Development Of Forest Ecosystems Research Articles

Fractionation of Inorganic Phosphorus in Cold Temperate Forest Soils: Associating Mechanisms of Soil Aggregate Protection and Recovery Periods after Forest Fire Disturbance

The soil aggregate is the fundamental unit of soil structure. The fractionation characteristics and influencing factors of phosphorus (P) in soil aggregates inherently link its geochemical characteristics and recycling mechanism. This work investigated the fractionation characteristics of inorganic P in cold temperate forest soils and studied the impacts of recovery periods after forest fires and soil aggregate protection mechanisms on P fractionation. Our results showed that the TP, active P, stable P, and total organic carbon (TOC) contents varied with increasing recovery years after forest fire disturbance. The TP content in the coarse particulate organic matter fraction (cPOM) exhibited an increasing trend with the number of recovery years. Redundancy analysis (RDA) and correlation analysis indicated that TOC played a crucial role in influencing the dynamics of P fractionation during the recovery process. The order of TP levels in different soil aggregate fractions was as follows: μClay > dClay > LF > cPOM > dSilt > μSilt > iPOM, with significant contributions from the cPOM and dSilt fractions. The ranking of P fractions in bulk soils was as follows: ACa-P > Fe-P > Oc-P > Or-P > De-P > Al-P > Ex-P. The protective mechanism of soil aggregates had a more significant effect on TOC than TP, with the order of protective abilities being: Phy×biochem-protected > Biochem-protected > Phy-protected > Non-protected mechanism. TOC and recovery years emerged as critical factors influencing the dynamics of different P fractions during post-fire recovery. Soil aggregate protection mechanisms demonstrated significantly higher effects on TOC than on TP. This study provides insights into the fractionation mechanisms of P in the soil–forest ecosystem of the Greater Khingan Mountains, contributing to the sustainable development and utilization of cold temperate forest ecosystems.

Geographical Peculiarities of Pinus sibirica Du Tour Natural Regeneration as Related to its Seed Crops

Forest ecology faces a significant challenge in understanding the dynamics of populations of forest-forming trees during their renewal phase, as it shapes the subsequent development and structure of forest ecosystems. The forest regeneration process relies on the dynamics of the seed yield of the woody plants and the unique characteristics of their distribution. In the case of the Cembrae sp. five-needled pines belonging, which have wingless seeds, their renewal is closely linked to the activities of Nucifraga sp. birds that scatter the seeds to create food reserves in the soil. This research aims to explore the geographical variations of Siberian stone pine (Pinus sibirica Du Tour) natural regeneration as a function of seed abundance. This study was conducted in three Russian mountain regions known for their forests predominated by Pinus sibirica: the Aldan Highlands, the Northern Urals, and the Khamar-Daban Mountains. It was discovered that each region exhibited distinct patterns in both cone yields and Pinus sibirica regeneration. The fluctuations in the thin-billed nutcracker (Nucifraga caryocatactes macrorhynchos Brehm C. L.) populations during the seed harvest season, influenced by the nature of the seed production dynamics in each region, we believed to play a major role in the quantity of Pinus sibirica seedlings appearing in the subsequent year. These findings explain the observed variations in the renewal dynamics of annual emergent seedlings of Pinus sibirica and its reliance on cone yield in the examined regions.

Relationship of selected properties of Cambisols to altitude and forest ecosystems of four vegetation grades

