Trees, Forests and People最新文献

{"title":"Capturing trends in forest structural complexity development using laser scanning techniques","authors":"Reinis Cimdins ,&nbsp;Tuomas Yrttimaa ,&nbsp;Juha Hyyppä ,&nbsp;Mikko Vastaranta ,&nbsp;Ville Kankare","doi":"10.1016/j.tfp.2025.100954","DOIUrl":"10.1016/j.tfp.2025.100954","url":null,"abstract":"<div><div>Forest structural complexity reflects realized niche occupancy, capturing how effectively the vegetation utilizes available resources and provides habitats for species. This makes it a key indicator of forest ecosystem diversity, and an important characteristic to be monitored to facilitate sustainable forest management and conservation planning. Laser scanning has been recognized as a feasible technology for the characterization of heterogeneity in forest structure, reflecting its structural complexity. However, less is known about the capability of different laser scanning techniques to capture structural complexity development through time, and whether the cross-use of various data types and analysis methods yields consistent observations of the development. We aim to address this knowledge gap by investigating the capability of different laser scanning techniques to assess forest structural complexity development and evaluate whether comparable observations can be obtained regardless of the laser scanning technology used. The experiments were conducted across 49 sample plots within southern boreal forests in Evo, Finland. A 7–10-year monitoring period was captured using terrestrial laser scanning (TLS), and airborne laser scanning (ALS) at three different resolutions representing low (0.4-1 pts/m²), medium (15-28 pts/m²), and high (200-3600 pts/m²) point densities. Eight metrics were used for structural complexity characterization: mean canopy height, canopy rugosity, gap fraction, vegetation occupancy, vertical evenness (Shannon entropy), variability in crown area and tree height, and mean fractal dimensions (box-dimension) among trees. Comparison of observations of structural complexity development showed that gap fraction and Shannon entropy exhibited consistent development directions and similar metric change magnitudes across all the investigated laser scanning techniques. In contrast, metrics characterizing three-dimensional complexity, such as vegetation occupancy and mean box-dimension, were more sensitive to point cloud data characteristics. These findings provide insights into selecting appropriate laser scanning techniques and analysis methods to monitor forest structural complexity development for applications such as conservation planning.</div></div>","PeriodicalId":36104,"journal":{"name":"Trees, Forests and People","volume":"21 ","pages":"Article 100954"},"PeriodicalIF":2.7,"publicationDate":"2025-07-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144711156","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Impact of the interaction between drought and wildfires on the gross primary productivity (GPP) of boreal forest exhibit time-scale dependence on time scales","authors":"Shaojie Lai ,&nbsp;Risu Na ,&nbsp;Li Na ,&nbsp;Yin Shan ,&nbsp;Mingxing Li ,&nbsp;Jisiguleng Wu ,&nbsp;Jiarong Wang","doi":"10.1016/j.tfp.2025.100953","DOIUrl":"10.1016/j.tfp.2025.100953","url":null,"abstract":"<div><div>Changes in forest gross primary productivity (GPP) are essential for understanding the dynamics of the global carbon cycle and impacts of climate change. Given the increasing frequency of droughts and wildfires due to climate change, assessing their impact on GPP in boreal forests has become increasingly important. This study utilized remote sensing data, including GPP data, the standardized precipitation-evapotranspiration index (SPEI), and burned area data from 2001 to 2022, and employed trend analysis, Pearson correlation analysis, and Shapley Additive Explanations (SHAP values) to examine the spatiotemporal characteristics of GPP in boreal forests and their response mechanisms to drought and wildfires. The results were as follows. (1). GPP in boreal forests exhibited a spatial pattern of being higher in the south and lower in the north, with approximately 54.14 % of the area exhibiting an increasing trend in GPP and approximately 41.0 % showing a decreasing trend. (2) Areas with a declining GPP highly overlapped