8 TRANSACTIONS OF ROVAL SCOTTISH ARBORICULTURAL SOCIETY. 



extends inland at all, it does so only along arms of the ocean, 

 and along the courses of streams. In Alaska it extends farther 

 north and west than any other Pacific coast forest tree. 



" Sitka spruce occurs generally in moist situations along the 

 coast, on alluvial and sandy bottom-land, along the courses of 

 streams, and also on moist slopes facing the sea. In parts of 

 British Columbia, Alaska, and the islands along the coast, 

 Sitka spruce thrives on very thin and light soils, where there is 

 an abundance of atmospheric and soil moisture. It follows 

 the moist soils in its extension eastward, and on the mountain 

 slopes. For its best development it requires constant soil 

 moisture, humid air and good soil. In situations deficient in 

 moisture the Sitka spruce is more or less stunted, and the 

 quantity and quality of soil becomes more important as the 

 moisture supply decreases. It can endure inundation along the 

 flood plains of the coast, but generally grows a short distance 

 from the water's edge, to avoid too wet situations." 



These then are the conclusions with regard to the demands 

 of the Sitka spruce on site and soil arrived at by the United 

 States Forest Service, as the result of a prolonged study of its 

 habit in its natural state ; and if these conclusions be added to 

 the experience gained in this country of the tree in a cultivated 

 state, a sufficiently reliable estimate of its physical requirements 

 may be formed to guide us in the selection of sites and soils 

 most favourable to its growth. That ample moisture, both soil 

 and atmospheric, is essential to its well-being in the British 

 Isles has already been abundantly proved, and hence we find 

 the largest and most vigorous trees of the species in the humid 

 climate of the Scottish Highlands, in the west coast of England 

 and Wales, and in Ireland, where the climate generally seems 

 favourable, and where also the largest trees are to be found. 



The lowlands of the south of Scotland, and the midland and 

 eastern countries of England generally, are not so suitable for 

 the growth of Sitka spruce, owing no doubt to the dryness of 

 the atmosphere, and it is also a noticeable fact that height- 

 growth is much slower on open plains than on the lower slopes 

 and valleys of a hill country ; it is only when planted on the 

 latter positions that full advantage of its inherent tendency to 

 produce rapid and sustained upward growth can possibly be 

 taken. 



On low elevations and moist soils, a rainfall of from 30 to 53 



