-1932 = 
For the purpose of investigating this question an area was selected in the 
Mahogany bearing forests of the North of the state of Goiás, Brasil, 
along the river Araguaia. The forests of this area are part of the transition 
region (between the Amazona forests and the savanna vegetation) and have 
a mean yearly precipitation of 1600 mm. SLAR strips (1971/1972), SLAR 
mosaics at scale 1:250,000 and maps, scale 1:1,000,000 of the "Projecto 
ana?) are available. The accuracy of SLAR interpretation can be compared 
with the results of the "FAO/SPEVEA forest survey 1961" of the pilot area 
of 251.500 ha (1). The vegetation maps of this survey, scale 1:50,000 and 
1:200,000 are based on fieldwork and photointerpretation of aerial 
photographs scale 1:45,000 taken in 1951/58. From these maps, a general 
vegetation map FAO/ SPEVEA survey at scale 1:1,000,000 and 3 vegetation 
maps on scale 13250,000 of selected areas M,, M, and M, were made for 
1f *2 
this paper. In 1961 the author assisted in the fieldwork and in the execution 
of photointerpretation for the above mentioned forest survey. 
FOREST SURVEY PILOT AREA IN 1961 (257,500 ha) 
Prior to the fieldwork the characteristics for photointerpretation in the 
natural Mahogany (SWIETENIA MACROPHYLLA, King) forest types were not known. 
Before fieldwork the photointerpretation was based on the differentiation 
of savanna, shrub forest, floodplain and palm forest along the streamlets 
with stagnating water and shifting cultivation from dryland forest subdivided 
into low and high types. After some field experience most of the low 
forest types could be reclassified as creeper forest and partly as a 
transition between high forest and shrub forest. At the end of the fieldwork 
period it was possible to differentiate the high forest into two subtypes, 
one the Mahogany forest type with a semi-open crown canopy and the forest 
type without Mahogany and with a more closed canopy. 
Between the Mahogany forest and the creeper forest type, there exists a 
transition zone in which individual large Mahogany trees are occasionally 
present and patches of creepers. It was possible to separate on the 
1:45.000 scale aerial photographs this forest type with creepers and 
occasionally Mahogany trees from the forest types without Mahogany (high - 
low and creeper forest). 
The re-photointerpretation was carried out according to the system given 
in the following scheme: