136 FOEESTS, WOODS, AND TEEES 



per acre, corresponding to an annual increment of 90 cubic 

 feet per acre. At 1020 feet elevation, in a sheltered 

 situation on good damp soil, the volume of a plot 43 

 years old amounted to 5610 cubic feet, or an annual 

 increment of 130 cubic feet per acre. 



In the Coombe Plantation at Keswick isolated trees of 

 spruce varied in height from 48 feet at 1450 feet elevation 

 to 35 feet on very exposed ridges at 1520 feet at 60 

 years old. Eeckoning the average height of a plantation at 

 1400 feet to be 45 feet at 60 years old, the yield would 

 be 2470 cubic feet per acre, an increment of 40 cubic feet 

 per annum. Such a yield would justify the planting of 

 spruce at this elevation from a financial point of view. 



At Durris, in Scotland, spruce felled at 60 years old 

 averaged 5600 cubic feet per acre in a plantation at 800 

 feet elevation, equivalent to an average annual increment of 

 over 90 cubic feet per acre. In the Kilworth plantation, 

 County Cork, at 300 feet elevation on good alluvial soil, a 

 plot of spruce, 78 years planted, measured about 12,000 

 cubic feet per acre, corresponding to an annual increment 

 of about 150 cubic feet per acre. These figures show the 

 great yields of spruce under varying conditions of altitude. 

 In hilly districts on suitable soil with moderate or slight 

 exposure, spruce may be expected to yield 90 to 100 cubic 

 feet per acre annually if grown in large areas in close order. 

 At higher altitudes it will produce enough timber to pay 

 for the expenses of planting ; and below such high belts of 

 spruce other plantations will flourish better on account of 

 the protection afforded. 



Sitka Spruce. — This tree is so important for the affores- 

 tation of the worst sites in our planting areas that some 

 account of its occurrence in its native habitat will be of 

 interest. It is a native of the Pacific Coast region from 

 Alaska to Northern California, where it grows along the 

 shore and inland for a few miles, ascending even in the far 

 north to 2000 to 3000 feet altitude on mountain slopes 

 exposed to the sea. It is unharmed either by the strong 



