes are tolerant to water deficit compared to IAN 873. The ECC 64 genotype, independent of seasonal changes and site conditions, presented the highest contents in Chl a, total Chl, reducing sugars, total sugars, and MDA, showing a tendency to adapt to fluctuating conditions. This study showed that water fluctuations do not cause the same metabolic responses, these vary within the same species, depending on their developmental stage and the climatic and seasonal variations characteristic of the Colombian Amazon. [ABSTRACT FROM AUTHOR]

ABSTRACT Tree‐ring data are pivotal for decoding the age and growth patterns of trees, reflecting the impact of environmental factors over time. Addressing the significant shortcomings of traditional, labour‐intensive and resource‐demanding methods, we propose an innovative automated technique that utilizes panchromatic images and deep learning for measuring tree rings. The method utilizes convolutional neural networks to enhance image quality, precisely delineate tree rings through segmentation and perform ring counting and width calculation in the post‐processing stage. We compiled an extensive data set from diverse sources, including Beijing Forestry University and the Summer Palace, to train our algorithm. The performance of our method was validated empirically, demonstrating its potential to transform tree‐ring analysis and provide deeper insights into ecological and climatological research. [ABSTRACT FROM AUTHOR]

Introduction: Understory removal is frequently used to relieve the renewal pressure on trees and promote the growth capability of trees for maintaining community stability, while the lack of previous study on temperate forests limits our assessment of the effectiveness of this essential management measurement. Methods: In this study, we calculated the niche characteristics and interspecific association of main understory species and community stability in temperate forests [original broad-leaved Korean pine forest (BKF), Betula platyphylla secondary forest (BF), and Larix gmelinii plantation (LF)] after understory removal for characterizing the resource utilization capacity of the regeneration trees. Results: During the restoration stage, the niche breadth of understory plants with similar habits varied across stands and layers; regeneration tree species with heliophile and semishade occupied a larger niche in BKF and LF, while it was the opposite in LF. Niche overlap among heliophile regeneration trees increased in both BKF and BF, but not in LF. The interspecific association among main species revealed that the distribution of each species was independent and the interspecific association was loose and it varied in different forests and different light-demanding species with regeneration trees. The stability of shrub communities in BF and LF improved whereas that of BKF declined, while that of the herb communities of corresponding forests showed the opposite state. Discussion: Our study demonstrated that the effectiveness of understory removal depends on species' ecological habits, which enhances the renewal and resource utilization capacity of regeneration tree species in temperate forests and shrub community stability in BF and LF. [ABSTRACT FROM AUTHOR]

Achelura yunnanensis is a destructive pest of forests, causing substantial damage on tree growth and severe economic losses. Additionally, as a daytime-active moth, this species also holds important scientific value for investigating the genetic mechanisms governing day-night activity patterns of Lepidoptera. To facilitate effective pest control and deepen our understanding of the diurnal behavior's genetic basis of moths, genomic data for this species are crucial. In this study, we present a chromosome-level reference genome of A. yunnanensis (368.15 Mb in 32 chromosomes; scaffold N50 = 12.61 Mb; BUSCO completeness = 98.0%). Genome annotation shows that the new assembly comprises 37.10% (136.55 Mb) repetitive elements, 1,828 non-coding RNAs, and 15,523 protein-coding genes. Genes involved in lipid metabolism and xenobiotics biodegradation and metabolism, such as cytochrome P450 families, experienced significant expansion in the A. yunnanensis genome. The chromosome-level genome of A. yunnanensis provides a valuable genomic resource for devising novel pest control strategies, and will also help to study the genetic mechanism of the shift of diurnal behavior in Lepidoptera. [ABSTRACT FROM AUTHOR]

Introduction: Nitrogen (N) and phosphorus (P) enrichment due to anthropogenic activities can significantly affect soil N transformations in forest ecosystems. However, the effects of N and P additions on nitrification and denitrification processes in Metasequoia glyptostroboides plantations, and economically important forest type in China, remain poorly understood. Methods: This study investigated the responses of soil nitrification and denitrification rates, as well as the abundances of nitrifiers and denitrifiers, to different levels of N and P additions in a 6-year nutrient addition experiment in a M. glyptostroboides plantation. Results: Stepwisemultiple regression analysis was used to identify the main predictors of nitrification and denitrification rates. The results showed that moderate N addition (N2 treatment, 2.4 mol·m-2) stimulated nitrification rates and abundances of ammonia-oxidizing archaea (AOA) and bacteria (AOB), while excessive N and P additions inhibited denitrification rates and reduced the abundance of nirS-type denitrifiers. AOB abundance was the main predictor of nitrification rates under N additions, whereas microbial biomass carbon and nirS gene abundance were the key factors controlling denitrification rates. Under P additions, tree growth parameters (diameter at breast height and crown base height) and AOB abundance were the primary predictors of nitrification and denitrification rates. Discussion: Our study reveals complex interactions among nutrient inputs, plant growth, soil properties, and microbial communities in regulating soil N transformations in plantation forests. This study also offers valuable insights for formulating effective nutrient management strategies to enhance the growth and health of M. glyptostroboides plantations under scenarios of increasing elevated nutrient deposition. [ABSTRACT FROM AUTHOR]

