66 



SILVA OF NORTH AMERICA 



CONIFERS. 



For a century and a half a favorite ornament of the parks and gardens of the United States and 

 Europe ^ Tsuga Canadensis has shown in cultivation a tendency to seminal variation, and a number of 

 the abnormal forms which have been produced in nurseries or have been found growing in the forest 

 are preserved by the cultivators of curious plants.^ In beauty none of them, however, equals the 

 normal form, which in stately grace has no rival among the inhabitants of the gardens of the northern 

 United States, when, with its long lower branches sweeping the lawn, it rises into a great pyramid dark 

 and sombre in winter and light in early summer, with the tender yellow tones of its drooping branchlets 



and vernal foliage. ^ 



Serious inroads have already been made into the Hemlock forests of the northern and middle 



states, and the best trees have everywhere been destroyed to supply the tanner, who finds in the 



astringent bark of this tree one of the most valuable materials for his industry.^ 



1 Loudon, Arb. Brit iv. 2322, t. (as Abies Canadensis). 



2 The abnormal cultivated forms of Tsuga Canadensis are dis- 

 tinguished in some cases by a dwarf and compact habit, in others 

 by fastigiate branches and by unusually broad or narrow leaves, 

 or by foliage slightly marked with white. About eighteen of these 

 forms are cultivated, but none of them has any particular beauty 

 or value. (See Beissner, Handh. Nadelk. 402. — Sudworth, Bull. 

 No. 14, U, S. DepU Agric. Div, Forestry^ 42,) More distinct 

 is a variety with short pendulous branchlets forming a dense 

 cushion from two to three feet in height and twenty feet across, 

 which was found about thirty years ago on the Fishkill Mountains 

 in New York, and which, introduced into gardens by Mr. Henry 



+ 



Winthrop Sargent, is occasionally to be seen in American coUee- 

 tions, where it is usually known as Sargent's Hemlock. 



® Tsuga Canadensis, which is commonly distributed and was 

 once abundant over a territory fully half a million square miles in 

 area, is one of the most valuable trees of the eastern forest. It is 

 estimated that in the year 1887 1,200,000 tons of bark of this tree 

 were harvested ; and although a large part of the timber of the 

 trees cut and stripped of their bark is allowed to rot on the 



ground, it is believed that the average annual value of the ma- 

 terial of all kinds obtained from this Hemlock is not less than 



$30,000,000. 



The seeds of the Hemlock, although they are produced in great 

 abundance, do not germinate freely in open situations or on 

 ground which has been recently burned over, and the young 

 seedlings grow slowly, plants under favorable conditions being not 

 more than three or four inches high at the end of their fourth sea- 

 son. The young plants are easily destroyed by fire and browsing 

 animals, and the prospect for the natural restoration of the Hem- 

 lock forests is not promising. (See Prentiss, Garden and Forest, 

 'in, 157.) Even under the most favorable conditions the Hemlock 

 increases slowly both in height and in trunk diameter. The 

 specimen in the Jesup Collection of North American Woods in the 

 American Museum of Natural History, New York, obtained in 

 northern New York, is thirteen and one half inches in diameter 

 inside the bark and one hundred and sixty-four years old, the 

 sapwood being two inches in thickness with twenty-nine layers of 

 annual growth. 



