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V. THE FORESTRY PROBLEM. 



By Professor W. SOMERVILLE, M.A., D.Sc, D.CEc, 

 Sibthorpian Professor of Rural Economy, Oxford. 



I UNDERSTAND that the object of this Conference is to attempt to effect 

 an improvement in the co-relation between research and practice, and 

 that my part in the programme is to examine the subject in its relation 

 to Forestry. 



The first reflection that occurs to me is this, that while Forestry, 

 Horticulture and Agriculture are essentially alike in principle, in so far 

 that all are immediately concerned with the conversion of air, soil and 

 water into vegetable products, forestry differs from the others in these 

 respects, (a) that its returns are long-deferred, (b) that the annual value 

 of its out-put per acre is relatively small, (c) that its operations are con- 

 ducted in less accessible areas, and (rf) that its crop (trees) is physically 

 less amenable to prophylactic or curative treatment and control. To 

 illustrate the last point, let us compare a typical disease of a crop in field 

 or garden, say Finger and Toe, with such a disease of trees as Chrysomyxa 

 abietis. I do not say we know all about Finger and Toe, but we seem to 

 know enough about it for all practical purposes. It can be prevented 

 (rt) by the avoidance of the infection of fresh areas through the agency 

 of parts of diseased plants, including contaminated manure and soil, 

 (6) by attention to cultural details, (c) by the use of an antiseptic sub- 

 stance such as lime, and {d) by the cultivation of resistant varieties of 

 particular cruciferous crops. But in the presence of Chrysomyxa abietis 

 one feels almost helpless. If one may take the order of its records as an 

 indication of its progress in this country, it seems to have started in the 

 valley of the Dee in Aberdeenshire, from which it spread into Kincardine- 

 shire, then it appeared in Perthshire, and more recently it has been 

 recorded in Northumberland. I do not suggest that the spread of this 

 disease is likely to threaten the spruce with destruction, though, through 

 loss of foliage, trees that are attacked do suffer in growth and may 

 succumb. I only mention it as an instance of a forest-tree disease which 

 some ten years ago, so far as we know, was confined to a limited area, 

 from which it has spread over a wide stretch of country, and in the 



