On 19 Dec 1999 21:19:19 -0800, [EMAIL PROTECTED] (Donald F.
Burrill) wrote:
> On 18 Dec 1999, Archtopist wrote:
>
> > Happy holidays! I am developing a map of the annual probability of
> > burning (in a wildfire) for a mountainous area. I have a map with
> > cells labeled according to
> > a) one of five vegetation types and
> > b) housing density and
> > c) the year(s) when wildfire occurred in the cell.
> > I want to find out if there are differences in the likelihood of fire
> > depending on vegetation and housing density.
>
> Sounds daunting. If your timeline is long enough, neither vegetation
> type nor housing density will be constant, and it is possible that
> housing density may be changing even for relatively short timelines,
> almost certainly changing at different rates in different cells. (After
> all, if you go far enough back, housing density = 0 for all cells...)
[ ...]
I like everything Donald says here, and also in the part I snipped.
The longer I look at the question, though, the more it seems to me
that any simple approach is terribly naive or probably horribly
political at the same time. What is the underlying question -- WHO
should be allowed to intrude into WHAT wilderness areas?
If the question is already undergoing a hot debate, you have to carry
out a study which responds to the concerns of the debate. Unless
someone has a motive for presenting some specious numbers, which is
what you must get from a non-responsive survey.
Then there is the biology which humans are interfering with. Certain
pines need the area to be burnt-out in order for their seeds to
propagate, so it ought to be at least once per century (I think it
was). If there is a natural burn-over rate, how much are humans
interfering with it, or how much *should* humans interfere?
I sure would hope that firefighters have at least a little bit of
effectiveness, so that for areas that are identical except that some
acres have homes (and will be protected), the ones with homes have
fewer fires.
--
Rich Ulrich, [EMAIL PROTECTED]
http://www.pitt.edu/~wpilib/index.html
