A method for using random parameters in analyzing permanent sample plots

Silva Fennica 29(4): 287–296

The use of random parameter models in forestry has been proposed as one method of incorporating different levels of information into prediction equations. By explicitly considering the variance-covariance structure of observations and considering some model parameters as random rather than fixed, one can incorporate more complex error structures in analyzing data.

Competition indices and variance component techniques were applied to 92 Scots pine (Pinus sylvestris L.)-dominated permanent sample plots on drained peatlands in northern Finland. By quantifying stand, plot, and tree level variation, it was possible to identify the level (stand, plot, or tree) at which the explanatory variables contributed to the model. The replication of plots within stands revealed little variation among plots within a single stand but significant variation occured at stand and tree levels. Positive and negative effects of inter-tree competition are identified by examining simple correlation statistics and the random parameter model.

Keywords
competition, drained peatland, Pinus sylvestris, random parameters

Addresses
Penner, Box 194, Huntsville, ON P1H 2G2, Canada; Penttilä and Hökkä, The Finnish Forest Research Institute, Rovaniemi Research Station, P.O.Box 16, FIN-96301 Rovaniemi, Finland. Fax to Penttilä +358 60 336 4640, E-mail mpenner@vianet.on.ca

Received 25 January 1995 Accepted 20 December 1995
ISSN 0037-5330

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