Growth Of Stands Research Articles

A perspective on the need for integrated frameworks linking species distribution and dynamic forest landscape models across spatial scales

Climate change significantly alters species distributions. Numerous studies project the future distribution of species using Species Distribution models (SDMs), most often using coarse resolutions. Working at coarse resolutions in forest ecosystems fails to capture landscape-level dynamics, spatially explicit processes, and temporally defined events that act at finer resolutions and that can disproportionately affect future outcomes. Dynamic Forest Landscape Models (FLMs) can simulate the survival, growth, and mortality of (stands of) trees over long time periods at small resolutions. However, as they are able to simulate at fine resolutions, study landscapes remain relatively small due to computational constraints. The large amount of feedbacks between biodiversity, forest, and ecosystem processes cannot completely be captured by FLMs or SDMs alone. Integrating SDMs with FLMs enables a more detailed understanding of the impact of perturbations on forest landscapes and their biodiversity. Several studies have used this approach at landscape scales, using fine resolutions. Yet, many scientific questions in the fields of biogeography, macroecology, conservation management, among others, require a focus on both large scales and fine resolutions. Here, drawn from literature and experience, we provide our perspective on the most important challenges that need to be overcome to use integrated frameworks at spatial scales larger than the landscape and at fine resolutions. Future research should prioritize these challenges to better understand drivers of species distributions in forest ecosystems and effectively design conservation strategies under the influence of changing climates on spatially and temporally explicit processes. We further discuss possibilities to address these challenges.

Bark Thickness of Forest-forming Species: Modeling and Comparative Analysis

The need to assess the carbon-depositing capacity of a stand, an individual tree and its components is constantly emphasized in the world literature, since mitigation of the effects of climate change has become the highest priority. Since the carbon concentration differs in different tree species and in different components of the tree, including in the stem wood and bark, it is necessary to develop species-specific mathematical models for estimating the proportion of bark in trunks to improve the accuracy of knowledge about the carbon balance of forests. The relationship of bark thickness with both age and diameter of the tree trunk is known, but with respect to its regional variability, the data are contradictory. According to the actual data from 1100 model trees of five forest-forming species, allometric models of a mixed type have been developed. They include as independent variables the age and diameter of the trunk, as well as a binary variable characterising the influence of the growing area itself on the bark thickness of Scots pine, silver birch and Siberian larch, as well as the difference in the thickness of the bark between Siberian spruce and Siberian fir in case of joint growth in mature stands of the taiga zone. At a statistically significant level, it was found that the bark thickness of Scots pine and silver birch trees in the steppe zone is significantly greater compared to the taiga zone, and the bark thickness of Siberian larch trees in the forest-tundra is significantly greater compared to the steppe zone. The bark thickness of Siberian spruce trees is significantly less than that of Siberian fir trees. The ranking of species by bark thickness is included in the paper.

The Legacy Effect of Mountain Pine Beetle Outbreaks on the Chemical and Anatomical Defences of Surviving Lodgepole Pine Trees.

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.

Stand growth and carbon stocks of community-based mangrove rehabilitation in Singkawang City, West Kalimantan, Indonesia

