TESTS ON THE DURABILITY OF 
GREENHEART 
(NECTANDRA RODIAEI SCHOMB.) 
C. J. Humphrey 
(With Plate 162, Containing 6 Figures) 
Greenheart is a tropical timber-tree/ belonging to the laurel 
family, which has a world-wide reputation for extreme dura- 
bility. The species grows in South America and some of the 
West Indian islands and is commercially exploited for home con- 
sumption as well as for export trade. In its native home it is 
used generally where a durable timber is required, it being re- 
sistant not only to wood-destroying fungi, but also to marine 
borers and white ants. Oustide its habitat it finds its greatest 
use in marine construction, to which it is particularly adapted on 
account of its resistance to the teredo. 
The wood is very hard, heavy (about 61 lbs. to the cubic foot 
when air dry), tough, very strong, and fine-grained. As in many 
tropical trees, annual growth rings are not distinguishable. 
The proportion of sapwood in a log is usually high, ranging 
from 3 to 4 inches in thickness in trvtnks 18 to 24 inches in 
diameter. Trees under 12 inches usually consist largely of sap- 
wood. It is said that dealers do not regard the sapwood as 
inferior to heartwood, but the tests below outlined indicate there 
is a marked difference. 
Freshly-cut sapwood is pale-yellow, darkening on exposure; 
the heartwood may vary from pale-yellow to black. Under the 
microscope the wood appears very dense, being interspersed with 
numerous single or double vessels, whose cavities are frequently 
stuffed with cellular ingrowths, called tyloses (Plate 162, figs. 4, 
5, 6). These tyloses, when very abundant, are said to give a 
darker appearance to the wood. 
^ Mell, C. D., and Brush, \X. D. Greenheart. U. S. Forest Serv. Circ. 
211. 1913. 
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