A quantitative succession model for nine montana forest communities

Abstract

/ A quantitative succession model was developed both to meet resource management needs in Montana's Lewis and Clark National Forest and to develop a modeling methodology. It builds upon previous concepts and incudes three new features: quantitative prediction of all tree species and seedlings; quantitative predictions of important understory species; and successional pathways determined by fire intensity and scorch height. The method is described and demonstrated for selected Montana habitat (community) types. It is also available in managerial guidelines and has been programmed as a new module in the FORPLAN simulator. Weaknesses of this and other models are discussed. Conclusions relate succession modeling to resource management needs.Recent studies of postfire plant succession have developed qualitative models of species replacement patterns. Several of these models consider the effects of fire periodicity, the species' adaptive traits, and their life-history characteristics. For example, Noble and Slatyer (1977) developed a model that described realistically postfire succession patterns observed in New South Wales (Australia) based on the interfire periodicity and the component species' characteristics. That model has been further refined and elaborated for the Australian situation Slatyer 1978, 1980). Cattelino et al. (1979;Kessell 1979a) successfully modified and applied that model to forest overstory species for several western Montana communities. Yet despite continued study of species' adaptive characteristics (see, for example, Lyon and Stickney 1076;Lyon 1971Lyon , 1976Gill 1977Gill , 1980, the modeling scheme of Cattelino et al. demonstrated the several weaknesses inherent in many of these recent succession models.First, the Cattelino model predicted presence or absence of species at various stages of fire recovery, but could not predict quantitative changes in species composition. Second, it ignored the role of fire intensity by assuming that all fires were of sufficient intensity to destroy most of the forest canopy. Third, it was unable to predict the succession of understory species (shrubs, grasses, and forbs). And fourth, it did not take into Environmental Management, Vol. 4, No. 3, account the probabilistic nature of seed dispersal from adjacent, undisturbed communities. We present here a more refined succession model, which rectifies the first three problems. This model produces quantitative predictions of the succession 0f~ both overstory and understory species and also includes the effects of fire intensity. The fourth problem of probabilistic seed dispersal patterns is not yet fully solved; however, we have developed a preliminary model for selected Montana forest communities which is described elsewhere (Potter et al. manuscript). Purposes of the StudyIn addition to addressing the noted deficiencies of previous models, this study had two other major purposes. First, it was conducted to improve plant succession modeling capabilities provided by FORPLAN as implemented on the Lewis ...

Data-intensive modeling of forest dynamics

“…The novelty of our modeling framework lies in the consideration of forest transitions within multiple dimensional space of macroscopic stand-level characteristics (biomass, average age of trees, biodiversity and shade tolerance index) that constitutes a generalization of the one-dimensional model of forest biomass transitions developed earlier . Our framework is also substantially distinct from previous models of forest dynamics, where successional stages are ordinated using empirical observations on successional pathways (Curtis and McIntosh, 1951;Kessell and Potter, 1980;Logofet and Lesnaya, 2000).…”

Testing the intermediate disturbance hypothesis: when will there be two peaks of diversity?

“…This Markovian approach is very common for describing community dynamics for instance in coral reefs (Tanner et al ., 1994), mussels (Wootton, 2001) or forests (Waggoner & Stephens, 1970;Kessell, 1980;Usher, 1981;Green, 1989;Moore & Noble, 1990;Acevedo et al ., 1996;Shugart, 1998). The successional stages are described by a stage vector F t consisting of their relative proportions f 1 to f n at time t .…”

Fire ecology of the forest habitat types of northern Idaho

“…In this report, we describe postfire stand development qualitatively, using the successional pathway concept described by Kessell and Potter (1980). These qualitative pathways provide a conceptual guide for applying quantitative models of succession and stand development.…”