Introduction: Coastal forests occupy low-lying elevations, typically adjacent to tidal salt marshes. Exposed to increased flooding with sea level rise, coastal forests have retreated as salt marshes advance upslope. Coastal forests likely currently experience periodic tidal flooding, but whether they temporarily accommodate or quickly succumb to rising sea level under changing climatic conditions remains a complex question. Disentangling how tidal flooding and climate affect tree growth is important for gauging which coastal forests are most at risk of loss with increasing sea levels. Methods: Here, dendrochronology was used to study tree growth relative to climate variables and tidal flooding. Specifically, gradients in environmental conditions were compared to species-specific (Pinus taeda, Pinus rigida, Ilex opaca) growth in coastal forests of two estuaries (Delaware and Barnegat Bays). Gradient boosted linear regression, a machine learning approach, was used to investigate tree growth responses across gradients in temperature, precipitation, and tidal water levels. Whether tree ring widths increased or decreased with changes in each parameter was compared to predictions for seasonal climate and mean high water level to identify potential vulnerabilities. Results: These comparisons suggested that climate change as well as increased flood frequency will have mixed, and often non-linear, effects on coastal forests. Variation in responses was observed across sites and within species, supporting that site-specific conditions have a strong influence on coastal forest response to environmental change. Discussion: Site- and species-specific factors will be important considerations for managing coastal forests given increasing tidal flood frequencies and climatic changes. [ABSTRACT FROM AUTHOR]

SUMMARY The lenticel is a channel‐like structure that facilitates oxygen, carbon dioxide, and water vapor exchange on secondary growth tissue, such as a tree stem. Although the structure of lenticel has been described, there is limited understanding regarding the impact of this secondary structure on secondary growth as well as the cellular and metabolic processes underlying its formation. The study reveals the essential role of the lenticel in the process of tree secondary growth and the cellular and metabolic processes that take place during its formation. Under the stomata, lenticel development occurs when cells divide and differentiate into a structure of disconnected cells with air spaces between them. During lenticel formation, specific metabolic pathways and wax biosynthesis are activated. The SERK (somatic embryogenesis receptor kinase) gene controls lenticel density, and serk1serk3serk5 triple mutants enhance lenticel initiation. The findings shed light on the cellular and metabolic processes involved in lenticel formation, laying the groundwork for further mechanistic elucidation of their development, function, and genetic regulation in trees. [ABSTRACT FROM AUTHOR]

The functioning of a tree is shaped by the neighbouring species through the interspecific interaction and local environments. The functional trait composition of the neighbourhood could provide mechanistic insights into the effects of neighbours on the resource strategies of focal trees.In this study, we deployed an automated high‐frequency measurement of the sap flow density (SFD) and the radial growth of 48 trees of 12 species at BEF‐China, a large‐scale forest biodiversity manipulation experiment, to investigate the consequences and underlying mechanisms of the functional trait composition of the neighbourhood on the sap flow and radial growth of focal trees.We found a positive relationship between SFD and growth, reflecting the important supportive role of sap flow in tree growth. High functional diversity (FD) of the neighbourhood depressed SFD but promoted growth when considering all species, and thus promoted water‐use efficiency. Acquisitiveness of neighbouring trees positively affected growth, suggesting interspecific facilitation. Furthermore, neighbourhood FD benefits evergreen focal trees by promoting growth. However, in deciduous focal trees, neighbourhood FD reduced SFD but had no significant effects on growth.Our findings suggest that considering the functional trait composition of neighbourhood communities will support effective afforestation and forest management. Read the free Plain Language Summary for this article on the Journal blog. [ABSTRACT FROM AUTHOR]

Correlation coefficients are widely used to identify and quantify climate signals in proxy archives. Significant relationships between tree-ring chronologies and meteorological measurements are typically applied by dendroclimatologists to distinguish between more or less relevant climate variation for ring formation. While insignificant growth-climate correlations are usually found with cold season months, we argue that weak relationships with high summer temperatures not necessarily disprove their importance for xylogenesis. Here, we use maximum latewood density records from ten treeline sites between northern Scandinavia and southern Spain to demonstrate how monthly growth-climate correlations change from narrow unimodal to wide bimodal seasons when vegetation periods become longer and warmer. Statistically meaningful relationships occur when minimum temperatures exceed 'biological zero' at around 5° C. We conclude that the absence of evidence for statistical significance between tree growth and the warmest summer temperatures at Mediterranean sites is no evidence of absence for the physiological importance of high summer temperatures for ring formation. Since correlation should never be confused with causation, statistical values require mechanistic understanding, and different interpretations are needed for insignificant correlations within and outside the growing season. [ABSTRACT FROM AUTHOR]

