Comparative analysis of carbon, water, and energy exchanges in co-located mid-latitude forests at various stages of development
Abstract
Biosphere-atmosphere exchanges of mass and energy vary with forest type, stand age, and following disturbance, but the degree, character, and persistence of these variations remain poorly understood. This work explores such gradients by synthesizing across a local network of flux tower sites within Harvard Forest (central Massachusetts). We examine how CO2, H2O, and energy exchanges compare among mature and intermediate aged deciduous forests, a mature hemlock forest, and a newly instrumented site in the early stages of secondary succession following a recent clearcut. We find markedly lower growing season evapotranspiration in the hemlock stand compared to adjacent deciduous forests, lower still in the revegetating clearcut. Daytime net ecosystem carbon exchange follows a similar pattern, with highest uptake in the deciduous forests, intermediate in the hemlock site, and lowest in the clearcut. This is true despite sizeable midday uptake in the clearcut during the second growing season post-harvest. Large nighttime CO2 emissions from the clearcut indicate high respiration rates of the early succession vegetation as well as vigorous decomposition of the abundant woody debris and litter left onsite after harvest. Surface albedo and corresponding net radiation are both surprisingly consistent across these adjacent cover types. Implications for water resources and carbon balance of New England landscapes will be discussed, particularly within the contexts of human and natural disturbances, such as harvesting and Hemlock Wooly Adelgid infestations.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2010
- Bibcode:
- 2010AGUFM.B22E..02W
- Keywords:
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- 0416 BIOGEOSCIENCES / Biogeophysics;
- 0426 BIOGEOSCIENCES / Biosphere/atmosphere interactions;
- 0428 BIOGEOSCIENCES / Carbon cycling;
- 0439 BIOGEOSCIENCES / Ecosystems;
- structure and dynamics