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Climate change is affecting forest ecosystems, leading to changes in the distribution of tree species, ecological relationships, and the functioning of forest plant communities. The study aimed to analyse the impact of climate change on forest ecosystems in the Western Polissia of Ukraine. To achieve this goal, in 2005-2023, the State Enterprise “Gorodetske” Research Farm studied the current state of the forest ecosystem, analysed the impact of climate change on it, and conducted detailed forest pathology reconnaissance surveys of the stands. Biodiversity indices were also determined, and the rate of degradation and death of forests was analysed using field data and satellite images. The study determined that climate change in the Western Polissia Region has a significant impact on forest ecosystems, causing changes in forest composition, the spread of diseases and pests, and a decrease in natural biodiversity. The study established that to ensure their sustainable functioning and conservation, it is necessary to take specific measures, including early diagnosis of the state of forests, adaptation to climate change, prevention of forest fires, and use of forest resources based on the principles of sustainable forestry. Implementation of such strategies can contribute to the preservation of ecological diversity and sustainable development in the region for years to come. The results obtained are of great importance for environmental management and conservation of natural resources in the Western Polissia Region, as they provide an opportunity to identify specific strategies and measures for the adaptation of forest ecosystems to climate change and other environmental challenges

In the field of ecology, more and more attention is paid to the analysis of the interaction of herbaceous plants with the structure of ecosystems, including forests. The aim of the study was to determine the impact of herbaceous plants on the biodiversity and stability of pine plantations in Western Polissia of Ukraine. To achieve this goal, in 2010-2023, the State Enterprise “Research Farm “Horodetske” assessed the diversity of herbaceous plant species, measured their number and cover, evaluated soil physical properties and biometric parameters of pine trees, and assessed how changes in the pine plantation ecosystem caused by herbaceous plants can affect carbon sequestration and oxygen productivity. The study found that herbaceous species among pine plantations in Western Polissia perform important ecological functions that contribute to the conservation and restoration of ecosystems. The presence of these plants enriches the soil with organic matter and helps maintain the structural and functional stability of ecosystems. The study showed that herbaceous plants contribute to the restoration of pine plantations by providing protection and support for young trees, and have a positive impact on their biometric parameters, increasing the total phytomass. Herbaceous plants also improve soil physical properties, such as pH, humus content, aggregate water resistance and water permeability, which can contribute to soil structural stability and the health of pine stands. In addition, the presence of herbaceous plants contributes to more efficient carbon sequestration and oxygen production, which is important for the balance of the air environment in the ecosystem. The results obtained are of great importance for environmental management and conservation of natural resources in the Western Polissia region, as they provide scientific basis for developing strategies for the conservation and restoration of forest ecosystems, taking into account the role of herbaceous plants in their functioning

In the field of ecology, more and more attention is paid to the analysis of the interaction of herbaceous plants with the structure of ecosystems, including forests. The aim of the study was to determine the impact of herbaceous plants on the biodiversity and stability of pine plantations in Western Polissia of Ukraine. To achieve this goal, in 2010-2023, the State Enterprise "Research Farm "Horodetske" assessed the diversity of herbaceous plant species, measured their number and cover, evaluated soil physical properties and biometric parameters of pine trees, and assessed how changes in the pine plantation ecosystem caused by herbaceous plants can affect carbon sequestration and oxygen productivity. The study found that herbaceous species among pine plantations in Western Polissia perform important ecological functions that contribute to the conservation and restoration of ecosystems. The presence of these plants enriches the soil with organic matter and helps maintain the structural and functional stability of ecosystems. The study showed that herbaceous plants contribute to the restoration of pine plantations by providing protection and support for young trees, and have a positive impact on their biometric parameters, increasing the total phytomass. Herbaceous plants also improve soil physical properties, such as pH, humus content, aggregate water resistance and water permeability, which can contribute to soil structural stability and the health of pine stands. In addition, the presence of herbaceous plants contributes to more efficient carbon sequestration and oxygen production, which is important for the balance of the air environment in the ecosystem. The results obtained are of great importance for environmental management and conservation of natural resources in the Western Polissia region, as they provide scientific basis for developing strategies for the conservation and restoration of forest ecosystems, taking into account the role of herbaceous plants in their functioning. [ABSTRACT FROM AUTHOR]

Forests are being threatened worldwide mainly due to the increased demand for wood, 50 % of which is extracted from forests. This is largely because the forest plantations which supply the market grow at a slow rate. Given that, one of the fundamental goals of forestry research is the construction of growth and yield models to be used as a planning tool. In this way, the proposal of this work is to show how, through the modeling and simulation of the growth of a forest stand, the uncertainty of investors is reduced because it allows for the quantification of the production of wood that will be obtained. The study was based on data obtained from inventories conducted between 2012 and 2015 in 31 permanent plots of Gmelina arborea Roxb., located in three municipalities of Tolima: Armero, Coello, and Guamo. Based on the inventory data, three regression models were implemented. These results will be particularly useful for silvicultural management planning as the implemented methodology can be applied in other regions of the world and with other varieties of forest species. As an additional stimulus for investors, the simulation is also able to quantify carbon capture in a technical way to be offered in the carbon bond market

Copyright of Tecnura is the property of Tecnura 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.)

Climate change is affecting forest ecosystems, leading to changes in the distribution of tree species, ecological relationships, and the functioning of forest plant communities. The study aimed to analyse the impact of climate change on forest ecosystems in the Western Polissia of Ukraine. To achieve this goal, in 2005-2023, the State Enterprise "Gorodetske" Research Farm studied the current state of the forest ecosystem, analysed the impact of climate change on it, and conducted detailed forest pathology reconnaissance surveys of the stands. Biodiversity indices were also determined, and the rate of degradation and death of forests was analysed using field data and satellite images. The study determined that climate change in the Western Polissia Region has a significant impact on forest ecosystems, causing changes in forest composition, the spread of diseases and pests, and a decrease in natural biodiversity. The study established that to ensure their sustainable functioning and conservation, it is necessary to take specific measures, including early diagnosis of the state of forests, adaptation to climate change, prevention of forest fires, and use of forest resources based on the principles of sustainable forestry. Implementation of such strategies can contribute to the preservation of ecological diversity and sustainable development in the region for years to come. The results obtained are of great importance for environmental management and conservation of natural resources in the Western Polissia Region, as they provide an opportunity to identify specific strategies and measures for the adaptation of forest ecosystems to climate change and other environmental challenges [ABSTRACT FROM AUTHOR]

