Plantation forests have been increasingly established in Fagita Lekoma District, located in the Northwestern Highlands of Ethiopia, over the past two decades. However, their interaction with climate variables remains largely unexplored. This study aims to investigate the spatiotemporal dynamics of plantation forests driven vegetation changes and their relationship with climate variables in the district from 2000 to 2020. Moderate Resolution Imaging Spectroradiometer (MODIS) data and Enhanced National Climate Services (ENACTS) data of the study area were processed for 21 years to examine trends using the Mann-Kendall test and Sen’s slope estimator, employing R 4.3 programming software. Concurrently, various climatic data, including evapotranspiration (ET), land surface temperature (LST), and rainfall, were processed, and analysed to explore the relationships between vegetation change and climate variability in the district during the study period. Increasing trends of Normalized Difference Vegetation Index (NDVI) greenness in the district were highlighted, with mean annual NDVI rising from 0.53 to 0.64, showing an average trend of 0.0036 year−1. This increase is primarily attributed to the widespread establishment of plantation forests across the district. The largest increase was revealed in ET, with a rate of 12.27 kg/m2 year−1. Conversely, LST and rainfall exhibited insignificant decreasing trends, with a rate of − 0.15 °C year−1 and − 10.54 mm year−1, respectively. Furthermore, a statistically significant positive correlation between NDVI and ET was observed, underscoring the critical role of vegetation in maintaining water availability. The negative correlation between NDVI and LST suggests that increased vegetation cover contributes to land surface temperature cooling. Additionally, the statistically insignificant negative correlation between NDVI and rainfall emphasizes the influence of land use change and human intervention on vegetation productivity. Overall, this study highlights the significance of long-term satellite observations in assessing the intricate interplays between vegetation dynamics driven by plantation forestry and climate variables at a local scale. The findings emphasize the role of plantation forests in enhancing vegetation greenness, improving water regulation, and mitigating land surface temperature warming, providing critical insights for sustainable land management and policy interventions in similar regions.

中文翻译：

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人工林推动了埃塞俄比亚西北部高地的时空植被趋势及其与气候变量的相互作用


在过去的二十年里，位于埃塞俄比亚西北部高地的 Fagita Lekoma 区越来越多地建立了人工林。然而，它们与气候变量的相互作用在很大程度上仍未得到探索。本研究旨在调查 2000 年至 2020 年该地区人工林驱动的植被变化的时空动态及其与气候变量的关系。研究区域的中分辨率成像光谱仪 （MODIS） 数据和增强型国家气候服务 （ENACTS） 数据处理了 21 年，以使用 Mann-Kendall 检验和 Sen 斜率估计器，采用 R 4.3 编程软件来检查趋势。同时，处理和分析了各种气候数据，包括蒸散量 （ET）、地表温度 （LST） 和降雨量，以探索研究期间该地区植被变化与气候变率之间的关系。突出了该地区标准化差异植被指数 （NDVI） 绿化的增加趋势，年平均 NDVI 从 0.53 上升到 0.64，平均趋势为 0.0036 年-1。这一增长主要归因于整个地区广泛建立的人工林。ET 的增加最大，为 12.27 kg/m2 year-1。相反，LST 和降雨量呈不显著的下降趋势，分别为 -0.15 °C 年-1 和 -10.54 毫米年-1。此外，观察到 NDVI 和 ET 之间存在统计学上显着的正相关，强调了植被在维持水资源供应方面的关键作用。 NDVI 和 LST 之间的负相关表明，植被覆盖度的增加有助于地表温度冷却。此外，NDVI 与降雨之间的统计不显著负相关强调了土地利用变化和人类干预对植被生产力的影响。总体而言，本研究强调了长期卫星观测在评估人工林林业驱动的植被动态与局部尺度气候变量之间错综复杂的相互作用方面的重要性。研究结果强调了人工林在增强植被绿化、改善水资源调节和缓解地表温度变暖方面的作用，为类似地区的可持续土地管理和政策干预提供了重要见解。