Increases in temperatures and atmospheric CO2 concentration influence the growth performance of trees worldwide. The direction and intensity of tree growth and physiological responses to changing climate do, however, vary according to environmental conditions. Here we present complex, long-term, tree-physiological responses to unprecedented temperature increase in East Asia. For this purpose, we studied radial growth and isotopic (δ13C and δ18O) variations using tree-ring data for the past 100 yr of dominant Quercus mongolica trees from the cool-temperate forests from Hallasan, South Korea. Overall, we found that tree stem basal area increment, intercellular CO2 concentration and intrinsic water-use efficiency significantly increased over the last century. We observed, however, short-term variability in the trends of these variables among four periods identified by change point analysis. In comparison, δ18O did not show significant changes over time, suggesting no major hydrological changes in this precipitation-rich area. The strength and direction of growth–climate relationships also varied during the past 100 yr. Basal area increment (BAI) did not show significant relationships with the climate over the 1924–1949 and 1975–1999 periods. However, over 1950–1974, BAI was negatively affected by both temperature and precipitation, while after 2000, a temperature stimulus was observed. Finally, over the past two decades, the increase in Q. mongolica tree growth accelerated and was associated with high spring–summer temperatures and atmospheric CO2 concentrations and decreasing intrinsic water-use efficiency, δ18O and vapour pressure deficit, suggesting that the photosynthetic rate continued increasing under no water limitations. Our results indicate that the performance of dominant trees of one of the most widely distributed species in East Asia has benefited from recent global changes, mainly over the past two decades. Such findings are essential for projections of forest dynamics and carbon sequestration under climate change. [ABSTRACT FROM AUTHOR]

The mineralogical composition of the parent material, together with plant species and soil microorganisms, constitutes the foundational components of an ecosystem's energy cycle. Afforestation in arid-semi arid regions plays a crucial role in preventing erosion and enhancing soil quality, offering significant economic and ecological benefits. This study evaluated the effects of afforestation and different parent materials on the physicochemical and microbiological properties of soils, including microbial basal respiration (MR), as well as how these changes in soil properties after 15 years influence plant growth. For this purpose, various soil physicochemical parameters, MR, soil microbial biomass carbon (Cmic), stoichiometry (microbial quotient = Cmic/Corg = qMic and metabolic quotient = MR/Cmic = qCO2), and tree growth metrics such as height and diameter were measured. The results indicated that when the physicochemical and microbiological properties of soils from different bedrock types, along with the average values of tree growth parameters, were analyzed, afforestation areas with limestone bedrock performed better than those with andesite bedrock. Notably, sensitive microbial properties, such as Cmic, MR, and qMic, were positively influenced by afforestation. The highest values of Cmic (323 μg C g−1) and MR (1.3 CO2–C g−1 h−1) were recorded in soils derived from limestone. In contrast, the highest qCO2 was observed in the control plots of soils with andesite parent material (7.14). Considering all the measured soil properties, the samples can be ranked in the following order: limestone sample (LS) > andesite sample (AS) > limestone control (LC) > andesite control (AC). Similarly, considering measured plant growth parameters were ranked as LS > AS. As a result, the higher plant growth capacity and carbon retention of limestone soil indicate that it has high microbial biomass and microbial activity. This study emphasizes the importance of selecting suitable parent material and understanding soil properties to optimize future afforestation efforts on bare lands. [ABSTRACT FROM AUTHOR]

The future of tropical forests hinges on the balance between disturbance rates, which are expected to increase with climate change, and tree growth. Whereas tree growth is a slow process, disturbance events occur sporadically and tend to be short‐lived. This difference challenges forest monitoring to achieve sufficient resolution to capture tree growth, while covering the necessary scale to characterize disturbance rates. Airborne LiDAR time series can address this challenge by measuring landscape scale changes in canopy height at 1 m resolution. In this study, we present a robust framework for analysing disturbance and recovery processes in LiDAR time series data. We apply this framework to 8000 ha of old‐growth tropical forests over a 4–5‐year time frame, comparing growth and disturbance rates between Borneo, the eastern Amazon and the Guiana shield. Our findings reveal that disturbance was balanced by growth in eastern Amazonia and the Guiana shield, resulting in a relatively stable mean canopy height. In contrast, tall Bornean forests experienced a decrease in canopy height due to numerous small‐scale (<0.1 ha) disturbance events outweighing the gains due to growth. Within sites, we found that disturbance rates were weakly related to topography, but significantly increased with maximum canopy height. This could be because taller trees were particularly vulnerable to disturbance agents such as drought, wind and lightning. Consequently, we anticipate that tall forests, which contain substantial carbon stocks, will be disproportionately affected by the increasing severity of extreme weather events driven by climate change. [ABSTRACT FROM AUTHOR]

