Several features or characteristics of hemlock dwarf mistletoe (Arceuthobium tsugense [Rosendahl] G.N. Jones subsp. tsugense, HDM)-infected residual trees affect spread of HDM into young trees. A knowledge of these aspects of HDM infection is needed to project rates of spread of HDM and development of growth effects in young stands in small and in retention-harvested blocks. Components of HDM spread in retention areas that can be measured include: ? Distribution and occurrence of HDM-infected residual and regenerated trees; and ? HDM seed production on, and dispersal from HDM-infected residual trees. To facilitate analyses of HDM effects at a forest ecosystem level, and to compare effects on qualitative attributes of forests, detailed information and data also need to be incorporated into higher level, ecosystem models. The models FORCEE and LLEMS being developed by J.P. Kimmins and associates at the University of BC incorporate several features and data from TASS and other tree growth models, and are being upgraded to include HDM effects (Muir 2003). Data on the rate of spread and infection of young trees by HDM in retention-harvested forests are needed to initialize these ecosystem models.
John A. Muir.
Muir, John A.. 2006. FIA monitoring project: monitoring hemlock dwarf mistletoe in coastal forests of British Columbia. Forest Investment Account (FIA) - Forest Science Program. Forest Investment Account Report. FIA2006MR236