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Carbon Sequestration Benefits –Tree Size, Tree Mortality & Growth Rate Factors

The energy savings benefits are derived based on the "mature tree" canopy, which means that the tree has a well-developed or established tree canopy. For the energy savings tree estimates, smaller trees are considered "mature" at 30 years; medium size trees are "mature" at 40 years, and for larger tress, 50 years. In other words, trees will continue to age but tree canopy will not get bigger (just like adults.)

However, a different or longer life growth curve is used for the carbon sequestration calculations; since trees continue to grow in terms of the tree volume (i.e. the trees continue to store more carbon). Smaller trees are considered "mature" at 60 years; medium size trees are "mature" at 80 years, and for larger tress, 100 years. In other words, trees will continue to age, and after the certain age the tree canopy will not get bigger but the tree volume (trunks, branches, etc) will increase (just like adults).

All trees were again grouped into three categories according to the tree size at the tree maturity: Small (which grows up to 25 ft in height), Medium (which grows up to 45 ft in height) and Large (which grows up to at least 46 ft in height). For the carbon sequestration estimates, the age of the tree from the planting date will vary depending on the tree size: from 1 to 60 years for Small trees, from 1 to 80 years for Medium trees and from 1 to 100 years for Large trees.

The assigned age of the Program Tree (trees planted by utilities) will then determine the tree growth rate factor and the tree survival rate factor (incorporating the assumed tree mortality rate), which will then determine together the level of the carbon sequestration benefits for any year. In other words, the combination of the tree size, tree growth rate and the tree survival rate will determine the final multiplier factor that will estimate the appropriate level of the carbon sequestration benefits for any year.

In order to estimate the carbon sequestration benefits for the Program Trees (trees planted by utilities) for any tree size and age, the Tree Benefits Estimator will multiply the carbon sequestration values of MATURE trees with the appropriate Tree Size, Tree Growth and Survival Rate FACTOR values. However, for the existing trees (which are currently alive), the Tree Benefits Estimator will NOT incorporate into the calculations the assumed tree mortality rate.

Click here to view the Carbon Benefits graphs in terms of Tree Mortality & Growth Rate Factors for each Tree Size (Small, Medium and Large)

Click here to display Tree Mortality & Growth Rate Factor for Small Tree for Carbon Benefits for Program Trees
Click here to display Tree Mortality & Growth Rate Factor for Medium Tree for Carbon Benefits for Program Trees
Click here to display Tree Mortality & Growth Rate Factor for Large Tree for Carbon Benefits for Program Trees