In order to understand the non-structural carbon (NSC) content, nitrogen (N) phosphorus (P) potassium (K) ecological stoichiometric characteristics and their responses to tending thinning in different age stages of Populus×xiaohei, and to provide a basis for scientific management of Populus×xiaohei, the young and middle Populus×xiaohei plantation in Hongqi Forest Farm of Daqing City, Heilongjiang Provinc was studied, the effects of tending thinning on NSC content and NPK ecological stoichiometry in each organ of the plantation were investigated and analyzed by setting up thinning plots with thinning intensity of 25% (based on number of trees). The results showed that there were different NSC content and NPK ecological stoichiometric distribution characteristics of two kinds of Populus×xiaohei plantations. The contents of NSC in the leaf, branch and root of middle-aged forest were decreased by 31. 76%, 21. 19% and 38. 98% compared with those of young forest, respectively (P < 0. 05). The N content of leaf in the middleaged forest was increased by 11. 85% compared with that in the young forest (P < 0. 05). Compared with young forest, the P content of branch, stem and root of middle-aged forest decreased by 17. 57%, 35. 85% and 60. 11%, respectively (P < 0. 05), and the K content of leaf, branch, stem and root decreased by 21. 05%, 34. 67%, 22. 99% and 46. 22%, respectively (P < 0. 05). Tending thinning significantly affected the NSC content in the stem and root of young forest, and the NSC content in the branch and roots of middleaged forest (P < 0. 05). NSC content in stem of young forest increased by 29. 35%, while NSC content in root decreased by 40. 37%. The contents of NSC in branch and root of middle-aged forest increased by 12. 81% and 33. 51%, respectively. Tending thinning significantly affected N content in organs, K content in branch, P content in stem and K content in leaf and root of young forest (P < 0. 05). After tending, N content in leaf, branch, stem and root of young forest increased by 5. 77%, 15. 68%, 53. 71% and 10. 85%, respectively, K content in branch increased by 36. 90%, and P content in stem decreased by 19. 63%. The K content in the leaf and root of the middle-aged forest increased by 20. 86% and 31. 69%, respectively. The NSC content in leaf was negatively correlated with N content (P < 0. 01), and positively correlated with K content (P < 0. 05); NSC content in branch was negatively correlated with N content, positively correlated with P content (P < 0. 05), and significantly positively correlated with K content (P < 0. 01); NSC content in stem was significantly positively correlated with N content (P < 0. 01); NSC content in root was significantly negatively correlated with N content, and significantly positively correlated with P content (P < 0. 01). The above results showed that the distribution pattern of NSC and N, P and K elements in the organs of young and middle-aged Populus×xiaohei were significantly different when the stands were not tended. The carbon resources of the young forest were more allocated to the root system to promote its growth and extension, and the middle-aged forest was more invested in the growth and competition of the aboveground part of the tree. The distribution pattern of NSC, N, P and K in each organ was changed by tending thinning. The proportion of carbon resources in the aboveground and underground parts of the two kinds of standing Populus×xiaohei changed after tending. Tending thinning of middle age Populus×xiaohei forest increased the carbon sink and improved the P limit. [ABSTRACT FROM AUTHOR]

Tree thinning and the application of prescribed surface fire are widespread forest restoration strategies used to regain ecological structure and function throughout dry forests of the western United States. Though such treatments are increasingly applied to broad extents, their effects on forest ecosystems are commonly evaluated at individual experimental sites or treatment units rather than large, operational landscapes. We evaluated the responses of forest structure, regeneration, old‐tree mortality, and tree growth to forest restoration for 21 years in a landscape‐scale (2114 ha) experiment in a Ponderosa pine (Pinus ponderosa)‐Gambel oak (Quercus gambelii) forest in northern Arizona, United States. Relative to the start of the experiment in 1996, tree density and basal area (BA) in the treated area were reduced by 56 and 38%, respectively, at the end of the study period compared to the untreated control. Conifer seedling densities generally declined and sprouting hardwoods increased following treatment. Mortality of old oak trees was significantly higher in the treated area compared to the control, likely due to fire‐caused injury during the prescribed burning. Mean annual BA increment of individual trees was 93% higher in the treated area than in the control. Our study provides new information on Ponderosa pine forest responses to restoration treatments at broad spatial scales and under realistic operational conditions. Results from this study can help inform landscape‐scale restoration projects in dry, fire‐dependent forests. [ABSTRACT FROM AUTHOR]

Copyright of Forestry Chronicle is the property of Canadian Institute of Forestry 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.)

Copyright of Forestry Chronicle is the property of Canadian Institute of Forestry 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.)

