{"id":180503,"date":"2020-10-28T13:54:19","date_gmt":"2020-10-28T17:54:19","guid":{"rendered":"https:\/\/www.bu.edu\/sph\/?post_type=bu-article&#038;p=180503"},"modified":"2020-10-28T14:10:14","modified_gmt":"2020-10-28T18:10:14","slug":"dead-urban-trees-point-to-gas-leaks","status":"publish","type":"bu-article","link":"https:\/\/www.bu.edu\/sph\/news\/articles\/2020\/dead-urban-trees-point-to-gas-leaks\/","title":{"rendered":"Dead Urban Trees Point to Gas Leaks"},"content":{"rendered":"<!--Moved from content banner on old site-->\n<div class=\"videoWrapper\" style=\"position: relative;padding-bottom: 56.25%; \/* 16:9 *\/height: 0;\"><iframe loading=\"lazy\" width=\"855\" height=\"481\" src=\"http:\/\/www.bu.edu\/buniverse\/interface\/embed\/embed.html?v=FdvPC0\" style=\"position: absolute;top: 0;left: 0;width: 100%;height: 100%;frameborder=\"0\" scrolling=\"no\" allowfullscreen> <\/iframe><\/div>\n\n\n<p>As a public health researcher, <a href=\"https:\/\/www.bu.edu\/sph\/profile\/madeleine-scammell\/\">Madeleine Scammell<\/a> has read plenty of case-control studies\u2014which identify sick or deceased people (cases) and then compare them with similar but healthy people (controls) to figure out what exposures may be causing the disease.<\/p>\n\n\n\n<p>But Scammell, associate professor of environmental health at the School of Public Health, had never designed and conducted a case-control study until recently. And instead of studying people, she studied trees.<\/p>\n\n\n\n<p>The resulting study, <a href=\"https:\/\/www.sciencedirect.com\/science\/article\/pii\/S0269749119376717\" target=\"_blank\" rel=\"noreferrer noopener\">published in the journal <em>Environmental Pollution<\/em><\/a>, found that dead urban trees were 30 times more likely to have detectable methane in their soil than healthy control trees. Higher levels of methane closer to the street pointed to leaky gas lines\u2014making urban trees a potentially valuable way to detect leaks that could also be harming human health, whether through slow exposure or <a href=\"https:\/\/www.nytimes.com\/2020\/02\/26\/us\/columbia-gas-massachusetts.html\" target=\"_blank\" rel=\"noreferrer noopener\">catastrophic explosions<\/a>.<\/p>\n\n\n\n<p>\u201cMethane is just what we measured, but the gas that&#8217;s now being used to heat people&#8217;s homes and fuel our appliances has other volatile compounds,\u201d Scammell says.<\/p>\n\n\n\n<p>\u201cMethane, however, is a potent greenhouse gas and a significant contributor to climate change.\u201d<\/p>\n\n\n\n<p>Massachusetts has one of the oldest gas pipeline systems in the country. Many of the pipes are made of now-degrading iron, Scammell says, and \u201cproactively finding and repairing gas leaks does not seem to have been a priority for utilities until recently.\u201d<\/p>\n\n\n\n<p>The first-of-its-kind study suggests dead urban tree might help point to a leak.<\/p>\n\n\n\n<p>Scammell is a longtime resident of Chelsea, a small city just north of Boston. \u201cIn Chelsea, people keep planting trees and replacing them, but that&#8217;s at a great cost,\u201d she says\u2014upwards of $50,000 a year. \u201cIt\u2019s not chump change.\u201d<\/p>\n\n\n\n<p>So, Scammell and the Chelsea environmental justice organization <a href=\"http:\/\/www.greenrootschelsea.org\" target=\"_blank\" rel=\"noreferrer noopener\">GreenRoots<\/a> decided to look for \u201cthe, no pun intended, root cause.\u201d<\/p>\n\n\n\n<p><em>(Read about Scammell and Greenroots\u2019 work measuring and responding to COVID in Chelsea, the epicenter of the commonwealth\u2019s outbreak, <a href=\"https:\/\/www.bu.edu\/sph\/2020\/04\/30\/researchers-aid-chelsea-epicenter-of-ma-covid-19-outbreak\/\">here<\/a>.)<\/em><\/p>\n\n\n\n<p>Two summers ago, Scammell and then-student Claire Schollaert (SPH\u201919) took on the project with Bob Ackley of Gas Safety, Inc. and retired Chelsea arborist Andy DeSantis. At first, they planned to do health assessments on a sample of Chelsea trees, dead and alive, healthy and ailing, and look for patterns in tree health and soil concentrations of methane and oxygen. GreenRoots youth did tree health assessments.<\/p>\n\n\n\n<p>\u201cBut,\u201d Scammell says, \u201cour ascertainment of trees and poor health was not great, and that was partly due to the fact that we are not arborists trained to recognize the unique signs of gas leaks damage. Andy [DeSantis] helped us understand this.\u201d<\/p>\n\n\n\n<p>However, they were determined, and continued the search last summer.<\/p>\n\n\n\n<p>\u201cThen, I passed one tree that was definitely dead,\u201d Scammell says. \u201cIt was a young tree in a stretch of trees planted at the same time, and it wasn\u2019t dead the prior summer. It was so undeniably dead, and there was no reason for it to be dead as far as I could tell.