The comprehensive impacts of biotic and abiotic factors on the natural regeneration of Abies georgei var. smithii (Abies) forests in Tibet are not thoroughly understood. To address this gap, our study focused on the regeneration densities of Abies seedlings, saplings, and small trees across 21 plots (each 20 m × 20 m) along an elevation gradient from 3730 m to 4330 m in the Sygera Mountains of Southeastern Tibet. We meticulously measured a suite of 11 variables that describe stand structures and ecological conditions. Through analyses using Spearman's correlation analysis, hierarchical partitioning, and multiple linear regression, we identified key ecological drivers for successful Abies regeneration. Our results highlighted a peak in the abundance of seedlings, saplings, and small trees at an elevation of 3930 m. As the elevation rose from 3730 m to 4330 m, we observed an initial increase followed by a decrease in canopy cover (canopy), mother tree density (MotherT), 1000-seed weight (SeedW), litter thickness (LitterT), moss cover (MossC), moss thickness (MossT), soil moisture (SM), and soil bulk density, while mean annual temperature and soil depth to permafrost consistently decreased. The critical ecological drivers for Abies natural regeneration were identified as follows: MossT was pivotal for seedling density; canopy and MossC were influential for sapling density, and MotherT was the main factor affecting the density of small trees. This study suggests that a high density of mother trees and a thick and highly covered layer of moss are conducive to the natural regeneration of Abies in the Sygera Mountains. Understanding the current status of regeneration is vital for informing conservation and management strategies for Abies forests in Tibet. [ABSTRACT FROM AUTHOR]

Litterfall is a link in the energy flow and material cycling of ecosystems, which maintain the primary productivity of forests. However, there is no consensus regarding the factors driving for the litterfall biomass dynamics because of the high spatial–temporal heterogeneity. Herein, we investigated and compared the stand litter biomass, litterfall biomass, including its components in the pure Robinia pseudoacacia forest (RL), pure Platycladus orientalis forest (PL), and mixed forest of Robinia pseudoacacia and Platycladus orientalis (ML) from 2020 to 2022 in the gully erosion area of the Loess Plateau. Correlation and multiple regression analyses were used to study the relationships among the amount of stand litter, litterfall biomass, and seasonal temperature and precipitation. Significant variation was found in the seasonal and annual litterfall biomass of the three types of forest stands. Annual stand litter biomass was in the order PL > RL > ML, whereas the annual litterfall biomass was in the order RL > ML > PL. The seasonal dynamics of litterfall biomass of twigs, leaf and fruits exhibited a ‘unimodal pattern’ with a peak in October. Annual leaf litterfall biomass formed, the main body of litter in all the components, accounting for 57.14–67.05 % of the total litterfall biomass. The correlation and regression analysis results showed that the stand litter biomass was primarily affected by the average temperature. Total litterfall biomass and twigs, leaf, and fruits were significantly affected by the precipitation and the maximum temperature, however, flower litterfall biomass was mainly affected by the average temperature. Overall, our results indicated that temperature plays a key role in the climatic factors affecting forest litterfall processes, while different climatic conditions and biological characteristics probably caused the differences in litterfall biomass. In the long term, temperature will potentially play a leading role in altering carbon storage and nutrient cycling as the climate warms.

This study investigates the temporal changes in species richness, composition, and diversity in forest stands spanning a 36-year period in the Western Himalaya. Four forest stands (subtropical Sal-forest, subtropical Chir-pine forest, temperate Banj-oak forest, and temperate Mixed-oak Forest) studied in 1980–1981 were resurveyed using similar methods. Over the past 36 years, 19 new species have been recorded in the four stands; eight species planted and eleven species naturally introduced. Dominant species continue to dominate in the forest stands. However, their contribution to the total tree density has decreased over the year. Species diversity, richness, and evenness increased in all forests except the Sal stand. Three species were newly introduced in the Sal stand, seven in the Chir-pine stand, eight in the Banj-oak stand, and seven in the Mixed-oak stand. The highest similarity in species composition was observed in the Sal stand (59 %), followed by the mixed-oak stand (57 %), Chir-pine stand (50 %), and Banj-oak stand (47 %). The results indicate an increase in tree density across all sites, with the Mixed-oak forest exhibiting the highest increase in tree density due to least biotic pressure. The findings of this study, based on two-time composition datasets, provide valuable insights into forest dynamics, supporting biodiversity conservation and management planning.

The study showed a correlation between the intensity of sap release by birch trees and the trunk diameter, degree of crown development, and tree age. In addition to the characteristics of trees, sap release intensity also depended on weather conditions and tapping methods. The study object was a mature birch stand with blueberry ground cover (Kirishi forestry unit of the Leningrad region, Russia). The composition of the stand consisted of birch (65 %), spruce (21 %), aspen (8 %), alder (3 %), elm (2 %), and maple (1 %); the basal area was 0.6. The projective cover was 0.73. The average age, diameter and height were 76 yrs, 25.0 cm and 24.3 m, respectively. Tapping was carried out by the closed method. The tapping channels were 30–40 cm above the root neck. The intensity of sap release was found to depend on the number of channels and their location. The maximum intensity of sap release from one tapping channel was 285 mL/h, depending on the trunk diameter and tree age. The intensity of sap release varied throughout the day: it increased in the morning and early afternoon (until 1–2 pm), and decreased in the late afternoon. At night, sap release intensity was the lowest, or it stopped completely regardless of the tree's age, degree of crown development, and trunk diameter. At the average daily temperature between +3 and +6 °С in moky weather, each tree produced 0.54–1.37 L of sap per day, and at a higher temperature in sunny weather, 2.50–6.22 L per day. The higher the air and soil temperatures, the more intense the sap release. At the air temperature of –3.0 °С, the sap freezes. When the average daily air temperature stays above +10.0 °С for several days, the sap begins to ferment. For citation: Gryazkin A.V., Danilov D.A., Zaytsev D.A., Hoang Minh Anh, Thanh Tran Trung. Regulation of Sap Release when Tapping Betula pendula Roth. Lesnoy Zhurnal = Russian Forestry Journal, 2023, no. 4, pp. 180–189. (In Russ.). https://doi.org/10.37482/0536-1036-2023-4-180-189

