plant poison occurs in ilia soil should absolutely prohibit the .growth of 
4 ' 
any ordinary upland forest tree. 
From moh Scnawledge as wo have ‘been able to obtain of Hawaiian forests 
. * <. -, . ■ i.. * 
and forest trees it would seem that t he majority of them trees require a 
i T$; 
well drained and well aerated soil, and *kwn located in such a soil they 
delight in a moist atmosphere and heavy rainfall. The growth which m iive 
• i*i i- -• 
trees hare md& on the more recent lava flows of windward Hawaii is moat 
jr> it !'■ : If ; ; | !| ■:; : 
remarkable, and testifies strongly to the correctness? of this view. In 
this region the re inf all is wry heavy, hut the underground drainage is 
good, a?: evidenced by the absence of surface streams* 
It would seem that at b&o time windward Fan.i must have presented ideflt 
conditions for the growth of the native trees, but the gradual charges in 
the substratum haw br-cn constantly rendering it less suitable for their 
growth, the upper basaltic lavaa have disintegrated to a fine grained 
*jf«J ibj i'l.;' Ijjbv ' $ 
soil, and under the constant soaking mi" Inching effects of a heavy rain¬ 
fall, the interstices of the lower sirs fa have be cams clogged with fine- 
material, while there remains at if.he surface the washed-out i^ervlous 
* 
. 
top soil that we have already noted. 
There can be no circulation of -air in this soil, since.it is always 
saturated with water., The hydrogen sulphide liberated fchroujt the fer¬ 
ments-I on of the organic matter by bacteria reduces the abundant ferric 
!W*\V;-*fr: r v, ip*>t lh'l : t L f j\ 1 . ’-.vv; (lyjjk .%* »;y • .. * ■• • • h--‘ v. ' • * ■■.*; • ; T’ ■ •".■[,;■ ‘ * ' ”^ 4 ' h. 
Compounds to ferrous compounds* The poisonous eowjpouftd a have gradually 
increased in the ^oil until now the native upland trees are m longer 
able to maintain themselves u^on it. Evidence has hem deduced rhich 
shows that the trees of this forest here m de no growth for tsany years 
past, and have, in reality, been alowly during. The excessively moist 
atmosphere has enabled the trunks and loaves of the trace to remain ; 
