Afforestation Projects Research Articles

Responses of Biomass and Allometric Growth Equations of Juvenile Mangrove Plants to Salinity, Flooding, and Aboveground Competition

China has implemented large-scale mangrove restoration and afforestation initiatives in recent years. However, there has been a paucity of research on the growth of mangrove seedlings in a composite stress environment and the allometric growth equation of mangrove seedlings. To enhance juvenile mangrove survival rates and develop precise carbon sequestration models, this study examines biomass accumulation patterns and allometric equation development under diverse environmental and biological conditions. A manipulative field experiment employed a three-factor full factorial design using seedlings from eight mangrove species. The experimental design incorporated three variables: salinity, flooding (environmental stressors), and aboveground interspecific competition (a biological factor). Following a two-year growth period, measurements of surviving seedlings’ basal diameter, plant height, and above- and belowground biomass were collected to assess growth responses and construct allometric models. Results indicated that high salinity reduced total mangrove biomass, whereas prolonged flooding increased tree height. Interspecific competition favored fast-growing species (e.g., Sonneratia caseolaris) while suppressing slow-growing counterparts (e.g., Avicennia marina). Synergistic effects between salinity and flooding influenced biomass and basal diameter, whereas salinity–flooding and salinity–competition interactions demonstrated antagonistic effects on tree height. High salinity, prolonged flooding, and competition elevated the proportion of aboveground biomass allocation. The results suggest that salinity stress and flooding stress were major growth-limiting factors for juvenile mangroves. Slow-growing species are not suitable to be mixed with fast-growing species in mangrove afforestation projects. Allometric models fitting for juvenile mangroves growing under different environmental factors were also developed. This study deepens our understanding of the growth of mangrove seedlings under composite stress conditions, provides effective tools for assessing the carbon sink potential of mangrove seedlings, and provides scientific guidance for future mangrove restoration projects.

Drought Amplifies the Suppressive Effect of Afforestation on Net Primary Productivity in Semi-Arid Ecosystems: A Case Study of the Yellow River Basin

As a critical ecologicalbarrier in the semi-arid to semi-humid transition zone of northern China, the interaction between afforestation and climatic stressors in the Yellow River Basin constitutes a pivotal scientific challenge for regional sustainable development. However, the synthesis effects of afforestation and climate on primary productivity require further investigation. Integrating multi-source remote sensing data (2000–2020), meteorological observations with the Standardized Precipitation Evapotranspiration Index (SPEI) and an improved CASA model, this study systematically investigates spatiotemporal patterns of vegetation net primary productivity (NPP) responses to extreme drought events while quantifying vegetation coverage’s regulatory effects on ecosystem drought sensitivity. Among drought events identified using a three-dimensional clustering algorithm, high-intensity droughts caused an average NPP loss of 23.2 gC·m−2 across the basin. Notably, artificial irrigation practices in the Hetao irrigation district significantly mitigated NPP reduction to −9.03 gC·m−2. Large-scale afforestation projects increased the NDVI at a rate of 3.45 × 10−4 month−1, with a contribution rate of 78%, but soil moisture competition from high-density vegetation reduced carbon-sink benefits. However, mixed forest structural optimization in the Three-North Shelterbelt Forest Program core area achieved local carbon-sink gains, demonstrating that vegetation configuration alleviates water competition pressure. Drought amplified the suppressive effect of afforestation through stomatal conductance-photosynthesis coupling mechanisms, causing additional NPP losses of 7.45–31.00 gC·m−2, yet the April–July 2008 event exhibited reversed suppression effects due to immature artificial communities during the 2000–2004 baseline period. Our work elucidates nonlinear vegetation-climate interactions affecting carbon sequestration in semi-arid ecosystems, providing critical insights for optimizing ecological restoration strategies and climate-adaptive management in the Yellow River Basin.

