Forests are quietly absorbing livestock emissions – study
Forests have been munching on the countrys trickiest climate problem : planet-heating methane produced by livestock and landfill. Scion and University of Lincoln scientists are studying how microbes living in the forest floor suck in and eat methane, destroying the potent greenhouse gas. Early results showed the methane-munching rate could be even higher than expected. Exotic forests are absorbing methane which contributed 43% of the countrys emissions in 2021. But Scion senior scientist Steve Wakelin warned the natural process was not a get out of jail free card. Farmer and rural groups have protested mass pine planting. The National party recently pledged to ban the conversion of entire farms into these new forests. But ultimately owners could eventually be able to claim credit for the methane absorbed. The vast majority of methane is burped by livestock such as cows, sheep and deer as they digest grass. Landfills produce about 8% of methane emissions. From where it originates, the gas mixes in the air like a drop of ink into the bathwater, Wakelin said. When methane enters forests, it encounters tiny soil microbes that can use it as food breaking it down as a source of energy. Overseas research had discovered these methane-munching microbes in the forest floor. But the joint research project is one of the first to measure the behaviour of these bugs and the concentration of methane in Aotearoas forest ecosystems. The researchers, led by Kathryn Walker, have set up methane testing stations in Kaingaroa Forest the countrys largest pine plantation and bush in Orton Bradley park and the McLeans Island regional reserve near Christchurch. The three offer different soil types, Wakelin said, from the moist, loamy Orton Bradley park to McLeans Islands gravelly, coarse, gnarly ground. To complicate matters, other bugs in the soil release methane to the air while other flexible species can switch from gas consumption to production, Wakelin added. Activity changes over the year. In theory, microbes methane consumption slows in the winter when the soil is cold and damp. For that reason, Wakelin and his team are tracking methane levels over 12 months. On the whole, its likely forests absorb more gas than they produce, he said. Early data in summer provided a surprising finding: Wakelin expected little change during this dry time. We got this really strong methane consumption data... We were like: Woah. The team will complete its research early next year. The study will help quantify how much of the countrys methane production is being offset by forests. Ultimately, foresters could cash in on this environmental service. New forests are already eligible for carbon credits for the carbon dioxide they absorb, with the credits sold to individuals and businesses. Could forests one day be eligible for methane offsets as well? It is a possibility, down the track, Wakelin said. Global climate principles mean governments count the negative and positive impacts of human activities (so we count the methane released by livestock farms but not the carbon emitted from volcanic eruptions, for example). As such, New Zealand is unlikely to ever claim the work of long-established forests. But the methane absorbed by plantation forests could be counted, if the science stacked up and became recognised internationally. With livestock farmers and foresters often at loggerheads, Wakelin hoped the research might show harmony between industries was possible, and desirable. Were all in this together. Our weekly email newsletter, by the Forever Project's Olivia Wannan, rounds up the latest climate events. Sign up here .