28 ANNUAL GROWTHS EECOKDED 



torn of the shoot, and we recognize in these numerous 

 girdles, the place where, during the previous winter, the 

 growing shoot remained in a state of rest. These bud- 

 traces often continue visible for many years on the bark 

 of irees, and through this means we can ascertain the 

 age of a branch and the amount of its annual growth, as 

 exactly as if we had ourselves observed and marked its 

 progressive growths from year to year. The clearest marks 

 of these bud-traces may be seen on the branches of the 

 beech, the horse-chestnut, and the maple, and are less 

 visible on the bark of the birch, the linden, and the fir, 

 where they are not recognized through the growth and 

 changes of the bark. 



The distance between two sets of bud-rings, estimated 

 from the under and upper limit of the rings, shows the 

 amount of shoot developed during the season ; and the age 

 of the shoot can therefore be estimated by counting the 

 number of sets of bud-rings visible on its bark. 



So also the rate of growth of the shoot may be deduced. 

 It will be seen from the variation in the amount of shoot 

 developed between the bud-rings, that the growth of the 

 primary axis and its branches varies from year to year, and 

 that powerful growths are sometimes followed by growths 

 which are greatly retarded. Each branch has, in fact, its 

 own peculiar history of growth ; and trees of different 

 species differ not more widely in this respect than two 

 branches on the same tree. 



But not only the fallen-off scales of the winter's bud, but 

 also the green leaves of the stem leave behind them a pecu- 

 liar scar on the bark, which marks the point of the stem 

 to which they were attached, and the number of leaf-scars 

 between two bud-traces, therefore enables us to estimate 

 correctly the number of leaves which were put forth daring 

 the year, and thus we are able to picture to ourselves, not 

 only the amount of growth of the branches, but also the 

 extent to which the foliage was developed on them, and 

 so, as it were, to make the tree live again. 



We may also add to all this, that in many trees the 



