In its native habitat this tree grows best at an elevation of 
from 2,000 to 3,000 feet at from 25° to 27 c north latitude, and. 
nearer the equator, reaching to fully 5,000 feet. The tempera- 
ture ranges from a winter minimum of 48° to a summer max- 
imum of 92 : F., with a yearly mean temperature of 73 : . The 
rainfall of the forest zone where this tree grows ranges from 
75 to 100 inches or more. The soils are somewhat' rocky, either 
volcanic or sedimentary. The yield of rubber varies widely. 
In the total yield from individual trees this species excels all 
others. P. van Romburgh secured the enormous yield of 405 
pounds of rubber from a very old tree in western Java (near 
Buitenzorg). A 23-year-old tree on an equatorial plantation in 
Borneo yielded 32 pounds of rubber at its first tapping. In As- 
sam trees averaging 100 feet in height, which had not been 
tapped for 15 years previously, yielded an average of 10 lbs. 
of rubber, the next year 4 lbs. and the third year only 1.8 lbs. 
In Xew Guinea 8-year-old trees of Ficus elastica yielded 5.7 
lbs. of rubber within a week. The growth of this tree is some- 
what slow in Hawaii ; nevertheless I believe that it is one of the 
most promising rubber trees for plantation culture, especially 
in such districts as Hilo, Puna, Olaa and Xahiku. where the 
rainfall is high. Ficus elastica will stand low temperatures 
that are extremely detrimental to the Para and Central Ameri- 
can rubber trees. 
Practically all the rest of the Asiatic rubbers are derived 
from vines. It is doubtful whether any of these could be suc- 
cessfully and profitably transplanted to Hawaii. 
THE BEST EUBBEB TEEES FOE HAWAII. 
Hawaii with its subtropical rather than truly tropical cli- 
mate, is limited to a very few species of rubber-producing 
plants. The most suitable species of those above enumerated 
are undoubtedly in the order of their importance 31 an Hi ot Gla- 
ziowii and Ficus elastica. The first of these, the Ceara rubber 
tree, should comprise the larger proportion of all new planta- 
tions, because of its extremely rapid growth and early maturity. 
In laying out a rubber plantation comparatively early returns 
are desirable. The Ceara trees will stand a moderate tapping 
when three years old, and may be counted on to yield a 1 consid- 
erable return in five years. 
The Assam rubber tree, Ficus elastica, while of much slower 
growth, yields much more abundantly when it does finally reach 
a bearing age. This is also true of the Manicoba rubber, Han- 
cornia speciosa. The white rubbers, Sapium Tolimense, S. ve- 
rum and £. stylare, native of high elevations where the climatic 
