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Declining Trees May Contribute to Global Warming

Reasons to Address Dead and Dying Trees

By Maureen Sexsmith-West ISA Certified Arborist

I have long understood that trees in decline or those suffering from other stresses (such as drought or topping cuts) attract a wide range of insects and diseases. Trees release pheromones that are interpreted by a wide range of insects that benefit from weakened trees. Some transport diseases that result in serious infections and decay. This often accelerates the process of decline. When the ‘host’ tree is exhausted or populations reach a threshold level, pests migrate to the next suitable tree in the neighbourhood.

Trees in an urban setting – be it boulevard/park, commercial property or private residence – all combine to make up our collective urban forest. Diseased, dead or those in decline impact all the trees in proximity by encouraging insect populations to colonize and multiply. I was doing some reading over the holidays and came across new statistics that will hopefully encourage tree owners to take a closer look at their yards. It has been understood that trees capture carbon to counteract greenhouse gases. I was surprised to learn of new research that identified that diseased trees in a forest may be a significant source of methane that causes climate change. Diseased trees however, according to a recent study by researchers at the Yale School of Forestry and Environmental Studies published in Geophysical Research Letters “Elevated Methane Concentrations in Trees of an Upland Forest”, release methane into the atmosphere. “The estimated emission rate from an upland site at the Yale forest is roughly equivalent to burning 40 gallons of gasoline per hectare of forest per year. It also has a global warming potential equivalent to 18 percent of the carbon being sequestered by these forests, reducing their climate benefit of carbon sequestration by nearly one-fifth. Diseased trees in forests may be a significant new source of methane that causes climate change. Although outwardly healthy, some older trees are being hollowed out by a common fungal infection that slowly eats through the trunk, creating conditions favorable to methane-producing microorganisms called methanogens.”

An assessment by our qualified personnel will help you identify the contributing reasons of tree decline. A plan of action can be developed to improve health and safety and to prevent movement of problems that can affect other trees in proximity. Resolve to care for your trees this year to reduce your environmental impact.


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