Here's what Linda Chalker-Scott has written about this subject:
http://www.puyallup.wsu.edu/~linda chalker-scott/horticultural myths_files/Myths/magazine pdfs/Woodchips.pdf

Here is a link that might be useful: Wood Chip Mulch by Linda Chalker-Scott

Thanks, brandon7. That is an excellent article, and it relieves the worries I had about using this particular pile of wood chips for mulch.

Thousands upon thousands of people use wood chips as their mulch of choice. We have an an agreement with an aborist we know to drop off his chips in our driveway a couple of times a year, if he's working somewhere in the neighborhood.

It won't last as long as the pine BARK, but the fact that it decomposes into the soil is a totally good thing.

The linked extension publication only touches on the big POSSIBLE drawback I see very, very briefly.

If it contained black walnut, it could be quite damaging to certain plants. Some things do have a very strong reaction to walnut in fairly low levels. And it might be hard to know if you're getting it unless the chips were extremely fresh and you could ID from the aroma and by visual ID of the fragments.

Just something to consider. The odds are slim that it would be a big deal, but it could happen.

I agree there are very few drawbacks to using this kind of woodchip mulch in the landscape. However:

The "high quality stuff you can get in bags at the big box stores" is usually anything but high quality. More and more it consists of ground up construction and other debris dyed to look as if it's naturally aged. One national brand says something like "natural forest product." In other words, wood, but you have no idea what kind, etc.

For rhododendrons and other ericaceous plants, real conifer bark mulch is still the best used either as mulch or as a soil conditioner. Sap wood from hard wood trees can raise soil pH and breaks down much faster than bark.

denn brings up a very minor issue... note his use of POSSIBLE ...

the stuff in bags is BETTER.. only in its ease of transport and consistency ...

the best time to get it.. is when the trees are bare ... this way you get all wood.. too much greenery can be a PIA ...

and best of all.. free is free ...

the only stuff rejected by me.. is imprelis damaged trees ... and back int eh day.. EAB ash ....

and stuff.. more like pulverized.. by guys who dont keep their grinders properly sharpened ... which usually leads to lots of long sticks in it ...

IMHO ... quality really matters ... i would shop it out.. and take.. only the best stuff ... in other words.. i wouldnt wait until i have to have it ... i would visit as often as possible.. and CHOOSE higher grade stuff ....

if you can not avoid the leaves.. then accumulate a pile in your yard.. and leave it stand for a season.. so the leaves decompose ...

again.. free is free ...

ken

Yes, I know what you mean akamainegrower. I purchased three bags of cedar mulch from a Wal-Mart. It said it was "cedar" mulch, but I have found bits of blue dyed construction wood, ply-wood, and even press board in it along with the cedar wood. I am curious...according to federal regulations, how much cedar wood is actually required to be in a bag of mulch advertised as "cedar mulch"? Does anyone know?
Thank you, Denn & Ken. Those are good points. I am going to try to take from the lower part of pile of wood chips where the leaves are all brown and mostly pulverized. They do a good job of grinding it. Most of the chips are no more than 1" cubed.
I believe that 90% of these wood chips are from silver maple and elm trees, since those are the predominant trees in my city. The other 10% are made up mostly of bald cypress, oak, and cotton wood and a little bit of Tree of Heaven.
And I am mulching around lantanas, mums, and Weigela shrubs, so if there are any Black Walnut chips, I would think, they shouldn't present any problems.

There is a mulch forum, btw. Soil, compost, mulch forum.

Thanks, purple.