On Colonial Timber Trees. 55 



There is one subject, which, although it may appear 

 scarcely consistent with the title of this paper, is of such 

 vast importance that I hardly like to conclude without a 

 brief reference to it. The subject alluded to is the effect of 

 forest country upon climate. 



I have already mentioned the attraction and condensation 

 of dew by trees, but reference has not been made to the 

 retention of water in the soil under trees in consequence of 

 the spongy nature of vegetable earth, or in other words a 

 deposit of leaves, causing the formation of leaf mould. 



This is particularly noticeable in all woods where decidu- 

 ous trees prevail ; but large deposits of leaf mould occur in 

 pine forests ; in fact, it is asserted as a feature in the growth 

 of the pine, that it thrives best in rocky mountainous 

 districts in shallow soils accumulated from the constant 

 deposit and decay of the leaves of the pines. 



I think I may say that it is a well-ascertained fact that 

 trees (deciduous in particular) growing in high situations 

 and formed into forests, so attract the moisture of the 

 atmosphere, condense it and again breathe it out as it were, 

 that those districts are genei'ally the sources of streams and 

 springs. Again, referring to "White's Selborne," he says, 

 " that in some of our smaller islands in the West Indies, 

 where there are no springs or rivers, the people are supplied 

 with water by some tall trees in the bosom of a mountain 

 which keep their heads constantly enveloped with fogs and 

 clouds, from which they dispense their never-ceasing 

 moisture, and so render those districts habitable by con- 

 densation alone ; and further on he says, " Trees perspire 

 " profusely, condense largely and check evaporation so much 

 " that woods are always moist ; no wonder, therefore, that 

 " they contribute much to pools and streams." 



" That trees are promoters of lakes and rivers appears 

 " from a well-known fact in North America ; for, since the 

 " woods and forests have been grubbed and cleared all 

 " bodies of water are much diminished ; so that some 

 " streams that were very considerable a century ago will not 

 " now diive a common mill. Besides, most woodlands, forests, 

 " and chases with us abound with pools and morasses ; no 

 " doubt for the reason given above." 



There can be little doubt that clima,tes of different 

 countries are much influenced by the features of the country 

 and the special vegetation. The countries which havelarge 

 surface deposits of vegetable earth and forests consisting of 