Currently, little is known about the spatial variability of significant soil properties and their relationships to forest ecosystems of different vegetation grades. This work evaluates the variability of the properties of the upper layer of Cambisol taxa and their relationship to altitude and forest ecosystems of 2nd to 5th forest vegetation grades selected in the Western Carpathians using PCA and regression analysis. The content of clay, total carbon and total nitrogen, humus, energy, and ash in the soils varied between 5.43 and 11.53 %, 21–65 mg g−1, 1.9–4.7 mg g−1, 36–112 mg g−1, 438.4–5845.7 J g−1 and 852.9–946.3 mg g−1, and C/N, pHH2O, and pHKCl values ranged between 11.2 and 16.7, 4.0–5.8 and 3.1–4.6. PCA showed that EAC in the 3rd oak-beech vegetation grade had significantly higher pH values and significantly lower energy content, ESC in the 4th beech vegetation grade had a significantly higher ash content and a significantly lower energy content, and DC in the 5th fir-beech vegetation grade had a significantly higher content of Ct, Nt, and humus. Linear regression revealed a strong negative correlation between the energy content and soil reaction (R2 for pHH2O = 0.48; R2 for pHKCl = 0.38) for all Cambisol taxa. Ct content and ash show a strong negative correlation (R2 = 0.78). The positive relationship between altitude and FVGs was found only for the soil Ct (R2 = 0.87), Nt (R2 = 0.81), and humus content (R2 = 0.87). A strong negative linear relationship between altitude and FVGs showed the ash content (R2 = 0.77). In turn, the oscillatory, polynomial course had a relationship between the clay content (R2 = 0.65) and energy (R2 = 0.75) to altitude and FVGs. Recognizing significant soil variables and better understanding their impact on the development of forest ecosystems is a prerequisite for distinguishing areas with the highest risk of their damage under conditions of various anthropogenic interventions and climate change. Therefore, this topic continues to require increased research efforts. For this reason, a better understanding of the relationships between soil properties and ecologically differentiated communities of forest ecosystems will allow us to identify areas with the highest risk of ecological changes that could lead to the degradation of European forests in the future.

Responses of Enzymatic and Microbiological Soil Properties to the Site Index and Age Gradients in Spanish Black Pine (Pinus nigra Arn ssp. salzmannii) Mediterranean Forests

This research analyzes how enzymatic and microbiological soil properties relate to site index (SI) and forest maturity (stand age) in Pinus nigra (P. nigra) even-aged forests. The soil parameters selected for multivariate analysis were four enzymatic activities (β-glucosidase, urease, dehydrogenase, and alkaline phosphatase), two microbiological properties (microbial biomass C and basal respiration), and five physicochemical parameters (TOC, N, P, pH, and soil water content). We used LiDAR, the digital elevation model, and the terrain model to obtain a result for the dominant height in each plot. The soil parameters were analyzed in the function of five site index classes (8, 11, 14, 17, and 20) and six age classes (50, 70, 90, 110, 170, and 210 years). Our findings emphasize that the dehydrogenase enzyme exhibited variations in response to both the site index and stand age. The activity of dehydrogenase positively correlated with sites characterized by a higher nutrient demand, particularly on young and poor-quality sites (lower SI), indicating activation. Therefore, dehydrogenase could serve as an index to elucidate both site quality and stand development in P. nigra stands, making it a potential indicator of forest ecosystem development.

Shelterbelt construction in the scenario of coordinated development of mountain, river, forest, farmland, lake, grassland, and sandy land ecosystems in semi-arid wind-sand areas: Principles and methods

We established the systematic concept framework of shelterbelt construction, with "shelterbelts" as the core concern in the construction of integrated ecosystems including mountain, river, forest, farmland, lake, grassland and sandy-land in semi-arid wind-sand areas. In the construction of shelterbelts, it is necessary to adhere to the principles of scientific coordination and systematic management, considering the carrying capacity of water resources, the demand for dust control, the greening and beautification effects, as well as the principle of improving economic benefits. In practice, the construction methods should base on the types and temporal-spatial distribution of shelterbelts, following the shelterbelts construction theory and technology to form different structure and service functions, achieving the functional goals of shelterbelts. By focusing on the key elements including people, forests, grass, fields, water, and sand, we put forward the timeliness, practicality, and scientificity of shelterbelt construction, proposing construction methods for farmland shelterbelts, pastureland shelterbelts, windbreak and sand-fixing forests and protective forest around village (city), which might provide production technical support for the high-quality construction of green ecological barrier in northern China.

