190 



Another feature will be a Guide Book to the grounds, buildings 

 and collections of the Garden to which will be appended a de- 

 scriptive list of the native trees of the Hudson River Valley writ- 

 ten by Mr. Norman Taylor, an assistant curator ; this list will 

 give a short popular account of each of the kinds of trees and a 

 number of them will be illustrated by reproductions of photo- 

 graphs. This document will be issued as a Bulletin of the Garden 

 and distributed to all members and to all institutions with which 

 the Garden has exchange arrangements. 



The question has been asked if any of the large trees of the 

 Hudson River Valley were in existence in 1609. The most 

 likely illustrations of this are the large white oaks {^Qiiercus alba) 

 which are found in many places, some of them approximating 

 four feet in trunk diameter, or perhaps even larger. The slow 

 growth of this tree after its first hundred years of life would make 

 it probable that some of these monsters were at least saplings 

 before the end of the sixteenth century. The average increase 

 in diameter of the white oak as calculated from the thickness of 

 annual wood rings of trees cut on Staten Island some years ago, 

 is 0.18 inch up to the age of 47 years. Subsequently* the 

 layer of wood annually laid on is much thinner. Observations 

 on the largest white oak within the grounds of the Garden, 

 growing in the woods south of the Museum Building along the 

 path leading to the waterfall near a cluster of sweet birches show 

 that its circumference, measured July 30, 1909, at four feet above 

 the ground, is 1 1 feet and 2 inches ; its diameter is, therefore, 

 about 42^ inches and its radius 24^ inches ; allowing for the 

 thickness of the bark the radius of wood is about 20 inches. A 

 little piece was taken out from the side of this tree with a sharp 

 chisel and the wound made carefully covered with tar. The 

 number of wood layers to the inch as revealed by this experiment 

 is 16, the average thickness of the layers being thus 0.062 inch. 

 From these observations and other data it is estimated that the 

 average thickness of the annual wood layer of the white oak in 

 trunks up to 42^ inches in diameter is approximately 0.09 

 inch, which would indicate that this individual tree is about 220 

 years old. It would, therefore, seem that white oaks with a wood- 

 radius of from 25 to 27 inches would be 300 years old. 