Abstract. Astiani D, Roslinda E, Widiastuti T, Ekamawanti HA, Ekyastuti W, Dwianto W, Alfikri F, Ngidu EY. 2024. Stand growth and carbon stocks of community-based mangrove rehabilitation in Singkawang City, West Kalimantan, Indonesia. Biodiversitas 25: 2799-2805. The ability of tropical mangrove ecosystems to store carbon in the form of biomass is well-founded. The mangrove forest in Setapuk Besar Village, Singkawang City, West Kalimantan Province, Indonesia has been managed by community members in response to the development of alluvial sediment land in recent years. The community's efforts in Setapuk Besar Village to rehabilitate and manage mangrove forests illustrate how essential mangrove forests are to the local ecology and should be applauded for their success. This study aims to investigate the growth and development, carbon stored and sequestered in mangrove forests planted by community in Setapuk Besar between 2015 and 2020. Field survey was conducted from July to November 2022 by mapping the sediment land that had expanded since 2015 and continued with the measurement of density and diameter of mangrove stands that were systematically planted in each planting year using sampling plot method. In addition, site factors such as pH, carbon content, nitrogen, phosphorus, CEC, and soil solution salinity were investigated. Our findings indicate that due to alluvial sedimentation, the coastline in Setapuk village is expanding by 3.3 to 4.6 ha annually, accumulating 24 ha throughout a six-year period. The mangroves planted in 2015-2016 are now thriving on the new land. The six-year-old trees diameter achieved an average of 6.80±0.13 cm, averaged 5.1 m in height, and increased from 0.45 to 2.2 cm in diameter. The total biomass (above and below-ground) of plants aged 4, 5 and 6 years was 250, 303 and 430 tons ha-1, with a potential to absorb carbon of 28-33 tons ha-1 year-1, correspondingly. Given that this mangrove area plays a crucial role in CO2 capture in nature and has a relatively high ability to absorb and store carbon, conservation efforts and best practices are necessary for this forest.

Spruce trees have stronger drought sensitivity at low- than high-elevation sites across China’s aridity zones

The ecological relationships between tree growth and climate factors are important for the adaptation, growth prediction, and forest management of tree species against a background of global warming. Yet how these relationships for drought-sensitive conifer trees are changed and affected by elevation remains unclear. To investigate the effect of elevation on spruce tree growth–climate interactions, we collected a total of 1886 tree-ring cores (two cores per tree) from four spruce species, including Picea crassifolia Kom., Picea meyeri Rehd. et Wils., Picea schrenkiana Fisch. et Mey., and Picea wilsonii Mast., in 10 pure forests at a pair of high- and low-elevation alpine sites with the same slope across two aridity zones in China. We then constructed 20 stand tree-ring chronologies for the low- and high-elevation sites. Overall, the growth of spruce trees was more sensitive to drought variability at sites in the semi-arid zone whereas it was weakly limited by drought in the semi-humid zone. Further, spruce trees growing at high-elevation sites were sensitive to temperature unlike the stronger positive drought responses of those at low-elevation sites. In the latter half of the 20th century, the positive drought–growth relationships of spruce were enhanced at both high and low elevation across both aridity zones due to warming and increased drought intensity. Our dendrochronology-based findings suggest that spruce trees’ radial growth in stands at high elevation may have faced drought stress during three recent decades. Nevertheless, the low-elevation trees incurred stronger drought stress compared to the first half of the 20th century.

Leaf Traits Explain the Growth Variation and Nitrogen Response of Eucalyptus urophylla × Eucalyptus grandis and Dalbergia odorifera in Mixed Culture.

Mixed cultivation with legumes may alleviate the nitrogen (N) limitation of monoculture Eucalyptus. However, how leaf functional traits respond to N in mixed cultivation with legumes and how they affect tree growth are unclear. Thus, this study investigated the response of leaf functional traits of Eucalyptus urophylla × Eucalyptus grandis (E. urophylla × E. grandis) and Dalbergia odorifera (D. odorifera) to mixed culture and N application, as well as the regulatory pathways of key traits on seedling growth. In this study, a pot-controlled experiment was set up, and seedling growth indicators, leaf physiology, morphological parameters, and N content were collected and analyzed after 180 days of N application treatment. The results indicated that mixed culture improved the N absorption and photosynthetic rate of E. urophylla × E. grandis, further promoting seedling growth but inhibiting the photosynthetic process of D. odorifera, reducing its growth and biomass. Redundancy analysis and path analysis revealed that leaf nitrogen content, pigment content, and photosynthesis-related physiological indicators were the traits most directly related to seedling growth and biomass accumulation, with the net photosynthetic rate explaining 50.9% and 55.8% of the variation in growth indicators for E. urophylla × E. grandis and D. odorifera, respectively. Additionally, leaf morphological traits are related to the trade-off strategy exhibited by E. urophylla × E. grandis and D. odorifera based on N competition. This study demonstrated that physiological traits related to photosynthesis are reliable predictors of N nutrition and tree growth in mixed stands, while leaf morphological traits reflect the resource trade-off strategies of different tree species.