АКТУАЛЬНОСТЬ ПРОВЕДЕНИЯ МОНИТОРИНГА СЕЛЬСКОХОЗЯЙСТВЕННЫХ КУЛЬТУР И ХВОЙНОГО ПОДРОСТА В ВЕГЕТАТИВНЫЙ ПЕРИОД

Modern agriculture faces a number of challenges, including climate change, resource constraints and the need to increase productivity. In this context, the assessment of quantitative parameters of crop growth by technical means during the growing season becomes particularly relevant. The scientific approach to this problem is becoming a key tool for optimizing production and ensuring food security, sustainable development of forest ecosystems. (Research purpose) To substantiate the relevance of monitoring crops and undergrowth during artificial reforestation during the vegetative period. (Materials and methods) Video monitoring of agricultural crops, automated segment recognition, geospatial data, literature review, statistical analysis were used. (Results and discussion) The statistics and problems of existing measures for monitoring coniferous undergrowth after reforestation measures were analyzed. The methods of using video monitoring of agricultural crops, in particular, for analyzing the yield of corn shoots, were considered. The use of a video monitoring system to control the care of coniferous undergrowth in the first five years after reforestation was substantiated. Key limitations and difficulties were cited, including high labor costs, insufficient monitoring, lack of systematic approach, limited human labor and low speed and accuracy of data processing. It has been shown that these factors emphasize the need for innovations in methods of controlling the growth of crops and caring for coniferous young. (Conclusions) It was revealed that the video monitoring system of coniferous undergrowth is one of the solutions to the problems of monitoring the condition of forest areas. It was determined that it allows assessing the quality of planting work, determining the growth and health indicators of seedlings, monitoring the environment by indirect signs and, due to a high level of digitalization and automation, responding quickly to violations. It was stated that the assessment of the parameters of crop growth in real time with the use of technical solutions makes it possible to identify problems such as diseases and parasites at an early stage, which will improve the possibilities for their prevention.

A forest management system based on sustainable development

The article substantiates the necessity of changes in the forest management system on the basis of sustainable development. The implementation of an interdisciplinary approach in the study convincingly demonstrates the increasing importance of the forest in connection with its ecological, economic and social functions at the local, national and global levels. Based on the analysis of scientific sources and official international documents approaches to the definition of the essence of sustainable (sustainable, established) forest management, balanced development of forestry, namely as: 1) harmonious combination of ecological, economic and social functions of the forest ; 2) sustainable development of forest ecosystems and the landscape as a whole; 3) integrated application of measures for the use, reproduction, formation, conservation and protection of forests, taking into account the interests of all stakeholders; 4) rational use of forest resources (capacity). The concept of forest management as a modern model of development of the forest sector of the state economy on the initiative of entrepreneurial and public entities is concretized. Forest management is considered from the perspective of the ecosystem approach. Negative trends in forest management in Russia after the beginning of large-scale administrative reform in the country are analysed. The scheme of the main stages in the development of forest policy is proposed. The scheme of the main stages of forest policy development is proposed. The results of the study can be used by scientific organizations engaged in forecasting the development of sectoral economies, forest companies in the formation of economic relations in forestry. The research can be continued in the direction of assessing the ecosystem services of forests and their inclusion in the system of economic relations.

The history of the Jizera Mts forests in the former heavily polluted area of Central Europe

The Jizera Mountains, situated on the Czech-Polish border and close to Germany, are today an environmentally valuable area attractive for visitors from sportspeople to nature lovers. In the 1980s, however, these mountains were among the most ecologically disrupted places in Europe. Emissions from lignite power plants largely destroyed the Jizera forests. This review summarises the development of forests in the Jizera Mountains and the human activities that influenced the area since the Middle Ages. Particular attention is given to the Industrial Revolution and also to the air pollution calamity in the 1970s and 1980s. The paper describes the causes of the decline of the forests and the factors that led to a significant improvement. Existing challenges for foresters and environmentalists are discussed. This paper views the development of forest ecosystems in the light of political and social events in the border area of three states where the Jizera Mountains are located.

Effects of AMF inoculation on the growth, photosynthesis and root physiological morphology of root-pruned Robinia pseudoacacia seedlings.

