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 A
very important step in understanding the development of the interior
Douglas-fir forests is understanding regeneration. A number of
studies have been initiated at Pothole Creek to investigate various
aspects of regeneration in this ecosystem.
Seedling Survey: A baseline census of seedlings was taken to estimate the number of seedlings present in the 5 ha study area and their survival probabilities from season to season.
Regeneration and Coarse Woody Debris: A small trial was established to study the influence of coarse woody debris (CWD) on microsite. Seedlings were planted at a range of distances from CWD to examine its
effects on seedlings.
Seedling Spatial Distribution: The location of trees and seedlings taller than 10 cm was mapped on three sub-plots within the Permanent Sample Plot. From these data, the spatial distribution of seedlings
can be compared to those in taller height classes.
Seed Rain: Thirty seed traps were set out
in random locations within the Permanent Sample Plot to monitor long-term
variation in seed fall. Mature trees within 25 m of the seed traps were mapped to relate the data to
the seed production of individual
parent trees.
Seed Bank: Soil samples were collected to test for the presence of viable Douglas-fir seeds in the soil seed bank.
Seed Predation: Seeds were set out in different densities, some protected from predators and some not, to test the effect of seed predation on germination and to determine if there is an interaction
between seed density and predation.
As a group, these studies are providing valuable information on the regeneration dynamics of interior Douglas-fir.
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