1. General Model Information
Name: Fire & Landscape Patterns - Exponential Age Distribution Model
Main medium: terrestrial
Main subject: forestry
Organization level: Landscape,
Type of model: 2D
Keywords: fire, disturbance, age distribution, exponential model, probability distribution
Integra Research Inc
D. Boychuk, A.H. Perera, M.T. Ter-Mikaelian
Van Wagner (1978) demonstrated the important insight as to the relevance of the exponential model to tree age at both the stand and landscape levels. He showed that, under certain conditions, the probability distribution of the age of a stand subject to periodic renewal by fire is exponential. The extension of this model to the landscape-level results, also under certain conditions, in an exponential shape for the forest age distribution. Empirical studies have given partial support to this hypothesis. The results depend upon the size of the landscape in question, the patterns of fire disturbance, and changes in the disturbance regime over time and space. We attempt to provide insight into some of the fundamental factors that determine the forest age distribution. We examine whether the forest age distribution would have an exponential shape, and whether it would be stable or variable over time under different conditions. We used different spatial and temporal disturbance patt!
erns, some of which represent correlation due to fire growth and episodes of high fire disturbance. We describe the theoretical models that we developed for this investigation, and give the results of computational tests based on hypothetical data. Our results show that, under typical boreal disturbance regimes, we should not expect to find forest age distribution stability even at very large spatial scales due to the correlation of disturbances.
II. Technical Information
Operating System(s): DOS
Programming Language(s): FORTRAN
FLAP-X 1.00 user's guide See http://www.pobox.com/~int/flapx.htm
See http://www.pobox.com/~int/flapx.htm The download package includes everything that is needed.
III. Mathematical Information
Landscape size, expected proportion burned, expected fire size, forest age class distribution
Landscape size, expected proportion burned, expected fire size
Forest age class distribution over time for the landscape
Boychuk, D., Perera, A.H. 1997. Modeling temporal variability of boreal landscape age-classes under different fire disturbance regimes and spatial scales. Canadian Journal of Forest Research 27(7): 1083-1094.
Boychuk, D., Perera, A.H., Ter-Mikaelian, M.T., Martell, D.L., Li, C. 1997. Modelling the effect of spatial scale and correlated fire disturbances on forest age distribution. Ecological Modelling 95: 145-164.
Boychuk, D., Perera, A.H. 1995. FLAP-X 1.00 user's guide: fire and landscape patterns -- exponential age distribution model. Forest Fragmentation and Biodiversity Project Technical Report Series No. 20. Ontario Forest Research Institute, Ministry of Natural Resources.
Van Wagner, C.E. 1978. Age-class distribution and the forest fire cycle. Canadian Journal of Forest Research 8: 220-227.
V. Further information in the World-Wide-Web
VI. Additional remarks
FLAP-X uses a graphical display to demonstrate the effect of alternative assumptions about spatial and temporal correlation of fire disturbance in a hypothetical landscape. Numerical results can be recorded for statistical analysis. A 386 or higher processor and VGA or higher display is required.
Documentation with a diskette is available from:
Ontario Forest Research Institute
1235 Queen Street East
Sault Ste. Marie, Ontario P6A 2E5
(705) 946-2030 Fax
Last review of this document by: Wed Jun 21 22:43:20 2000
Status of the document: Contributed by Den Boychuk
last modified by
Tobias Gabele Wed Aug 21 21:44:42 CEST 2002