The accuracy of vegetation indices (VIs) in estimating forest stand age is significantly inadequate due to insufficient consideration of the differences in the physiological functions of forest ecosystems, which limits the accuracy of carbon sink simulation. In this study, remote sensing inversion and mapping of forest stand age were carried out on the Loess Plateau under consideration of the remote sensing mechanism of VIs and the physiological function and canopy structure of the forest using multiple linear regression (MLR) and random forest (RF) models. The main conclusions are as follows: (1) The canopy reflectance of different forest stands has a significant change pattern, and the older the forest stands, the lower the NIR reflectance. The relationship between forest stands and red edge is the most significant, and r is 0.53, and the relationship between Simple Ratio Index (SR), near-infrared reflectance of vegetation (NIRv), normalized difference vegetation index (NDVI), Global Vegetation Index and forest stands is more nonlinear than linear. (2) Principal component analysis (PCA) of canopy spectral information shows that SR, NDVI and red edge (B5) could explain 98% of all spectral information. SR, NDVI and red edge (B5) were used to construct a multiple linear regression model and random forest (RF) algorithm model, and RF has high estimation accuracy (R2 = 0.63). (3) The accuracy of the model was evaluated using reference data, and it was found that the accuracy of the RF model (R2 = 0.63) was higher than that of the linear regression model (R2 = 0.61), but both models underestimated the forest stand age when the forest stand age was greater than 50a, which may be caused by the saturation of the reflectance of the old forest canopy. The RF model was used to generate the dataset of forest stand information in the Loess Plateau, and it was found that the forest is dominated by young forests (<20a), accounting for 38.26% of the forest area, and the average age of forests in the Loess Plateau is 56.1a. This study not only improves the method of forest stand age estimation, but also provides data support for vegetation construction in the Loess Plateau. [ABSTRACT FROM AUTHOR]

Simple Summary: Insects are a significant cause of harm and mortality to forest areas. In particular, the forests of Siberia, covering over 2.4 million square kilometers with a low or non-existent pest insect population, are at high risk. Under such conditions, observing insects from the ground is nearly impossible. Consequently, remote sensing techniques are the sole feasible option. However, many remote indicators only change after significant damage occurs to the stands of trees, making it too late to implement protective measures. The objective of this study was to construct distance indicators that could identify areas where forest stands have lost resistance to attacks by such a dangerous pest of Siberian forests as the Siberian silk moth Dendrolimus sibsiricus Tschetv. To create indicators, it has been suggested that estimations rely on the reaction of stands to weather conditions during the season, instead of absolute values. Such remote indicators were constructible, and these indicators in the areas of future outbreaks had changed already two or three years before the outbreak. Remote sensing data allow the development of complex indicators of forest stands' insect resistance anywhere in the world, thus making it possible to monitor large areas to identify risk of pest outbreaks. The feasibility of risk assessment of a Siberian silk moth (Dendrolimus sibiricus Tschetv.) outbreak was analyzed by means of landscape and weather characteristics and tree condition parameters. Difficulties in detecting forest pest outbreaks (especially in Siberian conditions) are associated with the inability to conduct regular ground surveillance in taiga territories, which generally occupy more than 2 million km2. Our analysis of characteristics of Siberian silk moth outbreak zones under mountainous taiga conditions showed that it is possible to distinguish an altitudinal belt between 400 and 800 m above sea level where an outbreak develops and trees are damaged. It was found that to assess the resistance of forest stands to pest attacks, researchers can employ new parameters: namely, characteristics of a response of remote sensing variables to changes in land surface temperature. Using these parameters, it is possible to identify in advance (2–3 years before an outbreak) forest stands that are not resistant to the pest. Thus, field studies in difficult-to-access taiga forests are not needed to determine these parameters, and hence the task of monitoring outbreaks of forest insects is simplified substantially. [ABSTRACT FROM AUTHOR]

A century and a half ago, in the European part of Russia (Moscow), forest scientists established the first long-term observations of forests, many of which are under observation to the present day. In the twentieth century, climate changes and, due to industrial development, forest areas were under air pollution. Based on observations from 157 sites, this study shows that the growth and density of Scots pine (Pinus sylvestris L.) have decreased by the end of the twentieth century. The environment has changed, and the growth and development of plantations has slowed. Pine yields (− 34% stand volume) and their life expectancy (on average 50 years) have decreased. These changes are critical for forestry and for the management of forests in urban centers. Due to the decline in growth, ecosystem functions by urban forests has decreased. In order to increase the sustainability of urban forests and the provision of ecosystem services, it is preferable to create multi-species stands with a complex structure. [ABSTRACT FROM AUTHOR]

This study analyzed the relationship between characteristics of annual tree ring time series and the intensity of attacks on forest stands by forest insects. Using tenets of the fluctuation–dissipation theorem (which is widely used in physics), time series parameters are proposed that can help to assess the susceptibility of a forest stand to insect pests. The proposed approach was applied to evaluate differences in parameters of tree ring widths among outbreaks of the pine looper, Siberian silk moth, and spongy moth. A comparison of trees characteristics between outbreak locations and undamaged forest stands (control) showed that the tested parameters statistically significantly differed between the outbreak locations and control stands and can be used to assess the risk of pest outbreaks in forest stands. [ABSTRACT FROM AUTHOR]

Yew tree (Taxus baccata L.) is mainly populated in Türkiye, Europe, and Caucasia regions. It has natural anticancer compounds and is a source of raw materials used in modern medicine. The present study aimed to examine the taxol contents of yew trees naturally grown in Marmara and Western Black Sea regions by subjecting needle samples taken from 17 yew populations to extraction and liquid chromatography tandem mass / mass spectrometer system (LC-MS/MS) analysis. It was also examined whether a relationship exists between some stand characteristics and taxoid contents of the needles. From these analyses, the highest taxol contents were found in Bartın-Gölderesi, Yığılca-Kurtkayası, İnebolu-Karagöl, and Yenice-Kızılkaya populations. The statistical analyses showed that there were significant relationships between compound contents and slope, humus content, total nitrogen content (%), and potassium (K). It is recommended to use these derivatives obtained from natural forests in sapling nursing and tissue culture studies, to produce pharmaceutical materials from leaves and protect and improve the current gene sources.

