270 



FOEESTBY INVLbTIGi-TIONb U. S DEPARTMENT OF AGRICULTURE. 



A 



Fig 28 —Bud development oi bi ech 

 if all iorraed buds were to live, A 

 failing to &®s elop 



JB as it would bo 

 is it is man} buds 



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 requnes careful regulation 

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



accounts for the failuie of many seedlings that spring 

 up m the viigm forest. 



The planter, then, is requned 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 

 BAMIPICATION. 



While the stalk of wheat 



or corn grows for one sea 



son, exhausts itself m seed 



production, and then dies, 



the tree continues to grow 



from season to season, 



m length as well as m 



thickness. The growth 



m length of shaft and 



branches proceeds from 



buds, made up of cell tis 



sues, which can subdivide 

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

 formed during summei, and when wmtei begins contain embiyo 

 leaves, more or less developed, under the protecting co\er of scales 

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

 the buds swell, shed their scales, distend their cells, mci easing their 

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

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

 formed, and the whole process repeats itself fiom year to } ear, 

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

 end buds being mostly stronger and better developed, the mam a\is 

 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 

 base of the limbs, their connection with the pith can always be 

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

 so called "adventitious ?? buds may be foimed from the young living 

 wood m 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, howevei, not de\ eloped at once, and perhaps not at all, especially as the 

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

 life when necessary (fig. 29). 



The fact that each ordinary limb starts as a bud fiom 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 " clears " the shaft. 



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



I ig 29 —Buds of maple A longitudi 

 nal section tluough tip of a maple 

 twig g end bud s latcial buds I 

 scars oi lea\ cs of last season B cross 

 section tl rough end bud showing 

 folded loaves m center and scales sur 

 rounding them 



