326 AMERICAN FOREST TREES 



and land can be cleared more cheaply. This increase in the value of 

 gum timber will be of great benefit to the South in many ways. 



Throughout its entire life red gum is intolerant of shade. As a 

 rule seedlings appear only in clearings or in open spots in the forest. It 

 is seldom that an overtopped tree is found, for the gum dies quickly if 

 suppressed, and is consequently nearly always a dominant or inter- 

 mediate tree. In a hardwood bottom forest, the timber trees are all of 

 nearly the same age over considerable areas, and there is little young 

 growth to be found in the older stands. The reason for this is the in- 

 tolerance of most of the swamp species. 



Red gum reproduces both by seed and by sprouts, fairly abun- 

 dantly every year, but about once in three years there is a heavy pro- 

 duction. In the Mississippi valley the abandoned fields on which 

 young stands of red gum have sprung up are, for the most part, being 

 rapidly cleared again. The second growth here is considered of little 

 worth in comparison with the value of the land for agricultural 

 purposes. 



A large amount of red gum growing in the South can be economi- 

 cally transported from the forests to the mills only by means of the 

 streams, owing to the expense of putting in railroads solely for handling 

 the timber. Green red gum, however, is so heavy that it scarcely floats 

 and, to overcome this difficulty, various methods of driving out the sap 

 before the logs are thrown into the river have been tried. One method 

 is to girdle the trees and leave them standing a year. That partly 

 seasons them, but does not give time for the sapwood to decay. The 

 logs from such trees float readily, and the swamps and streams are 

 utilized to carry the logs to the mills. 



Some years ago that method of seasoning red gum was extensively 

 advertised in England by contractors who sold paving blocks of this 

 wood. It was claimed that the common defects of red gum were thus 

 overcome. Large sales of paving material were made, particularly in 

 London, and red gum was popular for a time, but it finally lost its hold 

 as a paving wood in competition with certain Australian woods. The 

 theory that by girdling a tree and allowing it to die, the amount of heart- 

 wood will be increased has been abandoned. In selecting trees for 

 cutting, those with doty tops, rotten stumps, and heavy bark, indi- 

 cations of an old tree which contains a very small proportion of sapwood, 

 are now chosen. These are found mainly in the drier localities. In low, 

 wet places the trees have more sapwood and are smaller. The heart- 

 wood forms while the tree is living, not after it dies. 



The rapidity with which red gum has come into use in this country 

 and elsewhere is the best evidence of the wood's real value. Its range 



