A new approach to modeling stand-level dynamics based on informed random walks: Influence of bandwidth and sample size.
A new stand-level dynamics model based on observed stand growth trajectories is presented. This stand-level dynamics model uses the trajectories of observed plots through Reineke's quadratic mean diameter-density space to predict the change in quadratic mean diameter, ingrowth and mortality over time. The model uses the collection of observed trajectories as a probability distribution that is used to guide an informed random walk. An imputation model is used to select k nearest neighbors (bandwidth) which are then used to build joint kernel distributions. From these kernel distributions, m random samples (sample intensity) are averaged to predict the change in quadratic mean diameter, ingrowth and mortality. All levels of k tested (10, 20, 30) performed well as long as sampling intensity was above 1. Variability in predictions was reduced at sampling intensities above 1, but no significant differences were visible among sampling intensities 5 and above.
Digital Object Identifier (DOI)
McGarrigle, E., Kershaw Jr., J.A., Ducey, M.J., Lavigne, M.B. A new approach to modeling stand-level dynamics based on informed random walks: Influence of bandwidth and sample size (2013) Forestry, 86 (3), pp. 377-389. doi: 10.1093/forestry/cpt008
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