Aug. 1, 1925 
Girdling for Bemoval of Undesirable Tree Species 
271 
One hundred trees, varying in size from 7 to 28 inches in diameter, 
and in crown class from intermediate to dominant, were selected in 
an overmature white pine stand on the Priest River experimental 
forest. The average diameter of the 50 hemlocks was 15 inches at 
breast height, while that of the 50 white firs was 13 inches. Heights 
varied from 70 to 115 feet, averaging 90 feet for both species. The 
range in age was from 100 to 200 years or more. 
Four different methods of straight girdling w r ere used on each date, 
as follows: 
(1) Bark stripped off at base for a height of from 2 to 3 feet. 
(2) Trunk girdled with an axe notch cut in the sapwood to a depth 
of from 1 to 2 inches. 
(3) Bark stripped off at base for a distance of from 2 to 3 feet and 
an axe notch cut into the sapwood to a depth of from 1 to 2 inches, 
at about the middle of the stripped belt. 
(4) Notch from 2 to 3 inches deep, cut through sapwood with a 
saw and chipped out with axe. 
In addition to the girdling, poisoning experiments were begun on 
a small scale. The following three methods of introducing the 
poisonous material were used: 
(1) Two short notches, 6 to 7 inches long and 2 to 3 inches deep, 
with their inner edges an inch or two lower than their outer edges 
were chopped into the sapwood on opposite sides of the tree. They 
were then filled with a saturated solution of either copper sulphate, 
copper acetate, or zinc chloride. 
(2) Four auger holes, 2 inches in diameter and 3 inches deep, were 
bored at the base of the tree on opposite sides, and chemicals were put 
in the holes, as saturated solutions (in the May treatments) or in dry 
form with water added (as in the June and July treatments). The 
chemicals used in this treatment were copper sulphate, copper acetate, 
zinc chloride, copper carbonate, lye, and sodium chloride. 
(3) A notch 1 to 2 inches deep was cut completely around the tree, 
as in method 2 for girdling only, and two 2-inch auger holes were 
bored at the base of the tree on opposite sides. These holes were 
filled with the same chemicals used in the foregoing test (2), a 
saturated solution bein^ used in the May treatments and dry 
chemicals 3 with water added in June and July. 
EFFECT ON FOLIAGE 
Table II gives a summary of the effect of different treatments on 
the appearance of the foliage, in every instance where such an effect 
was noticeable at the end of the season. 
3 The reason for trying the dry chemicals was to see if the gradual dissolving and absorption into the sap 
would be any more effective than the rapid absorption of solution. 
