Forest Zone Research Articles

Thermal Comfort Simulation-Based Forest Management Scenarios for Forest Healing

Background and objectives: Forest environments provide various healing benefits for humans and have been widely studied. Nevertheless, the field of forest management for forest healing remains relatively understudied. The purpose of this study is to utilize thermal environmental simulation to derive forest management scenarios that are optimized for forest healing. Methods: This study focused on the Seogwipo Experimental Forest on Jeju Island, Korea. Three-dimensional forest models were generated based on field surveys. Thermal environment simulations were conducted using Grasshopper with the Ladybug and Honeybee plug-ins, and the thermal comfort levels of six forest management scenarios were evaluated using the Universal Thermal Climate Index (UTCI). Results: The simulation results showed that, among all the scenarios, only scenario (c), “10% thinning in the buffer zone”, led to an improvement in thermal comfort. Additionally, the study identified discrepancies in thermal comfort between different forest management scenarios. Conclusions: In the management of forests for healing forestry purposes, the distinction of forest zones by use and the application of different forest management scenarios have thermal comfort implications. Thus, the methodology could be employed in forest management for forest healing purposes.

The adoption of Best Management Practices: empirical evidence from oil palm farming in rural Ghana

ABSTRACT Purpose We examine how farmer characteristics, farm, institutional, perception and shock factors influence the adoption of the Best Management Practices (BMPs). A thorough understanding of how relevant drivers affect the adoption decision of diverse BMPs can contribute to the development of evidence-based policies. Approach We use a household survey of 1031 smallholder oil palm farmers in the forest zones of Ghana to assess the determinants of farmers’ adoption decisions. We employ a seemingly unrelated regression (SUR) model after a principal component analysis is used to extract five latent components. Findings Our findings indicate that different farmer characteristics, farm, institutional, perception and shock factors have differential associations with the adoption of diverse BMPs. Key among these are the positive perception of BMPs, access to mills, perception of soil fertility and pests and diseases. Practical implications Specific BMPs must be tailored to meet the prevailing individual socio-economic characteristics and challenges of farmers to facilitate their adoption and scale-up. Educational programmes and dissemination of information by extension agents and research institutions are needed in the promotion of BMPs to enhance effective uptake. Theoretical implication The paper contributes to the growing literature especially on the uptake of diverse management practices, utilizing both behavioural and socio-economic theories underpinning adoption, thus providing empirical evidence that adoption is influenced by both behavioural and socio-economic factors. Originality/value In the bid to increase agricultural productivity, while preserving ecosystem services, the adoption of sustainable management practices remains key for all stakeholders and policy makers. This paper presents credible information for policy makers in Ghana and Africa in designing polices to influence their adoptions.

Coexistence through sustainable conservation strategies for sitatunga Tragelaphus spekii in African ecosystems

Sitatunga Tragelaphus spekii is an antelope species adapted to the dense swamps and marshes of Sub‐Saharan Africa, where traditional population survey techniques have been ineffective and encountered difficulties in making estimations. The species formerly occurred alongside waterways throughout the lowland forest zone of West and central Africa, extending into swamp systems in the savanna zones of central, East, and southern Africa. In most parts of Africa, the sitatunga population is declining, and attracting the attention of conservationists. Furthermore, its geographical range has been recorded to have shrunk. The present study reviewed major threats to sitatunga, assessed previous and current management approaches, and proposed new approaches to effectively manage its declining populations in Africa. To achieve the study objectives, published literature, reports, online information, expert knowledge, and personal experience were reviewed to acquire relevant information. Results indicated that sitatunga are threatened due to increased habitat loss, population isolation, political instability, water level changes, habitat fragmentation, illegal hunting, and diseases. Current wildlife management approaches raise many doubts as to their effectiveness. National‐level management may unsustainably segment management actions while the protected area approach manages only part of the range of wildlife. The current tenure system in most parts of Africa discourages human–wildlife co‐existence, whereas human–wildlife conflict management approaches only treat the symptoms and not the root cause of the problems. If wildlife, including sitatunga, are to persist in Africa, management approaches should be changed and include re‐focusing of the management context at the ecosystems and landscape level; assessing the genetic diversity of sitatunga; promoting better wetland management, including the aspect of human dimension in management; using non‐invasive techniques to genetically estimate the minimum population size; assessing inbreeding; and enhancing the implementation strategy of wildlife policy in African countries. Changing the attitude of the local community may take time, but it is a pivotal point if humans and wildlife are to coexist.