Remote Sensing‐Based Assessment of Carbon and Water Ecosystem Services in Response to Climate and Vegetation Cover Changes Across Global Major River Basins

ABSTRACTImproving our understanding of terrestrial carbon‐water coupling processes at the basin scale is crucial for assessing the impacts of global change on river basin's ecosystem services. Supported by remote sensing technology, previous studies have investigated the variability of carbon sequestration or water yield of a basin separately. However, the integration of these two components in an assessment system has rarely been considered, which may lead to partial appraisals of eco‐hydrological services. To address this knowledge gap, we have developed a new remotely sensed index, the Carbon‐Water Efficiency Index (CWEI), which is derived as the product of the normalized precipitation use efficiency (PUE) and water yield efficiency (WYE) during a specified period for a given basin, to quantify the coupling carbon‐water ecosystem service. In this study, the spatial and temporal variabilities of CWEI were investigated using satellite‐based products across the 38 major river basins from 1982 to 2016. Furthermore, the response patterns of CWEI to its components were explored, and the contributions of the three variables (i.e., temperature, precipitation, vegetation coverage) on changes in CWEI were quantified for each of the basins. The results demonstrated that the CWEI exhibited an increase in 31.6% of the world's major river basins, of which 83.3% with an increasing CWEI demonstrated a response pattern of increasing PUE and decreasing WYE. Furthermore, temperature was identified as the primary contributor to CWEI in 50% of the basins. It is noteworthy that green hotspot basins, where afforestation projects were underway, exhibited enhancements in reduced water yield pressure and demonstrable benefits to local ecohydrology. The proposed CWEI provides a new framework for comprehending the sustainable development of river basins worldwide.

Characteristics of the Distribution of Village Enclosure Forests in the Beijing Plain Area and Influencing Factors

Beijing’s plain-region villages face significant shortages of internal green space, yet studies on village enclosure forests as a supplementary green infrastructure to serve rural communities are limited. So, this study examines village enclosure forests in Beijing Plain to address rural forest shortages. Using 2019 aerial imagery (0.5 m resolution) and forest inventory data, we analysed 1271 villages’ 300 m radius forest coverage via ArcGIS Pro. Key findings show (1) overall forest coverage is 45.30%, higher in outer suburbs (OA), traditional villages (TSH), and large villages; (2) functional types are mainly ecological landscape (37.58%) and ecological–economic forests (36.37%); and (3) afforestation projects (Million-Mu Project rounds 1–2) account for 47.37% coverage. Regression analyses reveal human activities as dominant influencers, with cultivated land area (CLA) having the highest explanatory power. Other significant factors (p < 0.05) include distance from commercial residences (DCR), village size (VS), distance from famous historical sites based on developmental zoning, and forest functions to optimize rural habitats.

Estimating medium-term (40 years) carbon uptake in living biomass from Life Terra’s afforestation and reforestation actions: challenges and recommendations

This study presents a comprehensive methodology for estimating potential biomass and carbon accumulation in European afforestation activities expected over a 40-year timespan, developed for the Life Terra project (LIFE19 CCM/NL/001200). We synthesized data from allometric equations, Yield tables, National Forest Inventories, and National Greenhouse Gas Inventory Reports across four European biogeographic regions: Alpine, Atlantic, Continental, and Mediterranean. While Life Terra encompasses six planting categories (ecological restoration, timber plantations, agroforestry/food forests, gardens, green infrastructure, and others), our analysis focused primarily on timber plantations due to data availability and reliability constraints. The study showed significant regional variations in planting density and growth patterns. Initial planting densities in timber plantations varied substantially across biogeographic regions (1,869–7,702 trees/ha), following exponential decline patterns over time. By year 40, individual tree biomass estimates ranged from 0.08 to 0.20 t/tree across regions and species types (conifers and broadleaves), with survival rates varying between 22.0 and 49.7%. This translated to stand-level biomass estimates of 54.7–232.6 t/ha at age 40 years. Our biomass estimates generally aligned with country-specific literature and IPCC default values, though showing considerable variation across sites, highlighting the importance of local conditions in tree growth and stand dynamics. The study provides a robust framework for assessing carbon sequestration potential in European afforestation projects, while acknowledging key uncertainties related to survival/mortality rates and climate change impacts. This methodology remains open to refinement through additional biomass equations and revised Yield tables. The future field validation studies should also include non-timber plantation categories that are not covered here.