Interactions among neighbouring plants are key determinants of plant growth. To characterise the cumulative effect of all neighbours on the growth of a focal plant, neighbourhoods are often described by 'competition' indices. Common competition indices calculate the summed size of neighbour plants (focal‐independent index [FII]) whilst others include the summed ratio of the neighbour size relative to focal plant size (focal dependent). A frequently overlooked statistical artefact is that focal‐dependent indices (FDIs) may lead to biased estimates of neighbourhood effects on plant growth when growth is size dependent.Here, we conduct a literature search to determine the most common index types used to explain neighbour effects on tree growth. We then assess the ability of two common index types—focal dependent and focal independent—to correctly infer neighbourhood effects in (1) observations of tree growth in an experimental forest in south‐east Tasmania, Australia, and (2) an artificially created dataset where tree growth is unrelated to the neighbourhood.Both indices detected the competitive neighbourhood effect on tree growth observed in our own dataset but differed in their conclusion regarding neighbour effects in the simulated data. Despite the simulated dataset being generated so there was no relationship between tree growth and their neighbourhood, the FDI detected strong, competitive neighbourhood effects when intrinsic growth was incorrectly related to tree size. In contrast, when we considered the FII as the neighbourhood metric, we correctly did not detect any neighbourhood effects in the simulated data regardless of how size‐dependent growth was described.Synthesis. 'Competition' indices are a useful method to characterise the cumulative neighbourhood effect on plant growth; however, we demonstrate that indices which include the size of the focal plant in their calculation can be biased by an inherent relationship between tree growth and initial size. Whilst this bias typically overstates the strength of competition in determining focal tree growth, we show that it can be mitigated by correctly describing intrinsic growth. We discuss the limitations of both index types, provide recommendations for performing statistical modelling and outline how to check for accurate neighbour inference. [ABSTRACT FROM AUTHOR]

Yew tree (Taxus baccata L.) is mainly populated in Türkiye, Europe, and Caucasia regions. It has natural anticancer compounds and is a source of raw materials used in modern medicine. The present study aimed to examine the taxol contents of yew trees naturally grown in Marmara and Western Black Sea regions by subjecting needle samples taken from 17 yew populations to extraction and liquid chromatography tandem mass / mass spectrometer system (LC-MS/MS) analysis. It was also examined whether a relationship exists between some stand characteristics and taxoid contents of the needles. From these analyses, the highest taxol contents were found in Bartın-Gölderesi, Yığılca-Kurtkayası, İnebolu-Karagöl, and Yenice-Kızılkaya populations. The statistical analyses showed that there were significant relationships between compound contents and slope, humus content, total nitrogen content (%), and potassium (K). It is recommended to use these derivatives obtained from natural forests in sapling nursing and tissue culture studies, to produce pharmaceutical materials from leaves and protect and improve the current gene sources. [ABSTRACT FROM AUTHOR]

Soil moisture (SM) and temperature (ST) are critical factors in forest eco-hydrological research. In this study, we investigated the inter- and intra-annual changes in SM and ST profiles in a mixed Mediterranean maquis forest stand together with soil and meteorological parameters. Hourly data from three field measurements points at four depths (−5, −20, −40 and −70 cm) for 6 years were interpolated using the kriging method to produce annual SM and ST profiles. The results indicate that air temperature highly affects the upper 5 cm of the mineral soil. In general, it increases with depth in winter at an average rate of 0.036 °C/cm and decreases in summer (0.035 °C/cm), presenting higher values compared to air temperature from April to August and lower ones during the rest of the period. Precipitation is the main factor driving SM variations up to a superficial soil depth of 40 cm. The upper soil layer (0–40 cm) infiltrates water faster and presents high SM variability, especially in monthly and seasonal (year to year) time steps. The maquis forest stands are likely to be strongly affected by climate change, therefore the results of this study could be useful in hydrological and climate change studies focused on maquis vegetation water management. [ABSTRACT FROM AUTHOR]

This study aims to determine how plant diversity changes at the alpha and gamma levels depending on stand type. Also, it tries to understand how plant diversity changes temporally and with relation to aspects during a given vegetation period. Sample areas were selected from pure Scots Pine stands with full canopy cover (70 - 100 %) and in different development stages (a, b, c, d) spread out within the Bolu Aladağ region of Türkiye. Field studies were carried out in 2016 from June-September. Sample stands were selected to cover two main aspects, north and south. The study was carried out by analyzing two repetitive and 10 quadrate samples in each stand. A total of 640 quadrate samples were analyzed, and the different plants were counted. In the study area, a total of 160 taxa were identified at the DUOF Herbarium. It was determined that while the stand type did not have a significant effect on taxon diversity, the effect of aspect and observation period was statistically significant (P < 0.05). Shannon index value was between 3.13 and 3.72 among the stands' different development stages, with the highest values found in the young stands. Diversity was higher on Northern aspects than Southern and rose and fell throughout the observation period with the highest values in June and August. Interestingly, while there was no significant effect of stand development stages on taxon diversity, a significant but low correlation has been found between stand diameter and evenness. [ABSTRACT FROM AUTHOR]

Copyright of ACTA Scientiarum Polonorum Silvarum Colendarum Ratio et Industria Lignaria is the property of Poznan University of Life Sciences Press 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.)

Ice storms, as important sources of frequent and injurious disturbances, drive forest dynamics in the Northern Hemisphere. However, stand-level differential vulnerability to ice storms and the associated factors that predispose forest stands remain unclear. This is particularly concerning in the subtropics where the frequency of ice storms is predicted to increase with global warming. Here we assessed how the impact on three forest stands (early and late secondary-growth forests, and old-growth forests) differed after an extreme ice storm during 20-21 March 2022, and identified the abiotic and biotic factors that determine the damage intensity in the Shennongjia World Natural Heritage Site, a biodiversity conservation hotspot in central China. We found a stand-specific 'middomain effect' where the late secondary-growth forest sustained the most severe damage, the early secondarygrowth forest sustained the least, and the old-growth forest suffered an intermediate amount. 'Crown broken' was the most severe damage type across all three forest stands, although the proportion of 'branch broken' was also high in the old-growth forest. Topography played a significant role in determining the vulnerability of the early secondary-growth forest to severe ice storms whereas the forest structure and composition were important factors in explaining the damage rates in the old-growth forest, although they differed among the damage categories. In contrast, topography, forest structure and composition generally explain the intensity of damage in the late secondary-growth forests. Our results highlight that, in subtropical forests, the intensity of damage caused by severe ice storms and related determining factors are stand-level dependent. We also suggest exploring potential management strategies (e.g., slow-growing hardwood species that can resist storms should be the main species for reforestation in early secondary-growth forests) to mitigate the risk of future severe ice storms, as well as other wind-related climatic extremes. [ABSTRACT FROM AUTHOR]

The feasibility of risk assessment of a Siberian silk moth (Dendrolimus sibiricus Tschetv.) outbreak was analyzed by means of landscape and weather characteristics and tree condition parameters. Difficulties in detecting forest pest outbreaks (especially in Siberian conditions) are associated with the inability to conduct regular ground surveillance in taiga territories, which generally occupy more than 2 million km2. Our analysis of characteristics of Siberian silk moth outbreak zones under mountainous taiga conditions showed that it is possible to distinguish an altitudinal belt between 400 and 800 m above sea level where an outbreak develops and trees are damaged. It was found that to assess the resistance of forest stands to pest attacks, researchers can employ new parameters: namely, characteristics of a response of remote sensing variables to changes in land surface temperature. Using these parameters, it is possible to identify in advance (2–3 years before an outbreak) forest stands that are not resistant to the pest. Thus, field studies in difficult-to-access taiga forests are not needed to determine these parameters, and hence the task of monitoring outbreaks of forest insects is simplified substantially.