Effect of Plant-derived Biofertilizers (Azolla filiculoides and Tithonia diversifolia) on Growth and Yield Parameters of Lokpa Yam (Dioscorea cayenensis-rotundata) Grown on Distric Plinthic Ferralsol in the Forest Zone of Côte d'Ivoire

Aims: The study aims to assess the fertilizing potential of Azolla filiculoides and Tithonia diversifolia leaves on Lokpa (D-rotundata) yam cultivation in the forest zone of Côte d'Ivoire. Place and Duration of Study: The study took place over 9 months (April-December) in 2022 at M'Bayakoffikro in the Daloa department of central-western Côte d'Ivoire. Methodology: After clearing a soil fallow classified Distric plinthic ferralsol, microplots in randomized Fisher blocks of 2 replicates each with five treatments (Azolla filiculoides-AZ; Tithonia diversifolia with fresh biomass-TDF; Tithonia diversifolia with decomposed biomass-TDD; Azolla filiculoides + Tithonia diversifolia with fresh biomass-AZ+TDF and Azolla filiculoides + Tithonia diversifolia with decomposed biomass-AZ+TDD) and a control without fertilizer were delimited in which,10 mounds were levelled for sowing yam tuber pieces. Before sowing the tubers, the mounds were opened by hand and 0.5kg of each formulated fertilizer was ploughed in and then resealed. After 14 days of fertilization, the mounds were reopened and a single seedling was buried 20cm deep in each mound from top to bottom, followed by 300ml of water and then resealed. After germination, growth and production parameters were evaluated and the data obtained were subjected to an analysis of variance with Statistica 7.1 software at the 5% threshold. Results: The different biofertilizer formulations had a significant effect on all growth and yield parameters of lokpa yam (D-rotundata). However, the highest values for both growth and yield parameters compared with other fertilizers at all measurement times and at maturity were obtained with Azolla filiculoides combining decomposed Tithonia diversifolia leaves on the one hand and fresh Tithonia diversifolia leaves on the other. Conclusion: Improving soil productivity in forest areas by finding reliable and effective alternatives to mineral fertilizers is a necessity, and the combination of Azolla filiculoides and Tithonia diversifolia could be a good alternative for sustainable, environmentally-friendly agriculture.

Coupled Effects of High Temperatures and Droughts on Forest Fires in Northeast China

High temperatures and droughts are two natural disasters that cause forest fires. During climate change, the frequent occurrence of high temperatures, droughts, and their coupled effects significantly increase the forest fire risk. To reveal the seasonal and spatial differences in the coupled effects of high temperatures and droughts on forest fires, this study used the Copula method and proposed the compound extremely high-temperature and drought event index (CTDI). The results indicated that the study area was subject to frequent forest fires in spring (71.56%), and the burned areas were mainly located in forests (40.83%) and the transition zone between farmland and forests (36.91%). The probability of forest fires in summer increased with high temperatures and drought intensity, with high temperatures playing a dominant role. The highest forest fire hazard occurred in summer (>0.98). The probability of a forest fire occurring under extreme meteorological conditions in summer and fall was more than twice as high as that in the same zone under non-extreme conditions. Droughts play a significant role in the occurrence and spread of forest fires during fall. These results can provide decision-making support for forest fire warnings and fire fighting in the Northeast China forest zone.