Технология восстановления лесных ландшафтов: разработка алгоритма функционирования справочной информационной системы FLR-Library

Most often, restoration of forest landscapes in the Russian Federation is carried out on the lands of the first group (forest lands not covered with forest), less often – the second group (non-forest lands of the forest fund). Afforestation of the lands of the third group – lands that currently do not belong to the forest fund, but after carrying out measures to plant forests and successfully implement them, in the future with prospects for transition to the lands of the forest fund – occurs locally. We analyzed standard projects on afforestation and reforestation, studied normative legal acts (Rules of afforestation, Rules of reforestation), local orders and resolutions in the field of afforestation, tax descriptions of forest taxing allotments, scientific works and recommendations of domestic and foreign authors in the field of reforestation and afforestation, on the design of technologies for afforestation and reforestation, the influence of soils on the choice of machines, mechanisms and technologies of afforestation. Based on the analysis, the classification of forest lands was clarified for the selection of adaptive restoration technology. We found some contradictions in the classification of soil types, which have a direct impact on the choice of technology and technical means, confirming the relevance of creating a unified classification convenient for the development of reforestation or afforestation projects. A statistical assessment of the degree of influence of the physical and mechanical properties of the soil, as well as the degree of dependence of the choice of technical means and the degree of controllability of soil properties (1 - weak, 2 – moderate, 3 – strong) in the decision–making process on the choice of technology for adaptive restoration of forest landscapes was carried out using hierarchical clustering by the method of J. Ward Jr. using the Minkowski measure, which is sufficiently resistant to emissions, at the significance level α = 0.05. Taking into account the analyzed input parameters, a basic algorithm for the functioning of the FLR system was formed, on the basis of which software will be developed to support management decision-making in the implementation of projects for adaptive restoration of forest landscapes.

Comparative Assessment of the Economic Efficiency of the Afforestation Project in the North-West of Russia

The study of carbon stocks in organic compounds within terrestrial ecosystems allows us to create a pool of potential carbon farming projects. At present, it is essential to assess the economic viability of natural-based solutions in order to develop strategies to encourage small and medium enterprises (SME) and governments to address climate change through specific measures. This article is devoted to the study of the economic efficiency of afforestation projects. The purpose of this study is to evaluate the economic efficiency of the project and, based on NPV sensitivity analysis, to identify the factors affecting economic efficiency. This will make it possible to formulate directions for stimulating the development of afforestation projects using tools to improve their economic efficiency. Based on data on the number of carbon credits issued, their price, and the costs and other revenue associated with the implementation of the afforestation project, a sensitivity analysis of economic efficiency was conducted, highlighting the most significant factors. Given that different tree species are characterized by variable seedling values, planting costs, and sequestration potentials, an afforestation project with the most carbon efficient tree species was selected as a pilot project. Black alder exhibits the most optimal proportion between the volume of carbon units released and the cost of planting trees. A sensitivity analysis of the project’s net present value was conducted in order to ascertain the factors that have the most significant impact on the project’s economic efficiency. These include the discount rate based on the cost of capital and the cost of tree planting. As a result, this article makes recommendations for improving the economic efficiency of afforestation projects for SME. The government’s role in enhancing the economic efficiency of such initiatives entails reducing the cost of capital through a reduction in the key rate or the provision of subsidies for the interest rate on bank credits. An alternative approach involves the granting of subsidies for the cost of tree planting, since the effects can be seen as a series of public goods, such as the creation of recreational areas and increased biodiversity of the ecosystem.

