154 TRANSACTIONS OF ROYAL SCOTTISH ARBORICULTURAL SOCIETY. 



The crown is dense and pyramidal, covering about two-thirds 

 of the stem. The lower branches persist for many years, hence 

 dense stands are essential to the production of clean lumber. 

 Sitka spruce is very tolerant in early youth, later it is less so 

 than its associates, the giant arbor-vitae and western hemlock. 



The root-system is shallow and spreading, the bole tapers 

 moderately, and has an enlarged base, in dense stands it is clear 

 for 50 to 80 feet. Sitka spruce is one of the largest trees on the 

 Pacific Coast, reaching a height of from 100 to 130 feet, and 

 diameter of 3 to 6 feet. Trees are found 150 to 200 feet high with 

 a diameter of 8 to 12 feet. Owing to the ameliorating influence 

 of the Japan current, and the warm, humid winds blowing from 

 it, the climate here is mild and uniform. In the northern part 

 of the tree's range the temperature falls to 30 degrees below zero. 

 Precipitation is heavy, 60 to 70 inches, in the middle part of its 

 range, and varies from 20 inches in California to over 100 inches 

 in Alaska. 



Sitka spruce forms large pure forests, especially in the northern 

 part of its range. On the coast, where it reaches its largest 

 size, its chief associates are Douglas fir, western hemlock, and 

 western red cedar. It can be procured in very large sizes, the 

 tall straight boles furnishing lumber of the best quality and of 

 the largest dimensions, usually clean and free from defects. The 

 wood varies in colour from white to light brown; it is soft, light, 

 and easily worked, but tough and very strong for its weight. It 

 is even-grained and long-fibred, flexible and resonant and 

 non-resinous. It does not split or warp. Being odourless and 

 tasteless, strong and light, it is specially suited for cooperage 

 and boxes for packing food-stuffs. 



For structural work where great strength is required Sitka 

 spruce is not so suitable as Douglas fir, but it is used for framing, 

 shelving and sub-flooring, piling and cribbing; it provides 

 excellent material for car stock ; it is also used for parts of light 

 implements and vehicles. When sawn tangentially (slash grain) 

 Sitka spruce has an attractive grain, and is admirably suited for 

 panelling, office fittings and furniture; it is very suitable for 

 interior finish, takes glue and paint well, is easy to nail and does 

 not split. 



It is unsurpassed for aeroplane construction, this being due to 

 the long straight grain and fibre, the toughness and lightness, 

 and the large clean sizes obtainable. In ten months, British 



