The role of climate and competition in shaping tree allometry, growth and function of miombo woodlands

Abstract

The miombo woodlands of Africa are among the world’s biodiversity hotspots that support livelihoods for millions of people while at the same time sequestering and storing huge amounts of atmospheric carbon dioxide in live standing woody trees – thereby mitigating climate change. The woodlands are however also on the frontline of global environmental change due to deforestation, forest degradation and climate change. Meanwhile, our understanding of tree allometry and growth and how these are shaped by climate and habitat fragmentation (which modifies how neighbouring trees compete for resources) remain at coarse level. This is despite the fact that tree allometry and growth underpin all our estimations of ecosystem services and goods. I undertook a tree-centric approach to deepen our understanding of tree allometry and growth in miombo woodlands. In Chapter 1, I discuss the current knowledge on tree allometry and growth and highlight knowledge gaps in the miombo woodlands. In Chapter 2, I show how consideration of tree allometry, specifically height-diameter relationship, can improve our estimations of biomass stored in miombo trees, thereby paving the way for accurately quantifying carbon fluxes under REDD+ and carbon marketing initiatives. Further, in Chapter 3, I describe tree allometric relationships (height-diameter-crown size) by considering how these compare to theoretical expectations and how climate and competition modulate these relationships. Notably, I show how the underappreciated effect of competition shapes allometric relationships. In Chapter 4, I extend our understanding of tree growth patterns in miombo woodlands, beyond annual, to hourly and daily resolutions, thereby demonstrating that we can determine when trees start and stop growing during the growth season. I also demonstrate how growth rates track soil moisture availability. Finally, in Chapter 5, I discuss the three data chapters by highlighting the salient findings and their implications for the miombo and propose research directions to be pursued.

Date of Award	20 Jan 2026
Original language	English
Awarding Institution	University of Bristol
Sponsors	Commonwealth Scholarship Commission
Supervisor	Tommaso Jucker (Supervisor) & Chris F Clements (Supervisor)