n? size 
lowing 
cover 
of all 
ion and 
‚000 m? 
5 values 
lometric 
tatistical 
now the 
obtained 
idy with 
on of the 
ry forest 
rassland, 
3). 
  
  
  
  
  
Figure 3 - Typical aspects of the savanna area. 
The mean biomass values obtained for primary and secondary 
forest is around 194.71 ton/ha and 47.06 ton/ha (dry weight) 
respectively (Figure 4). Areas of primary degraded forests, such 
as those sections of selective logging for example, present a 
significant decrease of species density and diversity, with a total 
biomass below 80 ton/ha. Those areas of secondary succession 
present 20 % of variation of biomass within this cover type, 
which is related to the degree of vegetation development and to 
the intensity to its’ previous use. Those areas of primary forests 
. inventoried (¢ > 10 cm) have an average of 430 individuals/ha, 
DBH of 23.60 cm and the dossel height 14.54 m (the highest 
individuals are up to 38 m height). The areas of secondary 
succession (¢ > 5 cm) present, in average, 1294 individuals/ha, 
DBH of around 11.22 cm and 7.94 m height. 
li 
  
A 
a 
Biomass (Ton/ha) 
  
a 
0-499]9 | 
| 
  
l.l 
| 
0 T T T ' 
eo eo o © © © o o eo eo 
98888888888888 
+ “+ “+ "f "t "b + 
x 3 3 FE TE FT ST I TI 
1 1 L ' ' ' ' ‘ ‘ - - -— = v 
o eo eo eo e e © © e : i 3 ! E 
oN e ~ co o e © © © o 
= 0° SS € Qq ® 8 
Q c x 
DBH Intervais 
D Savanna B Forest | 
  
  
  
Figure 4 - Distribution of aerial biomass by DBH intervals of 
primary and secondary forest. 
As for those areas covered with savanna formations, the 
estimated biomass (dry weight) was: for savanna grassland 4.86 
ton/ha, for parkland savanna, 7.28 ton/ha, and for savanna 
woodland 20.15 ton/ha. The savanna grassland is made up 
solely by an herbaceous stratum, formed by gramineas species 
and cyperaceae, presenting in average 48.57 % soil coverage. 
The parkland savanna presents 230 individuals/ha at the upper 
stratum (bush and small trees) wich represent the 40 % of the 
whole biomass. These values are different for savanna 
woodland, where 82 % of the biomass belongs to the 
arboreal/bush stratum, showing an average of 300 
individuals/ha. 
Based on these information from field survey of the typical 
physiognomic structure of forest and savanna in this region, it is 
possible to show the behavior of the backscatter values from 
JERS-1 (Figure 5). In the models of simple regression, biomass 
values were considered as dependent variable (y) and the 
equation y — 1.7881 In(x) - 15.821 has a significant performance 
(r^ value — 0.8746). The amplitude of backscatter values varies 
from - 9.04 to - 5.77 dB for forestry formations and from - 15.07 
to - 9.55 for savanna types. One can observe that this regression 
function shows a high sensibility of the model for biomass 
values until 100 ton/ha, the space of attributes where savannas, 
secondary forest and primary degraded forests are located. From 
this value on, there is a decrease of sensibility, and there are not 
significant changes of o^ values (saturation zone) with the 
increase of biomass from primary forest. 
  
ort 
dB Mean Values 
  
y = 1,7881Ln(x) - 15,821 | 
-14 = R? = 0,8746 | 
Biomass (Ton/ha) 
| $ Savanna WForest ad 
  
  
  
Figure 5 - Diagram of JERS-1 backscatter values of forest and 
savanna formations. 
The components “vegetation”, “soil” and “shade”, included in 
the resolution element of the orbital data, are those factors 
which are responsible for this backscatter signal, associated with 
the variability of the vegetation structure and soil moisture 
content. This concept becomes more evident when one observes 
the result of the linear spectral mixture model, applied to the 
TM-Landsat image (Xaud, 1998), which presents the dispersion 
of the proportions of each component for each of the classes 
identified in this contact area forest/savanna (Figure 6). 
  
Vegatation 
^ 
5095 2. -.-----" (Qc 5096 
O PRIMARY FOREST 
O SECONDARY FOREST 
® SAVANNA WOODLAND 
® SAVANNA PARKLAND 
O SAVANNA GRASSLAND 
e : \ 
; e 
Q 
; a 
ti “of o. 
o 3 Ô 
Oo Qv o6 
5 N 
£s 
Shade 50% Soil 
  
  
  
Figure 6 - Diagram of dispersion from components 
“vegetation”, “soil” and “shade” of forest and savanna 
formations. 
Source: Xaud, 1998. 
International Archives of Photogrammetry and Remote Sensing. Vol. XXXII, Part 7. Budapest, 1998 525