ZAZA 
(Photo by K. Hueck, courtesy IFLA.) 
Figure 12.—Tropical rain forest varzea along the Madeira River. 
have long clear boles; and most timbers are hard 
and heavy. 
Average annual rainfall over much of the Amazon 
lowlands exceeds 80 inches; there is no cool season 
and no really dry season. There is, however, a pro- 
nounced wet period which occurs from December to 
February at about the 8th parallel and moves north 
into the Amazon River area about February to May 
and the northern border area in June and July. This 
shift in rainfall spreads the time of flood water over 
a long period; the river commences to rise in Novem- 
ber, increases in volume until June, and falls until 
the end of October. The position of the land in re- 
lation to this water determines the character of the 
forest and its accessibility to exploitation. 
Species composition is generally similar over much 
of the great expanse of dry alluvial plain above the 
level of high water. A survey, taken in 1954-57 and 
covering 50,000 square miles of the dry land forest 
south of the river offering the best logging prospects, 
determined that the average acre held 46 trees 10 
inches d.b.h. (diameter breast high) or better with 
a total volume of 2.887 cubic feet in merchantable- 
size boles. These trees were representative of more 
than 300 species, some of the more important being 
abiurana, acapt, angelim, castanheira. itatiba, louro, 
magaranduba, and quaruba. Only a third of the 
FORESTS AND FOREST INDUSTRIES OF BRAZIL 
727-155 °—_64—_3 
trees, accounting for a little more than a third of the 
volume and involving some 60 species, have com- 
mercial value. 
The soils on the land above high water are well 
suited to truck and tractor logging. The forest 
itself is actually not a jungle: little undergrowth 
develops except where light reaches the ground as 
along streams and in clearings. 
During the wet season a belt up to 50 miles wide 
on each side of the main streams may flood. The 
area of flood plain between median water level and 
high flood stage, known as varzea. carries a stand whose 
composition varies with the length of time of flooding 
(fig. 12). 
months, fast-growing trees with soft wood, such as 
Where covered by water for several 
assacti, ceiba, imbatiba, tachi, and jauary palm, are 
more common. On slightly higher ground flooded 
only a few weeks, dry land species occur more often. 
The low, flat, recent alluvial lands never more 
than 15 feet above low water, called igapés, are wet 
and swampy most of the year (fig. 13). Vegetation 
on these lands is often dense but contains few trees 
of any commercial value. 
present a barrier to logging, the better forests behind 
them are usually inaccessible. 
Wherever the igapés 
fo) 
Extensive areas of excellent forest occur on the 
low uplands below 600 feet elevation. Commercial 
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