The Impacts of Leaked Natural Gas on the Integrity of Urban Street Trees
Abstract
Over 50% of Massachusetts households and businesses get their energy from natural gas via distribution pipelines that run underneath city streets. In cities such as Boston, these pipes can be more than 100 years old, made of leak-prone materials such as cast iron, wrought iron mains, and degradable steel service lines. As a result, natural gas intended for customers leaks into the surrounding environment. As natural gas, consisting primarily of methane, leaks, it moves vertically and horizontally into the soils surrounding the leak causing significant damage to vegetation and soils. When methane is introduced at high volumes to soil, root asphyxiation can occur and result in the damage or death of the roots in the contaminated area. In an effort to better understand the effects of leaked gas on vegetation, we focused on the impacts of leaked gas on urban street trees. We performed a series of statistical and spatial analyses across four MA municipalities to test the impact of gas leaks on the status of trees using a unique longitudinal database of impacted gassed trees. We utilized municipality arborist data and the location of reported gas leaks to test for spatial autocorrelation and significant differences in tree health between gassed and healthy trees. We analyzed the effects of patching and repairing the leak and searched for patterns of tree damage across the municipalities using supervised neural networks. Results from this study conclude that there are significant differences between healthy and gassed trees and there is a statistically significant relationship between tree health, gas leak grades, and proximity of a tree to a leak. This study has implications for urban planners and arborists looking to strategically plant new trees, as well as avoid tree death due to failing gas infrastructure.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2019
- Bibcode:
- 2019AGUFM.H13I1810W
- Keywords:
-
- 0412 Biogeochemical kinetics and reaction modeling;
- BIOGEOSCIENCES;
- 0414 Biogeochemical cycles;
- processes;
- and modeling;
- BIOGEOSCIENCES;
- 1871 Surface water quality;
- HYDROLOGY;
- 1880 Water management;
- HYDROLOGY