Projects

Fire regimes in circum-boreal forests (FIBOR database)

Scientist(s): Christian Wirth
Funding: Max-Planck-Society, DFG
Duration: 2003-present

Background: Fires are the main driver of forest structure and succession in the circum-boreal forest and represent an important component in boreal forest carbon budgets. Several authors have noted differences in the boreal fire regimes between Eurasia and North America especially with respect to fire severity (e. g. Viereck et al., 1980). While in Siberia in a typical year some 75 % of the fire area is burned by surface fires, crown fires dominate in the boreal forest of North America (Shvidenko et al., 2000a, Heinselman, 1981). Climate is an important driver of the fire regime, but vegetation structure also exerts a strong control on the frequency and severity of fires by determining the fuel distribution and its flammability. Boreal trees species have evolved a remarkable diversity of traits to ensure survival and/or reproduction in the face of fire and can be categorized according to their fire adaptation strategy into resisters, embracers, endurers, invaders and avoiders (Rowe, 1983).

Central Hypotheses: The meta-analysis project aims to test the following two hypotheses: (1) the dominant fire adaptations strategy in a given forest type determines the fire regime and (2) the circum-boreal distribution of fire adaptation strategies explains the continental difference in the fire regimes.

Methods: The literature is searched for original studies reporting point- or area-based estimates of the 'natural' fire return interval (FRI), the severity or type of the fires, and data on species composition. In addition, ancillary information on important geographical and site information, climate data, the extent of human impact, and methods of FRI determination is recorded. The following methods are considered: fire scar dating in trees, fire-cycle analysis based on fitting statistical distributions to age-class data, regeneration-epoch-analysis, dating of char coal layers in peat of lake sediments. The currently contains 135 entries from 67 studies

Collaborators: Sergey Verkhovets (Sukachev Institute of Forest SB RAS, Krasnoyarsk)

Publications:
Wirth C and Verkhovets S: Tree species effects on fire regimes in circumboreal forests: comparing Eurasia and North America (in preparation)

Wirth C (2004): Fire regime and tree diversity in boreal and high elevation forests: Implications for biogeochemical cycles. In: The ecological significance of forest diversity (eds. M. Scherer-Lorenzen, Ch. Körner and E.-D. Schulze). Ecological Studies 176. Springer New York, Berlin, Heidelberg, pp. 309-344.

References: Heinselman ML (1981) Fire intensity and frequency as factors in the distribution and structure of northern ecosystems. In Fire Regimes and Ecosystem Properties: Proceedings of the Conference Vol. WO-26, pp. 7-57. USDA Forest Service, Honolulu.

Rowe JS (1983) Concepts of fire effects on plant individuals and species. In The Role of Fire in Northern Circumpolar Ecosystems (eds Wein RW, McLean DA), pp. 135-154. John Wiley & Sons, Chichester.

Shvidenko A, Nilsson S (2000a) Extent, Distribution, and Ecological Role of Fire in Russian Forests. In Fire, Climate Change, and Carbon Cycling in the Boreal Forest Vol. 138 (eds Kasischke ES, Stocks BJ), pp. 132-150. Springer, New York.