Over the study period there were significant shifts in tree types,
with an increase in deciduous tree species. Deciduous species
shed their leaves in the cooler months and provide shade in the
hotter summer months and thus are functionally different than
evergreen species. Such changes in the availability of functional
types may affect the structure of the urban forest of Los Angeles, as old and diseased trees will likely be replaced by the tree
species now available Such a change may also affect the ecosystem
services provided. For example, while research is increasingly
showing that trees do little to sequester carbon in cities relative
to the amount of carbon generated in fossil fuel combustion, and
there is little evidence to date that trees improve air quality, trees do mitigate outdoor heat fluxes through outdoor shading and evapotranspiration