do chips kill trees?

[ArtB]

Had about 90 yard of alder/black cottonwood/bl maple, D fir chips and leaf/needle mulch from local trimmers/arborists(some certified) spread around on an acre in last 6 months. A few alders(avg 12 " dia), one undergrowth hemlock, a 14" dia wild cherry, and a 38" black cottonwood appear to have died this year (sprouted buds in the spring, but appear to have died). A few alders in the back die every year so not concerned about those, and this is a dry year (Seattle area). Have heard that the chips may absorb rain, thus the soil is drier than otherwise would be, exacerbating an already dry year. Any comments appreciated.

 

[M.D. Vaden]

Maybe its a trade off.

I grew up on a 2 acre lot - 1 acre landscaped, the other was wooded.

We opened a driveway for tree services to dump dozens of loads of chips.

They may have recieved the rain before it hit the ground, since I spread up to 6" deep, but I'm guessing that the chip mulch caused as much moisture to remain in the soil as what it prevented.

Whenever we removed some to put elsewhere, it was moist below.

At least in west Oregon, this is my experience.

 

[Newfie]

The chips from the certified arborists should be OK. It is probably the other chips from the "trimmers" that are causing the problem. I would suggest that the chips are mixed thoroughly to create a more homogenous mix so that your trees won't be able to detect the obvious quality difference.

What about fresh chips robbing nitrogen while they decompose? I think I heard that from JPS or JPM a while ago.

 

[Tom Dunlap]

My understanding is that there is a very small amount of N decrease. This decrease is most noticeable at a thin line at the chip/soil line, not deeper in the soil where the roots are found.

Tom

 

[Stumper]

Whether the nitrogen decrease is of any significance seems to depend on numerous factors but for what it is worth the only time I have seen trees struggling (and there was not another obvious cause besides the wood chips) the trees were new plantings which had uncomposted chips mixed into the backfill. This matches with what Tom is saying-if the chips are only on the surface the nitrogen decrease seems to be confined to the soil surface.
As far as wood chips preventing moisture penetration from rain----research has shown just the opposite. Many Soils resist water entrance when dry which encourages runoff. Furthermore a sudden cloudburst can actually cause compaction of the soil surface as the big drops pound the ground. A mulch layer helps maintain existing soil moisture easing penetration of "new" water and cushions the surface to avoid compaction. Mulch also seems to help prevent run off to a small degree in and of itself. Obviously a small amount of precipitation may not get through the mulch to the soil but even then the moistened mulch will help regulate soil temperature. Over the course of the seasons mulched soils invariably maintain a better growing environment/ more balanced moiture content and temperature fluctuations.

 

[Menchhofer]

We have used wood chips for 10-15 years and would douut they rob the soil of moisture. In fact, whenever we dig or plant in the chips the soil is always nice and moist...never dry.

The slight nitrogen decrease should not hamper the trees or plants. The larger chips (as compared to the other mulches) last longer and do not compact as much.

 

[duff]

Methinks allelopathy from the mixed chips, whether of certified or uncertified arborist origin, is a likely culprit.

In southern California I like Euc Chips under Eucs, Walnut under walnut, Pecan under Pecan, Ailanthus there is no good place for...like that. From whence they came, where possible.
I intercept free loads wherever found (saving them from fill-layer-duty at the landfill, at cost of $18/ton).

I grill the crew on species content, inspect and smell representative handfuls and do my best to avoid the massive load of Euc associated with our psyllid festerance. I've read that pine can be allelopathic also, and with so much pine mulch on the verge of being generated out of the bark beetle festerance to the slight east, that'll be a KEY chip to avoid in the next decade.

Every area has it's common allelopaths, I suppose.

I also carefully hoard oak mulch for my own 3 beauties and for clients whose regular mow crews tend by scratching and blowing away every last stitch of it, with astonishing attention to detail. Local oak duff has proven to be a valuable piece of my business.

 

[Dan F]

Since I haven't seen it asked yet, how deep are the chips spread? If over 3 inches or so, they *can* be counter-productive, not necessarily because of lack of water penetration.

Are the chips piled up on the trees (what I call a "mulch volcanoe"), or are they "bowled" away from/around the trunk? If at all possible, you don't want them on the trunk of the tree.

What was used to spread the chips? Machines or by hand, or a mix of the two?