Evaluation of Scots Pine (Pinus sylvestris L.) High Mountain Afforestation: The Case of the Galyan

This study aims to evaluate the afforestation success based on the 10-year development of Scots pine (Pinus sylvestris L.) seedlings planted at higher elevations within the current forest boundary as part of the "Galyan Afforestation Project." Sample plots were selected from the Scots pine reforestation area, established in 2007, based on three different aspects (north, northeast, northwest) and two elevation ranges (1790–1890 m, 1891–1990 m). In 2011, data were collected from each sample plot, including seedling length, root collar diameter, the number of branches on the latest shoot, the lengths of the longest branches in the north, south, east, and west directions, and the number of terminal buds. Additionally, the growth trends of the same areas were monitored based on on-site inspections conducted in 2016 (when the seedlings were 10 years old), and evaluations were made accordingly. Statistical tools such as ANOVA, Duncan test, t-test, and correlation analysis were employed to evaluate growth performance. The results showed that the average seedling height was 59.64 cm in 2010 and 93.85 cm in 2016, with height growth being more pronounced at lower elevations and on north-facing slopes. While initial growth was adequate, extreme climatic conditions such as frost, snow pressure, and waterlogging led to deformities, including branch and terminal shoot damage. Despite these challenges, the findings highlight that careful site selection—favoring northern aspects and lower elevations—can enhance growth outcomes. Furthermore, integrating ecological and forestry research with practical forestry strategies is essential for sustainable reforestation in mountainous regions.

Impact of Section 118 of Hptlra-1972 on Environmental Protection, Climate Change, and Entrepreneurial Environmentalism

Land ownership policies significantly influence environmental conservation, climate resilience, and sustainable entrepreneurship. Section 118 of the Himachal Pradesh Tenancy and Land Reforms Act, 1972 (HPTLRA-1972) regulates land ownership and acquisitions to protect local agricultural communities and prevent environmental degradation. While this provision has contributed to forest conservation, biodiversity protection, and climate resilience by restricting large-scale land acquisitions, it has also posed challenges to sustainable entrepreneurship, renewable energy development, and green infrastructure projects. The regulation plays a crucial role in mitigating climate change impacts by preventing deforestation and unregulated land use. However, it has also restricted external investments in eco-tourism, afforestation projects, and sustainable industries, limiting economic opportunities that align with environmental conservation goals. The restrictions have hindered the expansion of renewable energy projects like solar and wind farms, slowed climate-resilient infrastructure development, and constrained reforestation initiatives, thereby affecting carbon sequestration efforts. Additionally, Section 118 imposes limitations on land allotment for universities and green startups, creating bureaucratic hurdles for environmental education institutions, eco-tourism businesses, and sustainable agriculture ventures. Entrepreneurs face difficulties in acquiring land for organic farming, waste management enterprises, and green construction, impacting the growth of the circular economy and climate adaptation strategies. To balance environmental conservation with sustainable development, policy modifications are necessary. Recommended reforms include conditional exemptions for green investments, the establishment of Special Economic Zones (SEZs) for sustainable businesses, long-term leasing models, fast-track approvals for renewable energy projects, and public-private partnerships in green infrastructure. These measures would enable Himachal Pradesh to achieve climate resilience while promoting eco-friendly business models that support sustainable development goals (SDGs). This paper underscores the need for a balanced approach to land-use policies that protect natural ecosystems while facilitating environmentally responsible economic activities. By revising Section 118 strategically, Himachal Pradesh can unlock opportunities for green entrepreneurship and sustainable development without compromising ecological integrity.

Plant–Soil–Microbial Carbon, Nitrogen, and Phosphorus Ecological Stoichiometry in Mongolian Pine-Planted Forests Under Different Environmental Conditions in Liaoning Province, China

