36 BOTANICAL GAZETTE [january 



ground. Because of this cavity the age could only be estimated by 

 proportion; the tree was approximately 250 years old (allowing 

 for thicker early rings). 



The senile or last stage (age 5) is scattered, because definite 

 spacing is lost. Many primary limbs are gone, adventitious 

 branches along the trunk and on otherwise dead limbs and stubs tak- 

 ing up the work. The heartwood is largely rotted. The sawed-off 

 stump of one very old tree showed a cross-diameter of 120 cm., 

 but only a margin of 15 cm. around the outside was wood, the rest 

 being hollow. The base, at .or near ground level, is often inhabited 

 by a colony of big ants, and the breaking point is normally at this 

 place. A certain degree of pliability is still retained m ages 4 and 5. 

 The latter are apt to sway widely in a wind, some creaking loudly 

 also under the strain; yet the tree may stay thus at the verge of 

 fall for years. 



Approach of death is equally indicated by the crown where 



■ 



symmetry is lost by branch fall. The top of an old tree is always 

 ragged. These trees attain the maximum of height and diameter. 

 They represent a wider range of age, dimensions, and form than 

 any other of the life stages, partly because of their liberty of freer 

 development than the younger trees below. 



The beech follows the maple in general, but it is stockier, 

 broader, and shorter, reaching each age much more quickly. Its 

 terminal bud is weaker, and the tree apex is often injured by falling 

 trees, lightning, and other destructive agents, so that the nutrients 

 go to several branches near the top. As a result it is strikingly 

 deliquescent and rarely develops a bole over 15 m. in height below 



the branches. 



Stratification 



Maximum complexity. — Investigators in the tropics have 

 noted 5-7 strata in the rain forest (21). These were primarily due 

 to the leafing out of the various tree species at different levels. It 

 has been assumed that little or no stratification occurred in the 

 climax maple-beech forest, the belief being partly based on the 

 poverty of tree species (but two or three important) and the far 



forest. 



degree of luxuriance as compared with the 



