Progress made in the first year of a 5-year project is reported. Towards the first objective of providing relationships between tree height increment and light levels, growth measurements and hemispherical photos were taken for 30 Douglas-fir and western hemlock saplings. Percent above canopy light (PACL) was estimated from the hemispherical photos and the relationship between height growth and PACL was appears consistent with expectations. Further tree measurements and hemispherical photos will be taken. Towards the second objective of evaluating model estimates of light and tree growth in real forests, light measurements made with mobile or fixed quantum sensors were compared with light estimates made by the TASS-tRAYci light model for a partially cut interior Douglas-fir stand. For a single cloud-free day, model estimates show less spatial variation than do light sensor measurements. Comparisons for full growing season light estimates and measurements will be made in fy05/06. Further evaluation of the light model estimates will be done using the interior Douglas-fir stand as well as partially cut coastal Douglas-fir stands. Visualisation of 3-dimensional PACL estimates has been enhanced by modification of the VISTAS computer programme. This will help in the qualitative evaluation of light model PACL estimates and spatial patterns. Proposed future work will build on activities undertaken in the first year of this project as well as interact with other new and ongoing work undertaken by the BC Ministry of Forests Stand Development Modelling group.
David G. Simpson.
Simpson, David G.. 2005. Light and tree growth in complex forest stands: FY 2004-05 annual progress report : April 2005. Forest Investment Account (FIA) - Forest Science Program. Forest Investment Account Report. FIA2005MR083
Topic: FLNRORD Research Program
Keywords: Forest, Investment, Account, (FIA), British, Columbia
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