Mongolian pine (Pinus sylvestris var. Mongolia) has been widely utilized as a key species for afforestation projects within the Three-North Shelterbelt of Liaoning Province in China. Its impressive ecological resilience has made it a favorite choice for this endeavor. However, as the stands mature and climate conditions shift, some areas are experiencing premature decline or even mortality. Ecological stoichiometry is capable of uncovering the supply and equilibrium of plant and soil nutrients within ecosystems and is extensively utilized in the identification of limiting elements. Therefore, studying its ecological stoichiometry and internal stability dynamics is of crucial significance for clarifying the nutrient cycling process in the Mongolian pine region and alleviating the decline situation. The eastern and northwestern regions of Liaoning differ significantly in precipitation and soil nutrient availability. This study examines Mongolian pine plantations in both regions, analyzing the carbon (C), nitrogen (N), and phosphorus (P) content in plant tissues, soil, microbial biomass, and stoichiometric ratio under distinct environmental conditions. In order to provide a theoretical basis for alleviating the decline of artificial poplar forests and healthy management. Results indicate that (1) leaf C, N, and P contents in the eastern Liaoning region averaged 496.67, 15.19, and 1.66 g·kg−1, respectively, whereas those in northwestern Liaoning were 514.16, 14.82, and 1.23 g·kg−1, respectively. Soil C, N, and P concentrations exhibited notable regional differences, with eastern Liaoning recording 34.54, 2.62, and 0.48 g·kg−1, compared to significantly lower values in northwestern Liaoning (7.74, 0.77, and 0.21 g·kg−1). Similarly, microbial biomass C, N, and P were higher in eastern Liaoning (18.63, 5.09, and 7.72 mg·kg−1) than in northwestern Liaoning (10.18, 3.46, and 4.38 mg·kg−1). (2) The stoichiometric ratio of soil in the Mongolian pine plantations is higher than that in northwestern Liaoning, but the stoichiometric ratio of plants shows the opposite trend. Specifically, microbial carbon-to-nitrogen (MBC/MBN) ratios are higher in eastern Liaoning, whereas microbial carbon-to-phosphorus (MBC/MBP) and nitrogen-to-phosphorus (MBN/MBP) ratios are greater in northwestern Liaoning. Correlation analysis of plant–soil–microbe stoichiometry indicates that plant growth in both regions is co-limited by nitrogen, with Mongolian pine exhibiting strong internal stability.

Effects of soil moisture stress on water use and crop coefficient of <i>Pinus</i> <i>eldarica</i> and <i>Melia</i> <i>azedarach</i> at different growth stages in an arid region

Water scarcity, particularly in arid and semi-arid regions, is a critical issue affecting forest management. This study investigates the effects of drought stress on the water requirement and morphological characteristics of two important tree species Turkish pine and Chinaberry. Using a factorial design, the study examines the impact of three age stages (one-year-old, three-year-old, and five-year-old plants) and three levels of drought stress on these species. Microlysimeters of varying sizes were employed to simulate different drought conditions. Soil moisture was monitored to show the effect of the various irrigation schedules. The study also calculated reference crop evapotranspiration (ET0) using the PMF-56 method and developed plant coefficients (Kc) for the species. Results showed that evapotranspiration increased with soil moisture, peaking during summer and decreasing in winter. Turkish pine exhibited higher plant ET than Chinaberry, particularly among one-year-old seedlings. Drought stress significantly reduced evapotranspiration and water uses for both species, highlighting the importance of efficient water management in afforestation projects. The findings underscore the necessity of selecting drought-resistant species and optimizing irrigation practices to enhance the sustainability of green spaces in arid regions. These insights are crucial for improving urban forestry management and mitigating the impacts of water scarcity in Iran and similar climates globally.

Identifying seed families with high mixture performance in a subtropical forest biodiversity experiment.

Afforestation projects using species mixtures are expected to better support ecosystem services than monoculture plantations. While grassland studies have shown natural selection favoring high-performance genotypes in species-rich communities, this has not been explored in forests. We used seed-family identity (known maternity) to represent genetic identity and investigated how this affected the biomass accumulation (i.e. growth) of individual trees (n = 13 435) along a species richness gradient (1-16 species) and over stand age (9 yr) in a forest biodiversity experiment. We found that among the eight species tested, different seed families responded differently to species richness, some of them growing relatively better in low-diversity plots and others in high-diversity plots. Furthermore, within-species growth variation increased with species richness and stand age, while between-species variation decreased with stand age. These results indicate that seed families within species and their reaction norms along the species richness gradient vary considerably and thus can explain a substantial proportion of the overall variation in tree growth. Our findings suggest that the growth and associated ecosystem services of species-rich mixtures in afforestation projects can be optimized by artificially selecting seed families with high mixture performance in biodiversity experiments.

