Report of the Forest Commission. 179 



the cold, backward climate which prevails in the habitat of the 

 Adirondack spruce there is no early spring, and no premature 

 starting of the sap or liability to such interruptions. In that 

 region spring is late in coming, and barely ushers in the summer. 



Hough * says : " The record of the seasons for a long period 

 may be determined, at least in effect, by the width of the rings 

 of annual growth. We sometimes find, at recurring intervals, a 

 narrow ring, perhaps every third year, that may have been 

 caused by the loss of leaves from worms that appear at that 

 interval, and that have thus left their record when every other 

 proof of their presence has perished. We have seen sections of 

 trees in the museums of Schools of Forestry, in which these 

 proofs were recorded through a century or more of time, and the 

 years could be definitely fixed by counting inward from the year 

 when the tree was felled. 



" When the bark and wood of a tree are cut or wounded by 

 accident, as by the marking hammer of the forester, or the axe 

 of a surveyor, the growth from the side will gradually close over 

 the injury, and fill in the inequalities, so that, when afterward 

 split off, it will often show in relief any depressions or cuts on the 

 original trunk. Many Forest Academies in Europe have in their 

 museums specimens of timbermarks thus cut or stamped into 

 wood, with the cast taken by nature from the mold. The land- 

 marks of surveyors have thus been found more than a hundred 

 years afterward. Some scar, or, in coniferous trees, perhaps a 

 gum spot, would be noticed upon the outside, and by cutting 

 down through as many rings of growth as there had been years 

 since the former survey, the marks of the ax would be found." 



It is no new idea. Over 400 years ago, Leonardo da Vincif, 

 who was an observant botanist as well as a great painter, wrote : 

 " The rings of the branches of trees show how many years they 

 have lived, and their greater or smaller size whether they were 

 damper or drier. They also show the direction in which they 

 were turned, because they are larger on the north side than on 

 the south, and for this reason the center of the tree is nearer the 

 bark on the south than on the north side." 



But these statements need not rest upon any botanical theory. 

 In the course of our work we have often found it necessary to 



* Elements of Forestry, by Franklin B. Hough, Ph. D. 

 ill Nuovo Qiornale Botanico Italiano : Vol. I, No. 1, 1869. 



