Stumping out tree root disease – An economic analysis of controlling root disease, including its effects on carbon storage in southern British Columbia

Abstract

Abstract Stumping, or removing stumps after logging, is a forestry practice used to control the level of Armillaria and Phellinus root disease in temperate forests in British Columbia (BC) and elsewhere. A comprehensive assessment of the economic rationale for stumping is largely absent. This study attempts to fill this gap by using a detailed case study of a 46-year old trial and an assessment using growth and yield model simulations of a range of managed Douglas-fir stands in the southern interior of BC. The analysis considers both timber and carbon values over a variety of management costs and site conditions. There are conditions within which stumping is an economically viable strategy, especially on public forestlands, that will improve long-term timber yields and storage of carbon on the land base. Specifically, we find stumping at the Skimikin site increases annual stand productivity by 3.29 m3/ha/yr at age 44. Under reasonable economic conditions and an interest rate of 3%, this productivity growth leads to a minimum average increase in the soil expectation value (SEV) of $1105/ha. If carbon ($15/t CO2) is included in the calculations, the increase is a minimum increase of $2586/ha. We find that with carbon, and under similar economic conditions and discount rate, stumping is more profitable than not stumping on even less productive sites than Skimikin. On stands with productivity of 20 m at age 50 years (SI20), we find stumping generates at least $141/ha more than unstumped stands.