Comparison of growth, structure and production in stands of naturally regenerated Betula pendula and Populus tremula

Comparison of growth, structure and production in stands of naturally regenerated Betula pendula and Populus tremula

Справочная информационная система FLR-Library для адаптивного лесовосстановления: информационная модель

The process of restoring forest landscapes in the context of global urbanization and deforestation of relict stands,
 as well as climate change, is complex and important for studying, planning stages and technological operations and
 predicting the results of vitality and growth of stands. To solve this problem, a reference information system for adaptive
 reforestation is being developed. In this paper, the modeling and description of the adaptive reforestation process is carried
 out using functional diagrams constructed using the IDEF0 methodology, and the description of the arrows of the context
 diagram with explanations of the processes is given in detail. For a detailed analysis of the subject area and modeling of
 the adaptive reforestation process, we decomposed the context diagram into diagram A1, which shows the implementation
 of the process of choosing a technology for the restoration of the forest landscape from the point of view of technology
 and technical means, and diagram A2, which examines the restoration technology from the point of view of several
 forestry descriptors, which takes into account the specifics of the industry. As a result of the simulation, diagrams A0,
 A1, A2 were obtained, which show a structured image of the system functions, information and objects connecting these
 functions.

Forest Stand Growth Forecasting in the Context of Changes in the Insolation of Building Roofs

This article analyzed the long-term impact of tree growth on the decrease in sunlight of a planned photovoltaic installation. As trees grow, they can obstruct sunlight and reduce the amount of insolation reaching the PV panels, and knowledge about the degree of this reduction is crucial when assessing the long-term economic effects of the investment. Currently, when planning PV installation, the roof facing, latitude, topography, and neighboring buildings are taken into account. However, there is no tool to assess the impact of tree growth over time on changes in the level of sunlight on the roof surface. The authors propose a tool for performing such an assessment using geospatial analysis techniques. The data from airborne laser scanning (ALS) and unmanned aerial vehicles with laser scanning (ULS) were used to model trees in two epochs. The authors used two epochs of data to evaluate mathematical models of tree growth. The evaluated tree growth model was then used to predict forest stand growth over a 30-year period and to assess the change in sunlight due to the modeled growth. For the case study, two test sites have been taken into account. At site 1 and site 2, respectively, 25 and 12 points representing the centers of potential photovoltaic panels were designed, for which the annual sum of minutes during which the point remained exposed to sunlight was calculated. The results showed that the use of ALS and ULS provided valuable data for determining current and predicted shading of trees. Moreover, the presented studies showed that the changes in forest stand growth had a significant impact on decreasing the insolation of building construction. In the case of both test sites, the change in tree height after 30 years resulted in a reduction in the number of minutes of sunlight by more than 50%. The authors suggest that the developed technique should be incorporated into PV installation planning tools to ensure reliable prediction of the long-term profitability of designed PV installations.

Effects of Climate Change on Scots Pine (Pinus sylvestris L.) Growth across Europe: Decrease of Tree-Ring Fluctuation and Amplification of Climate Stress

