33 



every seed in a pod is destroyed. Owing probably to forest de- 

 pletion and the consequent upsetting of the balance of nature, 

 the native hymenopterous parasites which attack the larvae of 

 these moths are not so efficient in keeping them in check, with 

 the consequence that almost every new crop of koa seed is now 

 badly infested. 



A spanworm also in places denudes the koa trees of their 

 phyllodes or leaves, working in large numbers for a few weeks. 

 Here again the damage is due to disturbed forest conditions, 

 because under normal conditions which formerly existed the 

 dense undergrowth, since removed, presented favorable moist 

 conditions for the fungus which destroyed the spanworm larvae 

 when they came down to the ground to pupate. 



NATURAL REPRODUCTION. 



The common method that the koa has of reproducing itself 

 is by seed, but in order to germinate and grow it requires the 

 full, warm sunlight, and will not successfully sprout in the shade. 

 Young seedlings spring up remarkably w^ell after a fire has passed 

 over the ground. The seed that escapes incineration seems to 

 be prepared for germination by the warmth of the fire, and many 

 a burned-over area has been reclothed with a new forest in this 

 manner from seed that has lain dormant in the soil. Young 

 seedlings in large numbers are often found coming up from 

 seed in a fringe or circle around the mother tree, representing 

 the group method of natural reproduction.. The koa will also 

 reproduce in a less satisfactory manner by suckers coming up 

 from the roots of old trees. 



WOOD. 



The wood of the koa is probably the most valuable, commea-- 

 cially, of all Hawaiian trees and is the best known. The koa 

 does not exist in large enough tracts to make extensive logging 

 operations profitable. It was formerly put on the market as 

 "Hawaiian mahogany." Owing also to its comparative inaccessi- 

 bility and high freight rates, it is now cut only in small quanti- 

 ties, sufficient to supply the local demand for furniture, cabinet 

 work and musical instruments. The sapwood of the koa is white. 

 The heartwood, which seasons well without splitting, is moder- 

 ately heavy and hard, and varies in color through many rich 

 shades of dark red to a golden brown. The grain is fine and 

 indistinct, and is capable of receiving a high polish. The curly 

 grain, which is often found in the wood of trees growing in the 

 drier localities, gives the curious fiddle-back appearance and is 

 highly prized. The wood has been used for the interior finish 

 of houses with rich effects. The bark of the koa has valuable 

 tannic properties. 



