76 TRANSACTIONS OF ROYAL SCOTTISH ARBORICULTURAL SOCIETY. 



Especially in Scotland it has not been used at the higher 

 elevations, but it has a future there both from the point of view 

 of its productivity and also for the effective shelter it will give 

 to other species, notably larch. 



Sitka Spruce (Picea sitchensis). 



The habitat of this species is western North America. As 

 regards latitude the limits of its distribution are wide, viz. from 

 Alaska to California. It attains an average height of ioo feet 

 and a diameter of 3-4 feet, but it occasionally reaches much 

 larger dimensions. It has not been widely planted in this 

 country except as an ornamental tree. There is some 

 evidence, however, that this will be one of our most valuable 

 conifers. 



Its soil requirements in this country have yet to be fully 

 determined. In America, according to Sargent, it grows on 

 moist, sandy, often swampy soil, or less frequently, in the far 

 north, on wet rocky slopes. As regards soil, it is fairly certain 

 that this exotic species will grow on most areas suitable for 

 Norway spruce. There is indeed evidence that it is less 

 exacting than the European species, especially as regards 

 growth on peat. There is a plantation 40 years old, at 

 Durris in Lower Deeside, at a considerable elevation, giving 

 remarkable results on 2-3 feet of peat. The other species 

 present, viz. Scots pine, larch, Norway spruce, and silver fir, are 

 all doing poorly. It must be remembered, however, that the 

 term peat does not refer to a definite substance, for, from the 

 point of view of forestry, peat is very variable. Some guide 

 to its quality is given by the natural flora which it carries : 

 the peat referred to above is neither the best type nor is it the 

 worst. If further experiments show that Sitka spruce will give 

 good results on peat, for that reason alone it will be a most 

 valuable addition to our forest trees. The habitat of this 

 species indicates that an abundant water supply favours it. 

 Limited trials, however, show that it gives more satisfactory 

 results than Norway spruce under relatively dry conditions, 

 and it seems probable that Sitka spruce will do well under dry 

 conditions, for its growth on peat shows its ability to withstand 

 physiological drought. Its limitations as regards elevation and 

 exposure still remain to be determined, but it does not appear 

 to be more exacting than Norway spruce. 



