141 



the dead branch breaks off close to the trunk the problem is practically 

 the same as when the bark is injured, and new wood is formed around 

 and over the stump and finally encloses it, Many of the " knots" seen 

 in lumber are simply these old branches that were enclosed in this 

 way. They are darker than the surrounding wood because they were 

 exposed and had begun to decay The lumps on the beeches showed 

 what efforts the trees were making to cover the tiny dead branches. 

 In some cases they were so successful that there was nothing on the 

 surface to show that a t*ig was underneath. But when they were cut 

 open it was all plain enough, and a little search revealed all stages, 

 from twigs not yet buried to those with the tip still showing and then 

 the final step when a I trace was gone. In the course of time the 

 knobs disappear, and there is nothing to show that they had ever been 

 there, except when we cut into the wood and see the " knot." 



The beech is a tree whose branches are very responsive to light. 

 One close in to t*ie trunk will often grow only a small fraction of an 

 inch each year, while another at the end of a prominent branch in the 

 full sunlight may grow a footer more in the same time.. The winter 

 bud-scales of the beech leave ring-like marks around the twig when 

 they fall oS, and by these we can tell the age of the branch. Tney 

 are mot conspicuous on the under side of the twig for they seem 

 to appear sooner on the upper side, probably on account of the 

 slightly more rapid growth there. Occasionally a twig scarcely a 

 span in length will represent the growth of a quarter of a century, 

 but this does not give a correct idea of the age of the tree, because 

 most of the growth of the latter is at the top where it has enough 

 light. No doubt the twig started to grow when the tree was quite 

 small, and it would be of interest to cat into the trunk of some dead 

 tree to see just how far we can trace the branch The main point, 

 however, is that it is in an unfavourable situation, and in time suc- 

 cumbs, and at last breaks off. When the stump is short the tree has 

 little difficulty in protecting the wound in the way described. The 

 longer stumps are the cause of the formation of the lumps seen here 

 and there. 



The beech is not the only tree that gets rid of its superfluous 

 branches, though we do not often see trees with such knobs as we 

 have described. When a tree grows in the open it may have low 

 branches in a healthy condition but wherever they are crowded to- 

 gether the lower ones die. They are unable to ^-eceive enough light, and 

 the upper ones do the work for the entire tree. As fast as they die and 

 drop off, the scar is covered as we have seen. Failure to do this pro- 

 perly and soon enough, results in permanent injury, and the decayed 

 portion spreads dovvn through the trunk, giving in time a hollow. 



THE BREADFRUIT.* 



By Henry E. Baum. 



The breadfruit tree has for over a century occupied a unique posi- 

 tion in the vegetable kingdom. Its farinaceous fruit serves the Paci- 

 fic Islanders in lieu of the wheaten loaf of the western hemisphere, 



*Repriuted from Tke Plant World, VI., 197 : Sep., 1903. 



