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is not yet established ; by opposing obstacles to air currents, forests 

 prevent the dissemination of dust particles with their contingent 

 germs ; they reduce the extremes of temperature of the air ; they 

 increase the relative humidity of the air and the precipitation in rain- 

 fall, and they protect and control the waterflow from the soil. 



7. To us these effects do not appeal with the same force that they 

 do in continental areas. Our insular and geographical position renders 

 us in a measure independent of them. The data for these continental 

 results, it must be remembered, are derived from large forest areas 

 such as do not exist here. For this country I know of no experiment- 

 al evidence on the subject. As, however, the effects of forest influence 

 are felt mainly in local modification of climatic conditions, we are not 

 justified in regarding the conclusions that have been reached as in- 

 applicable to Britain. No little interest attaches, therefore, to a state- 

 ment based upon these continental observations to which Dr. Nisbet 

 has recently done well to call attention — that, " where the rainfall is 

 over forty inches it is undesirable to increase the forest area." The 

 significance of this dictum, if it be established, to Britain, dependent 

 so largely upon her agriculture, is evident. Wet years, unfavourable 

 to farm crops, are, under existing conditions, more numerous than 

 favourable dry ones, and any extensive tree-planting in agricultural 

 areas might therefore prove disastrous. But I may here emphasise 

 the point that, whilst for the growing of specimen trees we may agree 

 with Evelyn when he says, " If I were to make choice of the place or 

 ihe tree, it should be such as grows in the best cow-pasture, or upland 

 meadow, where the mould is rich and sweet," yet the harvest which 

 scientific sylviculture reaps comes from land unsuited to agriculture, 

 which would otherwise lie barren and waste, and therefore schemes 

 for the afforestation of such areas in non-agricultural districts need 

 not be prejudiced by the prospect of an increased local rainfall. At 

 the same time we must not fail to learn the obvious lesson that af- 

 forestation is not, as some suppose, a simple matter of employment of 

 labour, but that it involves the consideration of weighty scientific 

 problems. 



8. Forests, as a source of fuel, have not the direct importance to this 

 country, rich as it is in coal supply, that they have in States less 

 favoured, but their economic importance to us as a source of timber 

 needs no comment. There are no means available through which to 

 estimate the annual output of timber from our plantations, but in- 

 directly we can guage the insufficiency of our woodlands to supply 

 the timber necessities of the country by reference to the returns show- 

 ing the amount and value of forest produce annually imported. This 

 has been steadily increasing until in 1893 its value exceeded eighteenmil- 

 lion pounds. Of course a considerable proportion of the material thus im- 

 ported could not in any circumstances be produced in Britain. But, 

 after allowing a liberal discount for these, there remains a large bill 

 which we pay for produce, no small portion of which could be furnished 

 at home. Xo one would suggest that in the limited and densely 

 populated area of great Britain timber trees of kinds suiting our climate 

 could be grown sufficient to supply all our demands ; that would be 

 impossible. But few would venture to deny that we could do very 



