On US Forest Service land, observers report that 99% of fires are put out before they reach 300 acres. It's the other 1% that is of such great human concern. It's good to recognize the causes, to try to understand. The causes are singular... a convergence. In a place, a big one, usually with steep slopes, there converges
- low humidity,
- high temperatures (perhaps related to global warming)
- gusty wind, and
- a spark or fire source (with a probability related to road and human population nearness, even lightning strikes)
that together finds rich, abundant fuels. The losses and costs ... and first spark ... increase as people crowd into the borders of parks, forests, and public areas.
The fuel is of greatest concern of the faunal system manager. It is the only physical factor that he or she (faunal system managers, foresters and rangeland fire fighters) can readily influence (other than posting control crews). "Fuel" is another word for faunal food and cover. It is food for animals, food for insects and creatures upon which they feed, and stuff within which they live. Fuel is a mixture of the elements of changing faunal space over time. Foresters responsible for intense fires reduce the density of trees, remove surface fuels and those that allow fires to climb into trees. In the process they eliminate faunal spaces, those of the soil layers, the forage layers, and the nesting and insect-foraging layers. But in the process of eliminating some space, others may be created. Dead trees (snags) produce over time conditions for abundant insects for some species; some species of tree seeds are germinated by low intensity fires thus creating forage for some insects and big game. Ground litter (through which fire may sweep) is the home space of small birds and mammals and their insect and mollusc food supplies. The rodents spread the spores of fungi that produce root hairs for the trees, increasing "site index," the measure of tree growth potentials. Can we have one without the other? In what proportions? What to do...what to do?
The manager of lands for wild fauna need to
- have adequately equipped wildfire control systems in place
- have a plan for burning and removals of fuels (essential in carefully selected and timed actions)
- have a strategic prevention plan, one to reduce the unwanted fire "start"
- carefully compute the probable benefits from all of the resources of forest and rangeland space (species-specific trees, grass, and animals over a planning period of about 150 years) to a human population and assign the benefits expected "present" financial value)
- equally carefully, compute area-specific and species-specific probable loss (e.g., Alan Ager at aager@fs.fed.us) and compare 4 and 5
- compute wind-related tree moisture stress, soil moisture loss, bark beetle loss evidence, rain impact changes on soils and related silt and moisture runoff in areas of reduced tree-densities
- compute the relative costs of implementing the above, then compare that estimate to the estimated losses of the average of 100 simulated fires in areas without such planned action.
It's difficult; computers are needed; it may not be affordable. Once done, it does not have to be done in detail again ... just used for people and their lands and fauna.

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