THE HEYEA RUBBER TREE IX THE AMAZON VALLEY 45 
Table 11. — Data on rubber trees from the Acre Territory 
Locality 
Num- 
ber 
of 
trees 
Age of 
trees 
(years) 
Circum- 
ference 
atl 
meter 
(cm.) 
Bark 
thick- 
ness 
(mm.) 
Number 
of rows 
of latex 
vessels 
Remarks 
Cobija, Bolivia: 
Garden trees 
4 
1 
127 
54 
1 
50 
2 
±5 
16 
56.1 
136 
167.5 
136.1 
95 
187.7 
67.5 
5.8 
8.0 
8.2 
7.9 
9.0 
8.9 
8.3 
10.3 
19.0 
31.0 
On fine rich terra firma; not 
planted too close. 
Porvenir, Bolivia 
Fazenda Palmaris, be- 
low Xapury, Acre, 
Brazil: 
conditions. 
Old jungle trees, on varzea alta; 
tapped for many years. 
Seringueiro house 
yard. 
Old estrada . 
tions. 
Very old trees, on terra firma. 
Many other trees here of same 
age, but all uncared for, very 
small, and diseased. 
Four trees near Cobija, Bolivia, were found which had been grown 
in a garden and had been given reasonable care. These showed a 
very good development and appeared to be extremely vigorous. 
One other tree showing excellent growth was seen in the house yard 
of a seringueiro, whose wife had planted the tree immediately on her 
arrival at the seringal and knew its age. 
The old trees in the estradas are of great size, and for the treat- 
ment they have received their condition is good. The trees are very 
large and tall and have very thick soft bark which is extremely rich 
in latex vessels, as is shown in the average of 31 rows for a large 
number of trees which have been tapped for years. (Table 11.) 
The Acre Territory has long been famous for the quantity and the 
quality of its rubber. On this account, if for no other reason, it is 
deserving of consideration. Of all areas examined by the writer, 
this appears the best as regards the growth and development of rub- 
ber. Here the largest trees were encountered, and the general ap- 
pearance of the trees was best, though the data given in Table 11 
do not show great differences. Much is to be learned from general 
observation. Crops of various kinds — corn, coffee, rice, beans, 
cotton, cane, Manihot, etc. — thrive here and indicate the great possi- 
bilities of the region for general cultivation. 
There are great areas of terra firma, very well drained and suffi- 
ciently level to obviate terracing, except possibly in rare cases. This 
soil in general resembles the best rubber soils of Sumatra more than 
any other soils seen in the course of this expedition. Its loose friable 
condition admits of the extensive root development so necessary for 
success in Hevea planting. Mohr {28) thinks that proper physical 
condition is the paramount consideration in rubber soils, and this soil 
of the Acre Territory appears to possess the most desirable physical 
characteristics. 
This region is a magnificent one for colonization, and it appears 
likely that the territory is one in which the white race can thrive. 
The climate is not oppressive, nor does it appear deleterious, although 
the whole region has a very bad reputation as a pesthole. It may 
have been such in the ^ast but it certainl^ is not now. Malaria, 
