Height dynamics of the thinning canopy of a tropical rain forest: 14 years of succession in a post-hurricane forest in Nicaragua

Understanding the maintenance of the large diversity of tree species in a tropical rain forest has become something of a holy grail. Among the many factors thought to be involved is disturbance. One hypothesis is that repeated disturbance sets the process of competition anew, thus that competitive exclusion never occurs. In the context of a forest massive damage from storms is potentially the source of the damage that could preserve species diversity. After damage from a storm the canopy of the forest begins with a rapid growth, known as the building phase. Soon a very dense canopy is formed, called the “thinning canopy” which dictates the subsequent dynamic process of competition, where those individuals located near the top of the canopy will have a competitive advantage over those in the subcanopy. We here report on the first 14 years of the development and dynamics of the thinning canopy after the catastrophic hurricane damage occasioned by the landfall of Hurricane Joan in October 1988 in the general area of Bluefields, Nicaragua. The overall pattern of growth is clear, where larger trees have been growing and smaller ones more-or-less stagnant, for the past 8 years. The upper canopy was somewhere on the order of 11–18 m in 1996 and is somewhere between about 15 and 22 m in 2003. The dynamic pattern reflects the basic story of growth into the thinning canopy followed by intense competition where some individuals overtop others, thus creating a platykurtic distribution with a skewed bias towards smaller individuals, because of the few individuals overtopping the others. Mortality rates were between 7 and 33 stems per thousand per year, and were concentrated in individuals located beneath the canopy.