Piled densely and with green leaves mixed in with them fresh wood chips can self ignite, spontaneous combust, adding more Nitrogen (grass clippings) will only help make that happen sooner. I have taken what you have and plunked that down as a mulch, thinner layers do not let the heat build up, and have found the plants that were mulched with that appreciated it a lot.

I've only mixed the grass clippings with the wood chips in the raised bed I'm building, not in the large truckload sized pile. In the raised bed, I'm keeping it moist to speed up the initial cooking off, so it is too wet to catch fire. It was steaming this morning, but now smoking.

In the bamboo forum, I asked about the scraps of bamboo canes sprouting. Even though running bamboo will spread fast once it's established well, they said it is actually fairly difficult to propagate from cuttings.

According to this research paper by Drs. Mary Ann Rose1 and Elton Smith of Ohio State University on mulching:

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Wood chips or shavings. They have become available through utility companies and are usually not available in packaged form. Since they consist, along with sawdust, of more wood than bark, they decompose rapidly and should be supplemented with fertilizer at the rate of one pound of actual nitrogen per 1,000 square feet of mulched area.
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I have 16yards of those just delivered to my house by a local tree company. I am using them pure in my flower and shrub area.

But I am not sure if I should sprinkle the nitrogen fert. before adding the mulch or after? I think fert. for lawn are mostly N and would be ideal for this app?

Any feedback and help are appreciated.

I used to get truck loads of tree service chips. I just loved the stuff for mulching blue berries. What I did was shovel the stuff through the Super Tomahawk shredding chamber while using a 3/4" discharge screen. The resulting product was a fabulous feeding mulch that would be consumed each year.

It's fun dumping that stuff through the chipper as fast as you can shovel it and it's a better wood mulch then you can buy at any price.

captturbo, do you added nitrogen fet. as suggested by Ohio State Univ.'s paper?

Some asked about the size of the pieces of wood chips. Below is a picture of my new raised bed after I filled it up with chips. The second is a close-up after it rained this afternoon, and the bed settled down some. The close-up shows that the chips are mostly slightly bigger or slightly smaller than a quarter. The are about the same thickness as a quarter as well. Some of it has bamboo stems that are about half the diameter of a pencil and 12 to 24 inches longs. There aren't too many of these, which are sort of like stiff wheat straw. In each wheelbarrow full, I would normally find a piece the size of my hand that was about 1/4 inch thick. I would not have wanted an entire load of these big bits, but a few mixed in weren't a problem for me for the price. If it's Free, I can pick out some bits I don't like. I live on a fixed income, so the price is perhaps more important to me that it might be to other. If you had a chopper that would shred the stuff into smaller bits, it would really be grand.

Well now that it's settled down a bit, I'm going to put a single layer of newspaper, a few inches of finished leaf/grass compost, and transplant my strawberries from containers.

Since I'm using the chips as a filler in the bed below my plants, I'm going to start fertilizing them with dilute water soluble fertilizer once per week. The nutrients that wash down through the top layer should be absorbed by the chips and help their decomposition proceed. I've got almost 2 months until first frost, then I'll cover the strawberries with some pine straw until spring, when I will resume fertilizing again.

I've also used the chips to mulch around my fruit trees, blackberries, and muscadines that I'm growing in containers. It's worked great for that as well. I've got few dog paths in the backyard where my dogs aways run along the same route and keep the grass killed down. I've spread some the wood chips along their paths as well. They were a big bulky and hard to walk on at first. I watered these paths and then tamped then down by rolling a 5 gallon bucket full or dirt back and forth along the path twice. After that they were fine for walking on without tripping on bits sticking up.

Other people might not have had good experience with the chips from tree services, but I'm happy with mine. My only real problem has been that their truck was so big they could not drive up my driveway because of power lines. They had to dump the pile of wood chips in my front yard next to the street, and I've had to cart it all to my backyard where I garden. At first I used a wheelbarrow, but it didn't hold very much. Now I'm using the 100 gallon rolling trash can that my trash service supplies. It's making a lot faster work of hauling it about the yard.

Greg

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"Posted by toffee1 (My Page) on Sat, Sep 11, 10 at 18:11

captturbo, do you added nitrogen fet. as suggested by Ohio State Univ.'s paper?"

Toffee1, there is no need to add any nitrogen after you have put the tree sevice chippings through your own shredder. The machine pulverizes the material down to a size that will break down pretty fast. It makes a wonderful feeding mulch but you do have to renew it each year. If you added nitrogen you would have to renew it more often.

I was digging today in my pile of power-company wood chips. I don't have a shredder, so they didn't get a second shredding. But our power company shreds pretty nicely. My pile has mostly been under a swingset, so not treated as a compost pile, exactly!

When I dig down, the chips tend to be loose and dry in the top 2 or 3 inches, but below that they are thoroughly surrounded by white spongy fibrous fungi. It's just astonishing how it all is a springy crumbly texture down there. It definitely isn't all composted, but is visibly on its way. The chips were dumped in the spring this year, and have not gotten any special treatment (no extra waterings, no nitrogen or grass added, just piled and left to the elements).

I know this doesn't exactly answer any of your questions, but I thought it would be interesting for some to hear how the fungal decomposition is proceeding.

haha i am wondering what's the green/brown ratio in my small mountain of woodchips. I was told that it was a mixture of a few different trees. Some pine, I am sure as I can smell it, probably some oaks too. In the bay area, its still pretty warm so all the leaves were green, So I guess the green/brown mixture could be pretty ideal too.

anyways, I am excited. Just trying to decide if I should go the Ruth Stout route of 4-6" or the more common 2".

Any suggestions?

It is really difficult to know the green/brown mix ratio of different piles of wood chips since it can vary so widely. Even in my single pile, parts of it were smaller twigs and leaves, parts had lots of bamboo, and other parts are mostly wood. Even the parts that are mostly wood are not like sawdust from dried lumber, as the living wood had lots more sap and moisture. I was expecting that I would need to add quite a bit of grass clippings or other nitrogen sources to get this pile to heat up, but whenever I dig down more than a foot, it is steaming hot at over 140 F.

I was also surprised that they were inoculated with microbes to break down the material. Unlike leaves that have been raked and pick up bits of soil as you sweep them about, the chips from utility trimming were from limbs that were cut from the air and immediately blown into the truck with virtually no contact with the ground to pick up bacteria and fungi. The spores and dust in the air were enough to kick off the process by themselves.

I found the research article below interesting. It is comparing utility tree trimmings to other mulches. The shredded tree trimmings will decompose faster when used as a mulch than when put in a compost heap, because the microbes that digest the lignin in wood are more active when they get more air. The research showed that the tree trimmings decompose faster than other mulches, but they also provide more nutrients to the soil than other mulches as they decompose. The research suggests that tree trimming should be composted before being used as a mulch because the trimmings from some trees can contain some allelopathic compounds that will leach out when the trimmings are freshly cut, but the compounds dissipate quickly.

It works out fine that I'm a bit slow, since the wood chips are having the time to compost before I can get many of them moved about to where I want to use them in the yard.

Greg