Basis For Future Methodological Development

Gaps in this methodology exist because sufficient data are not available to quantify all of the pools and fluxes of greenhouse gases in settlements. Obvious gaps include:

• Methodology for estimating emissions of non-CO2 greenhouse gases (N2O and CH4);

• Detailed methodology to account for carbon stocks other than live biomass and soils (specifically, dead wood and litter);

• Discussion of carbon stocks and fluxes from turfgrass and turf management;

• Discussion of carbon stocks and fluxes from gardens and other herbaceous plants; and

• A generalized methodology to account for different classes of settled lands, with different amounts of woody and non-woody vegetation and different types of management.

Non-CO2 greenhouse gases. While some evidence exists to support the idea that nitrous oxide fluxes may be enhanced in urban areas relative to the native condition (Kaye et al, 2004), this result likely depends on the native condition (i.e., the climate and region in which the settlement is located) and the management regime typically applied in that settled area. Additional data are required before conclusions about the impact of settlement on non-CO2 greenhouse gas fluxes can be drawn.

Dead wood and litter. Dead wood is a class variously composed of fallen or pruned branches or trees, or dead standing trees not yet replaced with live individuals. This dead wood may be burned or disposed of as solid waste, used for composting, left to decay either in-site or off-site. This material is treated in this methodology as a loss from the live biomass term. Because dead wood is likely to be carried off-site in settlements (rather than left on-site to decay as in forests), a more detailed methodology developed in the future might account for the proportion of dead wood taken to landfills, disposed of in compost piles, burned, or left on-site to decay. The portion taken to landfills or composted might be treated as harvested wood products (HWP) or as waste, both of which are treated in other sections of the Guidelines.

Turfgrass and turf management. Turfgrass biomass consists of roots, stubble, thatch, and above-ground components. Though estimates of turfgrass productivity have been published (Falk, 1976; Falk, 1980; Qian et al., 2003), grass decomposes quickly and there is little information about the overall accumulation of biomass in the longer-lived components of turf biomass. Turfgrass allocation to the above-ground and below-ground components also depends on the management and mowing regime. Because of the lack of generalizable information on this topic, as well as the lack of activity data quantifying the area covered by turfgrass in settlements, there is currently no detailed methodology describing carbon removed by turf systems. A more detailed methodology would require additional information on turf productivity, turfgrass turnover, and allocation to different plant components as it varies with management regime. Of course, the activity data required to implement this methodology would include information on management regimes and the proportion of settlements covered by turfgrass.

Gardens and other herbaceous plants. Similar to the situation with turfgrass, information does not exist describing the annual biomass accumulation and allocation of garden plants to different above-ground and below-ground parts. Similarly, information is not available describing the variation in plant productivity with management regime. Activity data required to implement a more detailed methodology would include information on management regimes and the proportion of settlement area covered by this type of vegetation. These are mainly garden plants, so sampling them in private gardens presents the additional problem of their likely disturbance and consequent denial of access to them (cf. Jo and McPherson, 1995).

Land classes. A more detailed methodology would benefit from a consistent set of definitions of land classes within settlements, that could be applied to any country regardless of its climate, native vegetation, or typical settlement regime. This would make settlements parallel to other land uses - Forest Land, Grassland, Cropland,

Wetlands - which are easily defined based on a set of measurable and objective parameters. Some research has been applied in this direction (Theobald, 2004), but current classifications are inconsistent. While the rate of carbon sequestration per unit of tree crown cover is fairly consistent, for example, the overall rate of carbon storage per unit of settlement area depends entirely on the relative amounts of tree and turfgrass cover within that settlement. This land classification would be part of the set of activity data collected by countries, and the detailed methodology could be developed and applied consistently based on those land cover data. This type of land-use classification would also enable countries to account for changes in carbon storage resulting from management changes within areas broadly classified as settlements. For example, when vacant plots are developed, the adventitious vegetation remaining in the non-built areas might be replaced with landscape species differing in ability to store carbon.

References

Akbari, H. (2002). Shade trees reduce building energy use and CO2 emissions from power plants. Environmental Pollution 116:S119-S124.

Armentano, T.V. and Menges, E.S. (1986). Patterns of change in the carbon balance of organic soil-wetlands of the temperate zone. Journal of Ecology 74:755-774. 1986.

Brack, C.L. (2002). Pollution mitigation and carbon sequestration by an urban forest. Environmental Pollution 116:S195-S200.

Cairns, M.A., Brown, S., Helmer, E.H. and Baumgardner, G.A. (1997). Root biomass allocation in the world's upland forests. Oecologia 111:1-11.

Crane, P. and Kinzig, A. (2005). Nature in the metropolis. Science 308:1225-1225.

Elvidge, C.D., Milesi, C., Dietz, J.B., Tuttle, B.T., Sutton, P.C., Nemani, R. and Vogelmann, J.E. (2004). U.S. constructed area approaches the size of Ohio. EOS - Transactions of the American Geophysical Union 85:233-234.

Falk, J. (1980). The primary productivity of lawns in a temperate environment. Journal of Applied Ecology 17:689-696.

Falk, J.H. (1976). Energetics of a suburban lawn ecosystem. Ecology 57:141-150.

Gallo, K.P., Elvidge, C.D., Yang, L. and Reed, B.C. (2004). Trends in night-time city lights and vegetation indices associated with urbanization within the conterminous USA. International Journal Of Remote Sensing 25:2003-2007.

