6 BULLETIN 1112, U. S. DEPARTMENT OF AGRICULTURE, 
classes might be explained by the fact that of the 27 trees in the 
infection class, 11 per cent were isolated trees which did not form a 
part of the forest canopy, 28 per cent were dominant, 57 per cent 
were codominant, and 4 per cent were intermediate trees, while 
with the x infection class 60 per cent were isolated trees which did 
not form a part of the forest canopy and 40 per cent were in the 
codominant crown class. Table 2 consistently shows a decrease in 
the rate of diameter growth of yellow pine which varies directly 
with the degree of mistletoe infection. 
TABLE 1.—Comparison of the average diameter growth or accretion of 58 standing black 
jacks, for a 5-year period, grouped according to degree of mistletoe infection. 
| 
| Diameter breast-high. | Accretion, 1910-1915. 
Degree of infection. 5 as Basis. 
ae eriodic 
1910 1915 Periodic. inane 
Inches Inches Inches. Inch. Trees 
Tie Sts Se ae ah ear, es a PTR pe are, Me aes 16.16 16. 97 . 81 0.1 
Sead A rca atten Mea Mt is rated ey al 17.65 18. 63 98 . 20 6 
Xe eee eee ea) aes sot eo ae tes cues 15. 82 16. 57 75 15 15 
20.0 .6i; 5) Seg a ee Se eae eg eee 14, 24 14. 36 12 02 10 
TABLE 2.—Comparison of the average diameter growth or accretion of 33 standing yellow 
pines, for a 5-year period, grouped according to degree of mistletoe infection. 
Diameter breast-high. | Accretion, 1910-1915. 
Degree of infection. ‘ Basis. 
4 1910 1915 Periodic. Ferlogt 
ca a oe | a a ne 
Inches. Inches. Inch. Inch. Trees. 
Tee aoe ee a See ae aie nee PL ee 24. 60 25. 30 0. 70 0.14 9 
Ree SE EL 2 Pee Cpe Fy Se tet co ter. Peres! 25. 56 26. 04 - 48 .10 8 
Ree ae Ok YE Re, oe Seren hapa See aie 22, 14 22. 44 . 30 - 06 a 
Soman tog A aE PP Ey a PCIe eee os 21. 49 21.61 ee -02 19 
} | 
1 Five trees of this class died during the 5-year period and were not included in the computation. 
TABLE 3.—Comparison of total volume growth or increment of 58 standing black jacks, 
for a 5-year period, grouped according to degree of mistletoe infection. 
| Total volume. Increment, 1910-1915. 
| 
Degree of infection. Basis. 
1910 1915 | Periodic. Periodic annual. 
| Cubic feet. | Cubic feet. | Cubic feet. | Cubic feet. | Per cent. Trees. 
Gee Ss SASS S| SISAL et i tase 987. 2 1,100.9 113.7 22:7 2. 30 
Pe Cty jy Mehta oo ee en aR | 291.4 324. 4 33.0 6.6 2. 26 6 
v.02. ee BBY hs Ae Bae fre 2 hy Opes bP | 434.0 470.6 36.6 7.3 1.68 15 
ake Soe ae shee o ec SU LL 234.9 243, 2 8.3 AS AP? 10 
