All vegetation less than one meter in height within a lm2 quadrat was identified to
 species. Percent vegetative cover of the quadrat (cover abundance) of all vegetation less
 than one meter was estimated and assigned a number based upon the following scale.

 Cover Abundance Scale

 5 76% to 100% cover
 4 51% to 75% cover
 3 6% to 50 % cover
 2 10% to 25% cover
 1 < 10% cover

 Above-ground biomass of primrose willow and cattail present within the 1m2
 quadrats was harvested, dried, and weighed to determine standing crop (grams dry
 weight/square meter). Frequency of occurrence of primrose willow and cattail in the
 understory was calculated by dividing the number of 1m2 quadrats in which each
 occurred by the total number of quadrats sampled. Since relatively few samples of
 primrose willow and cattail resulted from sampling the chronosequence, data were
 supplemented with three to five quadrats selected from sites dominated by primrose
 willow and cattails.


 Canopy Photographs

 Hemispherical photographs for canopy cover analysis were taken using a Nikon
 35mm camera, a Nikon 16mm lens and Kodak Tri X black and white film. The camera
 was placed on a tripod approximately 50 cm above the ground or slightly above the
 surface of the water, whichever was higher. The camera was leveled with the lens
 pointing up and top of the camera facing north. A photographic light meter was used to
 determine the appropriate aperture and shutter speed. Three photographs were taken at
 each point bracketing the aperture and shutter speed recommended by the light meter.
 Dawn and dusk photographic outings allowed all photographs to be taken while avoiding
 direct radiation from the sun.

 After developing and printing photographic images, the image with highest
contrast was selected and scanned using a flatbed scanner. Each computer image, which
included pixels of all shades of gray, was then converted to a high contrast black and
white image. Gray pixels were eliminated by grouping all gray pixels as either black or
white. Once the black and white image was completed, percent canopy cover was
assessed to be the percent of the total image pixels that were black. Figure 7.4 shows a
sample photo image (Figure 7.4a) and the computer-enhanced high-contrast black and
white image (Figure 7.4b).


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