CHAP, xi.] Effects of Under planting 233 



2. Observations as to the rate of growth in crops that had 

 been underplanted for some time, and a comparison of that 

 with the rate of growth in other portions not underplanted. 



3. Clearance of underwood in crops underplanted, and 

 comparison of the next year's increment with that on those 

 under which the underwood had been left untouched. 



So far as the first class of experiments was concerned, 

 Borggreve found that the stems exhibited increment in the 

 breadth of the annual rings only for five years, whilst a decrease 

 set in whenever the underwood began to close up and form 

 canopy, and that the decrease became greater as the canopy 

 grew more dense. He therefore concluded that the initial 

 enhancement was solely due to the more complete insolation 

 of the trees and the diminution in the number of plants 

 drawing their food-supplies from the soil, and denied that 

 it could be due to any better and more rapid formation of 

 mould by the dead foliage covering the soil. But he over- 

 looked two points -firstly, that the degree of insolation of the 

 crowns of the standards could in no way be affected by the 

 removal of the coppice ; and secondly, that the demands on 

 food-supplies from the soil made by the coppice during the 

 first few years of its rapid growth would certainly be at least 

 equal to (and most probably higher than) were made later 

 on when it was growing in close canopy. When these points 

 are duly considered, it seems evident that the cause of incre- 

 ment must certainly be assigned to the advantageous formation 

 of humus or mould when the dead foliage was exposed to the 

 decomposing influences of sun, rain, warmth, and fungoid 

 growth. He maintained with a show of reason, but incor- 

 rectly that these processes were retarded rather than favoured 

 by the clearance of the coppice. Full, clear consideration of the 

 actual facts warrant the opinion that the increment took place 

 on the standards owing to the larger formation of humus from 

 the dead foliage which could not decompose normally under 

 the dense shade of the coppice, and that the subsequent 



