BlOTROPlCA 30(4): 502-509 1998 zyxwvuts Growth Rates of Tree Height Six Years after Hurricane Damage at Four Localities in Eastern Nicaragua’ John Vandermeer2 Department of Biology, University of Michigan, Ann Arbor, Michigan 48109, U.S.A. Andrew Brenner School of Natural Resources, University of Michigan, Ann Arbor, Michigan 481 09, USA. and zyxwvutsrqp lnigo Granzow de la Cerda Department of Biology, University of Michigan, Ann Arbor, Michigan 48109, U.S.A. ABSTRACT zyxwvutsr Growth rates for zyxwvutsr 44 species of trees in a posthurricane forest in Nicaragua were measured. The pattern is consistent with the interpretation of succession as a zyxwvut two stage process: an initial building phase after the hurricane followed by a thinning phase. Localities that were damaged less from the hurricane are now entering the thinning phase of postdisturbance succession, while those subjected to the most severe damage appear to remain in the building phase. zy Key word: disturbance; forest; hurricanes; tree growth. DIS TURRANCE IS RECOGNIZED AS AN IMPORTANT ECO- LOGICAL FACTOR (Miller 1982, Sousa 1984, Pickett & White 1985, Petraitis zyxwvutsr et al. 1989 Caswell & Cohen 1991). In forests, windthrows are a major component of natural forest dynamics, whether in the form of a single felled tree creating a light gap (Brokaw 1987, Denslow 1987) or a large storm creating an extensive area of damage (Vandermeer et al. 1990, 1996; Brokaw &Walker 1991, Yih et al. 1991). Understanding the details of postdis- turbance succession remains an important research goal of forest ecology. Here we present data on the rate of growth in tree height of the trees in a lower canopy of a regenerating rain forest, following the catastrophic damage of a hurricane six years ago. Hurricane Joan struck the eastern seaboard of Nicaragua in October 1988, causing extensive dam- age to the lowland rain forests (Boucher 1989,Van- dermeer et al. 1990). In the six years following the hurricane, we have witnessed the successional pro- cesses at four localities. The forest initially exhib- ited major physical damage with the majority of trees either coppiced, truncated or felled (Yih et al. 1991) with complete defoliation of all trees. How- ’ Received 2 July 1996; second revision accepted 6 June 1997. Corresponding Author: John Vandermeer, Department of Biology, University of Michigan, Ann Arbor, Michigan 48109; e-mail jvander@umich.edu ever, soon there was a large amount of resprouting in almost all damaged trees (Vandermeer et al. 1990, Yih et al. 1991), followed by a large delayed mortality the following year (Boucher et al. 1996). The trees that remained standing resprouted high on the trunk and formed a diffuse canopy, 15-20 m high. The resprouts, surviving saplings and seed- lings, and the newly arrived saplings and seedlings have grown to form a low-statured canopy that is currently very dense. The process of forming this low-lying canopy is referred to as the “building phase,” while the subsequent phase of intense com- petition is the “thinning phase” (Vandermeer et al. 1996). We now observe a diffuse upper canopy (ca 15-20 m high) and a dense lower canopy (ca 9 m high; Vandermeer et al. 1996). It is in this lower canopy that we expect the process of competition to be operative, eventually leading to the elimina- tion of many of the currently competing individ- uals. Tree growth in the lower dense canopy, es- pecially extension in height, is expected to follow certain patterns, depending upon the rate and de- gree of succession. We expect that the average growth rates will decline as succession proceeds. This expectation can be illustrated graphically (Fig. l), in which species are divided into pioneer, he- liophyte, and primary forest species, and the post- damage time sequence is divided into building 502