From an economic perspective, Scots pine (Pinus sylvestris L.) is one of Europe’s most important tree species. It is characterized by its wide ecological adaptability across its natural range. This research aimed to evaluate the forest structure, productivity and especially radial growth of heterogenous pine stands in 16 research plots in the Czech Republic, Poland, Spain and Great Britain. The study assessed the tree-ring formation and its relationship to climate change for each country, using 163 dendrochronological samples. The stand volume of mature pine forest ranged between 91 and 510 m3 ha−1, and the carbon sequestration in the tree biomass was 40–210 t ha−1. The stands had a prevailing random distribution of trees, with a high vertical structure close to selection forests (forest stands with typical very diverse height, diameter and age structure). Spectral analyses showed a substantial decrease in fluctuations in the tree-ring index and a loss in natural growth cyclicity in the last thirty years. The results also evinced that mean air temperature was the most important factor influencing the radial growth compared to precipitation totals. Pine thrives in precipitation-stable locations, as shown by the results from Great Britain. The conclusions of this study confirm the fundamental effect of ongoing global climate change on the dynamics and growth of pine forests in Europe.

POST-FIRE CONDITION AND RESTORATION OF FORESTS ON THE TERRITORY OF KOSTANAY REGION

The results of field studies of post-fire condition and reforestation of Kostanay region are presented. The purpose of the research is to study and analyze the post-fire condition and forest regeneration in the territory of Kostanay region. It was established that the magnitude of post-fire tree declines and their radial growth in stands of the main forest-forming species are determined by the type and intensity of fire. Taking into account the types of forest landscapes using space images, we have identified 7 key and control (background) sites that characterize the disturbed and background undisturbed forest cover. Among them, the most affected by the forest fire are key areas No5 and No7, where a top fire of medium intensity occurred. The forest litter of these key areas was completely burned in a severe fire, the soil seed stock was destroyed, and low intensity of natural regeneration is expected. The average grade of all studied key sites is estimated by us as III and it is connected with untimely harvesting, which resulted in the reduction of annual growth of the plantation. Sanitary condition of plantations in key sites No1, No5, No7 is unsatisfactory in comparison with other sites. Soils of the investigated key sites are not compacted and favorable for growth. In key plot No.1 there was a compacted crust in the surface soil layer. Uneven natural regeneration of common pine after the fire is observed. Predominantly friendly seed sprouting is associated with more moistened lowlands and loosened soil areas. Factors impeding the natural renewal of pine forests include deep burning of the forest floor and soil cover, mechanical effects on the soil and seedlings of the equipment used to develop harems, the mushroom wavy rhizina (Rhizina undulata) which affects the roots of coniferous trees.

Tree regeneration and ontogenetic strategies of northern European hemiboreal forests: transitioning towards closer-to-nature forest management.

Tree ontogeny is the genetic trajectories of regenerative processes in trees, repeating in time and space, including both development and reproduction. Understanding the principles of tree ontogeny is a key priority in emulating natural ecological patterns and processes that fall within the calls for closer-to-nature forest management. By recognizing and respecting the growth and development of individual trees and forest stands, forest managers can implement strategies that align with the inherent dynamics of forest ecosystem. Therefore, this study aims to determine the ontogenetic characteristics of tree regeneration and growth in northern European hemiboreal forests. We applied a three-step process to review i) the ontogenetic characteristics of forest trees, ii) ontogenetic strategies of trees for stand-forming species, and iii) summarise the review findings of points i and ii to propose a conceptual framework for transitioning towards closer-to-nature management of hemiboreal forest trees. To achieve this, we applied the super-organism approach to forest development as a holistic progression towards the establishment of natural stand forming ecosystems. The review showed multiple aspects; first, there are unique growth and development characteristics of individual trees at the pre-generative and generative stages of ontogenesis under full and minimal light conditions. Second, there are four main modes of tree establishment, growth and development related to the light requirements of trees; they were described as ontogenetic strategies of stand-forming tree species: gap colonisers, gap successors, gap fillers and gap competitors. Third, the summary of our analysis of the ontogenetic characteristics of tree regeneration and growth in northern European hemiboreal forests shows that stand-forming species occupy multiple niche positions relative to forest dynamics modes. This study demonstrates the importance of understanding tree ontogeny under the pretext of closer-to-nature forest management, and its potential towards formulating sustainable forest management that emulates the natural dynamics of forest structure. We suggest that scientists and foresters can adapt closer-to-nature management strategies, such as assisted natural regeneration of trees, to improve the vitality of tree communities and overall forest health. The presented approach prioritizes ecological integrity and forest resilience, promoting assisted natural regeneration, and fostering adaptability and connectivity among plant populations in hemiboreal tree communities.

