20 BULLETIN 1112, U. S. DEPARTMENT OF AGRICULTURE. 
EFFECT ON THE FOLIAGE. 
Tables 14, 15, and 16 show the effects of the mistletoe on the foliage 
of the western yellow pine. The data included in Table 16 were 
obtained as follows: 
Each tree crown was divided into three divisions—bottom, middle, 
and top—including in each division about one-third of the total leaf 
surface. One hundred tufts from each section were selected at ran- 
dom and measured; the mean length of these tufts was taken as the 
average length per tuft for that section. Then 10 tufts of this 
average length were taken from each of the three sections into which 
the crown had been divided. These tufts, 30 in all for each tree, were 
cut off and taken to the laboratory, where the number of leaves per 
tuft, the length, and the width of each leaf were determined. The 
total number of tufts in the bottom, middle, and top thirds was 
determined by actual count. The number of tufts thus obtained was 
multiplied by the average number of leaves found in the 10 tufts 
from each section. This gave the average number of leaves in each 
section. The sum of the leaves in the three sections gave the average 
number of leaves in any given tree crown. 
TABLE 14.—Comvarison of the length of leaves of 103 western yellow pine trees, classified 
according to degree of mistletoe infection. 
In lower portion | In central portion | In upper portion Mean for entire 
of crown. of crown. of crown. crown. 
infection. Mean | Mean | Mean | Mean Mean | Mean Mean | Mean i 
Be an [evar LeAVOL= | oa eers lies ose A VeE= Say [iz ~ | Aver- See ~ | Aver- 
mini- | Maxi- age, | mini- | maxi-| “24, | mini-|maxi-|“.,, | mini- | maxi- = 
mum. /mum. &e- | mum.|mum. 8e- | mum.|mum. 8. | mum.|mum.| 9% 
In In In. In In In. In In. In. In. In. In. | Trees. 
OS Pree a0 6.2 4.9 3.8 6.3 O50) 4.2 6.9 5.8 3.8 6.5 5.4 38 
Xngtoee 70 p43) 4.0 2.5 5.9 4.5 40 6.2 5.0 257 5.8 4.5 15 
2.0. ee igs | see: 38 | Ppa 5.4 4.1 DED Seat 4.6 255 Des 4.2 18 
Xe Ded. ell 3.6 | 2.4 b: I 4.0 27 eal 4.0 2.4 Re 3.9 32 
TABLE 15.—Comparison of the length of leaf tufts of 97 western yellow pine trees, classified 
according to degree of mistletoe infection. 
In lower portion In central portion | In upper portion Mean for entire | 
| 
of crown. of crown. | of crown. crown. 
| 
Dea of | Basis 
infection.) Mean | Mean | 4p, | Mean | Mean | 4... | Mean | Mean | 4... | Mean | Mean | 5 vo. 
mini- } Maxi- age mini- | maxi- age mini- | maxi- age mini- | maxi- age 
On. yaar. 3.4] 11.5 6.7 5.4] 15.5 0.0 G28) 22a0 Wane 5.2] 16.6 {| 10:2 
DOM, GED ihe? 3.0} 10.1 6.5 4.0} 12.0 8.0 5.5] 16.8] 10.3 4.2] 13.0 8.3 15 
Ke 2.4 8.2 4.9 2.3 9.1 5. 2 3.4} 11.1 7.3 2.7 9. 4 5. 8 15 
EKER At 2.3 8.1 4.5 2.6 8.6 5. 0 2.4 8.5 4.8 2.4 8.4 4,8 30 
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