Woods Hole Research Center

We examined the C sequestration consequences of a planned shelterwood harvest regime. After pre-harvest preparations, a 2002 harvest removed about one-third of the basal area of the forest. With the cooperation of International Paper Corporation, we tracked the fates of harvest products and have estimated their decay rates. We have carried out intensive on-site studies of the decay rates of harvest slash, soil respiration, rates of growth of the remaining trees, and net ecosystem exchange (NEE) of carbon dioxide.

Soil respiration has been measured at two areas around the control tower and three cover types around the harvest tower, including an area lightly impacted by the harvest, a heavily impacted area, and skid trails. Eight collars are randomly located in each of two plots within each area and fluxes were measured approximately biweekly from May through November using the manual method of soil respiration. Continual measurements of soil temperature and moisture are made at these locations.

Harvested trees awaiting removal.

• The forest has been gaining C since the harvest, with generally good agreement between tower-based measurements of total ecosystem net uptake of carbon and direct measurements of tree growth.
• While decay of harvest slash contributed significantly to ecosystem respiration, soil respiration declined after harvest in spite of increased soil temperatures, suggesting small overall changes in post-harvest soil carbon pools.
• Combining off-site decay estimates with on-site measurements of NEE, we can calculate the annual net C balance, which was initially negative immediately after harvest, but turned positive in 2005. The combination of biomass of the regrowing forest plus the remaining storage of C in off-site harvest products nearly equaled the pre-harvest C stocks in the forest in 2007 and surpassed this value by 2009.

Key Publications

Scott, N.A., C.A. Rodrigues, H. Hughes, J.T. Lee, E.A. Davidson, D.B. Dail, P. Malerba, D.Y. Hollinger. 2004. Changes in carbon storage and net carbon exchange one year after an initial shelterwood harvest at Howland Forest, ME. Environmental Management 33: S9-S22.