203 



other is dominant. In some low sites hemlock includes more than 

 75 per cent, of the stand. The remainder of the forest is made 

 up approximately as follows: Acer Saccharum — 12 per cent, of 

 the total number of trees; Betula liitea — 10 per cent.; Quercus 

 rubrum — 6 per cent.; Castanea dentata — 6 per cent.; Fraxinus 

 americana and Tilia americana — 7 per cent.; Prunus serotina, 

 Betula lenta, Acer rubrum, and Finns Strobus — 4 per cent. For 

 the most part the foregoing species occur scattered more or less 

 indiscriminately through the forest, interspersed amid hemlock 

 and beech. Chestnut, however, is somewhat localized, being 

 more abundant on certain upland slopes than elsewhere. 



Perhaps the most impressive feature of a virgin forest such as 

 this is the great size attained by the mature trees. Their massive 

 boles, from 60 cm. to more than a meter in diameter at breast 

 height, and towering upward to a height of from 27 to more than 

 33 m., are usually clear of branches for a distance of from 12 to 18 

 m. from the ground, a fact which serves to accentuate their im- 

 mensity. At 33 m. or less, height growth usually, though not in- 

 variably, ceases and commonly the trees become "stag-headed" 

 (fig. I ) . But growth in thickness continued so that the trunks wax 

 more and more bulky with age. Thus, in a typical instance, it 

 was found that the trunk of a hemlock 32 m. in height exhibited 

 the following diameter measurements at the indicated distances 

 above the ground: height 75 cm. — diameter 80x90 cm.; 8 m. 

 — 65 cm.; 16 m. — 60 cm.; 24 m. — 40 cm.; 27 m. — 20 cm. A 

 series of measurements and annual ring counts were taken with a 

 view of ascertaining as nearly as possible the size and age. attained 

 by various trees in the original forests, and on a basis of these 

 hemlock would seem to have included the oldest and most of the 

 largest trees in the present stand. For this species the average 

 diameter of mature specimens is nearly 90 cm., while three 

 stumps (height about 60 cm.) having diameters of 150, 127 (fig. 

 2j, and 115 cm., respectively, were noted. The majority of 

 trees with a diameter of more than 90 cm. are rotten at the heart. 

 The average age of mature trees is about 275 years, but a maxi- 

 mum was observed of about 350 years. As might be anticipated, 

 there is no exact correspondence between age and trunk diameter. 



