18 BULLETIN 154, U. S. DEPARTMENT OF AGRICULTURE. 
possible exception of larch. Lodgepole seedlings from 5 to 7 years 
old with leaders 36 inches long have been noted. In one case a young 
tree, about 8 years old, had made a height growth of 74 feet in the 
last 3 years. Another young tree of about the same age had a-45-inch 
leader. 
TABLE 4.—Average height growth of lodgepole pine seedlings on the Deerlodge 
National Forest, Mont., and the Arapaho National Forest, Colo. ; 
Height. | Height. 
| 5 
: f 
Age in years. Deerlodge | Arapaho | Age in'yeals. Deerlodge | Arapaho 
National National || National National 
Forest. Forest. ; Forest. Forest. 
Feet. Feet. Feet. Feet. 
seas RA ae see ee een Qu ee SSeS eee as Mee See 0.8 1.4 
52 BCR ac 2 ck ee Ye an PRES shape NC EO 5B. cata I oe ice ae aii 1.0 1.9 
Si pS TE are CC aeae s Spo tee 0.4 4 | i A) Messer pee ea ok US ES aisles a eh en a 4.5 
BS pees Sh eee apes 2 .6 9 | 1 Netaaeet Sao eae case Wine Rivers ce ler 7.9 
The growth figures so far given all apply to unthinned stands. If 
it were possible to make thinnings when needed that would favor 
the best trees, the growth of the latter would undoubtedly equal, or 
even considerably exceed, that shown for the dominant trees shown 
in Table 2. Such intensive management, however, could be under- 
taken only in a few favored localities where the market is unusually 
good. Lodgepole pine stands have been thinned in the past only in 
the course of ordinary lumbering, which has usually left the smaller, 
poorly developed trees, many of which could take no advantage of 
the operation. That even trees of this character often respond to 
such haphazard thinning with a remarkable increase in rate of 
growth has already been stated. Out of 91 average trees measured 
on the Deerlodge Forest, representing those which remained when 
the surrounding stand was cut, 54 trees, or 59 per cent of the total 
number, showed a marked increase in growth, while the remainder, 
or 41 per cent, showed no increase. Differences in rate of growth 
before and after cutting are shown in Table 5. 
TABLE 5.—Effect of thinning; average diameter growth of lodgepole pine trees 
left after cutting, Deerlodge National Forest, Mont. 
Part I. [Based on 91 trees, irrespective of whether they showed increased growth or not.] 
Periodic annual diam- 
eter growth for 20 Time required to grow 
1 inch in diameter. 
Diameter years. 
breast Trees. 
high. 
Before After Before After 
thinning. | thinning. | thinning. | thinning. 
Inches. | Number. Inch. Inch. Years. Years. 
3 8 0.028 0. 034 36 29 
4 10 j - 031 . 042 32 24 
5 15 . 037 . 039 27 25 
6 17 - 051 . 041 20 24 
7 at Cs | - 047 . 057 21 18 
8 15 | 059 064 17 15 
9 6 | 050 .046 20 | 21 
10 S| -058 | . 094 17 18 