\u201d<\/p>\n\n\n\n<p>She reached out to Schollaert and Ackley, who were out separately measuring soil gas concentrations. \u201cDo me a favor,\u201d she said. \u201cJust check the soil in this tree.\u201d They did, and found the highest methane concentrations of any tree they had checked so far.<\/p>\n\n\n\n<p>The researchers re-designed their study as a case-control, looking just at living versus dead trees. \u201cAndy went and confirmed all the dead trees were really dead, and that there was no obvious reason for them to have died from other causes,\u201d Scammell says. For example, power lines can be a big stressor for trees, so they eliminated trees directly under power lines from the study.<\/p>\n\n\n\n<p>With 84 dead trees and 97 living trees, and soil methane and oxygen measurements from four spots around each, they found that methane levels were much higher under dead trees, likely pushing out the soil oxygen that helps keep trees healthy.<\/p>\n\n\n\n<p>\u201cI&#8217;ve heard anecdotally that a lot of people who work for the gas utilities know very well that a gas leak will kill a tree,\u201d Scammell says, \u201cand have seen great big, old growth trees in suburban neighborhoods just drastically decline in health and fall, and they say, \u2018Oh, that&#8217;s a gas leak.\u2019\u201d<\/p>\n\n\n\n<p>But the hard evidence has been basically non-existent, until now.<\/p>\n\n\n\n<p>Instead of wasting money taking out gas-killed trees and planting new, equally doomed ones, Scammell says, \u201cinvest in either fixing the old infrastructure, or developing new infrastructure that&#8217;s not reliant on transporting flammable gas under our roads and into homes.\u201d<\/p>\n\n\n\n<p><a href=\"https:\/\/www.bu.edu\/sph\/profile\/erin-polka\/\">Erin Polka<\/a>, a research assistant in the Department of Environmental Health, also worked on this study.<\/p>\n\n\n\n<p>\u2014<a href=\"mailto:msamu@bu.edu\" target=\"_blank\" rel=\"noreferrer noopener\"><em>Michelle Samuels<\/em><\/a><\/p>\n","protected":false},"excerpt":{"rendered":"<p>As a public health researcher, Madeleine Scammell has read plenty of case-control studies\u2014which identify sick or deceased people (cases) and then compare them with similar but healthy people (controls) to figure out what exposures may be causing the disease. But Scammell, associate professor of environmental health at the School of Public Health, had never designed [&hellip;]<\/p>\n","protected":false},"author":14430,"featured_media":180507,"comment_status":"closed","ping_status":"closed","template":"","meta":{"bu_prepress_billboard":"","_bu_prepress_primary_term":"urban health","_bu_prepress_primary_term_manual":""},"tags":[2400,1086,3162,2418],"bu-publication":[3516],"sphnews-article-category":[3519,3529,3531,3540],"sphnews-topic":[],"bu_edition":[],"media_type":[],"profile_tax":[324],"_links":{"self":[{"href":"https:\/\/www.bu.edu\/sph\/wp-json\/wp\/v2\/bu-article\/180503"}],"collection":[{"href":"https:\/\/www.bu.edu\/sph\/wp-json\/wp\/v2\/bu-article"}],"about":[{"href":"https:\/\/www.bu.edu\/sph\/wp-json\/wp\/v2\/types\/bu-article"}],"author":[{"embeddable":true,"href":"https:\/\/www.bu.edu\/sph\/wp-json\/wp\/v2\/users\/14430"}],"replies":[{"embeddable":true,"href":"https:\/\/www.bu.edu\/sph\/wp-json\/wp\/v2\/comments?post=180503"}],"version-history":[{"count":1,"href":"https:\/\/www.bu.edu\/sph\/wp-json\/wp\/v2\/bu-article\/180503\/revisions"}],"predecessor-version":[{"id":180505,"href":"https:\/\/www.bu.edu\/sph\/wp-json\/wp\/v2\/bu-article\/180503\/revisions\/180505"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.bu.edu\/sph\/wp-json\/wp\/v2\/media\/180507"}],"wp:attachment":[{"href":"https:\/\/www.bu.edu\/sph\/wp-json\/wp\/v2\/media?parent=180503"}],"wp:term":[{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.bu.edu\/sph\/wp-json\/wp\/v2\/tags?post=180503"},{"taxonomy":"bu-publication","embeddable":true,"href":"https:\/\/www.bu.edu\/sph\/wp-json\/wp\/v2\/bu-publication?post=180503"},{"taxonomy":"sphnews-article-category","embeddable":true,"href":"https:\/\/www.bu.edu\/sph\/wp-json\/wp\/v2\/sphnews-article-category?post=180503"},{"taxonomy":"sphnews-topic","embeddable":true,"href":"https:\/\/www.bu.edu\/sph\/wp-json\/wp\/v2\/sphnews-topic?post=180503"},{"taxonomy":"bu_edition","embeddable":true,"href":"https:\/\/www.bu.edu\/sph\/wp-json\/wp\/v2\/bu_edition?post=180503"},{"taxonomy":"media_type","embeddable":true,"href":"https:\/\/www.bu.edu\/sph\/wp-json\/wp\/v2\/media_type?post=180503"},{"taxonomy":"profile_tax","embeddable":true,"href":"https:\/\/www.bu.edu\/sph\/wp-json\/wp\/v2\/profile_tax?post=180503"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}