Aug. 1, 1925 
Girdling for Removal of Undesirable Tree Species 
269 
Table I .—Germination of duplicate samples of 500 seeds each from girdled hem - 
lock trees 
Progress of germination 
Num¬ 
ber 
of 
days 
Percentage of germination of seeds from— 
Notch-girdled trees 
Peeled trees 
Test A 
Test B 
Average 
Test A 
Test B 
Average 
Beginning___ 
19 
11.2 
5.0 
8.1 
0.8 
0.2 
0.5 
Height_ 
28 
74.8 
51.8 
63.3 
31.4 
16.2 
23.8 
Last active_ 
38 
87.0 
68.0 
77.5 
51.4 
44.6 
48.0 
End___ 
50 
89.2 
73.8 
81.5 
53.4 
46.0 
49.7 
It is apparent from these tests that winter girdling, according to 
either the stripping or notching method, does not prevent the pro¬ 
duction of a crop of fertile hemlock seed the fall after girdling. 
Whether the girdling actually causes an increase in the amount of 
seed produced by these trees above the amount they would have 
borne if they had not been girdled is not definitely indicated. The 
crops from girdled trees appeared to be uniformly very heavy, but 
this occurred in an exceptionally good seed year for all species in 
the white pine region. 
That the percentage of fertility of the seed from the tree girdled 
by stripping was but little more than half that shown by the tree 
girdled by notching, does not lead to any definite conclusion, for 
individual trees are known to vary widely in the quality of seed 
produced, regardless of external influences. The seed produced by 
the tree that had been stripped was sufficiently fertile (50 per cent) 
to restock the area effectively, so it is not possible to consider strip¬ 
ping the bark a better method than notching on the basis of this 
data. The other object of the girdling, the reduction of shade, was 
also defeated by the fact that the trees remained green all summer, 
at the time when white pine and larch seedlings were germinating 
and establishing themselves. 
Thus during the first year after cutting, at the time when surface 
conditions for germination of desirable intolerant species are most 
favorable, the girdled hemlocks pot only produced heavy crops of 
fertile seed, which on one particular area resulted in a stand of some 
90,000 hemlock seedlings per acre by actual count, but also hindered 
by their shade the germination and establishment of intolerant 
white pine and larch on a considerable portion of the area. 
Particular note was taken of the effect during the second season 
after these girdling experiments. A great majority of the com¬ 
pletely girdled trees showed a very unthrifty appearance, and this 
was true, apparently to an equal degree, of the trees girdled by either 
the notch or stripping method. The girdling on the stripped trees 
was, however, more often incomplete on account of the strips of 
inner bark left, and consequently the notch girdling was effective 
m a larger percentage of cases of the trees girdled. 
On several of the sale areas where the girdling had been done, the 
brush had been burned in piles that autumn. It was noticed that 
this brush burning had been very effective in killing both large trees 