Achieving high-integrity tree-planting projects in the voluntary carbon market

Abstract Globally, the voluntary carbon market (VCM) is a popular mechanism for carbon emitters to purchase credits and offset their emissions. Despite criticisms of unclear carbon outcomes, long-term durability of projects, and impacts on local communities, there are few systematic studies that assess their ecological and social outcomes based on ground-level data and robust counterfactuals. This study synthesizes data from the carbon market registry, on-ground surveys, and satellite data to inform VCM standards and policies for land-use related carbon market projects in India. We analyzed satellite imagery to assess changes in tree cover in more than 20 000 plots participating in all VCM afforestation projects registered in the country as of 2022 and surveyed project developers to assess the implementation process and local households to and evaluate economic impacts for 366 households in two of the ongoing projects. We compare these results with comparable plots and households using statistical and machine learning approaches. We find robust evidence of increases in tree cover in both participating and comparable non-participating plots—however there are significantly higher increases in the former (average increase 48 compared to 26%). We also find increases in incomes and asset ownership in both participating and non-participating households in two projects, with significantly higher increases in income in one project and in assets in the other. However, half of the projects are no longer operational, which calls into question the durability of these projects despite positive outcomes for tree cover. Results suggest that VCM standards and policies that foster economic well-being of local stakeholders are more likely to deliver sustained carbon benefits. Successful, long-lasting projects provide examples that evaluation of project implementation plans for continuous engagement, economic incentives, and security of land tenure for local stakeholders at the outset could lead to more viable, long-term VCM projects. Robust counterfactual data on changes in tree cover and economic outcomes are critical for improving the integrity of the VCM.

Reducing Forest Fragmentation in Yunnan Province Dominated by Afforestation Projects

As a critical ecological security barrier, Yunnan Province has significantly reduced forest fragmentation through ecological restoration programs in recent years. However, the optimization process of the forest landscape and the most effective ecological restoration projects remain unclear. Our study combined land use data with 13 driving factors, including meteorological and socioeconomic data, to analyze the spatial distribution, temporal dynamics, and key ecological restoration programs of forest fragmentation using dynamic and static indexes, morphological spatial pattern analysis, boosted regression tree models, and partitioned statistical methods. We found that over the past 30 years, FF has significantly decreased. Fragmentation was higher before 2000 but has steadily declined, with eastern regions more fragmented than western areas. Forest landscapes have transitioned from degradation to recovery, with core forest areas expanding by 6997.72 km2. Afforestation was the main driver, adding 238,109.21 km2 of forest cover, while reforestation contributed 17,254.47 km2, improving patch size and connectivity. Regionally, the southwest has lower fragmentation due to ample rainfall and reforestation efforts, while central and northeastern areas face higher fragmentation from drought, human activities, and urban expansion. Our study offers a scientific basis for formulating effective ecological restoration policies.

Evolution of Disruption Resilience in the Wood Forest Products Trade Network, Considering the Propagation of Disruption Risks and Underload Cascading Failure

With the intensification of global resource competition, the issue of timber supply has escalated from an economic concern to a significant strategic challenge. This study focuses on the evolution of disruption resilience in the global trade network for wood forest products, aiming to reveal the patterns of resilience dynamics under disruption risks by simulating underload cascading failure phenomena. The study provides theoretical support for enhancing the security and stability of the global wood forest product supply chain. Utilizing global trade data from the UN Comtrade Database 2023, a directed weighted complex network model was constructed, spanning upstream, midstream, and downstream sectors, with trade intensity distances serving as edge weights. By developing an underload cascading failure model, the evolution of disruption resilience was simulated under various disruption scenarios from 2002 to 2023, and the long-term impacts of critical node failures on network performance were analyzed. The results demonstrate significant spatiotemporal heterogeneity in the disruption resilience of the global wood forest product trade network. The upstream network exhibits improved resilience in total node strength but reduced global efficiency. The midstream network shows marked volatility in resilience due to external shocks, such as the global financial crisis, while the downstream network remains relatively stable. Simulations reveal that failures in core nodes (e.g., China, the United States, and Germany) disproportionately degrade global efficiency and node strength, with node centrality metrics positively correlated with network performance loss. This study elucidates the evolutionary mechanisms of disruption resilience in the wood forest product trade network under risk propagation, offering actionable insights for optimizing network robustness and supply chain stability. It is recommended that policymakers promote green supply chain initiatives, accelerate afforestation projects, and enhance domestic timber self-sufficiency to reduce reliance on imported timber, thereby strengthening node resilience and fostering sustainable forest resource utilization for economic and environmental benefits.

