Forest site classification for cultural plant harvest by tribal weavers can inform management

Abstract

Do qualitative classifications of ecological conditions for harvesting culturally important forest plants correspond to quantitative differences among sites? To address this question, we blended scientific methods (SEK) and traditional ecological knowledge (TEK) to identify conditions on sites considered good, marginal, or poor for harvesting the leaves of a plant (beargrass; Xerophyllum tenax) used in tribal basket weaving. We relied on voluntary participation of six expert weavers, a stratified, randomized field sample, discriminant analysis (DA), a standardized color system, and paired t-tests. We accepted each weaver’s classification (good, marginal, or poor) of forested sites for beargrass harvest and then measured forest and plant attributes on two plots at each harvest area in each class (n = 72). The DA yielded descriptive but not predictive results. Coarse woody debris (CWD) levels and the number of trees (trees per acre [TPA]) differed significantly between good and poor sites across California, Oregon, and Washington, whereas basal area did not. Good sites had less CWD (P = 0.0360) and fewer TPA (P = 0.001) than poor sites. Variations in leaf color decreased as the site class for plant harvest improved. Results reveal a crosswalk between ecological knowledge derived via SEK and TEK for culturally important plants.