270 



FORESTRY INVESTIGATIONS U. S. DEPARTMENT OF AGRICULTURE- 



FIG. 28. Bud development of beech. If, as it would be 

 if all formed buds were to live; A, as it is, many buds 

 tailing to develop. 



The little seedlings of many, especially the conifers, are quite delicate, and remain very small 

 the first season; they need, therefore, the protecting shade of mother trees, or artificial shading, 

 and also protection against weeds. The amount of light or shade given requires careful regulation 

 for some of them; too much light and heat will kill them, and so will too much shade. This 



accounts for the failure of many seedlings that spring 

 up in the virgin forest. 



The planter, then, is required to know the nature and 

 the needs of the various kinds of seeds and seedlings, so 

 as to provide favorable conditions, when he will avoid sow- 

 ing in the open field such 

 as require the care which 

 it is impractical to give 

 outside of the nursery. 



GROWTH IN LENGTH AND 

 RAMIFICATION. 



While the stalk of wheat 

 or corn grows for one sea- 

 son, exhausts itself in seed 

 production, and then dies, 

 the tree continues to grow 

 from season to season, 

 in length as well as in 

 thickness. The growth 

 in length of shaft and 

 branches proceeds from 

 buds, made up of cell tis- 

 sues, which cau subdivide 



and lengthen into shoots, as well as make leaves. These buds are 



formed during summer, and when winter begins contain embryo 



leaves, more or less developed, under the protecting cover of scales 



(fig. 29). When spring stimulates the young plant to new activity, 



the buds swell, shed their scales, distend their cells, increasing their 



number by subdivision, and thus the leaves expand, and the bud 



lengthens into a shoot and twig. During the season new buds are 



formed, and the whole process repeats itself from year to year, 



giving rise to the ramification and height growth of the tree. The 



end buds being mostly stronger and better developed, the main axis 



of tree or branch increases more rapidly than the rest. All these 



buds originate from the youngest, central part of the shoot, the 



pith, and hence when the tree grows in thickness, enveloping the 



. FIG. 29. Buds of maple. A. lougitudi- 



base of the limbs, their connection with the pith can always be nai aec-tiim through tip of a maple 



traced. This is the usual manner of bud formation; in addition, 



so-called "adventitious " buds may be formed from the young living 



wood in later life, which are not connected with the pith. Such 



buds are those which develop into sprouts from the stump when 



the tree is cut; also those which give rise to what are known as "water sprouts." Many buds, 



although formed, are, however, not developed at once, and perhaps not at all, especially as the 



tree grows older; these either die or remain' "dormant," often for a hundred years, to spring into 



life when necessary (fig. 29). 



The fact that each ordinary limb starts as a bud from the pith is an important one to the 

 timber grower; it explains knotty timber and gives him the hint that in order to obtain clear 

 timber the branches first formed must be soon removed, either by the knife or by proper shading, 

 which kills the branches and thus "dears'' the shaft. 



The planter has it also iii his power to influence the form development of the tree by removing 



twig: 0, end bud ; *, lateral buds; I, 

 scars ol le;ivrs of last season. If. crows 

 sectiou through end bml, showing 

 folded leaves in center and scales sur- 

 rounding tliem. 