The accuracy of vegetation indices (VIs) in estimating forest stand age is significantly inadequate due to insufficient consideration of the differences in the physiological functions of forest ecosystems, which limits the accuracy of carbon sink simulation. In this study, remote sensing inversion and mapping of forest stand age were carried out on the Loess Plateau under consideration of the remote sensing mechanism of VIs and the physiological function and canopy structure of the forest using multiple linear regression (MLR) and random forest (RF) models. The main conclusions are as follows: (1) The canopy reflectance of different forest stands has a significant change pattern, and the older the forest stands, the lower the NIR reflectance. The relationship between forest stands and red edge is the most significant, and r is 0.53, and the relationship between Simple Ratio Index (SR), near-infrared reflectance of vegetation (NIRv), normalized difference vegetation index (NDVI), Global Vegetation Index and forest stands is more nonlinear than linear. (2) Principal component analysis (PCA) of canopy spectral information shows that SR, NDVI and red edge (B5) could explain 98% of all spectral information. SR, NDVI and red edge (B5) were used to construct a multiple linear regression model and random forest (RF) algorithm model, and RF has high estimation accuracy (R2 = 0.63). (3) The accuracy of the model was evaluated using reference data, and it was found that the accuracy of the RF model (R2 = 0.63) was higher than that of the linear regression model (R2 = 0.61), but both models underestimated the forest stand age when the forest stand age was greater than 50a, which may be caused by the saturation of the reflectance of the old forest canopy. The RF model was used to generate the dataset of forest stand information in the Loess Plateau, and it was found that the forest is dominated by young forests (

Stem‐mapped forest stands offer important opportunities for investigating the fine‐scale spatial processes occurring in forest ecosystems. These stands are areas of the forest where the precise locations and repeated size measurements of each tree are recorded, thereby enabling the calculation of spatially‐explicit metrics of individual growth rates and of the entire tree community. The most common use of these datasets is to investigate the drivers of variation in forest processes by modeling tree growth rate or mortality as a function of these neighborhood metrics. However, neighborhood metrics could also serve as important covariates of many other spatially variable forest processes, including seedling recruitment, herbivory and soil microbial community composition. Widespread use of stem‐mapped forest stand datasets is currently hampered by the lack of standardized, efficient and easy‐to‐use tools to calculate tree dynamics (e.g. growth, mortality) and the neighborhood metrics that impact them. We present the forestexplorR package that facilitates the munging, exploration, visualization and analysis of stem‐mapped forest stands. By providing flexible, user‐friendly functions that calculate neighborhood metrics and implement a recently‐developed rapid‐fitting tree growth and mortality model, forestexplorR broadens the accessibility of stem‐mapped forest stand data. We demonstrate the functionality of forestexplorR by using it to investigate how the species identity of neighboring trees influences the growth rates of three common tree species in Mt Rainier National Park, WA, USA. forestexplorR is designed to facilitate researchers to incorporate spatially‐explicit descriptions of tree communities in their studies and we expect this increased diversity of contributors to develop exciting new ways of using stem‐mapped forest stand data. [ABSTRACT FROM AUTHOR]

The aim of the work was to quantify the mass of logging residues (branches and tops; t yr−1 dry matter, DM) for energy generation starting from Forest Management Plans (FMP) data. The methodology was applied to public stands of an Italian district (area: 3.60 × 104 ha; period: 2009–2018). Compared to the previous preliminary analysis, the potentially available residues were computed considering forest accessibility and road traversability, by combining FMPs data with a geographic information system (GIS). New issues that were assessed here were: (i) representation of stands consisting of multiple disconnected parts; (ii) calculation of producible residues by using different values of biomass expansion factors (Scenario 1, S1; Scenario 2, S2). The potentially available residues computed for the analyzed period were used to quantify the current sustainable supply. Then, the potentially generated heat (thermal energy, TE; GJ yr−1) and electricity (EE; GJ yr−1), and the potentially avoided CO2 emissions into the atmosphere (EM; t yr−1 CO2) related to the final combustion process were computed by assuming that the current supply of residues was used as woodchips in a local centralized heating plant currently operating. For both S1 and S2, the large difference between the potentially producible and the potentially available residues demonstrated that geodata are essential for reliable estimations. Moreover, as the required information for the GIS analysis can be easily found in databases made available by forestry authorities, the proposed approach can be applied also to other areas; this could be helpful to support local decision-makers in defining sustainable practices for residues recovery. [ABSTRACT FROM AUTHOR]

Thinning is a necessary and complex forestry activity. The complexity increases due to theoretical disagreements, contradictory recommendations, and errors of modern practice, which require confirmation through long-time experiments. This article presents a summary of experimental results from plantations established 20–30 years ago and explains concepts of the theory, methods, and regime of thinning in permanent sample plots of pine stands in Gatchinsky forest of the Leningrad region. The research results allow for the clarification of growth patterns and age dynamics of pine stands subject to heavy, low thinning, as well as the results of applying the crown (high) thinning technique and a mixed treatment. A combined thinning and fertilization could improve wood quality and yield compared to conventional methods. Of particular scientific importance is the analysis of change in tree diameter classes during growth and after thinning. The research results allow for optimizing the treatment regime in pine plantations and reducing labor intensity by increasing the intensity of thinning and reducing the number of techniques. [ABSTRACT FROM AUTHOR]

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Soil moisture (SM) and temperature (ST) are critical factors in forest eco-hydrological research. In this study, we investigated the inter- and intra-annual changes in SM and ST profiles in a mixed Mediterranean maquis forest stand together with soil and meteorological parameters. Hourly data from three field measurements points at four depths (−5, −20, −40 and −70 cm) for 6 years were interpolated using the kriging method to produce annual SM and ST profiles. The results indicate that air temperature highly affects the upper 5 cm of the mineral soil. In general, it increases with depth in winter at an average rate of 0.036 °C/cm and decreases in summer (0.035 °C/cm), presenting higher values compared to air temperature from April to August and lower ones during the rest of the period. Precipitation is the main factor driving SM variations up to a superficial soil depth of 40 cm. The upper soil layer (0–40 cm) infiltrates water faster and presents high SM variability, especially in monthly and seasonal (year to year) time steps. The maquis forest stands are likely to be strongly affected by climate change, therefore the results of this study could be useful in hydrological and climate change studies focused on maquis vegetation water management.