with regions that experienced intense drought. The SPEI primarily showed a negative correlation with GPP; however, the proportion of positively correlated areas increased with longer SPEI time scales. (3) Wildfires generally exerted a negative impact on vegetation GPP, as burned areas typically decreased in productivity compared to unburned regions; however, most affected areas demonstrated a basic recovery in GPP within five years. (4) Shrublands, grasslands, and savannas exhibited a higher GPP sensitivity to drought and wildfires, whereas forest communities demonstrated greater ecological resilience. (5) The interaction between drought and wildfires exacerbated negative impacts on GPP over short-term time scales; however, a gradual weakening influence was observed over medium- to long-term timescales. This study offers novel insights into and a theoretical foundation for assessing and understanding the impacts of drought and wildfires on the GPP of boreal forests.</div></div>","PeriodicalId":36104,"journal":{"name":"Trees, Forests and People","volume":"21 ","pages":"Article 100953"},"PeriodicalIF":2.7,"publicationDate":"2025-07-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144711155","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Detecting oil palm plantations and mangroves overlooked by IGBP land-cover products with “ground-truthing from the sky” across Southeast Asia","authors":"Yadanar Ye Myint ,&nbsp;Joseph Emile Honour Percival ,&nbsp;Kaoru Kitajima","doi":"10.1016/j.tfp.2025.100950","DOIUrl":"10.1016/j.tfp.2025.100950","url":null,"abstract":"<div><div>Tropical deforestation in Southeast (SE) Asia is largely driven by expansion of oil palm plantations, which are difficult to detect with global- or regional-scale remote-sensing products. This paper demonstrates a straight-forward method for “ground-truthing from the sky” with very high resolution (VHR) photographic images to detect oil-palm cultivation and other drivers of deforestation across SE Asia. The MCD12Q1 land-cover is a widely used land-cover product that generates annual 500 m-pixel maps of 17 IGBP (International Geosphere-Biosphere Programme) classes. While this resolution is practical for regional assessments across SE Asia (∼4.5 million km²), it is too coarse to identify fine-scale, agriculture-driven conversions such as oil-palm expansion. Our approach was to integrate MCD12Q1 data with VHR imagery from Google Earth by random subsampling within each major land cover type to which forests had transitioned during two periods (2001–2010 and 2010–2018). Each of the 260 verification points in each post-transition land type was visually interpreted, from which we generated correction factors to calibrate land-use change probabilities. Whereas uncalibrated results showed that 12 % and 9 % of forested areas were converted to woody savanna and savanna, VHR-images showed that 32 % to 46 % of them were oil palm plantations. After application of these correction factors, we estimated that 40 % and 48 % of forest losses were due to oil palm expansion, whereas the remaining forest loss was attributed to degradation to savannas and grasslands. Additionally, permanent wetland classified by MCD12Q1 was found to consist of mangroves (63 %), aqua farms (20 %), and oil palms (8 %) rather than lakes, rivers and marshes in the region. While MODIS remains a valuable source for analyzing land use changes across large areas, detection of deforestation driven by agricultural activities benefits from calibration with VHR imagery. Our approach is straightforward and requires minimal expertise, making it easily adoptable by local governments, NGOs, land managers and others.</div></div>","PeriodicalId":36104,"journal":{"name":"Trees, Forests and People","volume":"21 ","pages":"Article 100950"},"PeriodicalIF":2.7,"publicationDate":"2025-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144695211","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Variation of heartwood-sapwood physicochemical properties in Populus euphratica along groundwater depth gradients in the Lower Tarim River, Northwest China","authors":"Tongyu Chen ,&nbsp;Tayierjiang Aishan ,&nbsp;Ümüt Halik ,&nbsp;Shiyu Yao","doi":"10.1016/j.tfp.2025.100948","DOIUrl":"10.1016/j.tfp.2025.100948","url":null,"abstract":"<div><div>Variation in physical and chemical