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Million Trees Los Angeles: Carbon dioxide sink or source?Author(s): E.G. McPherson; A. Kendall; S. Albers
Source: In M. Johnston; G. Perceival, eds. Proceedings of the Urban Trees Research Conference "Trees, People and the Built Environment II." Edgbaston, UK: University of Birmingham: 7-19.
Publication Series: Paper (invited, offered, keynote)
Station: Pacific Southwest Research Station
PDF: Download Publication (295.77 KB)
DescriptionThis study seeks to answer the question, 'Will the Million Trees LA (MTLA) programme be a CO2 sink or source?' Using surveys, interviews, field sampling and computer simulation of tree growth and survival over a 40-year period, we developed the first process-based life cycle inventory of CO2 for a large tree planting initiative (TPI). Carbon dioxide emissions and reductions were simulated for 91,786 trees planted between 2006 and 2010, of which only 33.6% were estimated to survive to 2045. Early monitoring results suggest that the MTLA programme is achieving success in terms of tree survival and growth. MTLA was estimated to release 17,048 t of fossil CO2 over the 40-year period, and to avoid -103,618 t of emissions from energy savings (-101,679 t) and biopower (-1,939 t). The largest sources of fossil CO2 emissions were irrigation water (8,095 t) and equipment (4,704 t). The trees were projected to store -77,942 t CO2 in their biomass. This amount was nearly offset by biogenic emissions from the decomposition of wood (54,293 t) and wood combustion (12,067 t). The MTLA programme will be a CO2 sink if the projected 40-year avoided emissions from energy savings and biopower are realised. Although the trees planted by the MTLA programme are likely to be a net CO2 sink, there is ample opportunity to reduce emissions. Examples of these opportunities include selecting drought-tolerant trees and utilising wood residue to create wood products or generate electricity rather than producing mulch.
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CitationMcPherson, E.G.; Kendall, A.; Albers, S. 2015. Million Trees Los Angeles: Carbon dioxide sink or source? In M. Johnston; G. Perceival, eds. Proceedings of the Urban Trees Research Conference "Trees, People and the Built Environment II." Edgbaston, UK: University of Birmingham: 7-19.
Keywordscarbon footprint, climate change, tree planting, urban forestry
- A life cycle carbon dioxide inventory of the Million Trees Los Angeles program
- Monitoring Million Trees LA: Tree performance during the early years and future benefits
- Forests and carbon storage
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