Growth model for uneven-aged loblolly pine stands : simulations and management implications

Abstract

A density-dependent matrix growth model of uneven-aged loblolly pine stands was developed with data from 991 permanent plots in the southern United States. The model predicts the number of pine, soft hardwood, and hard hardwood trees in 13 diameter classes, based on equations for ingrowth, upgrowth, and mortality. Projections of 6 to 10 years agreed with the growth of stands between the last two inventories. In 300-year simulations of undisturbed growth, softwood species were replaced by hardwoods, in accord with previous knowledge. Soft hardwood species became dominant on good sites and hard hardwoods on poor sites. Basal area oscillated over time, converging slowly towards a steady state. Changes in tree size diversity were correlated positively with basal area. Without disturbance, species diversity would decrease. For economic analysis, equations were developed to predict total tree height, sawlog length and volume, pulpwood volume, and volume of top sawtimber, as functions of tree diameter and stand basal area. Simulations of three cutting regimes showed that management would lead to a steady state faster than would natural growth. Management aimed at maintaining the current average distribution would result in size and species diversity similar to that of an unmanaged stand. From a financial point of view, the q-factor guide and a 13-in.-(330-mm-) diameter-limit cut would be superior to the average current management regime. The diameter-limit regime would have the greatest effect on lowering tree size diversity and an effect on species diversity similar to that of the q-factor guide. A computer program, SOUTHPRO, was developed to simulate the effects of other management alternatives.

Multinomial logit estimation of a diameter growth matrix model of two Mediterranean pine species in Spain

“…The upgrowth probability increased for Maritime pine stands and decreased for Scots pine stands. The effect of stand density on diameter growth (Buongiorno, Peyron et al, 1995) was negative in the species studied, as had been previously reported in Loblolly pine stands (Lin, Buongiorno et al, 1998). The model performance is adequate (success rate over 50%) along different variables (A, BA, SDI, DBH and SI).…”

“…The diameter distribution can be a reference to choose the width of the diameter class (López Torres, Fullana Belda et al, 2008) although narrow size classes are recommended in demographic studies using integral projection models (Zuidema, Jongejans et al, 2010). In other studies, various widths of the diameter class have been used (Lin, Buongiorno et al, 1998;Boltz and Carter, 2006), including 5.1 cm for Loblolly pine stands, 5 cm in dry forest or 4 cm for uneven-aged mixed-species forests (Hao, Meng et al, 2005).…”

Dynamics and management of Alaska boreal forest: An all-aged multi-species matrix growth model

“…Lin et al, 1998;Liang et al, 2005), and here they were significant at˛= 0.05 level and contributed a great deal to the overall goodness-of-fit (Table 6). The effect of species diversity (H), permafrost (P), and terrain variables of elevation (z), slope (s), and aspect (˛) were further examined with prior knowledge on the factors that contribute to boreal forest growth.…”

Non‐linear matrix modeling of forest growth with permanent plot data: The case of uneven‐aged Douglas‐fir stands

“…However, they can all be expressed in terms of matrices, in which the parameters are either constant (Buongiorno and Michie, 1980) or dependent on the stand state (Lin et al, 1998). This simple model structure can then be incorporated readily in deterministic optimization models (Adams and Ek, 1974;Haight, Brodie and Adams, 1985;Hotvedt and Ward, 1990) or in stochastic mode (Haight, 1990;Kaya and Buongiorno, 1987) with economic or ecological objectives.…”