Tree rings in high mountain forests represent a valuable natural archive for climate reconstructions and understanding the impact of climate change on forest ecosystems. In this context, the dendroclimatic potential of Alnus acuminata (alder) was evaluated by selecting 25 trees from seven localities in the Mantaro Valley. Computational programs such as Image-Pro Plus, COFECHA, ARSTAN, Sigma Plot, and the IAWA Standard List were utilized. Densitometry, performed with the QTRS-01X equipment using X-ray technology, provided ring width and apparent density diagrams. Seven chronological periods were identified, covering a span of 37.5 years, with the years 1960-1966, 1972-1978, and 2004-2010 showing the greatest growth, and the years 1966-1970, 1980-1986, and 1999-2005 showing the least growth. Furthermore, the alder exhibited particular sensitivity to low winter temperatures in the higher altitude sampling areas. Samples from Colpar 12-A* and Paca 10-A* showed wall thicknesses of 4.39 and 4.60 µm, respectively, attributable to low temperatures. Additionally, a significant negative correlation was observed between minimum temperature and ring width index (r= -0.38, p<0.005) from 1972 to 2008. In terms of precipitation and ring width index, a positive correlation (r= 0.26, p<0.005) was evidenced from 1949 to 2009, positively influencing its development. These findings underscore the dendroclimatic potential of the species, contributing to the understanding of climatic history and the prediction of future conditions in development areas. [ABSTRACT FROM AUTHOR]

Increasing the planting density of mango orchards appears promising for obtaining higher yields, particularly during the first productive years. However, the challenge is to maintain a good balance between vegetative growth and fruit production in the longer term. The objective of this study was to decipher the effects of planting density, training system and cultivar on young mango trees' growth and production. The experiment, conducted in North Queensland, consisted of five combinations of planting density and training system applied to the cultivars Keitt, Calypso and NMBP-1243. The planting densities were low (208 tree ha−1), medium (416 tree ha−1) and high (1250 tree ha−1). The closed vase conventional training system was applied at each density. Single leader and espalier on trellis training systems were applied at medium and high densities, respectively. The tree canopy dimensions were measured every 6 months from planting, and tree production was recorded from the third to the fifth years after planting. Vegetative growth and fruit production were the results of complex interactions between planting density, training system, cultivar and/or time. The expected increase in orchard yield with higher planting density was observed from the first productive year, despite lower individual tree production at high planting density. Lower vegetative growth and fruit production at high planting density were probably caused by competition between trees. NMBP-1243 and Keitt showed more rapid vegetative growth. Keitt was the most productive cultivar during the first three productive years. The detailed results of this study provide avenues to further explore the behaviour of mango trees at high planting densities. [ABSTRACT FROM AUTHOR]

Old trees are irreplaceable conservation resources with numerous ecological and socio-cultural values. While many forests have experienced significant declines under recent climate warming, the risk of growth declines in old trees remains unknown. Here, we tackle this problem by dendrochronological studies of 30 old trees in a Platycladus orientalis forest at the northern boundary of the Taihang Mountain of China. We examined annual growth trajectories of trees at individual level and discovered four severe growth decline events over the last 150 years, including the periods of 1894–1899, 1913–1919, 1964–1967 and 2004–2018. The most recent growth decline event lasted for 15-year and involced 50% to 75% of the old trees. This decline was unprecedented in both its extent and duration. Furthermore, the growth–climate relationship of these old trees has changed since 1990. Before 1990, tree growth was significantly correlated with minimum winter; after 1990, tree growth became significantly correlated with the self-calibrating Palmer Drought Index. These results suggest that warming-induced droughts after 1990 could be the primary driver of the recent growth decline. If climate warming continues and drought stresses intensify, the old trees may face an increased risk of growth decline and even mortality. [ABSTRACT FROM AUTHOR]

This document discusses the impact of climate change on tree growth worldwide. It emphasizes the importance of understanding the relationship between climate change and tree growth for predicting future forest composition and effectively managing forest resources. The document explains that climate variables such as temperature, precipitation, and moisture availability can affect tree growth, and different tree species respond differently to these variables. It also highlights the species-specific nature of tree growth response and the influence of factors such as drought and elevation. The document concludes by emphasizing the need for continued research and collaboration to monitor and understand the impact of climate change on tree growth and develop sustainable management strategies. [Extracted from the article]

Tree diameter distribution models are important tools for forest management decision making. Soil variables affect tree growth and thus diameter distribution. However, few studies have been conducted on diameter distribution models describing the effects of soil. This study developed a soil-sensitive diameter distribution model based on 213 sample plots of Larix principis-rupprechtii plantations in northern China. The Weibull distribution model was modified by a compatible simultaneous system and the percentile method with the inclusion of soil variables. The most significant factors influencing the diameter distribution of L. principis-rupprechtii in terms of both scale and shape were stand characteristics and available K and alkali-hydrolysable N. The adjusted coefficient of determination for parameter γ significantly improved by 16.0%, while the root mean square error for parameter β decreased by 10.4%. The F test indicated a substantial difference between the models with and without soil variables. From the perspective of adjustable R2 values, the Akaike information criterion, root mean square error, relative error index, and absolute error index, the inclusion of stand and soil factors in the tree diameter distribution model enhanced its performance compared to the model that did not consider soil factors. The soil-sensitive diameter distribution model is proven to be effective and accurate. [ABSTRACT FROM AUTHOR]

