International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, Vol XXXV, Part B-YF. Istanbul 2004
Visible blue-green reflectance(0.45-0.52um)
0,07
0,06
0,05
0,04
0,03
0,02
0,01
Shrub
Bamboo
Primary forest
Secondary forest
Rubber
Teak
Indigenous plant.
Acacia
Visible green reflectance(0.53-0.6 11m)
0,1
0,08
0,06
0,04
0,02
Shrub
Bamboo
Primary forest
Rubber
Teak
Acacia
Secondary forest
Indigenous plant.
Visible red reflectance(0.63-0.69um)
0.1
0,08
0,06
0,04
0,02 |
Shrub
Bamboo
Primary forest
Secondary forest |
Rubber
Teak
Indigenous plant
Acacia
Infrared reflectance(0.78-0.90um)
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Mid-infrared reflectance(1.55-1.75um)
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Mid-infrared reflectance(2.09-2.35um)
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Secondary forest
Indigenous plant.
Figure 3. Spectral reflectance from different vegetation types. Vertical lines show mean values with 95% confidence limit
In the visible red reflectance, shrub, rubber and teak are
identically different than primary and secondary forest,
bamboo and acacia (Figure 3). Differentiation between
primary and secondary forests using only the reflectance is
not possible in the visible bands. However, image texture
might help to separate primary from secondary forests.
Secondary forests usually have a smooth texture than the
primary one. Shrub and rubber have quite similar and high
reflectance. The reflectance of teak just follows them partly.
Shrub is usually having a relatively thin layer of canopy than
the other vegetation types and sometimes mixed with
background soil reflectance. Though the canopy of rubber is
quite different than the shrub, during the time of image
acquisition rubber canopy was quite leafless, and therefore
the understorey shrub layers dominated the reflection.
Consequently the reflection is not identically different from
the scrubby vegetation. Furthermore, teak has bigger leaves,
160
which usually are not dense enough to hide the understorey.
This plantation strongly discourages the growth of
understorey vegetation and therefore, the reflection perhaps
was a mixture of upper canopy leaves which are intermixed
with background soil reflectance. This assumption is likely
being true for the scattered trees, which are also not
differentiable form teak plantation
The reflection of primary forests and teak is identically lower
than shrubs, secondary forests and indigenous plantation in
the near-infrared spectral region (Figure 3). The reflection of
the rest category lies in between these two types of
vegetation. It is interesting to note that the reflectance from
primary and young secondary forest is different though they
are having the similar species composition on their top-
canopy. This difference might be associated with the
difference of age. So it can be concluded that the spectral