Root pruning hinders the absorption and utilization of nutrients and water by seedlings in the short term. Arbuscular mycorrhizal fungi (AMF) are an important source of nutrient and water for seedlings except for the root system. However, the mechanism by which AMF affect the physiological growth of seedlings after root pruning has rarely been studied. In this study, a pot experiment was conducted through a three-compartment partition system to clarify the effects of Funneliformis mosseae (F. mosseae) strain BGC XJ07A on the physiological growth of root-pruned Robinia pseudoacacia seedlings. Five root pruning treatments (zero, one-fifth, one-fourth, one-third and one-half of the taproot length were removed) were applied to noninoculated seedlings and those inoculated with F. mosseae. The results showed that the presence of F. mosseae significantly increased the shoot and root biomasses, leaf photosynthetic rate, stomatal conductance and transpiration rate. The root projected area, root surface area, average root diameter, root density, root volume and number of root tips of the inoculated seedlings were higher than those without inoculation in all root pruning treatments. The root cytokinin, gibberellins and indole-3-acetic acid concentrations, but root abscisic acid concentration, were higher than those measured in the absence of inoculation in all root pruning treatments. Moreover, the changes in the root endogenous hormone concentrations of the seedlings were closely related to the root morphological development and seedling biomass. The AMF increased the soil available nitrogen, soil available phosphorus, soil available potassium and soil organic matter concentrations compared with the noninoculated treatment. These results indicate that AMF can alleviate the adverse effects of root pruning on the physiological growth of R. pseudoacacia and soil properties, and can provide a basis for AMF application to forest cultivation and the sustainable development of forest ecosystems.

Understory vegetation removal significantly affected soil biogeochemical properties in forest ecosystems

Understory vegetation plays a crucial role in mediating the natural development of forest ecosystems. The removal of understory vegetation, as a common forest management practice, may have a significant impact on soil properties. However, a global perspective on how understory removal might affect soil biogeochemical properties is still lacking. To fill this knowledge gap, we performed a meta-analysis with 2059 observations collected from 71 peer reviewed publications to evaluate the effects of understory vegetation removal on soil carbon (C), nitrogen (N), phosphorus (P), potassium (K), and microbial biomass. We found that (1) removal of the understory significantly increased soil nitrates (NO3−) concentration by 6.5 %, but decreased the stocks of C and N, the concentrations of N, available K (AK) and microbial biomass C (MBC), and fine root biomass by 19.4, 15.1, 7.9, 19.9, 13.5 and 32.2%, respectively; (2) mycorrhizal association significantly mediated understory removal effects on soil organic C (SOC) and dissolved organic C (DOC) concentrations, and soil pH, while canopy type had a significant impact on the effects of understory removal on soil K, AK, NO3−, MBC concentrations, C:N ratio, and soil pH; (3) soil depth had a negative impact on the effects of understory removal on SOC, AK, ammonium nitrogen (NH4+) concentrations, and soil moisture; and (4) mycorrhizal association, soil depth, slope, forest stand age, elevation, and MAT were the most important moderator variables. Our results suggest that the removal of understory vegetation generally have negative effects on soil biogeochemical properties, and that managing understory vegetation is important for promoting the healthy development of forest ecosystems.

ANALISIS KELEMBAGAAN KELOMPOK TANI HUTAN (KTH) PADA AREA HUTAN KEMASYARAKATAN WOLOBOBO (Studi Kasus Desa Rakateda II Kecamatan Golewa Barat, Kabupaten Ngada, Flores, Nusa Tenggara Timur)

The WoloboboHKm area has experienced encroachment damage which was still found up to 2001 with a total land area of ​​481 hectares and fires that occurred in the last five years covering 117 hectares. To avoid increasing damage, it is necessary to emphasize the people who have an important role, one of the strategies used is the Social Forestry scheme in the form of community forestry (HKm), which involves the community directly as part of the forest ecosystem unit which is seen as one of the stakeholders who will determined to seek sustainable development of forest ecosystems and improve community welfare through the Forest Farmers Group (KTH) institution. The research was carried out in the WoloboboHKm area, Bajawa, Ngada Regency. This research was conducted to analyze the KTH Institutions in the Wolobobo Community Forest Area. The research was conducted for 2 months July - August 2022. Respondents in this study came from 3 KTH with a total of 39 members. The method used in this study is a qualitative method, using Stakeholder analysis with the 4R framework, namely Rights (Rights), Responsibility (Responsibility), Income/return (Results/benefits), Relationships (Relationships). The results of the research obtained through the interview method with the help of a questionnaire note that the Institutional Forest Farmer Group has not been effective due to reduced community development and assistance, reduced awareness of responsibility by each stakeholder role, low community income and relationships between stakeholders that have not worked well.

