116 TRANSACTIONS OF ROTAL SCOTTISH ARBORICULTURAL SOCIETY. 



VII. On the Influence of Different Degrees of Thinning on the 

 Growth of Beech. By A. C. Forbes, Wood Manager, 

 Bowood, Calne. 



In the May and July (1899) numbers of the Zeitschrift fur 

 Forst und Jagdivesen, edited by Dr Danckelmann of Eberswalde, 

 Professor Schwappach published the results of a series of observa- 

 tions on the growth of beech woods under different methods of 

 thinning, as carried out on numerous experimental plots set apart 

 for the purpose. The observations were made under the auspices 

 of the Association of Forestry Research Institutions; and although 

 the beech is not considered as a timber tree of the first import- 

 ance in Scotland, Professor Schwappach's article is of sufficient 

 interest and importance to forestry in general, and the practice of 

 thinning in particular, to justify the salient points contained in 

 it being brought to the notice of members of the Royal Scottish 

 Arboricultural Society. 



The observations were divided into two divisions, one being 

 devoted to the question of thinning proper, as understood in 

 German forestry practice, and the other being confined to what 

 is known as "light-felling." Thinning is usually divided into 

 three degrees — weak, moderate, and strong, — all of which are 

 confined to dead, dying, suppressed, and partly suppressed trees. 

 Anything beyond this which touches the dominant stems goes 

 under the name of main-crop thinning. These four degrees of 

 thinning are characterised in the following paragraphs by a, b, c, 

 and d, corresponding to weak, moderate, strong, and main-crop 

 thinning respectively. 



By "light-felling" is meant a reduction of the crop by the 

 removal of all badly-shaped, injured, or broad-crowned trees in 

 the first place, and a thinning out of the least promising of the 

 remainder in the second, until the crowns of the trees are isolated 

 and the leaf canopy broken up. Light-felling removes from one- 

 fifth to one-third of the total crop, and closely resembles the 

 thinning practised in Scots fir and larch woods in this country 

 between the thirtieth and fiftieth year. 



In the experiments in question, eleven main-areas were set 

 apart for the thinning observations, containing twenty-nine sub- 

 areas, all of which have been at least ten years under observation, 

 and in some cases as long as twenty -five years. 



The numerous and painstaking measurements and data are 



