Aug. 1, 1925 
Girdling for Removal of Undesirable Tree Species 273 
saturated solution of copper sulphate, and in the other with a satu¬ 
rated solution of copper acetate. In another case a white fir which 
had been both completely girdled with an axe notch and treated 
with dry lye placed in two auger holes, died toward the end of the 
season. The fourth case, a hemlock, showed signs of unthriftiness 
after a saturated solution of copper sulphate had been placed in 
four 3-inch auger holes bored in the trunk. 
Since the copper sulphate, copper acetate, and lye showed no 
apparent effect in the several other cases in which they were used, it 
is probable that they had little or no influence in these treatments. 
It was noted in the treatments where dry chemicals were usecl 
that the more easily soluble materials—zinc chloride, lye, and sodium 
chloride—had been entirely absorbed, while the copper sulphate, 
acetate, and carbonate, were only partially dissolved, the residue 
amounting to from one-fourth to one-half or more of the amount of 
chemicals used. 
One indication of the effect of girdling, it was thought, would be 
the extent to which the sapwood had dried out, since this would 
show the degree of restriction of the circulation of water and stored 
food upward from the roots to the crown. Accordingly, the depth 
of drying at the last observation, on November 17, was determined 
for a majority of the girdled trees. Measurements were taken at 
the center of the stripped portions, and inward from the inner edge 
of the notches. 
Considerable irregularity was noticed in different trees and at 
different points on the same tree. The dryness on the stripped 
trees extended from 0.1 to 1.1 inch with an average of 0.4 inch. 
In the case of the notched trees, the drying extended 0.75 inch to 
2 inches in from the innnermost point oi notch, with an average of 
1.1 inch. The depth of the notches ranged from 1 to 3.75 inches, 
averaging 1.7 inches. The average depth of drying on the notched 
trees was 2.8 inches compared to 0.4 inch on the stripped trees. 
Taking 15 inches as the average diameter at the point of girdling, 
the average reduction in the amount of wood available for the trans¬ 
mission of water and sap was 60 per cent of the cross-sectional area 
of the trunk on the notched trees compared to 5 per cent on the 
stripped trees. This difference indicates that the notching causes a 
tw T elve times greater restriction in the passage of water and food 
than does the stripping, and probably accounts for the fact that the 
only trees which died were those which had been notched. 
Careful observations were made in the fall with field glasses, but 
no new cones were seen on any of the trees, although several cones 
left from the preceding year’s crop were noticed on some of the hem¬ 
locks. This failure of the seed crop can not be attributed to the treat¬ 
ment, however, since there was an almost complete failure of the seed 
crop of all species in the region that year, due, probably, to severe 
frosts late in June. 
60304—25f-6 
