Functional types of trees in temperate and boreal forests: classification and testing
Article first published online: 24 FEB 2009
1996 IAVS - the International Association of Vegetation Science
Journal of Vegetation Science
Volume 7, Issue 3, pages 359–370, June 1996
How to Cite
Bugmann, H. (1996), Functional types of trees in temperate and boreal forests: classification and testing. Journal of Vegetation Science, 7: 359–370. doi: 10.2307/3236279
- Issue published online: 24 FEB 2009
- Article first published online: 24 FEB 2009
- Received 3 February 1995; Revision received 4 October 1995; Accepted 25 October 1995.
- Climatic change;
- Forest ecology;
- Gap model;
- Impact study;
- Europe: Hess et al. (1980);
- North America: Little (1953)
Abstract. Impacts of climatic change on ecosystems over large areas cannot usually be assessed on a species basis. The definition of plant functional types (PFTs) may make this task feasible, but its potential and limitations need to be evaluated carefully by quantitative tests. This paper presents such a method for testing a hypothesis about PFTs.
A deductive approach is used to elaborate a functional classification of temperate and boreal trees based on their response to climatic change and their feedbacks to the climate system using four attributes: (1) evergreen/deciduous; (2) cold tolerance; (3) drought tolerance; (4) shade tolerance. These attributes are combined to yield six PFTs.
The classification is tested by implementing the six PFTs in the forest gap model ForClim, and the behaviour of the PFT-based model is compared to species-based simulation results in Europe and in eastern North America.
The six PFTs provide an accurate description of both the physiognomy and the composition of European forests in both transient and equilibrium phases. Under the IPCC ‘Business- As-Usual’ scenario of climatic change for southern and central Europe, some differences in the forest composition are simulated, pointing at the need of testing PFT schemes not only under current, but also under hypothesized future climates.
For eastern North America it was necessary to estimate the parameters characterizing the six PFTs anew. When this was done, the PFT-based simulation yielded results paralleling those of the species-based model closely.
The potential and limitations of the present classification are discussed. It is concluded that deficiencies in current gap models, but probably also different evolutionary pathways in North America as compared to Europe, are responsible for the different parameterizations on the two continents.