Growth of Trees and Forests – From Germination to Tree Death

Abstract

Tree and stand growth are key processes for forest management and key indicators of tree performance and stand productivity. Understanding of the physiological processes that steer germination, growth and mortality of trees is crucial. Moreover, knowledge on the impact of abiotic and biotic factors is central for the understanding of forest dynamics on various spatiotemporal scales.

Objective

- To understand the physiological processes that steer germination, growth and mortality of trees. - To evaluate the impact of abiotic and biotic factors on tree physiology and tree growth. - To distinguish the key processes that govern growth at the tree, stand and forest level. - To quantify the effects of climate, environment, disturbances and management on tree and stand growth. - To provide an overview of the recent literature on these topics based on case studies / ongoing projects that are discussed in class.

Content

Introduction to forest dynamics from the growth of single trees to entire forest ecosystems. The course will provide an overview on characteristics of different climatic zones including xeric, temperate, boreal and tropical forests. It is structured into the following sub-topics: 1) Physiology of tree growth: Physiological processes steering tree growth from a small seedling to old, tall trees, with a focus on i) carbon allocation from roots to stem, branches and leaves, and ii) the hydraulic system. The effects of abiotic and biotic forcing factors on tree physiology will be considered in detail. 2) Physiology and ecology of tree death (mortality ecology): Why and how are trees dying? Significance of tree death for forest ecosystems, including stand dynamics, nutrient, carbon and water cycles. 3) Growth strategies of woody plants in extreme environments: From droughtlimited xeric sites to temperature-limited upper and northern treelines. Special focus on the effects of disturbances on tree and forest growth. Strategies of different (tree) species to deal with environmental extremes. 4) Forest stand dynamics: From the single tree to stand growth. Growth and yield – growth tables and growth models. Monocultures vs. mixed forests. Even-aged vs. structured stands, competition vs. facilitation, overyielding. Link to forest succession, disturbances and forest management, incl. agroforestry. 5) Carbon dynamics of forests: National and global trends in tree and stand growth. Drought-induced tree mortality versus global greening, carbon reporting (links to T. Crowther and S. Seneviratne). 6) Growth of tropical trees and forests - what is different in comparison to temperate forest ecosystems?

Resources