Monitoring tree growth helps operators better understand the growth mechanism of trees and the health status of trees and to formulate more effective management measures. Computer vision technology can quickly restore the three-dimensional geometric structure of trees from two-dimensional images of trees, playing a huge role in planning and managing tree growth. This study used binocular reconstruction technology to measure the height, canopy width, and ground diameter of Castanopsis hystrix and compared the growth differences under different nitrogen levels. In this research, we proposed a wavelet exponential decay thresholding method for image denoising. At the same time, based on the traditional semi-global matching (SGM) algorithm, a cost search direction is added, and a multi-line scanning semi-global matching (MLC-SGM) algorithm for stereo matching is proposed. The results show that the wavelet exponential attenuation threshold method can effectively remove random noise in red cone images, and the denoising effect is better than the traditional hard-threshold and soft-threshold denoising methods. The disparity images produced by the MLC-SGM algorithm have better disparity continuity and noise suppression than those produced by the SGM algorithm, with more minor measurement errors for C. hystrix growth factors. Medium nitrogen fertilization significantly promotes the height, canopy width, and ground diameter growth of C. hystrix. However, excessive fertilization can diminish this effect. Compared to tree height, excessive fertilization has a more pronounced impact on canopy width and ground diameter growth. [ABSTRACT FROM AUTHOR]

Over the last 50 years, groundwater levels have been decreasing and air temperatures have been increasing in Poland. Maintaining this trend may make it impossible to maintain hydrogenic habitats in good condition. Reactions to ongoing climate change recorded in tree rings may be a good indicator describing the degree of this threat. The aim of this study was to determine the influence of climatic and hydrological changes on the growth of scotch pine (Pinus sylvestris L.) and black alder (Alnus glutinosa (L.) Gaertn) in the Narew National Park over past 50 years. The research was based on tree increment cores extracted from 42 pine trees and 57 alder trees that were randomly selected and ranged in age from 25 to 88 years, as well as climatic and hydrological data. Standardised data (5-year index) were analysed by species, generation (Y—21–40 years, M—41–60, O—61–90), and decade using correlation analysis. The results of the study show that pine responded more strongly to changes in air temperature and changes in precipitation totals, while alder growth was more strongly related to fluctuations in the water level of the Narew River and changes in precipitation totals. Our research showed that differences in response to environmental factors also occur between tree generations. The decrease in the water level of the Narew River that occurred over the last 50 years did not adversely affect the condition of the trees. Analysis of DBH growth rates showed that the younger generations (Y, M) grow faster than the older generation (O). This is positive news for managers of commercial and protected forests, but accelerated tree growth may be associated with specific consequences, such as increased wind damage as a result of reduced wood density or reduced sensitivity of trees to climate and hydrological changes. [ABSTRACT FROM AUTHOR]

The distribution of vegetation in coastal wetlands is significantly influenced by soil properties. However, the mechanisms of how soil characteristics impact the physiological processes of Tamarix chinensis forests remain underexplored. This study examined changes in the soil physicochemical properties and structural attributes of natural T. chinensis forests in the Yellow River Delta with increasing distance from the shoreline. T. chinensis trees were classified into healthy, intermediate, and dying categories based on growth potential, and dynamic changes in salt ions and non-structural carbohydrates (NSCs) were investigated. Results indicated that increasing distance from the shoreline corresponded to decreased soil salinity and pH, and increased soil moisture. T. chinensis mortality rate decreased, while tree height and ground diameter increased with distance. Soil salt content was positively correlated with T. chinensis mortality, but negatively correlated with tree height and ground diameter. Trees with lower growth potential had higher Na+ but lower K+ and K+/Na+ ratio. Soil salt content was positively correlated with root and stem Na+, while soil moisture was positively correlated with leaf NSCs. These findings suggest that soil salt content and moisture significantly influence T. chinensis ion absorption and NSC accumulation, with sodium toxicity being a key factor in the spatial distribution of T. chinensis forests. [ABSTRACT FROM AUTHOR]

Copyright of Environmental & Social Management Journal / Revista de Gestão Social e Ambiental is the property of Environmental & Social Management Journal 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.)

