Understanding growth strategies from functional and photosynthetic traits of tree seedlings in southeast Asian seasonally dry evergreen forest

Abstract

Seedlings frequently suffer the highest mortality rate, as they have different requirements for growth and survival from their mature life cycle stage. However, the links between functional traits and photosynthetic traits of tree seedlings, especially from dry evergreen forests, remain largely unexplored. Here, we measured eleven functional traits and six photosynthetic traits of thirty species of tree seedlings from the seasonally dry evergreen forest in Southeast Asia. We explored the relationship between traits and photosynthesis, compared them with their canopy layers when mature, and classified growth strategies. The results showed that photosynthetic measurements were highly correlated with seedling growth traits. The measured functional and photosynthetic traits did not correspond with the canopy layers of the mature trees. Through k-mean clustering analyses of the tree seedling trait data, two main groups of growth strategies emerged: (1) the “fast-growing” group, which mainly consists of shade-intolerant or -avoidance species; and (2) the “slow-growing” group, which consists of shade-tolerant species. This finding can be applied by future practitioners to select tree seedlings accurately based on their juvenile physiology, which is fundamental to the success of species selection for forest restoration in the face of global climate change.