American Sycamore

Early height growth of American sycamore is very rapid, tapering off at about age 30. Soils on which the trees grow naturally range from loamy sand to heavy clay loam. Surface drainage varies from poor to very good. Thus, once established, trees of this species endure. Typical cottonwood sites and some friable and loose soils too dry for cottonwood are also locales in which one finds this species. Practically any condition of temperature and light intensity of seedbeds under stands of sycamore trees is expected to favor germination of American elm to the exclusion of the sycamore. However, sycamore seedlings may be as tolerant as elm; in that case, the ecological transition to

Figure 4.27 Virgin forests are often not pristine wilderness. This southern bottomland site has never been harvested. Two companies claimed ownership; to avoid the consequences of litigation, the site was essentially abandoned.

elms must be due to another factor. Temperature of the exposed soil at the time of seed germination may encourage elm over sycamore.39 After establishment, invaders include boxelder, winged elm, hackberry, and sweet pecan. Later, epicormic branches develop, the number depending on light intensity which, in turn, depends on stand density.

We now consider the management of the southern forest. This involves silviculture, "The art of growing trees in managed stands." This art is based on silvics, the sciences basic to the practice of the art.

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