A Bibliometric Review of the Impacts of Logging in Forests in Semi-Arid Zones

Forest massifs in semi-arid zones play an essential role in maintaining ecological balances and the livelihood of local communities. However, unsustainable logging in these regions can have devastating ecological, and socio-economic consequences. This bibliometric review aims to synthesize the available evidence regarding the impacts of logging in semi-arid ecosystem. Analysis of publication trends reveals a significant increase in research from 2008, reflecting a growing awareness of the issues related to sustainable forest management. The United States, Canada, Australia and China the most prominent countries in this field. The bibliometric analysis of the highlights major concerns related to climate change, clear-cutting, interactions with demographic dynamics and biogeochemical cycles. However, gaps remain, including a lack of data specific to semi-arid areas, limited understanding of the complex interactions between different dimensions of impacts, and insufficient integration of local perspectives and traditional knowledge. This review highlights the need to continue interdisciplinary and collaborative research efforts to ensure sustainable management of semi-arid forests in the face of current and future environmental challenges.

How does PM2.5 affect forest phenology? Integrating PM2.5 into phenology models for warm-temperate forests in China

Vegetation can regulate particulate matter (PM) through various mechanisms, such as facilitating the deposition of gases and particulates and purifying the air via photosynthesis. Conversely, PM directly damages leaves through dry deposition, while it also indirectly affects plant growth by altering weather conditions. However, the ways in which PM influence vegetation growth patterns, and the driving factors behind these impacts, remain unclear. In this study, we primarily focused on the start of the growing season (SOS) of warm-temperate zone forests in China with severe PM. SOS exhibited a trend of advancing at a rate of 0.15 days/yr during the study period from 2004 to 2022. We assessed the impact of satellite-derived fine PM (PM2.5) and coarser PM (PM10) on forest SOS across warm temperate forest regions in China using partial correlation analysis methods. After removing the effects of PM, we found that the correlation between temperature and SOS weakened. Additionally, PM exhibited a positive correlation with SOS in most pixels. Linear regression analysis revealed a significant negative correlation between relative humidity (RH) and the relationship between PM2.5 and SOS. However, in areas where RH exceeds 60.38%, this effect becomes unstable, presumably due to increased aerosol hygroscopicity or the saturation of aerosol particles. We also found that as road network density increased, the relationship between PM2.5 and SOS strengthened, whereas the impact of nightlight on this relationship was relatively weak. It is important to note that while the observed correlations reveal mechanisms by which PM2.5 affects SOS, they do not directly imply causation, as the complex interactions between environmental factors may influence these relationships. Finally, we incorporated PM2.5 into the phenology model and optimized its parameters using the least squares method, which improved the accuracy of SOS simulations and provided insights for predicting vegetation phenology in areas with severe PM pollution.

Patterns of Soil Stoichiometry Driven by Mixed Tree Species Proportions in Boreal Forest

Soil stoichiometry is essential for determining the ecological functioning of terrestrial ecosystems. Understanding the stoichiometric relationships in mixed forests could enhance our knowledge of nutrient cycling. In a mixed forest zone of Larix principis-rupprechtii (LP) and Betula Platyphylla (BP) in Hebei China, we conducted a study at six different sites with varying levels of tree species mixing. The proportion of L. principis-rupprechtii ranged from 0% to 100%, with intermediate values of 8.58%, 10.44%, 18.62%, and 38.32%. We compared soil stoichiometry, including carbon (C), nitrogen (N), and phosphorus (P), as well as chemical and physical properties across these sites. Piecewise structural equation modeling (piecewiseSEM) was used to assess the direct and indirect links between key ecosystem factors and their effects on soil stoichiometry. In mixed forests, the soil exhibited higher contents of soil organic matter (SOM), total nitrogen (TN), and total phosphorus (TP) compared to those in pure LP forests. Additionally, the soil C: N ratio in the 8.58% and 18.62% mixed forests as well as pure BP forests was significantly higher than that in LP forests. Structural equation modeling (SEM) revealed that the contents and ratios of soil C, N, and P exhibited different responses to mixed species proportions. The effect of mixed species proportions on soil nutrients was predominantly indirect, mediated primarily by variations in soil-available nutrients and, to a lesser extent, by physical properties and pH. Specifically, an increase in the proportion of LP in mixed forests had a direct negative effect on soil-available nutrients, which in turn had a positive effect on the content of SOM, TN, and TP and their respective ratios. Based on these findings, we can predict that soil nutrient limitation becomes more pronounced with increasing proportions of Larix principis-rupprechtii in the mixed forest. Our results emphasized the significance of changes in mixed species proportions on soil stoichiometry, providing valuable references for the sustainable development of forests.

