Carbon sequestration consequences of spruce budworm outbreaks and control in eastern Canadian forests

森林在从大气中吸收二氧化碳并将其储存在土壤中方面发挥着重要作用-从而抵消了大气二氧化碳使气候变暖的趋势。我们将问云杉芽虫的爆发是如何改变这一过程的，云杉芽虫是一种主要的森林害虫，它使数百万公顷的针叶树落叶并死亡。在落叶的森林中，死针叶和芽虫的粪便可能会在短期内增加土壤中的碳流。然而，从长远来看，落叶森林从大气中去除二氧化碳的能力较低，而较薄的树冠意味着土壤较温暖，因此，可能会从土壤中释放更多的储存碳。我们将研究这些影响和它们之间的相互作用，通过比较已被芽虫落叶的森林地块与类似的，附近的地块已被保护免受芽虫损害的空中喷洒生物杀虫剂，Btk。我们将测量针叶和毛毛虫粪便从树冠落到地面的情况，测量土壤芯中的碳含量，测量土壤中微生物排放的二氧化碳。我们还将测量“菌根”真菌的丰度--这种真菌与树根结成伙伴关系，从树中接收含碳糖并将其转移到土壤中。总之，这些测量将帮助我们了解虫虫的爆发如何改变森林中的碳循环，以及我们如何使用Btk处理来干预以保护森林的碳储存作用。这项研究将涉及两个既定的科学家和学生在培训从新不伦瑞克大学，加拿大林业局，农业和农业食品加拿大。

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.