Response of leaf and soil C, N and P stoichiometry in different Pinus massoniana forest types to slope aspect in the Dabie mountains region of North subtropical, China

Changes in slope aspect have important effects on the C, N and P nutrient contents and stoichiometric characteristics of plants and soils. As an important forest type in the subtropical region, Pinus massoniana forests play an important role in the restoration and development of forest ecosystems. In this study, the effect of slope aspect on the C, N and P contents and stoichiometry of leaves and soils of four P. massoniana forest types (i.e., pure P. massoniana forest (PF), P. massoniana-Liquidambar formosana mixed forest (PLM), P. massoniana -Platycarya strobilacea mixed forest (PPM), and P. massoniana-Quercus acutissima mixed forest (PQM)) in north subtropical region of China were studied. The results showed that slope aspect had significant effects on soil C, N and P contents, leaf N content (LNC), soil C:P and N:P ratios, and leaf C:N and N:P ratios in four P. massoniana forests. SOC, STN and STP contents differed significantly on the two slopes, with the three mixed forests having higher contents on the sunny slope than on the shady slope. Among the four forest types, the SOC, STN and STP contents of PQM were the highest on both slopes, and their soil C:P and N:P ratios were all the highest on the sunny slope. The LNC and leaf N:P ratios were higher on shady slope than on sunny slope, while the leaf C:N ratio was higher on sunny slope than on shady slope. At the species level, leaf N content and N:P ratio in the three deciduous species were higher than in the evergreen species of P. massoniana, while leaf C content and C:N ratio were lower than in P. massoniana. The interaction between slope aspect and forest type caused a certain range of fluctuations in stoichiometry of the four forest types, but the overall ecological stoichiometry remained stable, and plant growth of the four forest types in the study area was limited by N. Slope-induced changes in soil nutrient content of the four P. massoniana forest types directly affect leaf C:N:P stoichiometry, and soil N and P contents are key factors affecting leaf stoichiometry, especially soil P content.

In vitro growth of nine edible ectomycorrhizal fungi under a range of pH conditions

Ectomycorrhizal fungi are considered to play an essential role in the development of forest ecosystems and can protect plant against pathogenic infections. Among other factors, soil pH may affect the successful inoculation of forest seedlings in nurseries. The effect of pH on the growth rate of strains of nine species of edible ectomycorrhizal (ECM) fungi was evaluated in vitro. In the experiments, Boletus edulis, B. aereus, B. pinophilus, B. fragrans, Amanita rubescens, Xerocomus ferrugineus, Lactarius deliciosus, Lactarius sanguifluus and Suillus luteus were grown in Petri dishes containing modified Melin Norkrans medium and adjusted at seven different pH levels. Colony area was measured at 7-day intervals for 8 weeks. Final fungal biomass and residual pH of the medium at 8th week were also measured. The optimum pH levels and pH tolerance ranges for the tested ECM fungal species are presented and discussed in the text. The results showed that the greatest growth in vitro was produced by A. rubescens and S. luteus at high pH levels (between 6.5-8.5), and by X. ferrugineus at low pH (3.5-6.5). Almost all the strains acidified the medium where they were grown after eight incubation weeks.

Forest-Fire-Risk Prediction Based on Random Forest and Backpropagation Neural Network of Heihe Area in Heilongjiang Province, China

Forest fires are important factors that influence and restrict the development of forest ecosystems. In this paper, forest-fire-risk prediction was studied based on random forest (RF) and backpropagation neural network (BPNN) algorithms. The Heihe area of Heilongjiang Province is one of the key forest areas and forest-fire-prone areas in China. Based on daily historical forest-fire data from 1995 to 2015, daily meteorological data, topographic data and basic geographic information data, the main forest-fire driving factors were first analyzed by using RF importance characteristic evaluation and logistic stepwise regression. Then, the prediction models were established by using the two machine learning methods. Furthermore, the goodness of fit of the models was tested using the receiver operating characteristic test method. Finally, the fire-risk grades were divided by applying the kriging method. The results showed that 11 driving factors were significantly correlated with forest-fire occurrence, and days after the last rain, daily average relative humidity, daily maximum temperature, daily average water vapor pressure, daily minimum relative humidity and distance to settlement had a high correlation with the risk of forest-fire occurrence. The prediction accuracy of the two algorithms in regard to fire points was higher than that for nonfire points. The overall prediction accuracy and goodness of fit of the RF and BPNN algorithms were similar. The two methods were both suitable for forest-fire occurrence prediction. The high-fire-risk zones were mainly concentrated in the northwestern and central parts of the Heihe area.

