A study presenting these findings was recently published in the journal “Carbon Balance and Management”. Therein, Professor Michael Köhl and additional researchers from the KlimaCampus at the University of Hamburg studied two different climate scenarios for the year 2100. Each simulated different variations of forest management. The result: The fitness of a forest is much more dependent on the type of its management than on future changes in climate. The forest will be able to withstand climate change through 2100 using trees that can withstand dryness, shorter turnover – less time between planting and harvest – and regular thinning out of trees.
For the study, the researchers chose the A1B and the B scenarios from the IPCC’s World Climate Report for 2010. The first scenario assumes strong economic growth and thus a long-running increase in temperatures. In scenario B, people take a more sustainable approach so that the global temperature rise is limited to 2º Celsius. In both cases the researchers simulated three different management strategies for German forests. These extended from “maximized profit”, based on single species forests of the same age, shorter turnover times among the trees and less biodiversity – cultivation with higher earnings – through to natural management with longer life cycles and richer biodiversity.
The results show that the type of management consistently has a stronger effect on forests than climate change. The three forms of forest management present greater variation between themselves in each scenario than exists between the two climate scenarios. This is true for all researched criteria, including average wood volume, developments in carbon content per area, the existent biodiversity or the average age of trees.
Trees cannot change their location. They are able to quickly adjust to changing environmental conditions though, due to their genetic endowment – trees have about ten times more genetic material than humans. “Yet expected climate changes happen too quickly even for these flexible trees. The mechanisms they have to adjust would be functional first in descendents and hybrids, but a tree can live for well over 500 years”, said Prof. Köhl.
The study shows above all that action can – and should – be taken to guarantee the health of the forests. “If we were to leave the German forest alone now, it would quickly lose vitality”, according to Köhl. For the future, the forestry expert recommends species that do well in dry surroundings. At the same time, the forests should not be allowed to grow too old: they should be cultivated more often and trees selectively harvested – the best conditions for a “Fit Forest” in 2100.
Köhl, M. et al. (2010): Combating the effects of climatic change on forests
by mitigation strategies; Carbon Balance and Management 2010, 5:8
University of Hamburg
Institute of World Forestry
Prof. Dr. Michael Köhl
Tel: 040 / 7396 - 2100
University of Hamburg
Tel: 040 / 42838 - 7596