There is an increasing demand to produce stand and stock table information for each and every polygon in forest inventories. To the extent that this can be done reliably and realistically, it can be used to underwrite better management of social, environmental and economic values. This project is directed toward improving the degree to which stand and stock tables can be reliably and realistically represented within forest inventories, particularly as it relates to differences in tree sizes and species compositions. In phase I of this project the range of variability in cruise-types was assessed relative to an initial stand structure classification involving 17 classes that were independent of differences in species. It was found that relative to standard cruise-stratum definitions (e.g. PL 831-16, representing species, age class, height class, stocking class and site index) there was a range of stand structures represented within in each stratum. It was concluded that stand structure classification could be used to gain further precision in estimating the numbers of trees with respect to size class. It was also found that there were over 600 different cruise-strata representing 1799 observations. It was surmised that the number of different strata might be reduced to as few as 200 to 250 in number, while at the same time increasing the precision of estimation in the species-size distributions associated with each stand-type. The objective of this project (phase II) was to produce a system of stand structure classification that accounted for differences in the distributions of tree sizes and species. This objective was achieved by reconfiguring a custom-built algorithm that was initially built to account for differences in tree size classes, independent of species. Two hundred and fifty groups or strata were accordingly defined to represent different species-size class combinations. The methods for achieving this outcome are described. The finally derived groups are evaluated in terms of their differences as a means of cross validating the results. It is recommended that the enhanced system of stand structure classification described herein be used as the basis for completing Phase III of this project ? extrapolating stand and stock tables to each and every polygon in the inventory.
ForesTree Dynamics Ltd.. 2005. Stand Structure Classification: Accounting for Species Differences. Forest Investment Account (FIA) - Forest Science Program. Forest Investment Account Report. FIA2005MR076
Topic: FLNRORD Research Program
Keywords: Forest, Investment, Account, (FIA), British, Columbia
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