Goldman, M.B., Groffman, P.M., Pouyat, R.V., McDonnell, M.J. and Pickett, S.T.A. (1995). CH4 uptake and N availability in forest soils along an urban to rural gradient. Soil Biology and Biochemistry 27:281-286.

Gregg, J.W., Jones, C.G. and Dawson, T.E. (2003). Urbanization effects on tree growth in the vicinity of New York City. Nature 424:183-187.

Idso, C., Idso, S. and Balling, R.J. (1998). The urban CO2 dome of Phoenix, Arizona. Physical Geography 19:95-108.

Idso, C., Idso, S. and Balling, R.J. (2001). An intensive two-week study of an urban CO2 dome. Atmospheric Environment 35:995-1000.

Imhoff, M., Tucker, C., Lawrence, W. and Stutzer, D. (2000). The use of multisource satellite and geospatial data to study the effect of urbanization on primary productivity in the United States. IEEE Transactions on Geoscience and Remote Sensing 38:2549-2556.

IPCC (1997). Revised 1996 IPCC Guidelines for National Greenhouse Inventories. Houghton J.T., Meira Filho L.G., Lim B., Treanton K., Mamaty I., Bonduki Y., Griggs D.J. Callander B.A. (Eds). Intergovernmental Panel on Climate Change (IPCC), IPCC/OECD/IEA, Paris, France.

IPCC (2003). Good Practice Guidance for Land Use, Land-Use Change and Forestry. Penman J., Gytarsky M., Hiraishi T., Krug, T., Kruger D., Pipatti R., Buendia L., Miwa K., Ngara T., Tanabe K., Wagner F. (Eds).Intergovernmental Panel on Climate Change (IPCC), IPCC/IGES, Hayama, Japan.

Jenkins, J., Chojnacky, D., Heath, L. and Birdsey, R. (2004). Comprehensive database of diameter-based biomass regressions for North American tree species. General Technical Report NE-, USDA Forest Service Northeastern Research Station, Newtown Square, PA.

Jo, H. (2002). Impacts of urban greenspace on offsetting carbon emissions for middle Korea. Journal of Environmental Management 64:115-126.

Jo, H. and McPherson, E. (1995). Carbon storage and flux in urban residential greenspace. Journal of Environmental Management 45:109-133.

Kaye, J., Burke, I., Mosier, A. and Guerschman, J. (2004). Methane and nitrous oxide fluxes from urban soils to the atmosphere. Ecological Applications 14:975-981.

Kaye, J.P., McCulley, R.L. and Burke, I.C. (2005). Carbon fluxes, nitrogen cycling, and soil microbial communities in adjacent urban, native and agricultural ecosystems. Global Change Biology 11:575-587.

Koerner, B., and Klopatek, J. (2002). Anthropogenic and natural CO2 emission sources in an arid urban environment. Environmental Pollution 116:S45-S51.

Kuchler, A. (1969). Potential natural vegetation. US Geological Survey Map, Sheet 90, Washington, DC.

Milesi, C., Elvidge, C.D., Nemani, R.R., and Running, S.W. (2003). Assessing the impact of urban land development on net primary productivity in the southeastern United States. Remote Sensing Of Environment 86:401-410.

Nowak, D. (1996). Estimating leaf area and leaf biomass of open-grown deciduous urban trees. Forest Science 42:504-507.

Nowak, D. and Crane, D. (2002). Carbon storage and sequestration by urban trees in the United States.

Environmental Pollution 116:381-389.

Nowak, D., Crane, D.E., Stevens, J.C. and Ibarra, M. (2002). Brooklyn's urban forest. General Technical Report NE-290, USDA Forest Service Northeastern Research Station, Newtown Square, PA.

Nowak, D.J., Rowntree, R.A., McPherson, E.G., Sisinni, S.M., Kerkmann, E.R. and Stevens, J.C. (1996). Measuring and analyzing urban tree cover. Landscape and Urban Planning 36:49-57.

Pouyat, R. and Carreiro, M. (2003). Controls on mass loss and nitrogen dynamics of oak leaf litter along an urban-rural land-use gradient. Oecologia 135:288-298.

Pouyat, R., Groffman, P., Yesilonis, I. and Hernandez, L. (2002). Soil carbon pools and fluxes in urban ecosystems. Environmental Pollution 116:S107-S118.

Pouyat, R.V., McDonnell, M.J. and Pickett, S.T.A. (1995). Soil characteristics of oak stands along an urban-rural land-use gradient. Journal of Environmental Quality 24:516-526.

Qian, Y., Bandaranayake, W., Parton, W., Mecham, B., Harivandi, M. and Mosier, A. (2003). Long-term effects of clipping and nitrogen management in turfgrass on soil organic carbon and nitrogen dynamics: The CENTURY model simulation. Journal of Environmental Quality 32:1695-1700.

Qian, Y. and Follett, R. (2002). Assessing soil carbon sequestration in turfgrass systems using long-term soil testing data. Agronomy Journal 94:930-935.

Raturi, S., Islam, K.R., Carroll, M.J. and Hill, R.L. (2004). Thatch and soil characteristics of cool- and warm-season turfgrasses. Communications In Soil Science And Plant Analysis 35:2161-2176.

Smith, W.B. and Brand, G.J. (1983). Allometric biomass equations for 98 species of herbs, shrubs, and small trees. Research Note NC-299, USDA Forest Service North Central Forest Experiment Station, St. Paul, MN.

Theobald, D.M. (2004). Placing exurban land-use change in a human modification framework. Frontiers in Ecology and the Environment 2:139-144.

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