Возрастная динамика нормальных древостоев ольхи серой в таежной зоне северо-востока европейской части России

In order to organize, plan and conduct forest management on a scientific basis in stands with predominance and participation of gray alder (Alnus incana (L.) Moench), formed in the conditions of the taiga zone, reliable data on the structure, growth and productivity of stands are needed. At present, there is an urgent need to develop growth progress tables for gray alder stands, as the areas occupied by this species have significantly increased as a result of abandoned agricultural lands overgrowth. The development of a unified system of regulatory and reference materials for accounting the number, assessment of the condition and volume of use of stands of gray alder in the European North of Russia is an important and urgent task. Growth progress tables for normal gray alder stands located in the taiga zone of the north-east of the European part of Russia have not been developed by anyone before. The purpose of this research is to study the age dynamics of normal gray alder stands to compile growth progress tables. We used 193 model trees of gray alder, as well as data from 175 sample plots. As a research result for the growth progress tables with relative stands density of 1.0 we obtained the equations for determining the average height, diameter, and stands stock by bonity classes. On the basis of the obtained equations, the tables of growth progress of normal stands by bonity classes were developed. The proposed tables will contribute to improving the accuracy of forest inventory, will give the opportunity to objectively assess the forest resources of the most represented stands, to forecast their growth when performing a set of works on the protection, conservation, and reproduction of forest resources, improving the ecological functions of the forest, as well as to control management in stands. For citation: Tretyakov S.V., Koptev S.V., Karaban A.A., Paramonov A.A., Davydov A.V. Age Dynamics of Normal Gray Alder Stands in the Taiga Zone of the North-East of the European Part of Russia. Lesnoy Zhurnal = Russian Forestry Journal, 2023, no. 6, pp. 70–80. (In Russ.). https://doi.org/10.37482/0536-1036-2023-6-70-80

Predicting the Stand Growth and Yield of Mixed Chinese Fir Forests Based on Their Site Quality, Stand Density, and Species Composition

The Chinese fir (Cunninghamia lanceolata) is the largest tree species used for afforestation in China. The purpose of this study was to explore the effects of site quality, stand density, and tree species composition on the growth and yield of mixed Chinese fir forests and to build prediction models for their stand average DBH (diameter at breast height), average height, and volume. Using 430 plots of mixed Chinese fir forests in the Fujian Province of China, the optimal base models for predicting stand average DBH, average height, and volume were selected from the Schumacher, Korf, Logistic, Mitscherlich, and Richards equations. On this basis, the site class index (SCI), stand density index (SDI), and tree species composition coefficient (TSCC) were introduced to improve the model’s performance, and the applicability of the different models was evaluated. The optimal base models for the average DBH, average height, and stand volume of mixed Chinese fir forests all used the Richards equation. The best fitting effect was obtained when the SCI was introduced into parameter a in the average height model, while the inclusion of the TSCC did not improve the model significantly. The fitting effects of the average DBH and stand volume models were both best in the form of y=a1SCIa2[1−exp⁡(−b1SDIb2)t]c when the SCI and SDI were introduced. When the TSCC was further included, the fitting effects of the stand average DBH and volume models were significantly improved, with their R2 increased by 47.47% and 58.45%, respectively, compared to the base models. The optimal models developed in this study showed good applicability; the residuals were small and distributed uniformly. We found that the SCI had an impact on the maximum values of the stand average DBH, average height, and volume; the SDI was closely related to the growth rate of the diameter and volume, while the TSCC influenced the maximum values of the stand average DBH and volume. The model system established in this study can provide a reference for the harvest prediction and mixing ratio optimization of mixed Chinese fir forests.

