Grape Street Dog Park
A tree falls in an urban forest. So what? It is chipped, transported and gone. At best, it becomes furniture, art, mulch. The worst part: its carbon capture lifetime goes up in smoke.
If it’s a palm tree, Miramar Greenery won’t even take it. In any case, the city’s curbside recycling does not accept tree stumps over four feet, branches over six feet or any piece over six inches in diameter.
“End-of-life urban lumber in the San Diego area is mostly wasted,” according to Lumbercycle, a National City nonprofit sawmill that turns fallen trees into lumber and other items.
“The majority goes to landfills or is ground up and used as mulch or ground cover, which disintegrates quite quickly.”
As the city begins to incorporate organic waste into its recycling ordinance, trees are barely mentioned in the discussion of landscaping scraps. But drought and disease turn many of them into urban waste wood.
According to Calrecycle, which oversees the state’s organics recycling laws, this waste consists primarily of lumber, trim, pallets, branches, stumps and whole trees from street maintenance and parks.
California’s SB 1383 has set a statewide goal of reducing organic waste by 75% from 2014 levels by 2025. In addition to food waste, organics include food scraps. landscaping and non-hazardous wood waste.
In the landfill, decaying organic matter releases methane, a super pollutant 84 times worse than carbon dioxide, into the atmosphere.
Currently, approximately 30% of residential waste that enters the Miramar landfill is recyclable green material. (In 2005, the amount was 14%, according to city records.
Besides palm trees, the city refuses to take banana trees and corals into the curbside collection because they create poor quality mulch and compost and can damage shredding machines.
For city-owned trees, San Diego contracts with West Coast Arborists, a city-owned tree maintenance contractor, among others. The contract only states that the contractor is responsible for cleaning up the debris and transporting it.
While West Coast arborists have an urban timber program that recycles many trees into raw lumber, less healthy specimens are sold as firewood or sent to landfill. “Firewood is traditionally the most common use for large branches and logs.”
The carbon released during the combustion of this wood is not taken into account in the city’s greenhouse gas emissions calculations.
Maggie McCann, Kensington resident and tree advocate, thinks a greener strategy would be to let firewood decompose underground, “because this process takes 50 to 100 years, so the carbon would be stored underground. , or released slowly over time into the atmosphere.”
The fate of most downed trees, however, is in the hands of private waste haulers, as the city does not collect large items like trees.
Lumbercycle sometimes collects logs from homeowners to donate to their program.
According to Lumbercycle, while there are more than 40 uses for tree biomass, the four that make the most economic sense for the San Diego area are lumber; wooden parts for furniture and works of art; biochar to save water and provide nutrients to the soil; and fuel pellets that generate energy for local use.
Most valuable is the trunk and large branches where most of the carbon is stored. Not all tree species are good candidates for the four product types – especially palms, due to their fibrous trunks and fronds, which goes back to the start of the zero waste loop: “the right to plant” .
Yet a post on their Facebook page shows that even downed palms can have new life.
“I tried something with a piece of palm I got from Lumbercycle. It turned out better than I expected.”