properties of <em>Populus euphratica</em> Oliv. heartwood and sapwood under different groundwater depths reflect species-specific water and nutrient requirements. This study examines natural <em>P. euphratica</em> forest in the Arghan section of the lower Tarim River, analyzing groundwater depth-dependent changes in heartwood and sapwood characteristics and their interrelationships. Results demonstrate that heartwood rate exhibited the highest coefficient of variation (78.41 %), while heartwood density showed the lowest (7.57 %). With the increase of groundwater depth, both heartwood radius (HR) and sapwood width (SW) initially increased and then decreased. Heartwood area (HA) remained consistently larger than sapwood area (SA), and both showed significant differences under different groundwater depths (<em>p</em> &lt; 0.05). HR, HA, and SW exhibited significant positive correlations with groundwater depth (<em>p</em> &lt; 0.05). Chemically, maximum heartwood cellulose content occurred at 8.2 m groundwater depth, while sapwood cellulose peaked at 4.8 m. Heartwood consistently displayed higher cellulose content than sapwood at equivalent groundwater depths. Both heartwood and sapwood lignin contents reached maxima at 4.3 m groundwater depth. Random forest analysis identified heartwood cellulose, lignin content, and heartwood density as the most responsive parameters to groundwater depth variations. These findings suggest <em>P. euphratica</em> adapts to arid environments through optimized water utilization and physiological trait adjustments under water stress conditions.</div></div>","PeriodicalId":36104,"journal":{"name":"Trees, Forests and People","volume":"21 ","pages":"Article 100948"},"PeriodicalIF":2.7,"publicationDate":"2025-07-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144665806","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Drivers of forest structure and biomass along a climatic gradient in the Soutpansberg, South Africa","authors":"Martin A. Honold ,&nbsp;Torben Hilmers ,&nbsp;Coert J. Geldenhuys ,&nbsp;Lucky Makhubele ,&nbsp;Johan J. van Tol ,&nbsp;Shamim Ahmed ,&nbsp;Arno Buys ,&nbsp;Elmarie Kotze ,&nbsp;Ratsodo P. Tshidzumba ,&nbsp;Paxie W. Chirwa ,&nbsp;Ndivhuwo Tshaduli ,&nbsp;Mulugheta G. Araia ,&nbsp;Enno Uhl ,&nbsp;Hans Pretzsch","doi":"10.1016/j.tfp.2025.100945","DOIUrl":"10.1016/j.tfp.2025.100945","url":null,"abstract":"<div><div>Forest structure plays a key role for providing different ecosystem services in rural regions worldwide. In forests and woodlands of southern Africa, there is a lack of quantitative information on prevailing structures, their abiotic and biotic drivers, as well as how stand characteristics will be affected by climate change. In this study, we established permanent research plots in mature developing stages of representative forests and woodlands occurring along a strong climatic gradient. Effects of site-available soil water and forest type were investigated for relevant dendrometric, as well as structural forest variables. We found site-available soil water having a significantly positive effect on all variables, apart from tree density and the ratio of multi-stem trees. Among the factors influencing site-available soil water, climate had a higher impact than topographical wetness index and soil available water capacity. Studied variables were also strongly influenced by the different forest and woodland types emerging, probably due to different species compositions, survival strategies and fire adaptations. Structural forest variables were revealed to have a positive effect on AGB especially in taller stands having enough space to form multiple canopy layers. In light of climate change with less soil water available and a related ongoing species and biome shift in southern Africa, our findings indicate that in the future, most of the studied forest variables, their related ecosystem functions and services are likely to decrease in the Soutpansberg region. The results of this study could be of use as input data for landscape level modelling, as well as for creating local management policies.