Сибсовое потомство карельской березы на Заонежской лесосеменной плантации

The article reports the results of studies on the growth and development of curly birch sibs progeny (produced through controlled pollination) aged 35 and 15 years growing in the Zaonezhye forest seed orchard (sites 1 and 2, respectively) in south-eastern Karelia, Medvezhyegorsky District. The number of trees with signs of wood figure in the seed progeny of curly birch in site 1 was 67 % by the age of 20 years, and by the age of 35 years – almost 80 %. This can probably be attributed to the genetic characteristics of the parent (plus) trees on one hand and to the favorable conditions in the forest seed orchard during the first years of the sibs progeny development on the other. Four of the 36 hybrid families (selected to include forward- and backcrossing products) were used for the case study of the growth and development patterns in stands of different age. The sibs progeny of these hybrid families was dominated by high-stemmed plants, but the main trunk shape in the 15-year-old stand was one with necks and muffs, while in the 35-year-old stand – with small protuberances. The rate of height growth in the trees decreased notably with age, whereas radial (stem diameter) growth, on the contrary, accelerated. As the bark grew thicker, however, the formerly bulgy surface “smoothed down”. We have also identified specific features of the ground vegetation formed under the effect of curly birch plantations of different age (15- and 35 years old). A conclusion drawn from the study is that good results from targeted cultivation of curly birch with figured grain (e.g., for sliced veneer) can be achieved already by the age of 20–35 years. Furthermore, considering the number of trees and their origin, this forest seed orchard constitutes an essential part of the valuable gene pool of curly birch, which may turn into a source for expanded reproduction of the resources of this unique member of the European forest tree flora. For citation: Vetchinnikova L.V., Titov A.F., Kostina E.E., Zhigunov A.V. Sibs Progeny of Curly Birch at the Zaonezhye Forest Seed Orchard. Lesnoy Zhurnal = Russian Forestry Journal, 2023, no. 5, pp. 9–26. (In Russ.). https://doi.org/10.37482/0536-1036-2023-5-9-26

Drought-related mortality modifies mixing effects on light absorption and growth in mono-specific and mixed stands of Fagus sylvatica, Alnus glutinosa, and Betula pendula

Abstract Little is known about how drought-related mortality influences light absorption of surviving trees and consequent changes in tree species interactions. Here, we used the detailed tree-level light model (Maestra) in combination with measurements of tree dimensions, crown architectures, and stand structures to examine experimental mixing effects of Fagus sylvatica, Alnus glutinosa, and Betula pendula on light dynamics following a drought in Bangor, Wales. The experimental stands, planted in 2004, were composed of clusters with one to three species in different combinations. Droughts occurred in 2011 and 2014 during the growing seasons, and trees were measured in 2014 and 2015. Species mixing resulted, on average, in higher tree growth, absorption of photosynthetically active radiation (APAR), and light-use efficiency (LUE) compared with the mean of the monocultures. An exception was the monoculture of B. pendula, which was the most productive species and had higher growth, APAR, or LUE than some mixtures. Drought-related mortality reduced the stand basal area across all plots by an average of 8.3% and tree density by 11%. This moderate change in the structure did not result in significant increases in individual tree APAR, LUE, or growth. From a management perspective, mortality might need to reduce stand density more strongly than it did in this study before light absorption or LUE is altered.

