We began our long-term climate research in Stebbins Gulch in 2006. Our goal was to monitor how plants and soil fungi that associate with plant roots (called mycorrhizal fungi) respond to changes in air and soil temperature and moisture. Figure one shows one of our two weather stations in the old-growth beech-maple forest in Stebbins. The beech tree in the background that toppled over in 2015 was more about 219 years old when it fell based on tree ring data – the tree began to grow in 1796.
Since 2007, we have observed large seasonal fluctuations in some wildflower populations such as wild leek. The cause of these fluctuations is still unclear. We have found that over 5 years soil fungal communities responded strongly to soil moisture but were unaffected by soil temperature. This suggests that soil fungi will respond more to changes in rain and snow fall than temperature as the climate warms.
We began our work in 2006 and this large, old beech collapsed after a high wind event in April 2007. The process of tree death is closely linked to growth and recruitment within forests. The collapse and death of this tree created a light gap that other, younger plants can grow into and fill. The plants that replace this beech tree may be of another species, such as oak or tulip poplar. This process of gap creation and tree replacement means our forest are always changing and evolving.
After 13 years the tree that fell in Stebbins is still visible, but it has decayed considerably. The fallen tree has been home to fungi that have begun the process of wood decay and in turn have become food for myriad insects. Those insects support other animal life, such as woodpeckers and small mammals. The nutrients within the wood are also released as a part of this decay process and return to the soil to fuel future plant and tree growth.
David J. Burke, PhD
Vice President for Science and Conservation
My primary research interest as an ecologist has been the interaction between plants and soil microorganisms; especially mutualistic and associative soil organisms that live in the root zone of plants. Of special interest are mycorrhizal fungi that form mutually beneficial relationships with plant roots. Mycorrhizal fungi can enhance plant growth, disease resistance, drought tolerance, and affect plant community composition. These fungi can also influence other soil microbes that affect soil fertility through the cycling of nitrogen and phosphorous in natural systems. Consequently, mycorrhizal fungi may be key organisms in many communities, and a better understanding of how they interact with plants and other soil microbes is necessary for the future sound management of natural ecosystems. Our laboratory has two interrelated goals: 1) to describe the diversity of fungi in natural systems and to understand the environmental factors affecting this diversity 2) to understand the functional consequences of mycorrhizal diversity for plant growth, plant community structure, and ecosystem processes. Our laboratory uses modern, DNA-based techniques for describing soil micro-organisms including mycorrhizal fungi.