172 THE BOOK OF NATURE STUDY 



Trees may often be identified in winter by their bark. The lime 

 may be recognised by its sooty markings. The ash, if over 

 forty years of age, has fissured bark, with deep furrows, though 

 hardly as deep as in the oak ; the maple has very fine fissures. 

 In lopping off branches, great care has to be taken not to injure 

 the bark, for certain fungi attack injured limbs of trees. 



Bark is valuable for the tannin it contains. Young oaks 

 are stripped of their bark in May, just before the leaves burst 

 forth. The bark is stripped off before the tree is cut down, 

 the first ring extending from just above the roots to the height 

 of two and a half feet. When stripped, the bark is put out to 

 dry for about two weeks, and then cut into small pieces and 

 sent to the tanners. The bark of the birch is used for tanning 

 certain kinds of leather, particularly Russian leather. 



The first sign of spring in trees is the swelling of the buds, 

 which seem to grow visibly under the genial warmth and moisture 

 of a showery April day. The bud-scales, or stipules, as the case 

 may be, begin to unfold owing to the pressure of the growing 

 shoot within. As soon as the scales unfold, the leaves push 

 their way out ; then the scales hang down and gradually drop 

 off. In late April, or in May, according to the season, the ground 

 is strewn with the light-brown stipules of the beech, or the green 

 scales, tinged with pink of the sycamore. To watch the unfold- 

 ing of the leaves in spring is a fresh delight each year. The 

 best plan, if trees are not near one's house, is to pick buds that 

 are just bursting, and watch them unfold. Even in winter, if 

 placed in warm water, buds will usually burst in a warm room. 

 The beech is one of the most beautiful to observe. The leaf is 

 folded like a fan, and, as the stipules separate, the leaves spread 

 out fanlike, showing a delicate, ciliate margin. Sometimes, 

 as in the ash, cherry, hazel, elm, and ash, the leaves are folded 

 in two from the midrib like the two pages of a book, and each 

 half spreads itself out. The arrangement of the bud-scales and 

 leaves of the ash are seen in Fig. 51, which is a drawing of a 

 transverse section of a bud. The bud-scales, like the leaves, 

 are opposite each other. Each leaf is compound, consisting of 

 seven or more leaflets. In the centre two leaves are seen opposite 

 each other ; at right angles to these are two more leaves, each 



