sitka spruce: uses, growth, 'management. 17 



ESTABLISHMENT OF SEEDLINGS. 



Sitka spruce germinates slowly, and in this habit it is similar 

 to other low-altitude species of the coastal region, and in contrast 

 with Engelmann spruce and high-altitude Douglas fir, which re- 

 quire only a short time for germination. Similarly, Sitka spruce 

 seedlings do not respond quickly to atmospheric warmth early in 

 the spring, and their buds do not unfold until the season is well ad- 

 vanced. Were it not for this characteristic much injury to re- 

 production would result, for during early spring clear, warm weather 

 in the lowlands is often followed by killing frosts. 



Moisture, light, and heat are all essential for the germination and 

 establishment of spruce seedlings; but, as moisture is abundantly 

 supplied by rains and fogs in the region, and as the young seedlings 

 are capable of enduring dense shade, heat is the uncertain factor. 

 In this regard the warm exposures of old burns, clearings, and 

 logged-over lands offer conditions more suitable for growth than 

 elsewhere, and, as spruce can compete successfully with all other 

 species, it establishes itself with little difficulty on these sites. In 

 the choice of seed bed, Sitka spruce prefers loose mineral soil, but 

 it can thrive equally well in the decayed wood of down logs and in 

 the deep humus of the forest floor. Plate IX, figure 2, illustrates 

 the establishment of two spruce trees on an old windfall. Because 

 of its extreme tolerance in early youth, Sitka spruce sometimes occurs 

 on fresh earth slides, under a temporary cover type of alder, and 

 eventually becomes the predominating species. 



Stands of reproduction in the spruce type are densely stocked. 

 (Pis. XIV and XV.) Counts were made during the recent field 

 study on 10 square-rod quadrates in areas of reproduction, and these 

 counts showed that in thrifty stands under 10 years old there were 

 3,000 seedlings per acre, and that in stands 30 years old there were 

 500 trees per acre. Xearly one-quarter of the 30-year-old trees were 

 12 inches and over in diameter at breastheight. It was also shown 

 that a stand of maximum density, which was 5 years old, contained 

 35 .000 seedlings per acre. In each of these stands 50 per cent or 

 more was spruce, and the remainder was mostly hemlock, with a 

 few cedar and Douglas fir trees. In very dense stands Sitka spruce 

 seedlings generally comprise only 10 to 20 per cent, but this per- 

 centage often increases as the stands become older. Under ordinary 

 circumstances spruce is able to maintain itself and even increase 

 notwithstanding the competition of other species. These seedlings. 

 which air- rather delicate and slender stemmed during (he first lew 

 years, later develop heavy, stiff stems. They at first average nearly 

 r.nc half loo! in liciglit growth per year and beyond IT) years of 

 age increase in height at the rate of:? feet per year. 

 85360 i'i :; 



