Appendix C - Attachment 2 Oak Trees and Climate Change Memorandum Memorandum

To: Bruce Steubing, Vice President Resource Design Technology, Inc. From: Joe O’Bannon, Senior Air Quality Scientist Michael Brandman Associates Date: 2/26/2008 Re: Oak Trees and Climate Change

Statement of Understanding In the Chevron San Ardo to Coalinga Heated Oil Pipeline Draft EIR (DEIR), the document identifies the potential that oak trees will be impacted. Avoidance and mitigation measures are suggested, however, in a comment letter from the California Oak Foundation (COF), it was pointed out that there was no discussion of the oak tree’s part in the global warming/climate change.

Discussion Climate change refers to a statistically significant variation in either the mean state of the climate or in its variability, persisting for an extended period (typically decades or longer). Oak trees are part of a nature’s carbon warehouse. In fact, photosynthesis and respiration are the essential machinery by which forests store and release carbon. As a tree grows, it absorbs CO2 from the air and, through the process of photosynthesis, uses solar energy to store carbon in its roots, stems, branches, and foliage. Some carbon is released back into the atmosphere as CO2 during respiration, but a living tree acts as a carbon “sink”— storing more carbon than it releases. Trees continue to accumulate carbon until they reach maturity, at which point about half of the average tree’s dry weight will be carbon.

DEIR Oak Trees The DEIR identified seven species of oak trees that occur within the Project area: the coast live oak (Quercus agrifolia); the Alvord oak (Q. alvordiana); the scrub oak (Q. berberidifolia); the blue oak (Q. douglasii); the Tucker oak (Q. john-tuckeri); the valley oak (Q. lobata); and the interior live oak (Q. wislizenii). Research finds that trees sequester CO2 at rates that are related to their mature height and their leaf persistence (evergreen or deciduous). Table 1 shows the oaks mentioned in the DEIR and their relative CO2 uptake rate.

It is estimated that up to 1,000 oak trees may have to be removed during construction. Even though contractors will avoid if possible, and for the trees that have to be removed mitigations have been set that compensate their loss through one of three mechanisms mentioned in Mitigation 3.5-1b, the result of the mitigation on carbon sequestration may only be realized when replanted trees reach maturity. Therefore, for the purposed of developing a conservative estimate it is assumed that 1,000 trees with the highest CO2 uptake would be removed, which would result in 667,500 lbs (334 tons) less carbon sequestration occurring in the area.

Michael Brandman Associates 1 \\Rdtnas01\data\Data\Projects\186 - Chevron Heated Oil Pipeline\Final EIR\Appendices\Appendix C - Attachment 2 - Oak Memo.doc Table 1: Per Tree CO2 Uptake (lbs/yr)

Tree Mature CO Uptake Scientific Name Common Name 2 Type Height (ft) (lb/yr) Quercus agrifolia coast live oak Evergreen 65 667.5 Quercus alvordiana Alvord (Eastmans) oak Evergreen 20 102.8 Quercus berberidifolia scrub oak Evergreen 20 102.8 Quercus douglasii blue oak Deciduous 50 649.8 Quercus john-tuckeri Tucker oak Evergreen 20 102.8 Quercus lobata valley oak Deciduous > 65 649.8 Quercus wislizenii interior live oak Evergreen 65 667.5

Michael Brandman Associates 2 \\Rdtnas01\data\Data\Projects\186 - Chevron Heated Oil Pipeline\Final EIR\Appendices\Appendix C - Attachment 2 - Oak Memo.doc