THE MISSING TAIL AND OTHER CONSIDERATIONS FOR THE USE OF FIRE HISTORYMODELS

Authors
Citation
Ma. Finney, THE MISSING TAIL AND OTHER CONSIDERATIONS FOR THE USE OF FIRE HISTORYMODELS, International journal of wildland fire, 5(4), 1995, pp. 197-202
Citations number
32
Categorie Soggetti
Forestry
ISSN journal
10498001
Volume
5
Issue
4
Year of publication
1995
Pages
197 - 202
Database
ISI
SICI code
1049-8001(1995)5:4<197:TMTAOC>2.0.ZU;2-Q
Abstract
This paper reviews methods used for testing the fit of the cumulative form of a negative exponential distribution to the cumulative distribu tion of forest age-classes. It is shown that existing methods can lead to a greater chance of falsely rejecting the fit of the negative expo nential model and inferring that fire frequencies have changed through time. This results when the old-age tail of a negative exponential di stribution is mathematically assumed to be present at the end of the a ge-class distribution. In reality, the tail is censored from sample di stributions of forest age-classes. Censoring alters the shape of a cum ulative age-class distribution from the straight line expected for a s emi-log graph of the cumulative negative exponential model. A solution to this problem is proposed that restricts the tests-of-fit to the po rtion of the negative exponential distribution that overlaps with the data to be tested. The cumulative age-class distribution can then be c ompared directly with the cumulative of a truncated negative exponenti al distribution. Considerations for interpreting a poor fit are then d iscussed.