DATA SOURCES: Carbon Sequestration Conversion

From Redefining Progress: 0.95 metric tons of solid carbon per hectare of land per year

From Oak Ridge National Laboratory: CO2 is 3.67 x heavier than Carbon

0.95 metric tons x 3.67 = 3.49 metric tons of CO2 per hectare per year

Converting to US (short) tons:

3.49 tonnes CO2 x 1.1 tons/tonne = 3.84 tons per hectare per year
Converting to acres:

3.84 tons CO2 / 2.47 acres/hectare = 1.55 tons CO2 per acre, or 3,105 lbs.

Assuming 90 trees per acre on a 22' foot center (that is approximately 3 x 30 trees based on a 60' x 660' acre) = 3105/90 = 34.5 lbs CO2 per tree. Assume 25% loss to be conservative = 25.8 lbs of CO2 absorption per year.

You can calculate the carbon stored in a specific tree through The Cooperative Research Centre for Greenhouse Accounting's Tree Carbon Calculator.

Note: in the Ecological Footprint model, when individual impacts are being tallied, it is assumed that approximately between 27% and 35% of all CO2 is absorbed by the ocean, leaving the remaining CO2 (an average of 61%) to be absorbed by terrestrial biomass. There are differing theories on how to calculate carbon sequestration. See a comparison of 2 footprint models here.