Leaf nitrogen resorption is more important than litter nitrogen mineralization in mediating the diversity–productivity relationship along a nitrogen-limited temperate forest succession chronosequence

The resorption of nutrients by plants before litter fall and the mineralization of nutrients from plant litter by soil processes are both important pathways supporting primary productivity. While the positive relationship between plant biodiversity and primary productivity is widely accepted for natural ecosystems, the roles of nutrient resorption and mineralization in mediating that relationship remains largely unknown. Here, we quantified the relative importance of nitrogen (N) resorption and N mineralization in driving plant community N investment and the correlation between species diversity and community productivity along an N-limited successional chronosequence of the mixed broadleaved–Korean pine (Pinus koraiensis) forest in northeastern China. Leaf N resorption efficiency (NRE) at the community level increased significantly along the successional chronosequence, whereas litter N mineralization rate decreased significantly. Leaf NRE was more important than litter N mineralization rate in driving the diversity–productivity relationship. However, higher leaf NRE led to less N mineralization as succession progressed along the chronosequence. Our results highlight the importance of the N resorption pathway rather than the N mineralization pathway for forest N acquisition with community succession, and they provide mechanistic insights into the positive effects of biodiversity on ecosystem functioning. In future forest management practices, we recommend appropriate application of N fertilizer to mitigate the adverse effects of N-poor soil on seedling regeneration during late succession and thus maintain the sustainable development of temperate forest ecosystems.

气候变化驱动下黄土高原刺槐林气候适宜性和脆弱性

PDF HTML阅读 XML下载 导出引用 引用提醒 气候变化驱动下黄土高原刺槐林气候适宜性和脆弱性 DOI: 10.5846/stxb202003140544 作者: 作者单位: 作者简介: 通讯作者: 中图分类号: 基金项目: 国家自然科学基金项目(42141007, 41877539);中国气象科学研究院基本科研业务费专项(2020Z004) Climate suitability and vulnerability of Robinia pseudoacacia forest driven by climate change on the Loess Plateau Author: Affiliation: Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:刺槐是黄土高原乡土树种,具有优良的水土保持和固碳功能。黄土高原生态恢复实践中实施了大规模的植树造林,刺槐林面积占沟壑丘陵区人工植树造林面积90%以上。由于种植时没有考虑刺槐的气候适宜性,一些地区的刺槐林出现了退化现象。采用最大熵模型,在0.5km×0.5km空间精度上分别模拟了1961-1990、1966-1995、1971-2000、1976-2005、1981-2010,以及2100年(典型浓度路径RCP4.5和RCP8.5气候情景下)黄土高原刺槐的气候适宜性和敏感性。模拟结果显示:黄土高原刺槐分布及其动态变化主要受到最冷月温度、极端低温、降水量、年辐射量等气候因子影响,低温(最冷月温度、极端低温)是影响刺槐的最关键因子。黄土高原西北和北部广大地区,自然环境条件不适合刺槐林生长;黄土高原东南部(关中平原和山西南部)比较适合刺槐生长。相对1961-1990年,1961-2010年期间刺槐林适宜区分布格局基本没有改变,RCP4.5和RCP8.5气候情景下刺槐林适宜区分布格局也没有显著改变。图层叠加分析发现,刺槐的气候适宜度(即存在概率)发生了明显改变。黄土高原西部和北部属于不适宜刺槐生长的非敏感区,东部和东南部是适宜刺槐生长的区域,尤其是山西中南部和陕西关中平原对气候变化非常敏感,展示了刺槐气候脆弱性的一面。研究结果对植树造林,优化人工林空间分布格局,应对气候变化风险和维持黄土高原森林生态系统可持续健康发展具有重要参考价值。 Abstract:Robinia pseudoacacia is a native tree species on the Loess Plateau, which has excellent functions of soil and water conservation, and carbon sequestration. Large scale afforestation was carried out in the practice of ecological restoration in the Loess Plateau, and the area of Robinia pseudoacacia forest accounted for more than 90% of artificial afforestation in the gully and hilly areas. However, Robinia pseudoacacia forest degenerated in some areas because climate suitability of Robinia pseudoacacia was not considered during afforestation. In this study, MaxEnt (maximum entropy model) was used to simulate the climate suitability and sensitivity of Robinia pseudoacacia on the Loess Plateau in 1961-1990, 1966-1995, 1971-2000, 1976-2005, 1981-2010, and 2100 (under the climate scenarios of Representative concentration pathway RCP4.5 and RCP8.5, respectively) at the spatial resolution of 0.5 km × 0.5 km. The simulation results showed that the distribution and dynamic changes of Robinia pseudoacacia on the Loess Plateau were mainly affected by the coldest month temperature, extreme low temperature, annual precipitation, annual radiation and other climate factors. Low temperature (the coldest month temperature, extreme low temperature) was the most important factor affecting Robinia pseudoacacia. The natural environment was not suitable for Robinia pseudoacacia forest in the northwest and the north of the Loess Plateau, but it was suitable in the southeast (the Guanzhong Plain and the south of Shanxi Province) of the Loess Plateau. Compared with the period of 1961-1990, the geographical distribution pattern of Robinia pseudoacacia forest was basically unchanged during 1961-2010, and its geographical distribution pattern was not significantly changed under the climate scenarios of RCP4.5 and RCP8.5. Overlay analysis showed that climate suitability (namely exist probability) of Robinia pseudoacacia changed significantly. The regions in the west and north of the Loess Plateau were not suitable for Robinia pseudoacacia, where belonged to non-sensitive areas. The regions in the east and southeast were suitable for Robinia pseudoacacia, where was very sensitive to climate change, especially in the south central of Shanxi Province and the Guanzhong Plain in Shaanxi Province, showing significant climate vulnerability. This study has important reference value for choosing suitable area for afforestation, optimizing the spatial distribution of plantation, coping with climate change risk, maintaining the sustainable and healthy development of forest ecosystem on the Loess Plateau. 参考文献 相似文献 引证文献