Sustaining Urban Green Growth: Evaluating Ecological Efficiency and Resource-Use Drivers in Beijing’s Plains Afforestation Initiative

Efficiency assessment is a pivotal instrument in the pursuit of sustainable operations. It is imperative to evaluate government-funded afforestation initiatives to ensure the optimal utilisation of resources, thereby enhancing sustainability. In this study, a framework for measuring afforestation efficiency at the sub-compartment scale was established based on a Bootstrap-modified Data Envelopment Analysis (DEA) model. The empirical study included 48 afforestation sub-compartments from six districts involved in the Beijing Plains Afforestation Project. The results of the study indicate that the efficiency of the afforestation sub-compartment has much room for improvement and significant individual differences. The mean scores for comprehensive efficiency, pure technical efficiency, and scale efficiency of the sample sub-compartments were 0.646, 0.664, and 0.973, respectively. Compared to the pure technical efficiency, the scale efficiency is higher. Notably, prioritising native or climate-resilient species, adopting long-term ecological maintenance protocols, and fostering financially self-sustaining mechanisms were identified as key drivers for boosting efficiency. These findings underscore the need to embed sustainability principles—including resource optimisation and economic viability—into afforestation planning and governance to strengthen ecological restoration resilience and long-term project continuity.

Multi-Temporal and Multi-Resolution RGB UAV Surveys for Cost-Efficient Tree Species Mapping in an Afforestation Project

Accurate, cost-efficient vegetation mapping is critical for managing afforestation projects, particularly in resource-limited areas. This study used a consumer-grade RGB unmanned aerial vehicle (UAV) to evaluate the optimal spatial and temporal resolutions (leaf-off and leaf-on) for precise, economically viable tree species mapping. This study conducted in 2024 in Kasho, Bannu district, Pakistan, using UAV missions at multiple altitudes captured high-resolution RGB imagery (2, 4, and 6 cm) across three sampling plots. A Support Vector Machine (SVM) classifier with 5-fold cross-validation was assessed using accuracy, Shannon entropy, and cost–benefit analyses. The results showed that the 6 cm resolution achieved a reliable accuracy (R2 = 0.92–0.98) with broader coverage (12.3–22.2 hectares), while the 2 cm and 4 cm resolutions offered higher accuracy (R2 = 0.96–0.99) but limited coverage (4.8–14.2 hectares). The 6 cm resolution also yielded the highest benefit–cost ratio (BCR: 0.011–0.015), balancing cost-efficiency and accuracy. This study demonstrates the potential of consumer-grade UAVs for affordable, high-precision tree species mapping, while also accounting for other land cover types such as bare earth and water, supporting budget-constrained afforestation efforts.

