VEGETATION MANAGEMENT — EGLER 317 



even among botanists and foresters, as "seedlings." Upon investiga- 

 tion, however, the gi-eat majority appear to arise from the under- 

 ground parts of such root-suckering species as black locust, ailanthus, 

 quaking aspen, and sassafras; from large massive roots, so large in 

 the case of some oaks, that they are known as "stool sprouts" in the 

 Ozarks, with an age of several decades at least ; and from small plants 

 10 years of age or more, growing less than an inch a year, and being 

 constantly nipped back by animals. These last two categories are not 

 considered a management problem, as natural agencies have served 

 to keep them in check and may be presumed to continue to do so. 



Second are the true seedlings that are currently invading. From a 

 management viewpoint, these include all young trees less than 10 

 years of age w^hich will become a future brush problem requiring 

 "maintenance" sprayings. Thus, "conversion" is designed to leave 

 such plant communities as will resist invasion by these seedlings; and 

 a study of where these seedlings occur becomes a most important field 

 of botanical investigation. 



Most tree species are not actively invading nonforest plant com- 

 munities, despite the assertions of ecological theory and a wealth of 

 ecological literature which interprets mixtures of trees and shnibs 

 as demonstrations of such successions. Even the oaks and hickories, 

 predominant in a majority of eastern forests, show no evidence of 

 such active invasion. This is true for the southeastern pinelands, 

 where the hardwood invasion is an unquestioned silvicultural fact, 

 doubted by none but a few persons who consider the bulk of such 

 hardwoods as coming from root systems of the same age as, or older 

 than, the silviculturally desired pines. 



The following, and only the following, tree species have been seen 

 to invade in sufficient numbers to create a serious brush problem, 

 involving additional costly sprayings : 



Pimis strohus (white pine) 

 Pinus palustris (longleaf pine) 

 Pinus caribaea (slash pine) 

 Pinus taeda (loblolly pine) 

 Pinus rigida (pitch pine) 

 Pinus echinata (shortleaf pine) 

 Pinus virginiana (scrub pine) 



Betula popuUfolia (gray birch) 

 Vlmus americana (American elm) 

 Ulmus fulva (slippery elm) 

 Liriodendron tulipifera (tulip-tree) 

 Acer saccharum (sugar maple) 

 Acer rubrum (red maple) 

 Fraxinus americana (white ash) 



Of these, the one genus Pinus far outranks the others in acres and 

 in numbers of individuals so invading. "White ash is next in abun- 

 dance. The elms, maples, birches, and tulip-trees are less important, 

 and, in the case of gray birch, far less so than its commonly assumed 

 status as an old-field invader would indicate. 



A very sharp difference exists between the ability of these trees 

 to invade ih^ majority of thin grasslands (produced by indiscriminate 

 blanket spraying) and the shrublands (produced by selective spray- 



