SITKA SPRUCE! USES, GROWTH, MANAGEMENT. 
25 
The figures given in Table 6 indicate the average total height and 
average annual height growth in each decade of older spruce of vari- 
ous ages, averaged from the i ^surement of 554 dominant trees. The 
figures are dependable for trees up to 300 years; beyond that age 
reliable height-growth figure., are difficult to obtain, because very old 
spruce trees are commonly stag-headed. 
Table 6. — Average total height at various ages, and average annual height 
groivth in each decade of Sitka spruce on all sites in Oregon and Washington. 
[Based on 1,260 sectional measurements o/ 554 dominant trees.] (Curved.) 
Age. 
j Average 
decade. 
Age. 
Average 
total 
height. 
Average 
annual 
height 
growth 
in each 
decade. 
Years. 
20 
Feet. 
31 
51 
70 
87 
104 
119 
132 
144 
154 
164 
173 
181 
188 
194 
200 
205 
210 
214 
218 
221 
Feet. 
2.4 
2.0 
1.9 
1.7 
1.7 
1.5 
1.3 
1.2 
1.0 
Years. 
' 220 
230 
Feet. 
224 
226 
228 
230 
232 
233 
234 
235 
236 
236 
236 
237 
237 
237 
237 
237 
238 
238 
238 
Feet. 
0.3 
30 
.2 
40 . 
240 
.2 
50 
; 250 
.2 
60. 
: 260 
.2 
70 
', 270 
.1 
80 
J 280 
.1 
90 
i 290 
. 1 
100 
300 
.1 
110 
1.0 
.9 
' 310 
.1— 
120 
320 
.1- 
130 
.8 
.7 
.6 
.6 
. 5 
.5 
.4 
.4 
.3 
! 330 
.1— 
140 
1 340 
.1- 
150 
i 350 
.1— 
160 
360 
.1— 
170 
! 370... 
.1— 
180 
! 380 
.1— 
190 
390. . 
.1— 
200 
400 
. l — 
210 
DIAMETER. 
Diameter growth in this species is remarkably rapid and well sus- 
tained, as the figures in Table 7 indicate. In this table the figures 
represent the average of measurements taken of 557 dominant trees 
from seven localities in Oregon and Washington. Although its an- 
nual rate of diameter growth culminates at about the age of 40 years, 
it maintains a growth of over 3 inches per decade up to about GO 
years, and thereafter for a few decades over 2 inches per decade. At 
the advanced age of 400 years, the data in Table 7 indicate, the 
diameter is still increasing at the rate of over 1 inch per decade. 
Exceptionally rapid diameter growth is attained on wet sites, where 
sometimes it may amount to three-quarters and even 1 inch annually 
during early years of vigorous growth. Plate XX shows the 
diameter growth of Sitka spruce. 