Functional traits offer insights into plant performance. However, linking traits to individual tree performance requires considering the overall phenotypic context and utilizing traits measured at the individual level. Tree growth rates are informative metrics about performance, however how it is measured provides different information on tree or community growth dynamics and structure and can alter the relationships or their strength with functional traits and individual phenotypes. Moreover, at the community level, trees can adjust their crown shapes and sizes to optimize canopy space utilization, and a high level of canopy packing can enhance the individual to community-level growth rate. In this study, we assessed the crown area of 1144 individual trees, a simple trait measured at the individual level, and the leaf mass per area (LMA), a common functional trait, to test trait-growth relationships, considering absolute and relative growth rate. The observed total photosynthetic mass (integrating crown area and LMA) positively explained absolute tree growth rates, interacting with tree height. As higher the trees, more intense was the effect. Importantly, this effect was not solely based on LMA or crown size. This implies that LMA's predictive power could improve by integrating leaf-level traits with whole-plant allocation to leaf area. These variables, however, failed to predict the tree's relative growth rates. Additionally, our study found that increased canopy packing levels raised the community-level growth rate within our plots. This overall community growth seems be facilitated by denser tree arrangements and efficient light interception in the forest due to the higher canopy packing level. We highlight the importance of considering crown area as a critical variable to be measured during floristic inventories and in studies focused on tree performance. [ABSTRACT FROM AUTHOR]

Scale-free networks are prevalently observed in a great variety of complex systems, which triggers various researches relevant to networked models of such type. In this work, we propose a family of growth tree networks \(\mathcal{T}_{t}\) , which turn out to be scale-free, in an iterative manner. As opposed to most of published tree models with scale-free feature, our tree networks have the power-law exponent \(\gamma=1{ + }\ln 5/\ln 2\) that is obviously larger than \(3\). At the same time, "small-world" property can not be found particularly because models \(\mathcal{T}_{t}\) have an ultra-large diameter \(D_{t}\) (i.e., \(D_{t}\sim|\mathcal{T}_{t}|^{\ln 3/\ln 5}\)) and a greater average shortest path length \(\langle\mathcal{W}_{t}\rangle\) (namely, \(\langle\mathcal{W}_{t}\rangle\sim|\mathcal{T}_{t}|^{\ln 3/\ln 5}\)) where \(|\mathcal{T}_{t}|\) represents vertex number. Next, we determine Pearson correlation coefficient and verify that networks \(\mathcal{T}_{t}\) display disassortative mixing structure. In addition, we study random walks on tree networks \(\mathcal{T}_{t}\) and derive exact solution to mean hitting time \(\langle\mathcal{H}_{t}\rangle\). The results suggest that the analytic formula for quantity \(\langle\mathcal{H}_{t}\rangle\) as a function of vertex number \(|\mathcal{T}_{t}|\) shows a power-law form, i.e., \(\langle\mathcal{H}_{t}\rangle\sim|\mathcal{T}_{t}|^{1+\ln 3/\ln 5}\). Accordingly, we execute extensive experimental simulations, and demonstrate that empirical analysis is in strong agreement with theoretical results. Lastly, we provide a guide to extend the proposed iterative manner in order to generate more general scale-free tree networks with large diameter. [ABSTRACT FROM AUTHOR]

Heterobasidion root rot causes severe problems in the coniferous dominated forests of Northern hemisphere by decreasing timber value, reducing tree growth and making trees prone to other disturbance agents such as wind and bark beetles. According to current practices an infected stand is protected by treating fresh stumps at final cutting and generating the stand with tree species other than the host to reduce the current infection levels. However, prevailing guidelines do not provide instructions how to manage the neighbouring stands around the already infected stand. In contrast to earlier studies, we expand the analysis to an entity (a landscape) consisting of both infected and uninfected stands so that stand establishment of uninfected area is taken into account, too. The objective of the study is to optimize stand establishment of the uninfected area so that the revenue losses are simultaneously minimized when the average carbon storage is maximized within the whole landscape (infected + uninfected). Our results demonstrate the complexity of Heterobasidion root rot management: the optimum stand establishment strategy differs depending on the geographic location and interest rate (i.e., yield on capital). Further, the results implicate that for successful fight against Heterobasidion root rot the magnitude of infected area as well as the severity of the infection need to be taken into account. [ABSTRACT FROM AUTHOR]

Eucalyptus are trees sensitive to interference imposed by weeds mainly during the early growth phase. The repetitive use of herbicides with the same mechanism of action has led to the selection of resistant weeds, and Digitaria insularis stands out for its resistance to glyphosate. Due to its occurrence in eucalyptus plantations, knowledge regarding D. insularis interference in eucalyptus early growth is needed to develop management strategies. This study aimed to confirm D. insularis glyphosate-resistence; and also to evaluate the effect of densities and distances of glyphosate-resistant D. insularis, seeded and in regrowth, on the early growth of Eucalyptus urophylla × E. grandis (Clone AEC-144). Prior to eucalyptus' experiments, D. insularis glyphosate-resistance was confirmed through a dose–response curve experiment. After that, two experiments [one for weed's first growth (seeded) and other for second growth (regrowth)] were carried out in an open area, in 700 L pots, for 105 days after planting eucalyptus seedlings. The treatments consisted of increasing densities of D. insularis (0, 1, 2 and 3 plants m−2) planted at 10, 20 or 30 cm from the eucalyptus seedlings. Eucalyptus height, stem diameter, leaf area and dry matter were evaluated. The eucalyptus variables most sensitive to interference were leaf and stem dry matter, with reductions of 45% and 88.4%, respectively for weeds seeded and regrowth. Weed second growth (regrowth) interfered more aggressively in eucalyptus growth. The coexistence with D. insularis, regardless of density and distance, negatively interfered early tree growth. [ABSTRACT FROM AUTHOR]

