Date of Award


Document Type

Honors Thesis (Open Access)


Colby College. Biology Dept.


Judy L. Stone

Second Advisor

Cathy R. Bevier (reader)

Third Advisor

Herbert Wilson, Jr. (reader)


Biomass energy plants are considered to be carbon neutral systems under some definitions. However, this concept of carbon neutrality needs to be rethought in order to understand the true carbon impact of biomass plants upon global climate change. A biomass plant’s wood source, the extent to which the biomass plant emits carbon dioxide, and the timescale over which the biomass plant emits carbon should all be taken into account. In this study, I consider the Colby College biomass plant’s role in carbon cycling. Colby’s Physical Plant Department provided me with information on how much carbon (tons of woodchips) is used in the biomass plant annually. Using data on tree growth collected by the Forest Inventory Analysis National Program of the United States Forest Service I calculated annual forest growth rates of forested plots in Kennebec County. I then determined the area of land that would accumulate carbon (in tree growth) at the same rate as the biomass emitted carbon (tons of woodchips combusted). I argue that if these carbon emissions equal local forest growth rates, Colby’s biomass plant would be part of a carbon neutral system. Further, I explain how following this same logic, a fossil-fuel plant that emits carbon at a rate equal to carbon sequestration rates would be carbon neutral. Reducing carbon emissions, and not simply matching carbon emissions to carbon sequestrations, would be a much more effective way to mitigate climate change.


carbon neutrality, bio fuels, climate change, alternative energy, Central Maine, forests

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