R code to reproduce analyses of aboveground carbon stocks and associated plant diversity in fragmented and continuous forest sites in Sabah, Malaysian Borneo, 2017

The R code "carbon_stock_calculations.R" estimates aboveground carbon stocks for 49 plots in 14 fragmented forest sites and 4 continuous forest sites in Sabah, Malaysian Borneo, using the vegetation dataset âVegetation and habitat data for fragmented and continuous forest sites in Sabah, Malaysian Borneo, 2017â. The 14 fragmented sites were all in Roundtable on Sustainable Palm Oil-certified oil palm plantations, and are hereafter termed 'conservation set-asides'. The code also estimates the aboveground carbon stocks of oil palm plantations for comparison.
The R code "analyses_and_figures.R" runs analyses and makes figures of aboveground carbon stocks and associated plant diversity for these sites, as presented in Fleiss et al. (2020)
This R code was created in order to investigate the following: (1) to establish the value of conservation set-asides for increasing oil palm plantation aboveground carbon stocks; (2) to establish whether set-asides with high aboveground carbon stocks can have co-benefits for plant diversity; (3) to compare the carbon stocks and vegetation structure of conservation set-asides with that of continuous forest, including assessing tree regeneration potential by examining variation in seedling density; (4) to examine potential drivers of variation in aboveground carbon stocks of conservation set-asides (topography, degree of fragmentation, and soil parameters); (5) to scale-up the estimates of the aboveground carbon stocks of conservation set-asides, in order to predict average carbon stocks of oil palm plantations with and without set-asides, and for varying coverage of set-asides across the plantation. Full details about this dataset can be found at https://doi.org/10.5285/9ff5cdca-b504-4994-8b07-5912ee6aff47

R代码文件“carbon_stock_calculations.R”估算马来西亚婆罗洲沙巴地区14个碎片化森林地点和4个连续森林地点的49个样地地上碳储量，该估算基于植被数据集“Vegetation and habitat data for fragmented and continuous forest sites in Sabah, Malaysian Borneo, 2017”。其中14个碎片化地点均位于圆桌可持续棕榈油认证的油棕种植园内，并被此后称为‘保护区预留地’。该代码同样估算油棕种植园的地上碳储量，以供比较。

R代码文件“analyses_and_figures.R”对上述地点的地上碳储量和相关植物多样性进行数据分析，并制作图表，正如Fleiss等人（2020年）所展示。

此R代码的创建旨在探究以下问题：（1）建立保护区预留地对提高油棕种植园地上碳储量的价值；（2）探究具有高地上碳储量的预留地是否能够对植物多样性产生协同效益；（3）比较保护区预留地与连续森林的碳储量和植被结构，包括通过考察幼苗密度变化来评估树木更新潜力；（4）研究保护区预留地地上碳储量变化的潜在驱动因素（地形、破碎程度和土壤参数）；（5）扩大保护区预留地地上碳储量的估算范围，以预测有无预留地以及预留地覆盖率不同的油棕种植园的平均碳储量。关于该数据集的详细信息可在以下链接找到：https://doi.org/10.5285/9ff5cdca-b504-4994-8b07-5912ee6aff47