Thinning treatment is a necessary and complex forestry activity. The experimental results from plantations established 20-30 years ago and explains some concepts of the theory, practice, methods, and regime of thinning on the permanent sample plots of pine stands in Gatchinsky forestry of the Leningrad region were shown in this article. Choosing the right thinning method allows to optimize the yield, productivity and mortality of the stand. On the other hand, we observed improved merchantability of the stand, reduced time for forestation, and simplified thinning programs. Crown thinning is a less preferred method than bottom thinning, as it leads to a deterioration in the quality of trees and an increase in their mortality. The inexpediency of preliminary thinning of trees has been established. Tree thinning results in an improvement in the quality of the remaining stand, as nutrient utilization is greatly increased. Tree thinning must necessarily be combined with fertilization. Thinning without fertilization and fertilization without thinning show the worst results. In general, findings of this article can be used to improve approach of thinning treatment in the Leningrad or other regions in the North of Russian Federation. [ABSTRACT FROM AUTHOR]

The non-destructive method—using allometric models—of forest biomass estimation is one of the most effective and efficient approaches, however, there is an ambiguity to choose a particular type of model for predicting biomass. The study aimed to compare 11 different allometric models generally employing in Nepal using empirical data of 4,942 individual standing trees of 36 species from 134 sample plots considering 20 environmental variables from five community forests belonging in two ecological regions. Akaike Information Criterion (AIC), coefficient of determination (R2), and root mean square error (RMSE) of each model was estimated and compared. The biomass density predicted by different models differed significantly (p < 0.05) despite employing the same data set. A variation on the estimated biomass density differed from 4% (M4 and M11) to 364% (M5 and M10) among the models considered for the study. Results show that no models have relatively higher R2 (less than 0.61), lower AIC (more than 813) and RMSE (more than 16). This indicates that hardly any existing general models in Nepal estimates actual biomass of the forest ecosystems. The results suggest that a universal model may not be applicable for the given condition, indicating an imminent need for the development of allometric models for biomass prediction based on species type, ecological regions, degree of disturbances, considering diversity variables, and ground and crown cover scenario of the forests. Such models require regular calibration for validity, reliability, credibility, and integrity of forest data management. The results would be a reference for policymaker and forest conservationists to select appropriate allometric equation and, thereby accurate prediction of biomass and timber volume, which in turn, will have good value for REDD + (carbon payment from forestry sector) and other economic conversions of the forests' biomass. [ABSTRACT FROM AUTHOR]

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Models for carbon (C) stock assessment are widely applied in forest science, and mainly differ according to the scale of application, the required data, and the objectives for their implementation. This work presents the methodology implemented into the second version of an empirical model, WOody biomass and Carbon ASsessment (WOCAS v2), that uses the data of forest management plans (FMP) to calculate the mass of wood (t∙year−1 of dry matter, DM) and C (t∙year−1 C) at the stand level and from the year in which the FMPs came into force until a predefined reference year, for an Italian Case Study Area of Central Alps. The mass of wood and C are computed for (i) aboveground wood biomass (AWB), (ii) belowground wood biomass (BWB), and (iii) dead organic matter (DOM; i.e., dead wood and litter) according to the 2006 IPCC Guidelines. WOCAS v2 was tested for the first time for 2019 public forest stands (3.67 × 104 ha) of Valle Camonica for the period 1984–2018. Results showed that, in 2018 and at the landscape level, the total living wood biomass (TLB; AWB + BWB) reached 5.35∙106 t DM. TLB yield (t·ha−1·year−1 DM) ranged from 44.72 ± 44.42 t·ha−1·year−1 DM (1984) to 145.49 ± 70.76 t·ha−1·year−1 DM (2018). In the same year, DOM amounted to 6.12∙105 t DM, ranging from 8.28 ± 7.79 t·ha−1·year−1 DM (1989) to 17.11 ± 12.03 t·ha−1·year−1 DM (2015). The total weighted C yield, computed as the sum of C yield in AWB, BWB, and DOM of each stand, ranged from 26.63 ± 26.80 t∙ha−1∙year−1 C (1984) to 80.28 ± 41.32 t∙ha−1∙year−1 C (2018). The results demonstrated that FMPs data can be useful in estimating wood and C mass at the stand level and their variation over space and time for AWB as well as for BWB and DOM, which are not considered in the FMPs. This can represent a starting point for defining sustainable forest management policies and practices to improve forest vitality and conservation in compatibility with ecosystem services provision. Moreover, as the model is based on a standardized methodology it can be applied in any other forest area where the same input data are made available; this may constitute the basis for further applications on a broader scale. [ABSTRACT FROM AUTHOR]

We present the results of an analysis of forest stand dynamics on a permanent trial plot in the Sikhote-Alin biosphere reserve (Primorsky Krai). The materials of revisions for the period 1958–2019 were used, where the plot was established on young growth forest, which emerged after a strong wildfire in the 1920s succeeding in the place of which a highly productive pine trees. The last inventory (2019) reflects the state of the plantation after strong windfall due to the typhoon Lyonrock in 2016: the growing stock of the stand decreased from 254 to 180 m³ • ha–1. Currently the total average (stock) increment is 4.7– 8.4 m³ • ha–1 • year–1, losses due to windfall varied between 1.4–3.0 m³ • ha–1 • year–1 and were 12.0 m³ • ha–1 • year–1 for the last observation period. Sufficient seedlings for a further recovery of the main species (Korean pine Pinus koraiensis Siebold & Zucc.) are present only at sites without disturbance by windfall (up to five thousand plants ha–1). Using regional allometric equations, the above-ground biomass of trees and stands was determined for each inventory period, which made it possible to estimate the net growth of the biomass at 1.31 t C • ha–1 • year–1, which is more than two times higher than the average specific carbon stock in the biomass of the forests of Terney forest district estimated by the ROBUL system. Windfall decreased the biomass stock in the forest stand from 89 to 60 t C • ha–1. The stand developed following a long-term regeneration scenario, but further stand dynamics are unpredictable due to the instability of the rest of the stand.

