A critical component of assessing the impacts of climate change on forest ecosystems involves und... more A critical component of assessing the impacts of climate change on forest ecosystems involves understanding as- sociated changes in the biogeochemical cycling of elements. Evidence from research on northeastern North American forests shows that direct effects of climate change will evoke changes in biogeochemical cycling by altering plant physiology, for- est productivity, and soil physical, chemical, and biological processes. Indirect
Bulletin of the Ecological Society of America, 1995
The importance of atmospheric nitrogen deposition in forest nutrient cycling has increased with i... more The importance of atmospheric nitrogen deposition in forest nutrient cycling has increased with increasing anthropogenic emissions to the atmosphere over the last 50+ years. Concerns of excessive NOâ leaching and greenhouse gas emissions have led to initiation of field studies using long-term, low level nitrogen additions to simulate increased N wet deposition. Results of two studies with applications rates of 0,25,50 or 150 kg N haâ»Â¹yrâ»Â¹ as HNOâ (Bear Brook Watershed Maine [BBWM]) or NHâNOâ (Harvard Forest in Massachusetts [HF]) were compared. Control plot net mineralization rates were 85 and 70 kg haâ»Â¹yrâ»Â¹ for BBWM and HF, respectively. Net nitrification was 5 kg haâ»Â¹yrâ»Â¹ in BBWM control plots and 15 kg haâ»Â¹yrâ»Â¹ in the +50 treatment by 1991; no nitrification occured at HF. At the 50 kg N haâ»Â¹yrâ»Â¹ level, NOâ leaching losses were highest in year one (1988) at BBWM but negligible at HF even after six years of treatment. Foliar N increased with treatment at HF but not at BBWM. Although N deposition at BBWM (5 kg haâ»Â¹yrâ»Â¹) is half of HF (8-10 kg haâ»Â¹yrâ»Â¹) and the two stands are similar in age (40-50 yrs) BBWM appears closer to N saturation, perhaps due to differences in past land-use practices, biomass nutrient uptake or soil retention capacity.
Human activities such as the combustion of fossil fuels and changes in land use are increasing at... more Human activities such as the combustion of fossil fuels and changes in land use are increasing atmospheric concentra-tions of carbon dioxide and other greenhouse gases (eg, ni-trous oxide, methane, halocarbons). Climate models indicate that these heat-trapping gases ...
Abstract We followed the movements of 15N-labelled nitrate additions into biomass and soil pools ... more Abstract We followed the movements of 15N-labelled nitrate additions into biomass and soil pools of exper- imental plots (15 x 15 m each) in a mid-successional beech-maple-birch-spruce forest in order to identify sinks for nitrate inputs to a forest ecosystem. Replicate plots ...
A critical component of assessing the impacts of climate change on forest ecosystems involves und... more A critical component of assessing the impacts of climate change on forest ecosystems involves understanding as- sociated changes in the biogeochemical cycling of elements. Evidence from research on northeastern North American forests shows that direct effects of climate change will evoke changes in biogeochemical cycling by altering plant physiology, for- est productivity, and soil physical, chemical, and biological processes. Indirect
Bulletin of the Ecological Society of America, 1995
The importance of atmospheric nitrogen deposition in forest nutrient cycling has increased with i... more The importance of atmospheric nitrogen deposition in forest nutrient cycling has increased with increasing anthropogenic emissions to the atmosphere over the last 50+ years. Concerns of excessive NOâ leaching and greenhouse gas emissions have led to initiation of field studies using long-term, low level nitrogen additions to simulate increased N wet deposition. Results of two studies with applications rates of 0,25,50 or 150 kg N haâ»Â¹yrâ»Â¹ as HNOâ (Bear Brook Watershed Maine [BBWM]) or NHâNOâ (Harvard Forest in Massachusetts [HF]) were compared. Control plot net mineralization rates were 85 and 70 kg haâ»Â¹yrâ»Â¹ for BBWM and HF, respectively. Net nitrification was 5 kg haâ»Â¹yrâ»Â¹ in BBWM control plots and 15 kg haâ»Â¹yrâ»Â¹ in the +50 treatment by 1991; no nitrification occured at HF. At the 50 kg N haâ»Â¹yrâ»Â¹ level, NOâ leaching losses were highest in year one (1988) at BBWM but negligible at HF even after six years of treatment. Foliar N increased with treatment at HF but not at BBWM. Although N deposition at BBWM (5 kg haâ»Â¹yrâ»Â¹) is half of HF (8-10 kg haâ»Â¹yrâ»Â¹) and the two stands are similar in age (40-50 yrs) BBWM appears closer to N saturation, perhaps due to differences in past land-use practices, biomass nutrient uptake or soil retention capacity.
Human activities such as the combustion of fossil fuels and changes in land use are increasing at... more Human activities such as the combustion of fossil fuels and changes in land use are increasing atmospheric concentra-tions of carbon dioxide and other greenhouse gases (eg, ni-trous oxide, methane, halocarbons). Climate models indicate that these heat-trapping gases ...
Abstract We followed the movements of 15N-labelled nitrate additions into biomass and soil pools ... more Abstract We followed the movements of 15N-labelled nitrate additions into biomass and soil pools of exper- imental plots (15 x 15 m each) in a mid-successional beech-maple-birch-spruce forest in order to identify sinks for nitrate inputs to a forest ecosystem. Replicate plots ...
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Papers by Alison Magill