Agriculture Reference
In-Depth Information
Ecosystem fire
Fig. 2.1 Fire diamond schematic of factors necessary and sufficient for predicting
the distribution of fire as an ecosystem process. A certain level of primary productivity is
needed in order to spread fire, and climatic seasonality, with annual to decadal cycles of
drying, is required to convert these potential fuels to available fuels that will combust. Fire
regimes are controlled strongly by ignition frequency and fuel structure with important feedback
loops between all four factors.
spatial pattern of burning. This is captured in the concept of a fire regime, which
includes the fuel types consumed, frequency and timing of burning, intensity of the
fire and the spatial distribution of individual fire events (Keeley et al. 2009a ). Fires
are often referred to as disturbances, but in many plant communities fire is an
integral ecosystem process and disturbances are perturbations to the fire regime
that lie outside the historic realm. Such disturbances include increased fire fre-
quency, as well as suppression and exclusion of fire.
Fire Regimes
Generalizations about fire effects on plant trait distribution based on fire fre-
quency or intensity are widespread in the literature. However, these seldom are
broadly applicable beyond local settings because they ignore the fact that fire
regimes change across landscapes and these changes often represent substantial
shifts in both fire behavior and plant responses. Thus, the fire regime concept is
fundamental to understanding fire and fire effects, and switches in fire regimes
such as from a surface fire to a crown fire regime need to be factored into any
global generalizations.
On the basis of research in Australian sclerophyll forests and shrublands, Gill
( 1973 ) introduced the concept of a fire regime, which comprised patterns of fire
Search WWH ::




Custom Search