I read the other day a very interesting paper on the possibility of using roadside vegetation as carbon sink.
The study was carried out through GIS techniques and two regions were considered. A set of equations was used to estimate the rate of occupancy over the study areas, as well as amounts of fixed C under the above scenarios. The authors say the average occupancy rate was 0.06%. The simulation showed a higher potential for C sequestration in scenario 2, being the estimated amounts of CO2 sequestered from the atmosphere per km of roadside: 131 tons of CO2 km-1 of highway to native species and 655 tons of CO2 km-1 of highway for exotic species (over period of 10 years for both estimates). The authors claim that it is possible to predict the very high potential for C sequestration if managers and planners consider roadside as area for afforestation.
Roadside vegetation: estimation and potential for carbon sequestration
Braga Alves C , Alves SH
Journal of Biogeosciences and Forestry