This website provides a background information for a problem-based learning (PBL) case study, entitled “Effects of variable retention harvesting on soil microbial communities in coastal BC forests”, which is part of the the APBI 402 / SOIL 502 – Sustainable Soil Management course, offered at the University of British Columbia, Vancouver, Canada.
APBI 402 / SOIL 502 – Sustainable Soil Management course is delivered in a modified PBL format that simulates a real-life evaluation of soil properties to establish the most appropriate management practice in a particular land-use system. During the course, each student works on three, 4-week-long case studies. Each case is focused one of the following three areas: soil chemistry, soil physics, or soil biology. The case study on “Effects of variable retention harvesting on soil microbial communities in coastal BC forests” allows students to evaluate the effects of several types of timber harvesting on soil microbial communities and their functions (i.e., enzyme activities); and it fits withing the soil biology set of case studies in the APBI 402 / SOIL 502 course.
The handout with detailed description of the case study is provided to students via the course management system used by the University of British Columbia, Vancouver; and is not included at this website. However, here is a brief description of the case study:
Soil microorganisms play important roles in regulating key forest ecosystem processes, such as nutrient cycling and decomposition of organic matter. Living vegetation and soil microbes interact in complex ways, but the C cycle is central to understanding these interactions. The presence of living trees influences the diversity and functioning of soil organisms by altering the supply of belowground C needed for microbial growth. Consequently, forest harvesting methods that allow retention of certain proportion of the living trees on a site should be more beneficial to soil quality than clearcutting, which removes all trees from the site. From a belowground perspective, the key issues are whether variations in tree retention density affect the soil’s ability to maintain microbial communities and processes at levels comparable to unharvested stands, and how far any effects extend beyond retention patches. The case study focuses on the Silviculture Treatments for Ecosystems Management (STEMS) long-term experiment located in the Sayward Forest west of Campbell River, British Columbia, Canada.
