Commensurate with the increase in the planting rate of broadleaf species is the need to investigate forest management that uses mixtures of species and ages. Reliable data for woodland of this type is exceedingly rare and the need to advise managers is immediate. Management and investment decisions can be examined with models of forest growth and economics. Part 1: Forest growth models. Many models have been reviewed and the most appropriate selected for further development. This thesis concentrates on the improvement of distance independent individual tree models. This is a modelling approach that is compatible with current knowledge and ideas in ecology. Several general improvements have been made. New growth equations have been produced and then calibrated to diameter increment data. Estimates for height prediction have been derived from analysis of a large survey of trees. Competition has been represented by a new multiplier, with a consequent improvement in the predicted diameter frequency distributions. The prediction of biomass for a given quality of site was modified such that control is mediated by measures of density dependence and biomass increment, via mortality. Finally, the results from improved versions of the model were tested against the known change in diameter frequency distribution for Meathop Wood in Cumbria. The result showed a promising similarity, and the minor disparities appear to be linked to the modelling of regeneration. Part 2: A forest economics model. A new model to assess the relative profitability of a wide variety of management options has been devised. The model is easy to operate and allows comparison for many differing financial circumstances. It has been used for investigating the importance of major financial variables in the selection of forestry investments. Research into changing fiscal incentives, 'natural' management, and ideal planting densities for oak have also been completed by use of the model.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:580804 |
| Date | January 1990 |
| Creators | Spilsbury, M. J. |
| Contributors | Harrison, A. F. |
| Publisher | University of Oxford |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://ora.ox.ac.uk/objects/uuid:184046d8-5b34-45f8-b891-2bc234d33678 |
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