Collie 1980 - 1990
Collie
The last case study is of special interest. It encompasses an extensive
area of eucalypt forest in the southwest of Western Australia, near the
town of Collie. The forest landcover change that can be detected during
the period 29/10/80 to 29/03/90 is similar to earlier examples. Plantation
forestry is being established at the expense of native forest. The special
interest is that (at last) some of these plantations are of indigenous eucalypt
species. The species used are not native to this area. However, a non-local
eucalypt plantation is infinitely preferable to that of an exotic species
with respect to wildlife habitat. Plantations of exotic tree species, particularly
conifers, are essentially biological deserts.
Plantations of non-local species will certainly function as more effective
corridors between remnants of native vegetation.
Use your browser to open each image
in a new window to compare them.
Forest landcover change near Collie in Western Australia during the period
29/10/80 to 29/03/90. This scene is of special interest because it encompasses
an extensive area of eucalypt forest and the establishment of plantation
forestry. The special interest is that (at last) some of these plantations
are of indigenous eucalypt species. Can you detect differences in the spectral
signature of the plantations? Can you deduce just from the three FCC images,
which of the plantations is of eucalypts?
Let's think back over these last three examples. The absolute area of
landcover change of native forest and woodland to plantation forest varies
among the three. It is small for all but the Fraser Island example. Nonetheless,
it is a very informative exercise to estimate the following three numbers
for each of these scenes.
The first number is the proportion of the area of each scene that was already
cleared for agricultural landuse. The second number is the area of landcover
change resulting from forest landuse relative to the area of forests present
at the date of the earliest image. The last number is the area of landcover
change resulting from forest landuse relative to the area changed by agriculture.
The point I wish to make with these estimations is the relative influences
on forest landcover of the past and present landuses of forestry and agriculture.
Table: Areas under plantation forest