An Object- and Shapelet-Based Method for Mapping Planted Forest Dynamics from Landsat Time Series

Large-scale afforestation in arid and semi-arid areas with fragile ecosystems for the purpose of restoring degradation and mitigating climate change has raised issues of decreased groundwater recharge and ambiguous climatic benefits. An accurate planted forest mapping method is necessary to explore the impacts of afforestation expansion on fragile ecosystems. However, distinguishing planted forests from natural forests using remote sensing technology is not a trivial task due to their strong spectral similarities, even when assisted by phenological variables. In this study, we developed an object- and shapelet-based (OASB) method for mapping the planted forests of the Ningxia Hui Autonomous Region (NHAR), China in 2020 and for tracing the planting years between 1991 and 2020. The novel method consists of two components: (1) a simple non-iterative clustering to yield homogenous objects for building an improved time series; (2) a shapelet-based classification to distinguish the planted forests from the natural forests and to estimate the planting year, by detecting the temporal characteristics representing the planting activities. The created map accurately depicted the planted forests of the NHAR in 2020, with an overall accuracy of 87.3% (Kappa = 0.82). The area of the planted forest was counted as 0.56 million ha, accounting for 67% of the total forest area. Additionally, the planting year calendar (RMSE = 2.46 years) illustrated that the establishment of the planted forests matched the implemented ecological restoration initiatives over the past decades. Overall, the OASB has great potential for mapping the planted forests in the NHAR or other arid and semi-arid regions, and the map products derived from this method are conducive to evaluating forestry eco-engineering projects and facilitating the sustainable development of forest ecosystems.

