DISCUSSION. 235 



on account of tlie saving of moisture for the lesser vegetation, I 

 will venture, in a final brief extract, to refute it in the words of 

 the same writer in Chamhers^s Journal, just referred to. " Of 

 course, since rain comes, because the air is too cool to hold its 

 moisture any longer in solution, there ought to be more rain in 

 a wooded than in a treeless district ; and so there is, from 6 to 8 

 per cent., as M. Eaudrat found by putting up several rain-gauges, 

 some in a forest seven yards above the tree-tops, others on tree- 

 less ground, some two hundred yards off. ... It may be 

 said if the trees bring more rain, they use up more than the tree- 

 less ground, for their roots drain the soil, and their leaves drain 

 the atmosphere. Not so ; though wood is more than half water, 

 the amount of water contained in all the wood in a forest is the 

 veriest trifle compared with the rain that falls on it during a 

 year. Moreover, a series of experiments seems to show that the 

 amount of water decomposed by an acre of forest is very much 

 less than that required by an acre of cabbage, or wheat, or clover. 

 Again, because pines and other trees (notably the blue gum, 

 Eucalyptus gloluhts, which is being planted by the million in 

 Algeria) dry up marshes, it has been argued that trees must les- 

 sen the water supply. But here again experiment comes in and 

 proves that this drying up is not due to evaporation through the 

 leaves or to the water being in any other way sucked up by the 

 trees. All the trees that have this property can and do thrive 

 also in hungry soils ; they drain the soil by virtue of their spread- 

 ing roots, which enable the water to run into the lower strata, 

 and this meets the observation of my friend Mr. Brodribb (whom 

 I am glad to meet here to-night after twenty-five years' aoquaiDt- 

 ance, as a member of our Society), that the trees on the road to 

 Bowenfells are perfectly useless to mrni and beast — for they are 

 not perfectly useless in another way, as they supply water to the 

 deep creeks which are the feeders of the Nepean and Hawkesbury. 

 If any further argument is required, it may be well to refer to 

 the experiments carried on in Erance during the last tw-elve 

 years, and to leave opponents to be refuted as the Directors and 

 Inspectors of Forests refuted the misunderstandings of Louis 

 Napoleon and M. Fould. 



But if gum-trees, as well as others, produce accession of water 

 to the earth below, is it not suicidal to ring-bark trees, destroying 

 the capacity to do what nature demands ? If trees are to do 

 what experiment suggests, and what ring-barking indiscriminately 

 carried on altogether prevents, will it not hereafter be found to 

 be folly, when ioo late, whatever the temporary profits be at the 

 moment ? Lastly, I would ask why in the neighbourhood of 

 ring-barked areas the natural forestry loses its vigour, and 

 appears to suffer from a Avant of nourishment ? 



'J. A 



