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Urban Wood Waste

July 12, 2019

Announcer: Farm and Family is a production of the Mississippi State University Extension Service.

Amy Myers: Today, we're talking about urban wood waste. Hello, I'm Amy Taylor Myers and welcome to Farm and Family. Today, we're speaking with Jason Gordon, Mississippi State University Extension Assistant Professor. So Jason, what exactly is urban wood waste?

Jason Gordon: Well Amy, urban wood waste is also known as wood residue from urban areas, from cities and towns, and that's what's left after high risk trees, including those that are diseased or damaged, have been pruned or removed, such as after storms. So wood waste will include tree limps, stumps, and anything woody from the tree. One study has found that, on average, over 200 million cubic yards of organic residues are generated from urban landscapes each year and, of these, about 15% are unshaped logs that contain an estimated 3.8 billion board feet of lumber. That's a lot. Removal costs can add up very quickly and sometimes run into several million of dollars depending on the size of the city, particularly after a storm or a bad outbreak of a disease like emerald ash borer or dutch elm disease.

Amy Myers: Yes, that does sound pretty serious. Now, what happens to the wood?

Jason Gordon: Well, this is the problem. Unfortunately, it often ends up in landfills where it ends up costing taxpayers even more money in the long term because it takes up so much room and decays very slowly. Landscape residues have been found to make up as much as 35% of waste generated by some communities. But through careful planning and policy decisions, more affordable solutions are available.

Amy Myers: And what are some of these options?

Jason Gordon: Well, cities can use this wood waste on small scales or large scales. There's a recent article published by the USDA Forest Products Laboratory in Wisconsin about a program in Kenosha, Wisconsin that is utilizing the wood waste left from emerald ashe borer, which is an insect that was imported from Asia, and has killed all the ash trees in these areas, in the lake states and up north. A cut to tree length harvester, which is a type of machine, is removing 5400 trees that has been killed by the ash borer. Despite the scale of the operation, the price of removal is relatively little, only $13 per tree, which means the city pays $13 per tree for removal, which is a really good price. Like any forestry operation, the opportunity to remove the trees was presented to the forest products industry with a winning bid going to a local logger.

Recovered wood is then going to local forest products companies in the area, and, in the meantime, the city is conducting workshops to teach the public about the operation and so that the public can see these methods that are employed and understand what's going on. The project demonstrates the effectiveness of forest to market supply chain thinking with similar efforts used in places like western states where it's really important to clean up these trees that might be impacted by fires, those big western fires that happen out west.

Amy Myers: So is the practice of urban tree utilization always worthwhile economically?

Jason Gordon: Well, not always, but there is another documented case where the sale of urban trees to a local mill was four times the trucking costs for pulp wood. In another case, cities have offset storm damage tree removal by selling firewood, pulp. They can sell saw logs, wood chips and many other products. There are many cases of municipalities using urban wood waste to generate heat in municipal buildings as well. In fact, that's one of the most common uses for urban wood waste, besides chips for landscaping. One analysis of costs and financial returns found that energy conversion was an economically more attractive alternative than land filling. St Paul, Minnesota stands out among large cities in this and they use around 250 metric tons of wood annually as an energy and heat source for downtown buildings, usually public buildings and around 25 megawatts of electricity, just from their urban wood waste.

An analysis found that it would be possible for 57 similar sized plants to produce bioenergy across the United States.

Amy Myers: So Jason, if we wanted to go to somewhere for more information, could we go to our Mississippi State University County Extension Office or the Forestry Commission Office?

Jason Gordon: That's always a great place to go and also is a great place to find more information.

Amy Myers: Thank you so much. Today, we've been speaking with Jason Gordon, Mississippi State University Extension Assistant Forestry Professor. I'm Amy Taylor Myers and this has been Farm and Family. Have a great day.

Announcer: Farm and Family is a production of the Mississippi State University Extension Service. 

Department: Forestry

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