360 Coombe Plantation, Keswick. [august, 



proposed to enter further into the question here, but merely 

 to point out the need of collecting data and undertaking 

 experiments on the subject. 



The Value of Spruce at High Elevations. — It has already 

 been noted that the plantation has not been a success in the 

 highest parts, and it is interesting to attempt to fix the limit 

 at which pure larch ceases to be profitable. 



For the whole area the average volume per tree in 1909 may 

 be put down at 10 cubic ft. If one assumes that the inter- 

 mediate returns are proportional to the final volume per 

 tree for each quality of locality,* one finds that the profit 

 becomes nil if the average volume per tree falls to 4 cubic ft. 

 — a volume attained at about 1,450 ft. This is without doubt 

 the maximum elevation at which the wood has paid under 

 these conditions, and a safer limit would be 1,400 ft., although 

 the trees above this elevation have been of value in sheltering 

 the rest of the crop; The question now arises whether the 

 spruce or Scotch pine will pay to grow' at this elevation, since 

 the larch does not. 



The height-growth of Scotch pine above 1,400 ft. is poor, 

 and does not reach more than 30-35 ft. in sixty-one years. 

 According to German yield tables, f this would correspond 

 with a final yield at sixty years of about 1,600 cubic ft. true 

 measurement, or not more than £40 per acre at 6d, per 

 foot. There is no chance of such a crop proving a financial 

 success under present conditions. 



In the case of spruce the height-growth, in open groups, 

 is considerably better, and varies from 48 ft. at 1,450 ft. to 

 35 ft. on the very exposed ridges at about 1,520 ft. An 

 average height for the whole area above 1,400 ft. would be 

 about 45 ft. This estimate makes some allowance for the 

 fact that if grown in denser groups the trees in the higher 

 parts would protect each other against wind to the benefit 

 of the height-growth. 



Under fairly dense canopy conditions it is held that the 

 following returns per acre might be expected from 

 spruce + : — 



* This assumption will give the intermediate returns too high in the case of the 

 poorer qualities and therefore place the limit too high, 

 t Schlich's Manual of Forestry, Vol. III., p. 366. 



% The volumes are taken from Schiffel's Wuchsgeselze Normaler Ftchtenbestande, 

 page 57, and were compiled for Austrian forests. 



