120 TRANSACTIONS OF ROYAL SCOTTISH ARBORICULTURAL SOCIETY. 



areas for the light-felling experiment. The former was severely 

 thinned in 1887, and the growth made is rather in excess of what 

 it would have been under ordinary conditions. The two light- 

 felling areas were thinned down to 80 per cent, of the control 

 area, but while on Sub-area I. strong stems were removed gener- 

 ally, on Sub-area II. chiefly stems with wide-spreading crowns 

 were taken out. The result of this difference in the treatment 

 was that Sub-area I. showed an increase in the ten years of 9 per 

 cent, and Sub-area II. one of 17 per cent, over the control area, 

 although the growth of the latter was higher than the average. 



3. Research on Seebactis System. — Seebach's system of light- 

 felling consists in removing, within a period of about ten years, 

 two-thirds of the crop about the seventieth or eightieth year of 

 its age, and encouraging an undergrowth of beech seedlings, either 

 by natural or artificial means. After thirty years or so the leaf 

 canopy again closes up, and the original stock of timber is again 

 present on the ground. The wood is then treated with a view to 

 natural regeneration in the ordinary way, by preliminary seed- 

 fellings, etc. 



Several areas were devoted to this research, one of which was 

 set apart by Seebach himself in 1843, and is still under observa- 

 tion. The result of this treatment on the research areas gener- 

 ally is to confirm the assertion that one-third of the sectional 

 area of the wood is sufficient to produce as much absolute growth 

 under this system as the growth made by a wood left in close 

 order, while the advantages claimed for it are earlier realisation 

 of part of the crop, and larger timber at the final felling. It is, 

 however, only suitable for good soils and localities, and is prob- 

 ably less advantageous on the whole than the gradual isolation 

 of the best stems, as described in the former methods. 



Tn the above light-felling experiments the ages of the respective 

 woods varied between seventy-five and one hundred and ten years, 

 that of the area originally set apart by Seebach running up to 

 one hundred and twenty-six years. 



General Conclusions. 



The general conclusions arrived at by Professor Schwappach, 

 so far as the results hitherto obtained are concerned, are as 

 follows : — 



1. By an increase of warmth and light, the additional room at 

 the disposal of the roots, and the removal of mechanical obstacles 