Estimating Aboveground Biomass and Carbon Sequestration in Afforestation Areas Using Optical/SAR Data Fusion and Machine Learning

The growing population and the impacts of climate change present a major challenge to forests, which play a crucial role in regulating the carbon cycle. Pakistan, as a Kyoto Protocol signatory, has implemented afforestation initiatives such as the Khyber Pakhtunkhwa (KP) government’s Billion Tree Afforestation Project (BTAP). Quantifying the environmental impacts of such initiatives is very important; however, carbon pool data for BTAP plantation regions remain unavailable and are underexplored. This study aims to quantify aboveground biomass (AGB) and carbon sequestration potential (CSP) in the BTAP plantation regions using remote sensing and field data. Random sampling of 310 circular plots (17.84 m radius) provided measurements for tree height and diameter, from which AGB was calculated using allometric equations. Remote sensing data from Sentinel-1 and Sentinel-2, combined with polarization rasters and vegetation indices, were used to train and evaluate multiple regression models including multiple linear regression (MLR), support vector regression (SVR), and random forest regression (RFR). The RFR model outperformed the others (R2 = 0.766) when using combined optical and radar data, yielding a mean AGB of 4.77 t/ha, carbon stock of 2.24 t/ha, and CO2 equivalent of 10.36 t/ha. For BTAP plantations, the total biomass reached 1.19 million tons, with 2.06 million tons of CO2 equivalent sequestered, corresponding to an annual sequestration of 0.47 tC/ha/yr and a potential of 99.18 ± 15 tC/ha. This research introduces innovative predictive models and a comprehensive carbon assessment framework for afforestation projects, providing critical insights for policymakers and climate change mitigation efforts.

The Effects of Climate Change and Greening of Vegetation on Spatiotemporal Variation of Evapotranspiration in the Haihe River Basin, China

ABSTRACTHighly accurate evapotranspiration (ET) estimation and understanding the impacts of climatic and land use change on ET are essential for water resources management in the Haihe River Basin (HRB). This study estimated spatial and temporal changes of ET and its drivers over the period 2000–2020, using the Priestley‐Taylor Jet Propulsion Laboratory (PT‐JPL) model. Validation performed with the observations of 11 eddy covariance sites showed that the PT‐JPL model can simulate ET with high accuracy (R2 = 0.64, RMSE = 1.32 mm/day, NSE = 0.57). During the 21‐year study period, the mean annual ET in HRB was 583 mm/year and showed an insignificant increasing trend (0.45 mm/year). Canopy transpiration (ETc, 2.96 mm/year) and interception evaporation (ETi, 0.74 mm/year) significantly increased whereas soil evaporation (ETs, −3.25 mm/year) significantly decreased. The mean annual net radiation (Rn), relative humidity (Rh), and wind speed (Ws) showed insignificant decreasing trends. In contrast, mean annual air temperature (Tm), vapor pressure deficit (VPD), and precipitation showed insignificant increasing trends. The significantly increased leaf area index (LAI) demonstrated that vegetation in the HRB is greening. We explored the relationship between ET and its components to climate and vegetation parameters. The results showed that net radiation was the most important parameter for ET variations. Vegetation and temperature had large impacts on ETc. Vegetation greening in HRB dominates the increasing trend in ETc. Net radiation and relative humidity showed an important role in changes in ETs. Temperature and vegetation were key impact parameters for ETi. The increase in ETi is mainly located in the region of forests, which is due to the forest protection and afforestation projects in HRB. This study highlights the importance of isolating the contributions of vegetation and climate changes to the changes in ET and its components, which is useful for water resources management in HRB and other regions of the world.

Divergent patterns and determinants of resistance and resilience in short and tall forests across global drylands

Abstract Forests play a crucial role in mitigating climate change, and global afforestation initiatives are in full swing, with drylands having great potential for afforestation. However, many dryland afforestation projects lead to short forests with significantly lower canopy height than their typical height. Meanwhile, the potentially increasing probability of drought threatens short forests and their tall counterparts. Yet, it remains largely unclear whether these short forests respond differently to drought compared to tall forests. Here, we used the K-means clustering method to classify global dryland forests into short and tall forests. We found significant differences in drought resistance and resilience between short and tall forests, with tall forests demonstrating higher resistance and short forests having higher resilience. Furthermore, our study indicated that in severe and extreme drought conditions, resistance and resilience of short forests were more likely influenced by climatic factors than tall forests, which were more likely affected by soil factors. These findings suggest that climatic monitoring should be intensified for short forests, and post-drought management should be strengthened for tall forests to enhance their persistence under climate change.