Effect of detrital subsidy on the Collembola community structure in winter wheat agroecosystems

Mulch is widely used for improving soil quality and maintaining crop productivity. The effects of mulch use in agroecosystems can be assessed by the state of the soil biota. Springtails (Collembola) are a representative group of soil animals in agroecosystems that survive well under agricultural field conditions. We assessed the effect of adding a detrital subsidy with different carbon to nitrogen ratio (C:N) on springtails in a 4-year series of field experiments in winter wheat agroecosystems located in two agroecological zones (broad-leaved forest and steppe). The mulch effect depended on weather conditions. In dry years, the addition of mulch led to an increase in the proportion of epedaphic (upper-litter dwellers) springtails in the broad-leaved forest zone and to an increase in the proportion of atmobiotic forms (mostly inhabiting macrophytes) in the steppe zone. These changes begin to manifest approximately 1.5 months after the detrital subsidy addition. In general, mulch application had a positive and stabilizing effect on the springtail community structure in winter wheat agroecosystems, regardless of the agroecological zone. Our study showed that the addition of detrital subsidy helps to increase the abundance and stabilize the diversity of the springtail community. Changes observed in the structure of the Collembola community can be an indicator of improved soil health, and springtails can be used in assessing the effectiveness of agricultural practices.

Natural durability of Eucalyptus species harvested as electricity transmission poles in two different ecological zones of Ghana

This study assessed the possibility and feasibility of using two Eucalyptus species for electricity transmission poles in Ghana as a means of minimizing the import of transmission poles in the country. Eucalyptus species are grown in private and government-owned plantations in Ghana due to its growing demand for use as power line transmission poles. The species are seldom used by the furniture industry. The demand from the pole treatment industry for raw materials exceeds the domestic supply of teak, which is commonly used as transmission poles, resulting in the importation of pine poles to cover the deficit, hence the need for this study. The natural durability of Eucalyptus alba and Eucalyptus robusta in the Coastal Savanna Zone (CSZ) and Moist Semi-Deciduous Forest Zone (MSDFZ) was tested using white rot fungus (Coriolopsis polyzona) under an accelerated laboratory test. The results indicated significant variations in the mass lossess be-tween trees in the two vegetation zones. The sapwood and outer heartwood of the E. alba tree species of CSZ recorded the highest mass losses of 41.21 % and 20.79 %, respectively, compared to the E. robusta trees felled from MSDFZ that recorded mass losses of 32.3 % and 5.42 %, respectively. Also, the outer heart- wood and inner heartwood of the E. robusta MSDFZ felled trees were highly resistant (5.42 % and 6.99 %). CSZ wood species were less naturally resistant to C. polyzona attack than those harvested from MSDFZ, which appeared to be less susceptible and more naturally resistant to decay by C. polyzona. Both species are feasible for use as transmission line poles; however, trees from both ecological zones would need chemical preservatives to improve their service life, especially for outdoor applications.

Temperature Sensitivity of Peatland Soils Respiration Across Different Terrestrial Ecosystems

Sequential (S) and equal-time (ET) methods were applied to assess the temperature sensitivity of respiration of peat soils in different terrestrial ecosystems: southern tundra, northern taiga, and mixed coniferous–broadleaved forests. The Q10 values varied widely (1.3–4.8) and in case of the ET method decreased from northern to temperate latitudes. In the cold range (5–15°С), Q10 increased from the southern tundra (3.5) to the northern taiga (4.8) and then sharply decreased in the zone of mixed forests (2.5). Meanwhile, warm range (15–25°С) showed a clear decline of Q10 from northern to temperate latitudes: southern tundra (2.6) > northern taiga (1.6) > coniferous–broadleaved forests (1.3). Application of the S method resulted in low variability of Q10 values. Our results demonstrate a higher temperature sensitivity of the respiration of peat soils in northern latitudes as compared to that in the temperate zone. The Q10 values obtained in this study can be useful for calibration of regional carbon cycle datasets that consider the contribution of peat soils.

