Complimentary 
NEW SERIES VOL. VI 
NO. 17 
ARNOLD ARBORETUM 
HARVARD UNIVERSITY 
BULLETIN 
OF 
POPULAR INFORMATION 
JAMAICA PLAIN. MASS. NOVEMBER 9. 1920 
Conifers. The Conifers in the Arboretum on the whole look fairly 
well considering the exceptional severity of the winters of 1917-18 and 
1919-20. None of them have been killed this year; and the Black Pines 
of Japan {Pinus Thunbergii), which lost most of their leaves and suf- 
ered from the winter perhaps more than any conifer in the collection, 
are now thinly covered with young leaves, and if the coming winter 
is not too cold these trees, which had been growing in the Arboretum 
for twenty-seven years in perfect health, may entirely recover. Young 
plants of the Mexican White Pine (P. ayacahuite) and the California 
form of Abies concolor which lost most of their leaves are now covered 
with a new crop. Several plants of the variety of Abies homolepis 
with gray cones (var. umbellata) have been injured by cold, and this 
variety has generally proved to be a less desirable ornamental tree in 
the Arboretum than the blue-coned A. homolepis: the leaves are lighter- 
colored, and in habit the trees of the variety are more open and irregu- 
lar, and are not worth general cultivation in this country. The Chin- 
ese Hemlock, Tsuga chinensis, was again badly injured by the winter 
and there now seems to be little hope that this interesting tree will be 
able to adapt itself to the New England climate. Trees of doubtful 
hardiness here, like Abies grandis, Picea Breweriana, Tsuga hetero- 
phylla, Libocedrus decurrens, Chamaecyparis Lawsoniana, and Crypto- 
meria japonica have in exceptionally protected positions been uninjured. 
The new Spruce-trees from the Chinese Tibetan border-land appear to 
be all hardy with the exception of Picea Sargentiana which has grown 
badly and is less hardy than the others. It is not probable that this 
tree will ever grow to a large size in this climate. The new Firs from 
western China have not grown as well as the Spruces, and, judging by 
the present appearance of the plants in the Arboretum, give little 
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