Data from: How do functional traits influence tree demographic properties in a subtropical monsoon forest?

1. Functional traits are good predictors of plant responses and adaptations to ever-changing environments. However, forecasting forest community dynamics is challenging because the relationships among different tree demographic properties (growth, mortality, and recruitment) and how functional traits are associated with tree demography remain largely unknown. 2. Here, in a 20-ha subtropical forest permanent plot, we quantified the rates of tree growth, mortality, and recruitment across 53 dominant tree species (diameter at breast height; DBH ≥ 1 cm) from 2005 to 2020. Functional traits that are closely related to plant photosynthesis, nutrients, hydraulics, and drought tolerance were measured. 3. We found that tree growth rate (GR) varied independently from rates of tree mortality and recruitment. Hydraulic conductivity was positively correlated with GR (explaining 27% variation – the strongest relationship observed) whereas wood density was negatively correlated with GR. Leaf life span was negatively related to tree mortality. Species with high carbon assimilation rate, nutrient concentration and hydraulic conductivity had high recruitment rates. Leaf turgor loss point was unrelated to plant demography. Principal component analysis revealed that species with quick resource-acquisition rates had high rates of growth and recruitment. 4. Our results illustrate that the correlations among tree demographic properties were weak in this subtropical forest with monsoonal climate. Most notably, against expectations there was no observed tradeoff between growth and mortality. Individual functional traits explained up to 27% of each demographic rate. Variation in recruitment rate was aligned with traits indexing the leaf economic spectrum and also plant hydraulic variation. A better understanding of the role of disturbances on trait-demography relationships would help build a deeper and more nuanced understanding of the ecology of subtropical monsoon forests.

1. 功能性状（functional traits）是预测植物对不断变化环境的响应与适应的良好指标。然而，预测森林群落动态仍颇具挑战，因为不同树木种群统计属性（生长、死亡与补充更新）之间的关联，以及功能性状与树木种群统计的关联机制，目前仍尚未明确。2. 本研究依托一块20公顷的亚热带森林永久样地，对2005年至2020年间53个优势树种（胸径（DBH）≥1厘米）的树木生长、死亡与补充更新速率进行了量化，并测定了与植物光合作用、养分、水力性状及耐旱性密切相关的功能性状。3. 研究结果显示，树木生长速率（GR）与树木死亡和补充更新速率各自独立变化。植物水力导度与生长速率呈正相关（解释了27%的变异，为观测到的最强关联），而木材密度与生长速率呈负相关。叶寿命与树木死亡率呈负相关。碳同化速率、养分浓度及水力导度较高的物种，其补充更新速率也更高。叶片膨压损失点与植物种群统计特征无显著关联。主成分分析（Principal component analysis）结果表明，资源快速获取型物种具有较高的生长与补充更新速率。4. 本研究结果表明，在这片季风气候亚热带森林中，树木种群统计属性间的相关性较弱。尤为值得注意的是，与预期相悖的是，本研究未观测到生长与死亡之间存在权衡关系。单个功能性状可解释各种群统计速率最高达27%的变异。补充更新速率的变异与表征叶片经济谱的性状及植物水力变异均存在关联。若能更好地理解干扰在性状-种群统计关联中的作用，将有助于更深入且细致地认识亚热带季风森林的生态学机制。