(IX-B8, 2012
owered (average)
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lowered (average)
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ctra from Erica
action in WV2
ent phenological
ents: Given its
, it was difficult
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1g a conversion
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ation method to
vas used to mask
Only pixels with
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ree endmember
nsis -because of
ey were fused
the pixels with a
of M. faya + L.
cycle allowed us
ce species in the
a.
International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, Volume XXXIX-B8, 2012
XXII ISPRS Congress, 25 August — 01 September 2012, Melbourne, Australia
3. RESULTS
Preliminary results show remarkable distinction between well-
conserved and degraded monteverde forest (figure 3a).
However, subsequent MESMA cycles were needed to separate
very similar species, like M. faya and L. novocanariensis
(figure 3b).
Figure 3. Results obtained from MESMA. Colored
images represent combinations of three endmembers
corresponding to species or group of species used in the
analysis; each color intensity correlates to the cover fraction of
the species. a) mesmal: M. faya + L. novocanariensis (RED),
E. arborea (GREEN) and fern-herbaceous (BLUE). b)
mesma2: M. faya (RED), L. novocanariensis (GREEN) and
P.radiata (BLUE). c) Shade fractions estimates, darker cells
corresponding to lower proportion of shade.
Total Sc
Endmember distribution Q2 Q3
area (ha) p
; 1 t 88.9 536 | 070 | 0.86
3 2 (Erica) 54.5 132 018 | 033
3 (fern/herb.) 31.5 3.8 0.08 | 0.15
« | 1 (Morella) 28.3 18.5 0.67 | 0.86
E 2 (Laurus) 22.8 8.2 031 | 051
s 3 (Pinus) 122 33 0.19 | 0.37
Table 2. Overall species distribution areas obtained after
mesmal and mesma2. The total distribution area is derived
from the total number of cells where the species were detected,
whereas the actual cover area takes into account the species
cover fraction in each cell as well. Q2 and Q3 correspond to
the 50" and 75" percentile respectively.
Endmember Mature Degraded Pine
forest forest plantation
à ur qe 0.62 0.09 0.57
: 2 (Erica) 0.23 0.01 0.11
3 (fern/herb.) 0.09 0 0.07
a | | (Morella) 0.12 - 0.04 0.14
E 2 (Laurus) 0.03 0.14 0.11
E 3 (Pinus) 0.04 0.02 0.04
Table 3. Cover fractions derived from MESMA grouped by the
three main vegetation covers in the study area: mature forest,
degraded forest and pine plantations.
The table 2 shows the total species distribution area obtained
for each species in the entire study area after mesmal and
mesma2. Although E. arborea seems more spread than M. faya
(it is found in a greater number of cells), if we take into
account the sub-pixel cover fraction, the second one has a
greater total cover area. Less abundant species were found to
be L. novocanariensis, fern/herbaceous and P. radiata, by
decreasing order. Percentiles 50" (Q2) and 75" (Q3) give an
idea of overall pixel purity distribution. The degree of pixel
purity appears to be particularly high in M. faya with respect to
the rest.
MESMA was less sensitive to pines than expected, although
the remarkably higher proportion of shade in their presence
made it easier to map them (figure 3c) Mesmal showed, in
mature and degraded natural forests a mean shade fraction
estimate of 0.13 and 0.11 respectively, whereas in pine
plantations the mean shade fraction increased to 0.24, being
above 0.6 in a 10% of the plantation area. Even though the
dominant tree species in plantation areas of the study region is
P. radiata, the presence of P. canariensis (for which no
spectral signatures were available) could have contributed to
the underestimation of pine cover fraction. E. arborea,
