Over the past decade the value of red alder products has steadily increased. Consequently the forest industry has moved from merely conifer replacement of alder stands to active reforestation and management of alder on short rotations. Two critical factors in management of short rotation crops are: growth and yield projections and fertilization regimes. This project evaluates various management regimes for red alder plantations in coastal BC. In experiment #1, effects of spacing, thinning, and pruning on growth and wood quality are assessed over the length of an alder rotation (25-30 years). In experiment #2, effects of phosphorus (P) supply on long-term growth, site fertility and water use efficiency will be assessed. The ongoing study of growth responses to P supply builds on earlier short-term studies showing that stem growth of young alder was often limited by low availability of P (Brown 1999, Brown and Courtin 2003ab). This study will provide data on long-term, stand-level growth responses of alder to P nutrition, as well as information on long-term accumulation of soil nitrogen and carbon. Alder is less tolerant of moisture stress than is Douglas-fir. This may limit its usefulness as an alternative species on sites with laminated root rot. However, P fertilization can have greater effects on growth of alder on drier soils. Possibly, improved P nutrition compensates for growth reduction due to moisture stress. If so, fertilization of young alder with P might expand the range of sites in which alder could be used to mitigate root rot. Experiment #2 is located on a slightly dry-fresh, root-rot infected site. Growth has increased with P supply to-date and the stand is now at a stage appropriate for examining how P supply affects water use. This experiment will demonstrate how water use and water use efficiency varies with P nutrition. It will analyze carbon discrimination in plant tissue as an integrative measure of water use efficiency. In experiment #3, additional P fertilization trials are established on different site series to broaden the application of research to operational conditions. This experiment will periodically measure growth responses from a one-time fertilization with P. This will complement the ongoing fertilization of experiment #2 that has an objective of maintaining differences in P nutrition and has necessitated periodic re-fertilization of plots.
Brown, Kevin R., Courtin, Paul J.. 2005. Management regimes for red alder plantations. Forest Investment Account (FIA) - Forest Science Program. Forest Investment Account Report. FIA2005MR362