66 BULLETIN 1380, U. S. DEPARTMENT OF AGRICULTURE 
ties of Pohjstictus sanguineus, Trmnetes hydnoides, and other unde- 
terminable saprophytic wood-destroying species. The edges of the 
wounds were not healing, being prevented from doing so by species 
of Diplodia and Corticium. 
It is sufficient to state that in cleaning up areas of plantations in 
the Amazon Valley it will be found desirable to expend as much 
time and money as the project will permit in burning all forest litter 
before the trees are set. During the dry season fire may be ex- 
pected to spread in open plantations if grass and weeds are allowed 
to grow. Owing to the absence of dead grass and weeds fire does 
not run in the jungle even during the dry season. This is in marked 
contrast to the forest conditions in the Temperate Zone. The ex- 
periment was tried of setting fire to large termite nests which had 
fallen to the ground, but aside from the destruction of the nests the 
fire did not progress farther. 
INJURY DUE TO SUDDEN EXPOSURE (SUN SCALD) 
At the edge of a small clearing near Para a small Hevea showed 
effects of sudden exposure to the direct rays of the sun. The tree 
had grown up under heavy canopy. The bark on the exposed side 
of the tree had shrunken in patches and was checked through to the 
wood. In the absence of any evidence of fire abrasion or other 
injury it appeared clearly a case of sun scald. 
It is expected that serious injury from sun scald would result 
from the sudden exposure of wild Hevea left on plantation areas. 
The Avounds caused would open the tree to infection by fungi and 
to insect attack. 
PROTECTION OF WOUNDS 
Holding in mind what has been stated regarding the process by 
which wounds are healed it is evident that the methods of treatment 
should be varied to suit the case in hand. Treatment, however, has 
the one object, viz, to prevent infection by either parasitic or non- 
parasitic fungi. 
BANDAGING 
If through accident the bark is separated from the wood without 
injury to the latter during the period of cambial activity the wound 
should not be treated with chemical substances. The cambium 
covering the exposed wood will rapidly form a protective layer if 
it can be protected against drying, direct sunlight, and the weather- 
ing influence of rain. This may be done by placing a bandage of 
some impervious cloth around the stem, covering the wound. The 
bandage should be stretched tight; otherwise the cloth may come in 
contact with the delicate cells of the cambium and cause their dis- 
integration. The application of grafting cloth at the union of stock 
and scion or the protection by means of screens of peeled surfaces 
in the treatment of brown-bast are cases in point. After the cam- 
bium has developed epidermis the bandage may be removed. The 
suberized epidermis is not susceptible to infection by the spores of 
wound fungi, and the conditions favoring germination and penetra- 
tion of parasitic fungi are greatly lessened. 