</div></div>","PeriodicalId":36104,"journal":{"name":"Trees, Forests and People","volume":"21 ","pages":"Article 100945"},"PeriodicalIF":2.7,"publicationDate":"2025-07-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144680783","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"National growth models for stand basal area, volume, and biomass in Chinese larch plantations: integrating stand structure and species effects","authors":"Yangping Qin ,&nbsp;Xiao He ,&nbsp;Hong Guo ,&nbsp;Chaofan Zhou ,&nbsp;Weisheng Zeng ,&nbsp;Xinyun Chen ,&nbsp;Xiangdong Lei","doi":"10.1016/j.tfp.2025.100943","DOIUrl":"10.1016/j.tfp.2025.100943","url":null,"abstract":"<div><div>Forest growth and yield models are essential tools for forest management decision-making, but most models have neglected the inclusion of stand structure. The relationship between stand structure and stand growth has been widely reported, but the results remain inconsistent. The objective of the study was to develop national growth models for stand basal area, volume, and total biomass of four larch species plantations and quantify the effect of stand structure on basal area, volume, and total biomass. After testing nonlinear mixed effects, we developed stand basal area, volume, and total biomass models for <em>Larix gmelinii, Larix olgensis, Larix gmelinii</em> var. <em>principis-rupprechtii, and Larix kaempferi</em> plantations by incorporating tree size differentiation indices (DBH-based Shannon-Wiener index, D_Sh; DBH-based Simpson index, D_Si). Models were calibrated with 2, 129 permanent sample plots from four periods of China's National Forest Inventory. The national-scale models demonstrated high predictive accuracy, with adjusted <em>R</em>² &gt; 0.95, and 10-fold cross-validation confirmed robust generalization without over/underfitting. Stand basal area, volume, and biomass showed significant positive correlations with D_Sh and D_Si. Our approach successfully captured growth differences among the four larch species. We quantified the effects of tree size diversity on stand growth and enable tree species-specific management. These findings highlight that both tree species selection and structural optimization (e.g., regulating D_Sh/D_Si through density control) are critical for enhancing stand productivity. It is recommended to apply thinning regimes to maintain high tree size diversity for promoting stand growth and quality improvement of larch forests nationwide.</div></div>","PeriodicalId":36104,"journal":{"name":"Trees, Forests and People","volume":"21 ","pages":"Article 100943"},"PeriodicalIF":2.7,"publicationDate":"2025-07-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144654372","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Impact of drought stress and fertilization on plant traits and nonstructural carbohydrates of Red-Heart Chinese fir","authors":"Ren You ,&nbsp;Xiangwen Deng ,&nbsp;R. Alex Thompson ,&nbsp;Inès A. Cauquil ,&nbsp;Henry D. Adams ,&nbsp;Shuai Ouyang ,&nbsp;Wenhua Xiang","doi":"10.1016/j.tfp.2025.100946","DOIUrl":"10.1016/j.tfp.2025.100946","url":null,"abstract":"<div><div>Understanding how drought stress and fertilization influence plant physiological responses is essential for improving forest management under climate change. Previous research has primarily focused on the effects of drought stress on resource allocation and mortality. However, the interaction effect of fertilization and drought on key plant traits and non-structural carbohydrates (NSCs) dynamics remains uncertain, particularly in Red-Heart Chinese fir (<em>Cunninghamia lanceolata</em> (Lamb.) Hook.). In this study, the effects of different drought stress gradients and fertilization on aboveground plant traits (different organ biomass, water content, needle number, needle area), belowground plant traits (tap root depth and lateral root spreads), leaf water potential and NSCs were examined in a pot experiment. The trade-offs in growth between aboveground and belowground plant traits become increasingly evident with soil drought gradients. Saplings in the wettest (<em>W</em>_25min) and driest (<em>W</em>_0min) group in both fertilized and unfertilized groups show clear differentiation along the two principal component axes, which are primarily determined by variations in the number of leaves on branches and leaf predawn water potential. Drought intensity mainly influences the leaf total NSCs, and the drought duration mainly influences the branch total NSCs. Fertilization typically promotes the growth of plants, especially below ground tissues. However, fertilization during drought exacerbated mortality in our experiment, especially for the moderate drought. The work highlights that Red-heart Chinese fir traits respond to drought stress gradients and fertilization, demonstrates that fertilization in combination with drought has an antagonistic effect on the growth and survival of red-heart Chinese fir saplings.