Monumental cedar on British Columbia’s Haida Gwaii/Queen Charlotte Islands: Abundance, distribution, and implications for land-use planning and forest management

Abstract

Executive summary This study involved the analysis of timber cruise data1 to learn more about the abundance and distribution of large-diameter red cedar (Thuja plicata), and yellow-cedar (Chamaecyparis nootkatensis) on British Columbia's Haida Gwaii/Queen Charlotte Islands. The impetus for this project was to ensure that concerns about the present and future supply of large-diameter cedar for the creation of monumental art e.g. totem poles, canoes) could be addressed in the Haida Gwaii/Queen Charlotte Islands Land Use Plan. While this project focused specifically on Haida Gwaii, the results may also be relevant for other areas in the Pacific Northwest where cedar is a subject of concern. The study attempted to answer three specific research questions: •What is the approximate density of large-diameter cedar in remaining old-growth stands on the Queen Charlotte Islands? •What percentage of large-diameter cedar is of 'monumental quality'? •How does the density of large-diameter cedar vary with site conditions? Key Findings • Large-diameter red cedar (> 100 cm DBH) is relatively common, with an approximate density of 10-15 trees/hectare across the landscape. Large-diameter red cedar is most prevalent in the CWH wh1 subzone, however, the wh2 and vh1 subzones also contain significant amounts of large-diameter red cedar. Large-diameter red cedar is found predominantly in cedar-leading and mixed cedar-hemlock stands. • Large-diameter yellow-cedar is much less common than large-diameter red cedar. Very large yellow-cedar (> 160 cm DBH) is particularly rare. Large-diameter yellow-cedar is concentrated within the CWH wh2 subzone, with negligible amounts in the other two subzones. It is found predominantly in yellow-cedar leading stands. • Only a small percentage of large-diameter cedar ( approximately 10%) is of suitable quality to be used in monumental art. The exact proportion varies depending on the quality definition, and the tree species and size. • The three major biogeoclimatic subzones on the Queen Charlotte Islands have significantly different densities of large-diameter cedar. However, within a biogeoclimatic subzone, differences in large-diameter cedar densities between site series are relatively small. • The leading species in a stand is an excellent predictor of the stand's density of large­ diameter cedar. Height class and maximum slope are not significant predictors for the abundance of large-diameter red cedar. In conclusion, the project was successful in increasing knowledge of the abundance and distribution of large-diameter cedar, although concerns remain about the non-random nature of the sample data. Progress has also been made in identifying the site factors that determine where large-diameter cedar is likely to be found, and in determining what percentage of large-diameter trees are of monumental quality. However, field verification is needed to confirm the accuracy of site series data and the reliability of the 'monumental quality' definition used in this study. Land­-use planners must consider cedar's role in monumental art together with cedar's other functions to ensure that this valuable resource is managed to bring maximum benefits to the inhabitants of Haida Gwaii, and the citizens of British Columbia.