273 



Coombe Plantation, Keswick. [July, 



suffers a gradual decrease in volume from 14 to 11 cubic ft., 

 or approximately 8J per cent, per 100 ft. of ascent. From 

 1,250 ft. the decrease is more abrupt, probably owing to a 

 change in the topography of the land which resulted in in- 

 creased exposure to wind. The average volume falls off to 

 5 cubic ft. at 1,400 ft., 4'5 at 1,450 ft., and 2-5 cubic ft. at 

 1,500 ft. All the measurements are quarter-girth. 



In the case of spruce, since there are no experimental 

 groups, measurements were made at various elevations of the 

 small groups scattered over the area. It must be pointed out 

 that the curve is not a true gauge of what the land would 

 carry under spruce, since the trees have nowhere been grown 

 close together as in a full crop. While the spruce has, under 

 these conditions, put on a greater volume than would be 

 normally obtained per tree, its isolation among a lot of larch 

 has often resulted in its suffering damage from wind to a de- 

 gree which would not occur if it were grown in dense masses. 



The average volume falls gradually from 44 cubic ft. at 

 900 ft. to 27 cubic ft. at 1,250 ft., and somewhat abruptly to 

 15 cubic ft. at 1,430 ft., and then very abruptly to 7 cubic ft. 

 quarter-girth at 1,500 ft., 4he curve following a course very 

 similar to that for larch. 



The resemblance between the two and the general shape 

 of the two curves are perhaps of more than passing interest. 

 That part of each curve which lies between 1,000 ft. and 

 1,250 ft. is practically a straight line ; and since the conditions 

 as regards exposure are practically constant, one might con- 

 clude that the gradually decreasing volume is due solely to 

 increased elevation and decreasing vegetative activity. If 

 such be the case, one finds that under similar conditions the 

 larch would attain a volume of about 8 cubic ft. at 1,500 ft., 

 and 7 cubic ft. at 1,600 ft., while the spruce should attain 14 

 and 10 cubic ft. respectively at these elevations. Well- 

 sheltered localities at such elevations are, of course, rare, but 

 they do exist in the Lake District, notably in the Coombes on 

 the north and east sides of the higher mountains. If such 

 volumes can be actually attained, plantations at these eleva- 

 tions and under these conditions should pay well, but in the 

 absence of data this must be regarded as a mere expression of 

 opinion and a suggestion for experimental work. 