Widespread plant species temporal variation along environmental and microclimate gradients in Norwegian mountains in a climate change context

The effect of climate change on mountain vegetation is influenced by environmental factors and site effects. To monitor the effect of climate change we therefore need to understand species' sensitivity to microclimate and environmental gradients. The objective of this study is to study widespread plant species' temporal and spatial variation along environmental and microclimate gradients in Norwegian mountains along a coast–inland gradient. Occurrence and abundance of plant species were surveyed in 110 study plots in four mountains at two points in time, seven years apart. Of the 222 plant species registered, Salix herbacea, Phyllodoce caerulea, Carex bigelowii, Juncus trifidus, Vaccinium myrtillus, Avenella flexuosa, and Empetrum nigrum were widespread across all mountains. These species responded differently to environmental and microclimate gradients, and abundance data were more sensitive than occurrence data. During the short time span we observed some indications of response which might support the assumption that boreal species outcompete alpine species in the forest transition zone, but our data do not indicate this effect at higher altitudes. Monitoring of climate change in mountains needs to include plots along environmental and microclimate gradients as well as an abundance of a set of widespread plant species that represent regional, local environmental, and climate gradients. However, when monitoring perennial plant species, the need for long‐term monitoring projects is high because such species develop slowly over several decades.

Eneolithic and Bronze Age of the Forest Zone of Eastern Europe: disharmony of archaeological periodization

The results of the study of the discrepancies problem between regional cultural and chronological schemes in the context of the modified "system of three centuries" are presented. The study is based on the materials of the Garino and Chirki cultures, which sites are located in the extreme northeast of Europe, and on the results of radiocarbon dating of the Eneolithic and Bronze Age complexes of the Eastern European Plain forest zone. The disharmony of the archaeological periodization is expressed in the presence of both populations of the culture attributed to the Late Bronze Age and the Eneolithic culture in the studied region. As a result, it was determined that the sites with Chirkovsko-Seiminskiy or Fatianoid pottery types including the complexes of the Atamannur culture, are synchronous with the Garino culture within the Eneolithic or the 2nd half of the 3rd millennium B.C. However, the main arguments in favor of the Eneolithic of the Chirki culture are the use of pure copper artefacts together with intensive flint knapping with a developed bifacial industry. Therefore, it is predicted that existing ideas about the periodization of early metal sites in north-eastern Europe will be corrected. The comparison of radiocarbon dates showed that complexes with porous and asbestos pottery with sparse decoration (Orovnavolok XVI and Pelya types) are generally older than the pottery of the Garino (Choinovty) culture. This complicates the problem of the origin of the latter, since it is likely that its ceramic traditions originated to the west of the extreme north-east of Europe.

Preliminary study on hand dimensions as potential predictors of female populations native to forest and savanna zones in Ghana.

The hand is a versatile structure that performs numerous tasks, ranging from exertion of great force such as grip, pinch and torque to execution of precise fine motor skills. The aim of current study was to undertake a preliminary study on hand dimensions as potential predictors of female populations native to the forest and savanna zones of Ghana. A total of one hundred (100) female students aged between 17 and 24years were recruited into this study, comprising of 53 native to the forest zone and 47 native to savanna zone of Ghana between 12th June to 27th July, 2023 at the Department of Anatomy, School of Medicine and Dentistry, Kwame Nkrumah University of Science and Technology. Statistically significant positive correlation was observed between left hand length and right hand length (R = 0.923, p = 0.000). From the binary regression model, it could be speculated that left-hand breadth could predict female populations native to the savanna zone (LHB: β = -2.37, Expβ = 0.09, p = 0.014). However, right-hand breadth and length and left hand length did not show any potential of prediction (RHB: β = 0.900, Expβ = 2.460, p = 0.410; RHL: β = 0.168, Expβ = 1.683, p = 0.803; LHL: β = -0.300, Expβ = 0.741, p = 0.656). The study therefore may speculate that left handbreadth could have the potential to differentiate female populations native to savanna zone from females native to forest zone in Ghana.