Spatiotemporal variation in bamboo Solar-induced chlorophyll fluorescence (SIF) in China based on the global Orbiting Carbon Observatory-2 (OCO-2) carbon satellite and study on the response to climate and terrain

ABSTRACT Bamboo forests have a high carbon sequestration potential. Solar-induced chlorophyll fluorescence (SIF) provides fresh insights into the temporal and geographical variations in bamboo development and its interactions with the environment. SIF can serve as a probe for photosynthesis. In this study, we used distribution information on Chinese bamboo forests as well as a global SIF product, the global Orbiting Carbon Observatory-2 (OCO-2) SIF (GOSIF), which is derived from the OCO-2 carbon satellite. Thus, we used SIF as an indicator of bamboo forest growth. We investigated the spatial and temporal variations as well as the trends of bamboo forest SIF in China from 2008 to 2019 and explained the response mechanisms of bamboo forest growth to climate change and terrain differences in the region. We also evaluated the combined effects of climate and terrain on bamboo forest growth using the partial least squares path model (PLS-PM). The results were as follows: (1) Low values were found in the west and north, while high values were found in the east and south, according to the average bamboo forest SIF values in China from 2008 to 2019. More than 88% of the pixels had significantly increasing values. In conclusion, bamboo forests in China are growing well. (2) Solar radiation (Rad) and minimum temperature (Tmin) promoted the growth of most bamboo stands, while precipitation (Pre) and maximum temperature (Tmax) did the opposite. (3) The terrain, with a digital elevation model (DEM) less than 1000 m and a slope less than 9°, had a positive effect on bamboo forest SIF. (4) Climate and terrain jointly explained 45% of the bamboo forest growth change, and the major factor was climate change.

Course of Stand Growth and Yield in the Pine Forest Types of the Kologrivsky Forest Nature Reserve

The purpose of the study is to study the course of growth of forest stands of the main forest-forming species in pine forest types using the example of the Kologrivsky Forest Nature Reserve (Kostroma Region). The object of the study was the stands of pine, birch, aspen and gray alder growing in pine forest types (lichen, lingonberry, sorrel, bilberry and long moss) of the Kologrivsky Forest Nature Reserve. To study the course of growth, materials from the forest inventory of 1998 and 2009 were used. In total, data on 3934 elements of dendrocenoses were analyzed. The generally accepted empirical regression models were used to analyze the experimental data. In the study, regression equations were obtained that describe changes in average heights and diameters, wood stocks from the age of the main forest-forming species in pine forest types of the Kologrivsky Forest Nature Reserve. It was revealed that the best forest growth effect in terms of the stand indicators under consideration is manifested in the type of forest – oxalis pine forest, and the worst – in lichen and long-moss pine forests. At the same time, for all considered tree species, a general pattern is manifested that in the best forest growing conditions, forest stands are less durable than in the worst ones. Based on the obtained regression dependencies, tables of the course of growth can be compiled by calculating the basal areas, the number of trees, the current and average changes in stocks according to the methods generally accepted in forest measurement and inventory. Such tables can serve as a basis for predicting changes in the stand indicators of the totality of forest stands in the forest area of the Kologrivsky Forest Nature Reserve. Изучен ход роста древостоев основных лесообразующих пород в сосновых типах леса на примере государственного природного заповедника «Кологривский лес» имени М.Г. Синицына (Костромская обл.). Объектом исследования являлись древостои сосны, березы, осины и ольхи серой. Для изучения хода роста использованы материалы лесоустройства 1998 г. и 2009 г. В общей сложности проанализированы данные 3 934 элементов дендроценозов. Для анализа экспериментальных данных применяли общепринятые эмпирические регрессионные модели. В исследовании получены регрессионные уравнения, описывающие изменения средних высот и диаметров, запасов древесины в зависимости от возраста основных лесообразующих пород в сосновых типах леса заповедника «Кологривский лес». Выявлено, что лучший лесорастительный эффект по рассматриваемым таксационным показателям проявляется в типе леса сосняк кисличный, худший – в сосняках лишайниковых и долгомошных. При этом для всех рассматриваемых древесных пород установлена общая закономерность, что в лучших лесорастительных условиях древостои являются менее долговечными, чем в худших. По полученным регрессионным зависимостям могут быть составлены таблицы хода роста путем расчета сумм площадей сечений, числа деревьев, текущего и среднего изменения запасов по общепринятым в лесной таксации методам. Такие таблицы могут служить основой при прогнозировании изменений таксационных показателей совокупности древостоев на землях лесного фонда заповедника «Кологривский лес».

