Grant: Advancing Climate Change Science in Canada

Forests play an important role in removing carbon dioxide from the atmosphere and storing it in soil - thuscountering the tendency for atmospheric carbon dioxide to warm our climate. We will ask how outbreaks ofspruce budworm, a major forest pest that defoliates and kills conifers over millions of hectares, alter thisprocess. In defoliated forests, dead needles and budworm feces likely provide a short-term boost in carbonflow to soils. However, in the longer term, defoliated forests are less able to remove carbon dioxide from theatmosphere, and the thinner tree canopy means warmer soils and therefore, potentially, more release of storedcarbon from the soil. We will study these effects and their interactions by comparing forest plots that havebeen defoliated by budworm with similar, nearby plots that have been protected from budworm damage byaerial spray with a biological insecticide, Btk. We will measure the fall of needles and caterpillar feces fromthe canopy to the ground, measure carbon content in soil cores, and measure the emission of carbon dioxidefrom microbes in the soil. We will also measure the abundance of ""mycorrhizal"" fungi - fungi that formpartnerships with tree roots and which receive carbon-containing sugars from the tree and move them into soil.Together, these measurements will help us understand how budworm outbreaks change the carbon cycle inforests, and how we can use Btk treatments to intervene to protect the carbon-storage role of the forest. Thisresearch will involve both established scientists and students in training from the University of NewBrunswick, the Canadian Forest Service, and Agriculture and Agri-Food Canada.