Background Since the mid-2000s, long-term monitoring of various components of natural ecosystems under conditions of industrial pollution has been carried out in the Southern Urals. As a part of these monitoring programmes, the data on various components of biota in different biotopes, collected with different methods and in different time intervals, continue to be gathered. In addition, data collected through these monitoring programmes can also be used to study the local biodiversity of non-polluted areas. In 2012, in the vicinity of the Karabash Copper Smelter, a study of communities of small mammals was carried out, considering the heterogeneity of their habitats. Within the framework of this project, we presented a detailed description of the state of woody vegetation in the study area. New information The dataset (available from the GBIF network at https://www.gbif.org/dataset/61384edd-2d0a-437b-8cf0-ff4d2dfcc0da) includes the results of an assessment of the woody vegetation biomass at seven habitats (pine, birch and floodplain forests, reed swamp, sparse birch stand, marshy meadow and dump of household waste) of areas with different levels of industrial pollution in the vicinities of the Karabash, the Southern Urals. Karabash Copper Smelter (KCS) is one of Russia's most significant point polluters; the main components of its emissions are heavy metals, dust and sulphur dioxide. Parameters of woody vegetation (diameter at breast height, diameter at root collar level and biomass) were estimated for seven forest elements (forest stand, subcanopy (undergrowth and underwood), half-dead tree of a forest stand and four types of coarse woody debris (downed bole, fragment of downed bole, standing dead tree and stump)) at 41 sampling plots (20 at unpolluted and 21 at polluted areas) and 165 subplots (81 and 84, respectively). The dataset includes 411 sampling events (estimation events of the forest elements at sampling plots and subplots), corresponding to 5786 occurrences (estimations of the woody vegetation components) observed during July 2012. For most woody vegetation components (72%), an estimate of the above-ground phytomass is given. For each sampling event, information on the presence or absence of woody vegetation species at the considered habitats is provided (a total of 1479 occurrences with status "absent"). The dataset can be used for environmental monitoring, sustainable forest management, modelling forest productivity considering global changes, studying the structure and biodiversity of forest cover and assessing forests' carbon-sequestration capacity. In addition, the dataset provides information about different forest ecosystems under the influence of strong industrial pollution. [ABSTRACT FROM AUTHOR]

The first aim of the study was to present the methodology applied by the model WOody biomass and Carbon ASsessment to compute the past potentially available residues (RA; branches and tops only; t·yr−1 of dry matter, DM), potentially generated heat and electricity (TE, EE, respectively; GJ·yr−1) and potentially avoided CO2 emissions into the atmosphere (EM; t·yr−1 CO2) for the final combustion process. The available residues are computed at the forest stand level through a recovery rate based on six technical parameters. The methodology was applied to the public stands of Valle Camonica district (Italy) (total area: 3.67·104 ha; period: 1984–2016). The mass of residues calculated for that period was used to estimate the current supply, i.e. 2.15·103 ± 6.04·102 t·yr−1 DM. By assuming that this mass was used in an Organic Rankine Cycle (ORC) unit of a local centralized heating plant, TE = 2.06·104 ÷ 2.41·104 GJ·yr−1 and EE = 5.08·103 ÷ 5.95·103 GJ·yr−1. By assuming that: (i) heat generated by the ORC replaced heat produced by conventional natural gas-based plants; (ii) electricity generated by the ORC replaced electricity generated by Italian natural gas-based plants-mix (combined heat and electricity production) EM = 1.85·103 ÷ 2.17·103 t·yr−1 CO2. [ABSTRACT FROM AUTHOR]

• Significant variation was found in the seasonal and annual litterfall biomass of the three types of forest stands. • The seasonal dynamics of litterfall biomass of twigs, leaf and fruits exhibited a 'unimodal pattern' with a peak in October. • Temperature played a key role in the climatic factors affecting forest litterfall processes. Litterfall is a link in the energy flow and material cycling of ecosystems, which maintain the primary productivity of forests. However, there is no consensus regarding the factors driving for the litterfall biomass dynamics because of the high spatial–temporal heterogeneity. Herein, we investigated and compared the stand litter biomass, litterfall biomass, including its components in the pure Robinia pseudoacacia forest (RL), pure Platycladus orientalis forest (PL), and mixed forest of Robinia pseudoacacia and Platycladus orientalis (ML) from 2020 to 2022 in the gully erosion area of the Loess Plateau. Correlation and multiple regression analyses were used to study the relationships among the amount of stand litter, litterfall biomass, and seasonal temperature and precipitation. Significant variation was found in the seasonal and annual litterfall biomass of the three types of forest stands. Annual stand litter biomass was in the order PL > RL > ML, whereas the annual litterfall biomass was in the order RL > ML > PL. The seasonal dynamics of litterfall biomass of twigs, leaf and fruits exhibited a 'unimodal pattern' with a peak in October. Annual leaf litterfall biomass formed, the main body of litter in all the components, accounting for 57.14–67.05 % of the total litterfall biomass. The correlation and regression analysis results showed that the stand litter biomass was primarily affected by the average temperature. Total litterfall biomass and twigs, leaf, and fruits were significantly affected by the precipitation and the maximum temperature, however, flower litterfall biomass was mainly affected by the average temperature. Overall, our results indicated that temperature plays a key role in the climatic factors affecting forest litterfall processes, while different climatic conditions and biological characteristics probably caused the differences in litterfall biomass. In the long term, temperature will potentially play a leading role in altering carbon storage and nutrient cycling as the climate warms. [ABSTRACT FROM AUTHOR]

The concept of forest as the unity of growing stock (living tree component), climate and soil, that is, as ecosystems, was first defined by A.A. Krüdener. The scientist has developed a classification of forests according to the fertility of the soils on which they grow, in the coordinates of their provision with nutrients and moisture. A.A. Krüdener proposed the first ecological classification of forests of European Russia on the principle of zoning its territory according to the main climatic indicators, with the subsequent division of forests within climatic zones and regions into types of stands according to the peculiarities of the petrographic composition and water regime of soils. A.A. Krüdener, like G.F. Morozov, assigned the decisive role to the soil conditions in the formation of types of stands in the midst of homogeneous climatic areas, emphasizing that the main factor is not the soil itself as such, but the soil as a substrate, as a medium for plant growth. The scientist, in the process of intensive study of soils of different types of forest, revealed a close relationship of the nature of forest vegetation, not with the genetic types of soils, but with their fertility, and with their forest growth potential. In so doing, to assess soil fertility, A.A. Krüdener used a new approach - the phytoindication method, that is, the vegetation, its composition and productivity were accepted as a criterion for the quality of soils. In developing the classification of forests, A.A. Krüdener clearly adhered to the coordinate principle of soil quality assessment by the two main components of their fertility - the supply of nutrition and moisture, which became the determining factor in all subsequent classifications of the forest typology of the G.F. Morozov school. The total measure of fertility of the environment is the amount, proportion and distribution by seasons of limited environmental resources - heat, moisture and nutrition. Forest typological classification models are constructed in the coordinates of these resources – the climate grid in the coordinates of heat and atmospheric humidity, edaphic – in the coordinates of nutrition and soil moisture. Therefore, they can be used not only to classify forests, but also nature in general. The article also describes the main achievements of the Ukrainian Ecological School of Forest Typology formed on these principles. The existing shortcomings and issues that need to be further addressed are noted.

