Bayou-Diversity (10 March 2019) From most people’s point of view, spring storms that produce strong winds are destructive and anything but beneficial. However, if a forest is capable of a perspective, it would be that such storms are critical to their survival. Most of the forested lands in Louisiana once had some species of oak as a major component. The exception was the region blanketed with longleaf pine. Alluvial bottomlands were covered with several types of oaks and other hardwoods. The hill country grew different types of oaks mixed with pines. These forests were mosaics of trees of different ages. Large stands of even-aged trees were rare.
Oaks have growth habits that foresters refer to as “shade intolerant,” meaning that young oaks cannot grow in the deep shade of other trees. It is not uncommon to see hundreds of oak seedlings under a parent tree in the forest. Most, however, will never grow taller unless the big tree falls and sunlight reaches the seedlings. During the infrequent storm events in which strong winds occur, the most susceptible trees to wind-throw are the largest and oldest individuals. If the adage that asserts, “the fittest survive” is considered, one might conclude that the big trees that were toppled were less fit than the younger, stronger trees that withstood the winds. The opposite is true. The fact that the big, old trees reached such size and age in the first place proves they were more vigorous, disease resistant, and stronger than their neighbors. They were the fittest, and they survived through their offspring that were released from the bonds of shade when the old trees fell.
Most forests in the state today are even-aged. They originated when earlier forests were cut down, and the new trees all began growing at the same time. Trees in these forests will be cut long before they reach the size and age of their ancestors. A windstorm in a modern forest WILL fell the weakest trees and perpetuate the survival of their correspondingly weak offspring below. Over time, the general health of the forest will decline. Human manipulation of the environment on a large-scale can even reverse the natural role of a windstorm.