Growth models for Sitka spruce in Ireland.

  • Lance R. Broad Technical Forestry Services, New Zealand.
  • Ted Lynch Coillte Research and Development, Newtownmountkennedy, Co. Wicklow, Ireland.
Keywords: Assortments, growth models, multivariate growth, Sitka spruce, weighting techniques.


Ad hoc techniques were used to fit stand-level growth models for Sitka spruce in Ireland in the presence of sampling biases. Panel data, sourced by aggregation over a set of repeated measures experimental designs, admitted sampling biases when considered as a data set for yield modelling purposes. Remedial action towards sampling imbalances was taken, whenever possible, through the use of weighting techniques. Further action to address data omissions involved using data substitution. The growth component model used was the multivariate Bertalanffy-Richards model formulated by Garcia. The model allows aggregated state-space representations of stand development to be formulated and fitted. For stand simulations, growth equations were augmented with functions accepting state variables as arguments and compute basal area reduction during any thinning, stand volume and volume assortments.
How to Cite
Broad, L. R., & Lynch, T. (2006). Growth models for Sitka spruce in Ireland. Irish Forestry. Retrieved from

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