Abstract:
How forests respond to anthropogenic climate change raises challenging
questions that are both fundamental and urgent. Vulnerability of forest to
changing rainfall patterns and increasing extreme events such as droughts
is clear from wide-spread tree mortality and can have large scale consequences
on forest diversity, services and global climate sysetm. However, underlining
processes such as
how meteorological drought translates into tree mortality, species-specific
vulnerability are unclear.

This thesis begins with addressing some perplexing issues in assessing
forest tree growth response vis-à-vis rainfall gradients, both in space and time.
It then addresses some fundamental questions as to where do trees source water from,
and what is the dynamics of water availability by depth that species actually
respond to
in terms of growth and survival. It employs a novel method to assess species-specific
water uptake in a forest over two decades and evaluates how belowground
“hydrological niches”
operate for these long-lived organisms that are trees; assisting their co-existence,
but
leading to differential fates under extreme drought.