Antiradical activity and bioactive substances of Eleutherococcus senticosus (Rupr. and Maxim) grown under hydroponic and soil conditions in Ararat Valley and Dilijan Forest zone

Antiradical activity and bioactive substances of Eleutherococcus senticosus (Rupr. and Maxim) grown under hydroponic and soil conditions in Ararat Valley and Dilijan Forest zone

The Analysis of NPP Changes under Different Climatic Zones and under Different Land Use Types in Henan Province, 2001–2020

Net Primary Productivity (NPP) is a crucial indicator of ecological environment quality. To better understand the carbon absorption and carbon cycling capabilities of Henan Province, this study investigates the trends and driving factors of NPP across different climatic zones and land use types. The Theil–Sen Median trend analysis method and the Mann–Kendall trend test are employed to monitor NPP changes from 2001 to 2020. The average annual NPP in Henan Province during this period was 414.61 gC·m−2·year−1, showing a significant increasing trend with a growth rate of 3.73 gC·m−2·year−1. Spatially, both the annual average NPP and its increase rate were higher in the western part of Henan compared to the eastern part, and NPP variability was more stable in the southern region than in the northern region. By classifying climatic zones and using the Geodetector method to assess NPP sensitivity to natural factors, the results show that climate and vegetation factors jointly influence NPP variations, with annual precipitation being the primary natural factor affecting NPP trends in Henan Province from 2001 to 2020. By analyzing the NPP gain and loss matrix, the impact of land use changes on NPP was evaluated. Forests had the highest average annual NPP at 483.52 gC·m−2·year−1, and the conversion of arable land to urban areas was identified as the primary land change type leading to NPP reductions. In the subtropical zone of Henan, forests, croplands, and grasslands exhibited higher NPP values and increase rates compared to those in the warm belt. This study provides new insights into the spatial variation of NPP caused by changes in climatic zones and land use types.

Initial soil moisture and soil texture control the impact of storm surges in coastal forests

Flooding and salinization triggered by storm surges threaten the survival of coastal forests. The forest root zone (top 40 cm of soil) is the most affected by surge flooding. Determining the effect of a storm surge on edaphic conditions is essential to estimate vegetation response. Pre-storm soil hydrology could mitigate or enhance the salinization effect, ultimately determining the resilience of the forest. Here we assess the influence of pre-storm soil water content and salinity on storm surge effects in coastal vegetated areas. A 1D model (HYDRUS-1D) is used to simulate saltwater infiltration from above through the unsaturated zone. Different water content and concentration scenarios, along with scenarios with variable storm surge salt concentration, storm surge height and storm surge flooding duration are considered. In soils characterized by silt and clay, the maximum salinized soil depth increases as water content increases, affecting the top 40 cm of soil, except for clay loam soil, for which only the top 20 cm are salinized. In sandy soils, the salinization process involves the entire soil column. The contribution of water content to salinization varies from 12 % to 30 % along the top 40 cm in fine soils. In fine soils, the storm-surge height also becomes relevant. A study case is presented to support the numerical results. Field data confirm that soil water content controls the salinization of the root zone in clay and silt soils. Overall, we conclude that the root zones of coastal forests with clay and silt soils and low water content are the most at risk during storm surges. These events have the potential to radically change edaphic conditions and affect ecosystems.

Evaluation of forest ecosystem resilience to drought considering lagged effects of drought.

