Wood chip pesticide residues

Hello everyone!

I tried doing some googling but unfortunately there is t much on this topic. I leave in a very windy area, farmers often plant wind blocks to reduce wind erosion.
There is a large pile of free wood chips, a mix of poplar and cottonwood. These trees were once used as a windbreak for a hops field. Should I be worried about pesticide residues in the chips?

Ashton Soete wrote:Hello everyone!

I tried doing some googling but unfortunately there is t much on this topic. I leave in a very windy area, farmers often plant wind blocks to reduce wind erosion.
There is a large pile of free wood chips, a mix of poplar and cottonwood. These trees were once used as a windbreak for a hops field. Should I be worried about pesticide residues in the chips?

I would assume there is pesticide residue. I think that before you can decide if the free chips are worth it you should see if you can find out what pesticides they use. I know that hop farmers deal with a lot of fungal pathogens but I don't know what compounds they typically use. I tend to think that the benefits of chips out weigh most contamination concerns but its ultimately a personal decision

Hi Ashton, welcome to Permies!

Ashton Soete wrote: Should I be worried about pesticide residues in the chips?

Excellent question, and I wouldn't worry about it, and here's why. Wood chips are are a beacon and magnet for fungal life to come and live, and fungus including but not limited to mushrooms, wild or intentionally inoculated, are incredibly good at breaking down man made toxic chemicals into innocuous lesser compounds and even individual atomic elements. There are good people out there doing incredible things with mushrooms called mycoremediation, where they use mushrooms to clean up things such as soils at a toxic site. I believe that as fungus breaks down those wood chips into a beautiful soft and crumbly black mass in a few short years, they will also break down any chemicals as well, yielding an end result that I would readily use in my beyond organic garden. Hope this helps you make a decision.

Thank you!! This is helpful. I’ll be sure to go load up then it’s mostly going to be used in pathways right now so shouldn’t have to worry very much about residues.

The one class of pesticides that has a sinister long half-life is the aminopyralids, which come under many different names. They do not kill grasses but kill broadleaf plants, so they are often found contaminating hay and straw. Very unlikely in trees or hops, and supposedly not approved in the US for ornamental or home plantings so unlikely in grass clippings though not inconceivable there. As far as I've heard, all the other pesticides and herbicides degrade pretty well by composting, time, moisture, sunlight, and /or fungal activity. However, I don't know what anti-fungal compounds can do. My personal guess would be to ask the people who were managing the trees and the land what was used, look it up myself, and then if there was anything dubious, pile it up and encourage composting and fungal activity for a year or so before spreading it. (Except if aminopyralids had been used, I wouldn't allow it anywhere near my land). If you are planning on organic certification you have to be a lot more careful though.

Well I’d say I made out like a bandit today! Was able to find about 20 bags of leaves, plus tons more I couldn’t grab today but will go back for.
The wood chips are really nice. They were actually used as a privacy screen between properties, they ran perpendicular to the hops field a hood 150 feet up wind. The chips had a lot of mycelium and a bunch of JUICY earthworms in it, so I’m confident it’s safe. Will be going back for a lot more in the coming weeks.

Other than orchard trees (fruit, nuts), trees are rarely sprayed.  If they were sprayed, it would be on the leaves, and those break down the quickest and are actually a small percentage of the biomass.  The wood itself forms the bulk of the pile, and that interior wood would not have any spray on it, nor would those chemicals be sucked up into the heart of the tree through the vascular system of the plant.

You should be just fine.  What little residue that might be on that tree will be quickly remediated by the fungi that colonize the chips.