</div></div>","PeriodicalId":36104,"journal":{"name":"Trees, Forests and People","volume":"21 ","pages":"Article 100946"},"PeriodicalIF":2.7,"publicationDate":"2025-07-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144654375","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Altered composition and structure of plant communities in response to Lantana camara invasion in forest ecosystems of Kumaun Himalaya, India","authors":"Charu Joshi,&nbsp;Vartika Joshi,&nbsp;Archana Fartyal,&nbsp;Kiran Bargali,&nbsp;Surendra Singh Bargali","doi":"10.1016/j.tfp.2025.100947","DOIUrl":"10.1016/j.tfp.2025.100947","url":null,"abstract":"<div><div>Ecosystem stability is being threatened by the invasion of exotic plant species. This study examined the impact of <em>Lantana camara</em> (Verbenaceae) on associated plant communities and regeneration status across three different forests: Banj oak (<em>Quercus leucotrichophora</em>), Chir pine (<em>Pinus roxburghii</em>) and Sal (<em>Shorea robusta</em>) in Kumaun Central Himalaya, India. In each forest site, two paired plots (invaded by <em>L. camara</em> and uninvaded) of 0.5 hectare each were established. Within each plot, 5 random quadrats of 10 × 10 m for trees, 10 quadrats of 5 × 5 m for shrubs and 20 quadrats of 1 × 1 m for herbs were sampled and community variables for each species were recorded. Regeneration status was studied by classifying individuals into different size classes and developing population structure for tree species. Results showed decreasing trend in the density (92 % in oak, 74.7 % in pine, and 80.3 % in sal forests) and basal area of tree layer in invaded plots. However, shrub and herb layers exhibited higher density and diversity in invaded areas. Tree regeneration was decreased in invaded sites with few seedlings converting to sapling and mature trees mainly in oak and pine forests. Statistical analyses (ANOVA) revealed that invasion had significant impact on density, diversity (H′), evenness (e) and species richness (SN), especially in the seedling and shrub layers. Principal Component Analysis indicated that variation due to invasion was explained by differences in diversity, species richness and dominance. The invasion by <em>L. camara</em> led to increase in the shrub and herb layer, which in turn had a detrimental impact on the tree layer of the studied forests. The observed decline in species diversity and richness indicate loss of ecosystem resilience and function. This decline in the native flora could have long-term harmful effect on the forest ecosystem.</div></div>","PeriodicalId":36104,"journal":{"name":"Trees, Forests and People","volume":"21 ","pages":"Article 100947"},"PeriodicalIF":2.7,"publicationDate":"2025-07-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144654374","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Diurnal variation and prediction method of floor fuel moisture content in a Pinus massoniana-dominated forest in Guizhou province, China","authors":"Yunlin Zhang ,&nbsp;Man Liu ,&nbsp;Na Jin","doi":"10.1016/j.tfp.2025.100940","DOIUrl":"10.1016/j.tfp.2025.100940","url":null,"abstract":"<div><div>Fuel moisture content (FMC) on forest floor exhibits consistent diurnal fluctuations between daytime and night-time, and the construction of a high-precision prediction model is important for estimating the diurnal variation of forest fires and implementing scientific management strategies. In this study, typical fuel from a <em>Pinus massoniana</em> dominated forest in southwestern China was selected as the research object, and its moisture content was monitored during the fire prevention period. Analyze the diurnal variation of FMC and its driving factors, establish a prediction model of moisture content based on the classification of diurnal changes, and discuss the necessity of predicting FMC separate during the daytime and night-time. The results show that: (1) a significant difference exists in the