Despite numerous studies there are still uncertainties regarding regeneration strategies that are optimal for productivity and profitability. Thus the aim of this study was to establish effects of three regeneration methods (planting, direct seeding and natural regeneration) on the production and profitability of Scots pine (Pinus sylvestris L.) stands in southern Sweden. Long-term stand development was simulated, with the StandWise application of the Heureka decision support system, starting from short-term regeneration outcomes observed in several field experiments at sites with relatively high productivity (H100 site indices, i.e. heights of dominant pines at 100 years: 27–30 m). Financial and production results of each approach were assessed in terms of Land Expectation Value (LEV) and Mean Annual Increment (MAI), respectively, across a whole rotation. Planting on clear-cuts with 1600–3265 seedlings per hectare resulted in the highest profitability and production, whereas high-density planting (10,000 seedlings per hectare) resulted in negative LEV. However, sensitivity analysis showed that the results depended on the interest rate. Retention of seed-trees incurred additional costs relative to single-operation clear felling. In contrast, retention of shelter-trees had good financial results (at 0% and 2.5% interest rate), although they depended on the site index and average tree size. [ABSTRACT FROM AUTHOR]

Cuvier's gazelle (Gazella cuvieri) was reintroduced in Tergou reserve (TR) in 2018–2019 to help restore its population at the Moroccan Central Plateau. A study on browsing trees and shrubs was conducted in this reserve to identify (i) the seasonal pattern of this activity and (ii) the most solicited tree and shrub species. Here, we used six random 500-m transects to collect, each month and at each transect, the number of fresh browsing traces of each encountered tree and shrub species. We used principal component analysis (PCA) and linear regression model (LM) to test seasonal variation of the composition of trees and shrubs browsed. Our results showed that, in this reserve, Olea europaea, Quercus ilex, Cistus salviifolius, and Cistus creticus are mostly browsed during winter, whereas Tetraclinis articulata and Ruta angustifolia are mainly used during spring. This information is useful to the managers of the TR not only to consider the importance of the aforementioned trees and shrubs for reintroduced gazelles but also to take the necessary measures so that the forest stand of this reserve is maintained at an appropriate level. Thus, the pursuit of monitoring is necessary to understand the bio-ecology of this semi-captive population more deeply. For this reason, the TR remains a useful and appropriate reference framework offering the opportunity for consolidating and improving the knowledge on this vulnerable mammal species in the view of a future successful release in the wild. [ABSTRACT FROM AUTHOR]

Populations of the forest dormouse (Dryomys nitedula Pallas, 1778) are widespread across Europe and south-western Asia, but their ability to survive in a mosaic of forest stands is insufficient, and they are extremely scarce in Russia. In 2013–2019, we studied the taxonomic and ecological composition of forest stands in the Middle Volga. Forest dormice were recorded in 30% of the investigated forest stands, being 4–70 ha in size. Habitats of the forest dormouse were characterized by higher species richness of woody plants, by presence of woody plant species with juicy fruits, dry fruits and seeds, and by dominance of shrubs (52.1% of all plant species). Out of 98 species of gymnosperms and angiosperms, species belonging to families Rosaceae and Salicaceae dominated. Out of the 98 registered plants, 43 species formed juicy and 55 species formed dry fruits and seeds, including Quercus robur L., Corylus avellana L., Tilia cordata Mill. Alien plant species (26.4%) had no impact on the habitat attractivity. Favorable conditions for existence the forest dormouse in the Middle Volga are secured by high diversity of woody plants in the forest stands, providing these animals with plant-based food. Usage of only optimal habitats resulted in patchy distribution of the species. [ABSTRACT FROM AUTHOR]

This study evaluates soil hydraulic conductivity (SHC) and water repellency (SWR) in three mixed forest stands in relation to site plant and soil characteristics. The studied forest stands were (i) Pinus nigra Arn. ssp salzmannii and Quercus ilex; (ii) P. nigra Arn. ssp salzmannii and Juniperus Thurifera; (iii) P. nigra Arn. ssp salzmannii, Q. ilex and Juniperus Thurifera. A 100‐ to 120‐year‐old unmanaged P. nigra Arn. ssp salzmannii stand was also chosen as control. The hydrological variables, physico‐chemical properties and surface characteristics of soils were surveyed. Soil water infiltration was higher in Pinus + Juniper mixed forest and Pinus + Quercus + Juniper mixed forests compared to unmanaged Pinus stands. None of the studied forest stands shows a high level of repellency. Only a slight repellency (in unmanaged stands dominated by pines) or moderate repellency (in soils with Pinus and Juniper) were evident, while soils with Pinus and Quercus were not repellent. Differences in SHC among the forest species were driven primarily by the soil texture and associated structure and secondarily by soil organic matter and associated SWR. The latter was mainly due to organic matter content of the soils, but others of the soil physico‐chemical properties and covers analysed were found as influencing parameters to discriminate SWR among mono‐specific and mixed forest stands. While SHC at the studied forest stands could be predicted using organic matter as well as sand and clay contents of the soil, SWR is the result of several hydrological and physico‐chemical parameters. [ABSTRACT FROM AUTHOR]

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This study was carried out to evaluate gap characteristics and gapmakers for different development stages of an oriental beech forest in northern Iran. Development stages of 1 ha square-shaped mosaic patches were identified using 100 × 100 m sampling grid and all gaps within these mosaics were recorded. Gap areas were calculated and classified into four classes and gapmakers were counted and classified into 4 decay and 4 diameter classes as well. Results showed that gaps comprised 13.7, 9.1 and 17.6% of the study area in initial, optimal and decay stages, respectively. There was a significant difference between development stages with respect to gap size and the highest amount was observed in decay stage. Medium-sized gaps were the most frequent in all three stages. Frequency distribution of gapmakers varied among development stages. Our findings revealed that 200-500 m2 is the most preferable gap size for close-to-nature silvicultural approaches in Hyrcanian beech forests. To achieve this gap size 1-2 trees should be marked for harvesting operations.

Copyright of Forest Research is the property of Forest Research Editorial Office 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.)