Union of an Oak and a Birch^ 



William T. Davis 



(with plate I, FIG. i) 



The figure accompanying this article represents two trees, a 

 white oak, Quercus alba L., on the left, and a black birch, Betula 

 lenta L., on the right, that have grown together in such manner 

 that if the trunk were all that could be seen, they would ordinarily 

 be taken for one individual. They stand close to Richmond Turn- 

 pike on the property known as the Cebra Homestead, and were 

 first described in the Bulletin of the Torrey Botanical Club 13: 

 221. 1886. At that time the measurements were given as follows : 

 " For the space of 3 ft. 7 in. from the roots they have grown solidly 

 together, so that the line of juncture is no more marked than 

 the weatherworn crevices down the sides of many large trees, the 

 character of the bark "serving as the best guide in distinguishing 

 the trunk of one tree from that of the other. At the height 

 mentioned from the ground the trunks part or branch, forming 

 a Y, the oak being 4 ft. 2 in. in circumference, and the birch 4 ft. 

 5 in., while the main trunk, formed by both trees, measures 7 ft. 

 4 in. around." 



Last summer a photograph was taken of the trees and they were 

 measured as in 1886, with the following results: Line of juncture 

 4 ft. 4 in. ; circumference of oak 5 ft. i in. ; of birch 4 ft. 5 in. ; of 

 main trunk formed by both trees 8 feet. It may be seen that in 

 twenty-seven years the length of the line of juncture increased 9 

 inches, the circumference of the oak 11 inches, and the birch, 

 which died in 1912, did not make any perceptible growth. The 

 individual circumferences of the oak and birch would of course be 

 somewhat greater if the measurements could have been made at the 

 same distances above the ground where they were taken in 1886 

 instead of 9 inches farther up the united trunk. 



There are evidences that the oak cannot live much longer, and 

 thus one of Staten Island's most remarkable twin trees will cease 

 to exist. 



1 Presented at the meeting of the Association December 20, 1913. 



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