FMC between day and night-time in <em>Pinus massoniana</em> dominated forests, and the daily variation patterns of FMC are similar (2) with an increase in air temperature and wind speed, the FMC showed a significant downward trend, whereas the dynamic changes in humidity and FMC showed a significant positive correlation. Simultaneously, the impact of meteorological factors on the dynamic changes of FMC had a certain lag effect. (3) The Nelson method was the most effective in predicting the diurnal moisture content of <em>Pinus massoniana</em> dominated forests in the southwest forest area. The mean absolute errors for the entire day, daytime, and night-time that were 0.303, 0.329, and 0.197 %, respectively. (4) It is necessary to distinguish between daytime and night-time to predict the FMC separately. We elucidated the law of diurnal variation of FMC, and FMC prediction models should be established separately for daytime and night-time periods, which has important guiding significance for research on diurnal changes in forest fires and night-time fire prediction, and provides basic data support for managing extreme fires that may occur under extreme climate conditions.</div></div>","PeriodicalId":36104,"journal":{"name":"Trees, Forests and People","volume":"21 ","pages":"Article 100940"},"PeriodicalIF":2.7,"publicationDate":"2025-07-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144654376","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Air temperature and particulate matter 2.5 are key environmental drivers of negative air ion dynamics: Results from long-term monitoring in subtropical evergreen broad-leaved forest","authors":"Aibo Li ,&nbsp;Ziqing Zhao ,&nbsp;Yuhao Yang ,&nbsp;Kun Sun ,&nbsp;Jilai Chen ,&nbsp;Benzhi Zhou","doi":"10.1016/j.tfp.2025.100944","DOIUrl":"10.1016/j.tfp.2025.100944","url":null,"abstract":"<div><div>Negative air ions (NAIs) are widely studied for their role in evaluating the therapeutic effects of forests on human health and mitigating air pollution through mechanisms such as neutralizing airborne particulate matter and reducing reactive gaseous pollutants via oxidative pathways. This study examined NAI temporal dynamics and key environmental drivers in forests. On-site monitoring (June 2021-May 2023) included NAIs, air temperature, relative humidity, wind speed, direct radiation, and particulate matter. We found that NAI concentrations in the forest generally met the World Health Organization's clean air threshold, averaging 1698 ± 347 ions·cm⁻³. NAI concentrations followed a single-peak diurnal pattern, peaking at 12:00–15:00 and reaching a minimum at 5:00–8:00. Seasonal variations in NAI concentrations were significant, with the highest levels in summer (1919 ± 260 ions·cm⁻³), followed by autumn (1734 ± 115 ions·cm⁻³), spring (1580 ± 338 ions·cm⁻³), and winter (1535 ± 226 ions·cm⁻³). Correlation analyses indicated significant positive correlations between NAI concentrations and air temperature, wind speed, and direct radiation, while relative humidity and particulate matter showed significant negative correlations. Multiple regression and random forest analyses identified air temperature and particulate matter 2.5 as the primary factors influencing NAI concentrations. A predictive model (NAIs = 18.4 × Ta–17.5 × WS–3.6 × RH–8.0 × PM_2.5 + 5.3 × PM₁₀ + 1.8 × 10³) was developed to estimate NAI concentrations in forest environments. Given these temporal patterns of NAI, the findings support scheduling forest therapy in summer and autumn afternoons to maximize exposure to NAI at peak concentrations. Additionally, the predictive model offers a practical tool for air quality management in forested areas, supporting evidence-based decisions in urban green space planning, forest therapy zone scheduling, and environmental health policy development. This study addresses a crucial knowledge gap regarding NAI dynamics and environmental drivers in forests, potentially informing evidence-based decision-making in forest-based health interventions and ecological planning.</div></div>","PeriodicalId":36104,"journal":{"name":"Trees, Forests and People","volume":"21 ","pages":"Article 100944"},"PeriodicalIF":2.7,"publicationDate":"2025-07-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144632486","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}