Most reforestation in Colombia, especially in the Andean region, are monocultures of pines and eucalyptus with defined nursery and silvicultural packages. Planting native species would avoid the widespread controversy over reforestation with exotic species. Nevertheless, there are few studies that evaluate the growth and yield of native species and provide supported data to establish new projects. Here, we modeled the growth and yield of the native coniferous Retrophyllum rospigliosii in different areas of the Colombian Andes in terms of mean diameter (D), height (H), and volume (V) as a function of age, based on longitudinal data from 115 research sample plots from three sites that were remeasured between 4 and 9 times for 20 years. We fitted the von Bertalanffy growth model for D, H, and V through Bayesian generalized nonlinear mixed models to model tree growth. The adjustment of the models for the absolute growth of R. rospigliosii was 0.99, 0.99, and 0.97 for D, H, and V, respectively. All models fulfilled all regression assumptions. Although the growth rates of R. rospigliosii differed between planted sites, R. rospigliosii plantations generally exhibited low growth and barely reached the sizes required for commercialization. These results suggest that the extensive use of R. rospigliosii in pure plantations is unlikely and discourages the massive propagation of R. rospigliosii. [ABSTRACT FROM AUTHOR]

GlobalAllomeTree is an international network platform that shares differential equations, which has gradually received high global attention. Currently, aiming at the lack of growth differential equations for major tree species in China on this platform, this study updated the standardized tree height-diameter relationship equation for major tree species in China. Due to the canopy and lower shrubs and grass cover, the measurement of tree height relative to diameter at breast height (DBH) is difficult, so mathematical tools need to be used for regression calculations. 36 tree species were selected as materials to construct a tree height-diameter relationship equation. Based on the binary volume model of major tree species in China and the one-dimensional volume table of each region, 1 692 sets of tree height-diameter data generated with a sampling diameter order of 1 cm interval were used as equation samples, and 1 238 sets of field survey data were used as validation samples. The modeling results showed as followed: the correlation coefficient (R²) of the national universal tree height-diameter equation fitting based on 1 692 sets of tree height diameter data from 36 main tree species was 0.801, indicating that the equation fitting results were good, so the tree height can be estimated by measuring the diameter at breast height (H, m) - diameter at breast height (D, cm) square H = aDb; using the equation to fit 36 main tree species, the results showed that the determination coefficients (R²) of the tree height-diameter at breast height equation for 36 main tree species were all greater than 0.916, and the values of mean error (ME), mean absolute error (MAE), and root mean square error (RMES) were relatively small. The overall accuracy of the equation was high, which could be widely promoted; using 1 238 analytical tree data collected from field work, the accuracy of the equation was verified based on the fitting formulas and parameter estimates a and b of the tree height diameter equation for 36 main tree species. The results showed that the average relative error of the equation prediction was 16.86%, within the allowable range of error, and the model format was standardized. Above results provided scientific reference for users of the GlobalAllomeTree platform. [ABSTRACT FROM AUTHOR]

The recent mountain pine beetle outbreaks have caused widespread mortality among lodgepole pine trees in western North America, resulting in a reduced population of surviving trees. While previous studies have focused on the cascading impacts of these outbreaks on the physiology and growth of the surviving trees, there remains a need for a comprehensive study into the interactions among various physiological traits and the growth in post-outbreak stands. Specifically, the relationship between chemical (primarily terpenes) and anatomical (mainly resin ducts) defences, as well as the allocation of non-structural carbohydrates (NSCs) to support these defence modalities, is poorly understood. To address these gaps, we conducted a field survey of surviving lodgepole pine trees in post-mountain pine beetle outbreak stands in western Canada. Our retrospective analysis aimed at determining correlations between the post-outbreak concentrations of monoterpenes, diterpenes, and NSCs in the phloem and the historical resin duct characteristics and growth traits before and after the outbreak. We detected strong correlations between the post-outbreak concentrations of monoterpenes and historical resin duct characteristics, suggesting a possible link between these two defence modalities. Additionally, we found a positive relationship between the NSCs and the total concentrations of monoterpenes and diterpenes, suggesting that NSCs likely influence the production of these terpenes in lodgepole pine. Furthermore, historical tree growth patterns showed strong positive correlations with many individual monoterpenes and diterpenes. Interestingly, while surviving trees had enhanced anatomical defences after the outbreak, their growth patterns did not vary before and after the outbreak conditions. The complexity of these relationships emphasizes the dynamics of post-outbreak stand dynamics and resource allocations in lodgepole pine forests, highlighting the need for further research. These findings contribute to a broader understanding of conifer defences and their coordinated responses to forest insect outbreaks, with implications for forest management and conservation strategies. [ABSTRACT FROM AUTHOR]