10 TREES 



the separation between wood and bark. It seems to have 

 no perceptible diameter, though it impregnates with its 

 substance the wood and bark next to it. This cambium is 

 a continuous undergarment, Hning the bark everywhere, 

 covering the wood of every root and every twig as well as 

 of the trunk and all its larger divisions. 



Under the cambium is the wood, which forms the real 

 body of the tree. It is a hard and fibrous substance, which 

 in cross section of root or trunk or limb or twig is seen to be 

 in fine, but distinctly marked, concentric rings about a 

 central pith. This pith is most conspicuous in the twigs. 



Now, what does the chestnut tree accomplish in a single 

 growing season? We have seen its buds open in early 

 spring and watched the leafy shoots unfold Many of 

 these bore clusters of blossoms in midsumm.er, long yellow 

 spikes, shaking out a mist of pollen, and falling away at 

 length, while the inconspicuous green flowers developed 

 into spiny, velvet-lined burs that gave up in their own 

 good time the nuts which are the seeds of the tree. 



The new shoots, having formed buds in the angles of 

 their leaves, rest from their labors. The tree had added to 

 the height and breadth of its crown the exact measure of 

 its new shoots. There has been no lengthening of limb or 

 trunk. But underground the roots have made a season's 

 grov/th by extending their tips. These fresh rootlets 

 clothed with the velvety root hairs are new, just as the 

 shoots are new that bear the leaves on the ends of the 

 branches. 



There is a general popular impression that trees grow in 

 height by the gradual lengthening of trunk and limbs. If 

 this were true, nails driven into the trunk in a vertical line 

 would gradually become farther apart. They do not, as 



