Effects of environmental variability on forest tree growth and demography

Abstract

Understanding forest ecosystems is an enormous task, and long term monitoring of individuals traits and processes give us critical insights into this subject. Studies on tree growth are rare in the Indian subcontinent, however, data from permanent plots as well as tree ring records have been studied across the Americas, Africa, and South-East Asia. Amongst climatic factors, precipitation and the subsequent soil water content, solar radiation, and temperature influence tree growth patterns on a pan-tropical scale. Other site-specific studies show that growth rate positively correlates with rainfall, although the strength varies, and sunlight. In this thesis, I analysed the tree growth rates in permanent forest plots in South India. I show that species averages of growth rates vary significantly within plots. Absolute growth rates increase slightly with size, while relative growth rates decline with the same. Species identity and size are better indicators of growth rates than rainfall; however, developing a simple model that captures these effects better, and the effects of other abiotic factors, with limited data, is challenging.