The trees that have died, did they all of a sudden turn brown and drop needles/leaves, or did it start at the top and work down/start at the bottom and work up?

I'm not ready to blame it entirely on the chips...... Yet.


Dan

P.S.- pictures always help!

 

[ArtB]

pix and details

spread wih JD 440 loader

avg chip depth about 1-2 feet, all level

hemnlock dropped all needles mid-June, all at once (within a week)

Cottonwood leafed out, then started to shrivel about end of May.

hopefully attachment added?

 

[John Paul Sanborn]

Sounds more like method then anything else. Yes the depth could have an impact in a drought year. That with soil compaction may have done it.

Could just be the extended dry period some areas have been having the past few years.

Cant really say without examining the area.

Contact a consulting arborist to have an evaluation. You pay for their time, but they work for you, not with an eye on future work.

 

[Treeman14]

OK, I think we may have pinpointed a suspect here. 1 - 2 feet of mulch!!! WAYYYYYYY too much.

 

[Kneejerk Bombas]

There is no doubt that two feet of chips will kill a tree! Perhaps even faster than two feet of soil.
Roots need soil oxygen, decaying wood gives off carbon dioxide, thick green woodchips give off ammonia. If I put your head in a garbage bag full of CO2 and NH3, how long will you live?
Try to keep chipbeds at about two or three inches deep, maximum. Deeper than that is great for killing plants, including woody plants.


Dan F., study this picture and remember our thread from not to long ago on this topic.

 

[MasterBlaster]

I thought I was doing bad saying 8 to 10 inches!

(In a earlier post)

 

[ArtB]

Actually, one of the certified arborists suggested last fall I take out a couple of the alders so their trucks could get in easier <G>, guess they will come out now. Anyway, was going to take down one 150+ foot cottonwood threatening a building and play area, will be lots easier to fell with the dead one dropped also.

BTW, looked up black cottonwood on the web, said the tallest was 158 feet. The 160+ feet of the dead one was measured with a 200 ft dacron tape and transit, although it is only 1/3 the dia of the record.

 

[ArtB]

PS: here is the 'spreader' - the adjacent cottonwood is still living, 44 in dia. , about 20 feet from the one that died.

 

[duff]

vulch molcanoe

John Paul said it all.

You may be able to do some good for the remaining living trees by removing a LOT of the mulch, right away. Either stockpile it for future use or share it with your neighbors. That's a job for local teenagers with wheelbarrows, I might add. Soil compaction from the loader compounds the problem.

What's going on with the chain and lines in the living cottonwood?

 

[ArtB]

Duff:

The living cottonwood is the most lopsided tree I've ever seen (far left hand side of first attachment) , and the weight is over the pumphouse tower in the background - plus, it has dropped an 8" and 11" limb in the last 2 years, so is a hazard IMHO. If the dead one is out of the way first (had been going to leave it due to possible record height if it were living), then a difficult dutch cut and jacks to twist the live one as it falls won't be needed. The 7/16 HS chain is for protection against a barber pole, the nylon rope to pull a 5/8 wire rope up thru a 60 foot high crotch.

Have over 1000 trees on 4 acres, likely to get annexed to a town with a 5 tree per year cut limit (live or dead), so not worried about dropping a bunch now, as likely will 'need' to drop hundreds just before annexation.

Figured probably the big trucks (MUCH higher ground load than a crawler) from the certified arborist's company probably did the root system in <G>.

 

[duff]

Originally posted by ArtB
[Have over 1000 trees on 4 acres, likely to get annexed to a town with a 5 tree per year cut limit (live or dead), so not worried about dropping a bunch now, as likely will 'need' to drop hundreds just before annexation.
<G>. [/B]

'need'
enuf sed.
Continue forth, as you were...no further procedural analysis is required. 'Twould have made for one holy heck of a conservation easement....

 

[Dan F]

Mike,
If you were referring to the thread about the home addition, I agree that excessive mulch is not good!

However, I don't believe I ever said that the mulch should be left at full depth. All I said was to spread a healthy layer of mulch (I don't remember what depth I said) to reduce the compaction caused by machines driving over the root zone. If failed to mention that the excess should be removed when the construction was finished, well, I guess I failed to mention that but it was in the back of my mind the whole time.


Dan