BULLETIN NO. 60. 
Most of the conifers still retain the delicate colors of the foliage of 
their young branchlets, and this is a good time for the lover and 
planter of these trees to examine the Arboretum pinetum. 
Eastern North America is not a good region for these trees. Many 
of them cannot long bear our hot dry summers, cold winters, and the 
cold nights, the hot sun and the winds of a New England March. For 
ornamental planting here better and more permanent results are ob- 
tained by the use of deciduous leaved trees and shrubs than by the 
general planting of conifers and broad-leaved evergreens. Two of the 
handsomest of coniferous trees, however, are native to this part of 
the country, the White Pine ( Pinus strobus) and the Hemlock ( Tsuga 
canadensis), and where these two trees thrive the lover of evergreen 
trees need not lack material for his plantations. It can be said gen- 
erally that the conifers of northeastern North America, the Rocky 
Mountains, northern, central and southeastern Europe, Siberia, north- 
ern China and northern Japan, are hardy in this climate, and that those 
of the southern United States, Mexico, Central America and the coun- 
tries south of the equator, the Himalayas and southeastern Asia are 
not hardy; that only a few of the species of western North America 
can be safely planted in this climate, and that so far as it is possible 
to judge by our experience here many of the Pines, Spruces, Firs and 
Larches which cover the mountain slopes of the Chinese-Tibetan frontier 
promise to be hardy in New England. In the Arboretum there is prob- 
ably the largest collection of species and varieties of conifers which can 
be found in eastern North America, although in a few collections like 
that at Wellesley in this state, and in the Hoopes Pinetum at West 
Chester, Pennsylvania, there are larger specimens of several species. 
Many exotic species are hardy and grow rapidly and vigorously here, 
but only time can tell whether any of these trees will ever reach here a 
large size and become permanently valuable as ornamental or timber- 
trees. 
The most interesting thing, perhaps, which the Arboretum has taught 
about conifers is the fact that when a species is widely distributed 
over regions of different climates plants raised from the seeds of the 
trees growing in the coldest parts of the area of distribution of the 
species are the hardiest. For example, the Douglas Spruce ( Pseudo - 
tsuga taxifolia) from the shores of Puget Sound, where this tree grows 
to its largest size, is not hardy here, but the same tree from the high 
mountains of Colorado is one of the hardiest and most promising of 
the exotic conifers which have been planted in New England. Abies 
grandis from the cold Coeur d’Alene Mountains of Idaho has been 
growing for years in the Arboretum, while the same tree from the 
northwest coast-region cannot be kept alive here. The same is true of 
the so-called Red Cedar or giant Arbor-vitae ( Thuya plicata) of the 
northwest. Plants from Idaho are perfectly hardy in the Arboretum 
and now promise to grow to a good size, while those from the coast 
are tender here. The experience of the Arboretum with the Cedar of. 
Lebanon is interesting, for this is a famous tree which it is desirable 
to establish wherever it can be induced to grow. The Cedar of Leba- 
non of European nurseries is raised from seeds produced in Europe by the 
descendants of the trees brought originally from the Lebanon in Syria. 