Drought can cause significant disruption to forest ecosystems and may have long-term impacts on the structure and function of ecosystems after the end of drought. This is the key to quantifying the ability of ecosystem to respond to disturbance events by comprehensively analyzing the impact of drought on vegetation, the lagged effect, and ecosystem resilience to drought. This article takes broad-leaved forests and coniferous forests in multiple temperature zones of China as the object of study, using distributed lagged nonlinear model (DLNM) to construct a systematic method. Our results show that the main sensitive lagged time for coniferous forests and broad-leaved forests is the first 3 months in various temperature zones, with the strongest lagged effect in the month when the drought incidents occur. Coping capacity represents ecosystems to remain stable during droughts, and we quantified the indicator by the ratio of the resistance (the difference between NDVI value before the drought and during the drought) to recovery (the difference between NDVI value after the drought and during the drought). When dealing with intensive drought events, the coping capacity of subtropical broad-leaved forests (-0.67) and tropical broad-leaved forests (-0.88) exhibit the strongest coping capacity (value tends to -1). Overall, vegetation growth in subtropical and tropical regions is less affected by drought compared to temperate and cold temperate zones. The research results help us understand the comprehensive impact of drought on vegetation and the strategies for different vegetation to cope with drought.

Eutrophication of Lakes: From Global Process to Regional Implication in the Kola Arctic Region

ABSTRACTEutrophication of water bodies is analysed as a global process. The volumes of globally increasing use of nitrogen and phosphorus are demonstrated, with the dispersion of these elements leading to increased nutrient contents in lakes and rivers. Results of original studies on remote lakes in the Arctic zone indicate that the content of nutrients in these lakes has increased over the past decades. Concentrations of nitrogen, phosphorus and organic matter in lake waters tend to increase in the absence of anthropogenic effects. Simultaneously, the silicon concentrations were found to decrease because of the consumption by diatoms. Low concentrations of bioavailable nutrients confirm that these nutrients are rapidly spent in the production processes of ecosystems. The calculated trophic state index (according to R. Carlson) indicates that the number of oligotrophic lakes in the forest tundra zone decreased by 50% by 2010–2018, and these lakes are absent from the northern taiga zone. Temperature increase and climate warming in the Arctic zone first caused the increase in the contents of nutrients in the lakes and their trophic states.

"Two zones and three centers" distribution and suitable areas shift of an evergreen oak in subtropical China under climate scenarios.

Understanding the impact of climate change on the geographical distribution of species is a fundamental requirement for biodiversity conservation and resource management. Quercus oxyphylla, an evergreen oak endemic to China, plays a crucial role in maintaining the ecological stability in subtropical regions and high economic value attributed to its dark and high-density heartwood, but the existing resources are close to endangered. Currently, limited knowledge exists regarding its distribution and potential influences of climate change on suitable areas. This study utilized 63 occurrence records and Biomod2 platform, to predict changes in suitable areas for Q. oxyphylla under future climate change. The results revealed that (1) Q. oxyphylla showed a pattern of three disjunctive geographical centers in the eastern subregion of subtropical evergreen broad-leaved forest region (IVA): Qinling-Daba Mountains, Nanling Mountains and Wuyi Mountains center. Currently, the highly suitable areas concentrated in two zones divided by the Yangtze River, that is, the northern subtropical evergreen and deciduous broad-leaved forest zone (IVAii) and the mid-subtropical evergreen broad-leaved forest zone (IVAi). (2) The temperature-related variables, such as annual temperature range (Bio7), the mean diurnal range (Bio2), and annual mean temperature (Bio1), were identified as the key determinants of the distribution pattern. Because of its considerable climatic variations in temperature and water conditions, Q. oxyphylla's habitat displayed a wider climate niche and strong physiological tolerance to climate change. (3) Under future climate scenarios, the suitable area of the species was expected to overall expand with significant regional differences. The suitable area in IVAi was expected to expand significantly northward while that in IVAii was expected to gradually shrink. To address the impact of climate change, it is necessary to develop conservation plans focused around the three distribution centers, implement localized and regional conservation policies, and conduct educational outreach among local people.