Inconsistent Response of Abundant and Rare Bacterial Communities to the Developmental Chronosequence of Pinus massoniana

There are differences in the environmental adaptability and regulation of nutrient cycling between abundant and rare bacterial communities during the development of planted forest ecosystems. In this study, we aimed to elucidate the relationships between the soil characteristics and the composition and diversity of abundant and rare bacteria across a chronosequence (i.e., 13-yr, 25-yr, 38-yr, 58-yr-old stands) of Pinus massoniana. Abundant bacterial OTUs, richness, and Shannon index showed a different variation with stand age compared with the rare taxa bacterial community. Both abundant and rare bacterial communities showed significant differences between the 13-yr and 25-yr-old stands, but were similar in the 38-yr and 58-yr-old stands. The dominant phyla were Acidobacteria, Proteobacteria, Chloroflexi, Actinobacteria, and Planctomycetes in both abundant and rare taxa. However, the same phylum of abundant and rare taxa was inconsistent across the four forest ages. Network analysis further demonstrated that rare taxa had a greater network scale and complexity than abundant taxa, which may contribute to buffering the environmental stress. The Mantel test showed that soil pH, nitrogen pool (i.e., MBN, NH4+, NAlkali), and enzyme activities were the key factors that were associated with the changes in abundant bacterial diversity and structure during the development of P. massoniana. However, more soil variables (i.e., pH, SW, MBN, NH4+, NAlkali, AP, nitrite reductase, and sucrase) regulated the rare bacterial communities. Our results indicate that rare taxa are important contributors to soil bacterial community diversity, and their community dynamics responded to changes in soil physicochemical properties significantly distinct from the abundant taxa. We suggest that future studies should focus more on the response of different taxa subcommunities, rather than on the community as a whole, when studying the changes in microbial community dynamics.

A Dynamical Model Based on the Chapman–Richards Growth Equation for Fitting Growth Curves for Four Pine Species in Northern Mexico

Tree growth models describe the growth and development of forest ecosystems by considering how the dimensions of each simulated tree change within a certain time. These models have commonly used three growth parameters that describe various biological processes and behaviours, considering a sigmoid growth function: (i) the upper asymptote (θ1), which is the maximal yield indicated by a final dimension (such as the maximal stem diameter); (ii) the maximum specific growth rate (θ2), defined as the slope of the tangent at the inflexion point; and (iii) the time elapsed (θ3), defined by the intercept of this tangent with the abscissas. To the best of our knowledge, however, associations between the three parameters have not been documented for tree species. Using diameter growth data from pine trees located in typical mixed and uneven-aged pine-oak forests in the Sierra Madre Occidental, Mexico, our study aims were: (i) to quantify the putative associations between the three growth parameters and (ii) to test the accuracy of a proposed Hybrid Chapman-Richards growth model based on associations between the three growth parameters, but including only one single parameter, relative to the widely used Generalized Algebraic Difference Approach (GADA) based on the Chapman-Richards, Lundqvist and Hossfeld models and the Hybrid Weibull Model. For statistical comparison of the quality of the models, we used the mean relative percentage error, root mean square error, coefficient of determination and Akaike information criterion to assess the quality of the fit. Although the quality of the five growth models studied was similar, from a practical point of view, the proposed Hybrid Chapman-Richards Model (CR-H) is easier to apply than the other models and has a lower data collection and computational cost. The parameter of CR-H can be easily obtained, by measuring just the dominant trees, especially in coniferous forests with irregular ages. Moreover, in contrast to the Chapman-Richards-GADA factor χ0, when θ2 is assumed to be site-specific, the CR-H has always a closed-form solution.

Variation in Hydraulic Properties of Forest Soils in Temperate Climate Zones

The structure of forests in temperate climates has been changing to ensure the resilience of trees. This change affects the local water balance. Knowledge of soil hydraulic properties (SHP) is essential to assess the water cycle in ecosystems. There is little knowledge about the impact of tree species on SHP and the water balance. Based on a compilation of 539 related studies we aimed at identifying the effects of tree species and age on SHP in temperate climates. However, most studies concentrated on soil biogeochemical properties, whereas only 256 studies focused on SHP. The literature presents no standard methods for assessing SHP and there is no knowledge of their variations in forests. We present a systematic overview of the current state of knowledge on variations in SHP based on forest type in temperate climates. We identify the gaps and weaknesses in the literature and the difficulties of evaluating the reviewed studies. More studies following standardised methodologies are needed to create a robust database for each forest type and soil texture. It would improve the assessment of the forest water balance through calibrated plot/site-scale process models. Such a database does not yet exist, but it would greatly improve the management and development of future forest ecosystems.