. Dispersal of white spruce seed on Willow Island in interior Alaska. White spruce Propagation; White spruce Alaska. Figure 1—Location of harvest units containing seed trap transects on Willow Island in the Tanana River near Fairbanks, Alaska. The ratio of filled seed per square meter to total seed per square meter within seed source areas was estimated for 1987. Plots of mean number of total seeds per square meter versus the mean number of filled seeds per square meter indicated a linear relation passing near the origin. The relation logically should pass through the origin because if total s
. Dispersal of white spruce seed on Willow Island in interior Alaska. White spruce Propagation; White spruce Alaska. Figure 1—Location of harvest units containing seed trap transects on Willow Island in the Tanana River near Fairbanks, Alaska. The ratio of filled seed per square meter to total seed per square meter within seed source areas was estimated for 1987. Plots of mean number of total seeds per square meter versus the mean number of filled seeds per square meter indicated a linear relation passing near the origin. The relation logically should pass through the origin because if total seed production is zero, then production of filled seed also is zero. Based on these plots, a ratio of means estimator (Cochran 1977, Krishnaiah and Rao 1988) was selected, R = Y/X, (1) where R = the estimated ratio, Y = the sample mean of number of filled seed per square meter, and X = the sample mean of number of total seed per square meter. The ratio was estimated from 11 observations. Each observation was the total seed count and all filled seed collected throughout the year and was based on the average of the three traps placed within the stand at the beginning of each transect line. The standard error of R was estimated by using a jackknife estimator (Cochran 1977) because sample size (n = 11) was small. The jackknife estimator was selected to reduce bias in the estimated standard error. 3. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Youngblood, Andrew P; Max, Timothy A; Pacific Northwest Research Station (Portland, Or. ). Portland, Or. : U. S. Dept. of Agriculture, Forest Service, Pacific Northwest Research Station
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