Mixed of arbor-shrub significantly enhanced the drought stress adaptive capacity of plantation forests—An interpretation based on dendroecology

Multispecies arbor-shrub mixed stands have long been applied in vegetation restoration of the Chinese Loess Plateau, and are expected to provide better production and ecosystem services than pure stands. However, whether higher species and structural diversity will help mitigate the limitations of drought on plantations growth remain poorly quantified. We collected samples of the arbor Platycladus orientalis Linn. and shrub Caragana korshinskii Kom. under different stand structures with the same site conditions, using dendroecological methods analyzed the resistance, recovery, and resilience of mixed and pure stands in response to extreme drought, and compared the differences of recovery capacity under different tree species and stand structures based on the theory of full resilience. Results suggest that drought has a lag effect on plantations growth. Radial growth of mixed and pure stands was mainly limited by drought stress in autumn and winter of the previous year and late spring and early summer of the current year. The recovery after the extreme drought of both planted P. orientalis and C. korshinskii mixed stands were significantly (p < 0.05) higher than pure stands, and there are tradeoffs between resistance and recovery. Comparing the different tree species, even if the drought-induced P. orientalis growth reduction reaches 58.5% (mixed stands) and 41.6% (pure stands), it still has the possibility of recover fully, while C. korshinskii is difficult to recover to the previous level, and the mixed mode also affects the response of plantations to drought stress. Therefore, the growth habits and adaptability of different planted species to drought stress should be considered in the future afforestation projects, and select tree species with complementary traits for mixed planting. Taken together, these findings have important significance for mitigating the limitations of drought on plantations growth and maintaining the ecological function stability of plantations in the western Loess Plateau.

Using Microorganismal Consortium and Bioactive Substances to Treat Seeds of Two Scots Pine Ecotypes as a Technique to Increase Re-Afforestation Efficiency on Chalk Outcrops

The present research is focused on various pine ecotypes’ seed reproduction in the chalky substrate, challenging environmental conditions on the carbonate soils on chalk outcrops in the south of the Central Russian Upland in relation to pine woods re-afforestation. The winter and spring sowing methods were studied, along with a pre-seeding treatment, by biopreparations based on a consortium of Glomales fungi, bacteria of the genus Bacillus, and bioactive substances. The seeds of two pine ecotypes, Pinus sylvestris L.; Pinus sylvestris var. cretacea Kalenicz exKom, underwent treatment. The study revealed that biopreparations and bioactive substances promote higher pine seed germination rates and ensure the stability and survivability of seedlings in an environment that is unfavorable for plant and tree ontogenesis. Applying biopreparations proved effective during spring sowing, whereas, in the case of winter sowing, their positive impact was not statistically significant. The net effect size of the three organized factors studied in the experiment (pine ecotype, biopreparation, sowing term) (h2x) on the “survivability of P. sylvestris seedlings” effective feature significantly increased from 90.8 to 93.8%. The effect size of the “pine ecotype” factor on seedling survivability in P. sylvestris was at its highest (14.4%) during the seedlings’ first-year growth period. The effect size of the “sowing term” factor was at its highest (79.4%) at the stage of seed germination. The effect size of the “biopreparation” factor was at its highest (44.0%) during the seedlings’ second-year growth stage. Our results indicate that it is preferable to create forest plantations on chalk outcrops using Pinus sylvestris var. cretacea ecotypes and with pre-sowing seed treatment via biopreparations based on a microorganismal consortium and Biogor KM. The Spearman correlation between the nitrification capacity of soil substrate and seedling survivability during the first three growth periods (from planting till the next year’s springtime) was of a moderate size (rs = 0.617–0.673, p &lt; 0.05). To improve the growth and productivity of young and mature Scots pine stands, a Biogeosystem Technique (BGT*) methodology was developed.