This study assessed the variability of sample estimates for downed and dead woody fuel weight in natural lodgepole pine (Pinuscontorta Dougl.) stands using line-intersect sampling procedures. Equilateral triangles (30 m/side) were established at each of 40 sample sites with variable length transects on each side to estimate fuel weights by diameter class. Regardless of the number of sides measured, the standard error for fuels less than 7.0 cm was at most 20% of the mean. Even measuring only one side of the triangle, using a single transect instead of the triangular sample unit, still achieved standard errors less than 20% of the mean. Standard errors for classes greater than 7.0 cm were all greater than 20% of the mean. For these classes, more samples are required to achieve the 20% standard error limit; however, depending on costs, the triangular sample unit may not be the best solution. In this study, intracluster correlations were above 0.7 for the fuel diameter classes greater than 7.0 cm, suggesting that multiple transects at a given sample location contribute little new information. This effect, although less pronounced, was also observed with the smaller diameter classes.

RQumeRegression equations that predict the foliage and roundwood Les Cquations de rCgression qui prkdisent la biomasse du biomass by diameter classes: 0.0-0.5 cm, 0.5-1.0 cm, feuillage et de la matibre ligneuse brute par classes de diambtre 1.0-3.0~m,3.0-5.0cm,5.0-7.0cmand7.0-10. Ccarts types sont faibles. Les classes de diambtre plus importantes sont mieux prCdites en multipliant le nombre d'arbres affect& par une constante. La valeur en amCnagement de cette nouvelle information est significative lorsqu'CtudiCe selon une perspective Ccologique.

Equations were developed to predict the ovendry weight of the total crown, live crown, foliage, and the roundwood diameter classes of <0.5, 0.5–1.0, 1.0–3.0, 3.0–5.0, 5.0–7.0, 7.0–10.0 cm for lodgepole pine (n = 27) and white spruce (n = 23) occurring in Alberta, Canada. The nonlinear allometric model using total tree height and a measure of crown width provided high R2 and low SEE values. This precision could not be duplicated when total tree height was used as the only independent variable. Our results suggest the possibility of using tree height and crown width measured from aerial photographs to estimate standing live and dead fuel loadings in undisturbed forest stands.

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