Data and code from: Fertilization influences overyielding through dominance of species with high specific leaf area in young tree mixtures

This dataset accompanies the study “Fertilization influences overyielding
through dominance of species with high specific leaf area in young tree
mixtures” and documents the effects of nutrient addition on tree
diversity–productivity relationships and community functional structure in
young experimental forest communities. The data originate from a tree
diversity experiment including monocultures and two- and four-species
mixtures of six European tree species (Acer platanoides, Betula pendula,
Larix decidua, Picea abies, Pinus sylvestris, and Quercus robur), grown
with or without four consecutive years of mineral fertilization. The
dataset comprises measurements at multiple hierarchical levels, including
individual-tree data (tree height, stem diameter, aboveground woody
biomass, and specific leaf area), species-level summaries, and
community-level variables. Derived variables include trait-based metrics
such as community-weighted means (CWM) and functional diversity (FD) of
tree height and specific leaf area, as well as indices of species- and
community-level overyielding. These data enable analyses of how
fertilization influences productivity in mixed-species tree communities,
both directly and indirectly, through changes in community functional
trait structure and species composition.

本数据集配套于研究《施肥通过高比叶面积（specific leaf area）物种的优势作用调控幼树混交林的超产（overyielding）效应》，系统记录了养分添加对实验幼林群落的树木多样性-生产力关系以及群落功能结构的影响。本数据集源自一项树木多样性野外实验，实验设置包含单优种植林，以及由6种欧洲树种（挪威槭Acer platanoides、垂枝桦Betula pendula、欧洲落叶松Larix decidua、欧洲云杉Picea abies、欧洲赤松Pinus sylvestris、夏栎Quercus robur）构建的两物种混交林与四物种混交林，并设置连续四年施加矿质肥料与不施加肥料两组对照处理。数据集包含多层级的观测数据，涵盖单株树木水平数据（树高、茎直径、地上木质生物量、比叶面积）、物种水平汇总统计量以及群落水平变量。衍生变量包括基于功能性状的计算指标，如树高与比叶面积的群落加权均值（community-weighted means, CWM）和功能多样性（functional diversity, FD），以及物种与群落尺度的超产效应指数。上述数据可用于解析施肥如何通过改变群落功能性状结构与物种组成，直接或间接调控混交林群落的生产力水平。