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Wood Chips

Posted by Clair Kauffman 
Wood Chips
November 23, 2012 06:04PM
I'm just getting into the use of wood chips in our existing orchards and have questions about aging the chips. Are aged (as opposed to green) wood chips critical or are they just better? Can green chips deplete nitrogen to unhealthy levels? If they are green ramial wood chips (versus heart wood or bark mulch), does that offset nitrogen concerns?

Also, any input on how to undertake the aging process? I understand that turning the pile won't make the fungi happy, but wonder how long to leave them sit, is inoculation necessary, etc.?

Clair Kauffman
Zone 6b, Lancaster, Pennsylvania
Re: Wood Chips
December 08, 2012 07:50AM
A couple things to consider about using wood chips . There is a white rot that aids deciduous trees and orchards , and brown rots that aid coniferous trees and the forest floor. In deciduous trees a large part of the nutrients are "stored " in the ramial wood , branches that are about 2 1/2 inches and smaller. If you use wood larger than this the carbon to nitrogen ratio gets to large and then yes, you will tie up the nitrogen you are trying to get. So the best to use, deciduous ramial wood, and green or aged are fine.

I've never brought in chips to use, I just use my prunings. These will get chipped and shot at the base of a tree and I just go thru the orchard making little piles . They will get kicked down so they are about 4-5 inches in depth . They don't get any special treatment as I use neem, kelp, effective microbes regularly throughout the season to stimulate biological action.

I do bring in horse manure and bedding from a neighbour . The chips in this are more than likely pine , spruce or fir ; hay as well . So all this does go into my compost pit . As I am unloading it will get sprayed with my holistic brew . It will sit for about 6-8 weeks then I move it into a proper row . As I do this it will again get a treatment and then it sits for 3 years (a magic number from my grandfather about compost). When ever I have left overs from a spray run I will use it up on the compost pit. It breaks down nicely and I'm looking to add humic acid to the mix as well.

Edited 2 time(s). Last edit at 12/10/2012 01:29AM by Michael Phillips.
Re: Wood Chips
December 21, 2012 05:13PM
Winter without snow seems like a great time to get ahead of the game and get chips down under trees. If you simply buy chips having no knowledge of the type of wood or size diameter of the origional wood could you get yourself in trouble with a young orchard? Also if chip mulch is a definate plan for weed control does it make sense to buy a chipper........any "three-point" recomendations? Has anyone had luck sourcing small diameter wood...seems cumbersome to transport.
Re: Wood Chips
December 22, 2012 02:36AM
Hi Eric,

Sourcing small diameter wood . . .

We have had good success out this way by letting our local utility pruning subcontractors know that they can dump their loads at our place 'free of charge' . . . I tell them I will take all they can bring. Only once did I get a little nervous when the 9th load arrived in a 3 hour window a few years back! . . . A good problem to have none the less.

The advantage of the utility pruning crews chippings is that they are constantly doing touch up pruning of younger growth that is encroaching on their required power line clearances & setbacks, so you don't usually end up with larger diameter trees in the chippings.

I started watching for the companies that were doing the work as well as the ones who would come to our property to do the work, then I would simply ask them what they are doing with the chips and if they would appreciate having an easy place to dump their loads. . . I am successful about 1/3 of the time in getting the chips delivered. The other 2/3 of the time, I think they either forget or they get a sweeter deal ($$$, warm brownies, beer, etc.) from someone else down the line also asking for the chips too.

Good luck!


Gopher Hill Apples
Zone 8 in California
Re: Wood Chips
December 24, 2012 12:33AM
Were they willing to keep evergreens out of the mix or was that not an issue for you?

Clair Kauffman
Zone 6b, Lancaster, Pennsylvania
Re: Wood Chips
December 27, 2012 03:53AM
In a perfect world the evergreen chippings would be absent, but there is usually some in the mix on most loads I get.

A few of the loads I have received have been as much as 75% evergreen -- Incense Cedar, Douglas Fir and Ponderosa Pine being the dominant species in those cases.

When I get them for free, I can't complain too much

So far, I am not seeing any issues with the mixed chippings at our place. These evergreen species are all native to our area and our local soil borne organisms have surely evolved to deal nicely with them. As such, I often see some impressive mushroom fruiting bodies come from some of the evergreen mixed chippings -- more so than when it is mostly hardwoods.

One of the loads I got about 18 months ago, was mostly pine with a large qty of pine needles evident in the pile. I left that pile essentially as it was dumped and the nearest tree, a Mother Apple is within 7-8 feet of it. That tree had some of the strongest growth of the season for me this year.

Go figure.

You asked about aging, in your original post . . .

I believe aging is a good thing. I love the idea of the haphazard mulching concept that Michael Philips champions and letting the chips age in place. Take a wheel barrow load and dump it where you may, at the edge the drip line, or anywhere else that just feels right at that moment in time (just dont bury the trunks). Those wheel barrow piles are small enough that the air can still penetrate them and the tree will send roots into the layers just below it. Very few weeds will grow through those piles (expect Bermuda grass and an occasional strong bunch grass like Tall Fescue) and the worm and invertebrate activity below and within that pile is fabulous.

When I began this method, I selected the south side of all of my trees first to give the extra benefit of cooling and helping to maintain moisture in that more exposed soil area.

Every year, I add another haphazard pile to another area around each tree, maybe the north side, the west side, or wherever it feels right. I have even tripped up and dumped a load in the middle of two rows and just shrugged it off and said "oh, that one was perfect" . . . haha! I keep saying 'feel' as I believe this is more of an art than a science. Connect with your growing ground and it will help guide you to the needed spots . . . more often than not.

As the piles decompose each year, you will have multiple stages of humus being created at each pile site. The tree will be able to gather the nutrients it needs from each location.

Last item, Claire, I often take grass and herbaceous cuttings and manually stuff them into these ramial chip piles, sometimes beneath them, sometimes into the middle or simply just adjacent (as a 2nd pile so to speak). This is another source of nutrients, including nitrogen, for both the decomposing pile and the tree.

Gopher Hill Apples
Zone 8 in California

Edited 2 time(s). Last edit at 01/01/2013 09:16PM by Michael Phillips.
Re: Wood Chips
January 11, 2013 03:44AM
Having used a chipper in the past, I have since retired it. Here’s why:

I don’t need it. Orcharding like many other endeavors, requires a cost-benefit analyses.

1.The unit we could afford, for one, took an awfully long time to run material through (along with all the stink and exhaust we breathed). Sure, running softwood boughs through is a joy, but try apple or poplar with all those funky angles. I love long hours with outdoor tasks, this I would not number among them.

2. This one isn’t for everyone, but central to our mission: Environmental impact. Yes, it takes longer to trim things down by hand or remove them (ie prunings), but we find it is worth it. Trying hard to model our system on nature, we let natural decomposition run its course. There is also a disturbing trend I am noticing, even in thoughtfully managed landscapes and farms- the need to rush things to decomposition. The earth has a system for breaking things down, yes even big things. How many hundred foot ginko and monkey puzzle trees do you see lying in a pile? So do we really have to worry about a branch half an inch thick? It is also important to have different levels of matter out there to decay at different times. This way if you cannot add material each year with your regime, different caliper wood will become available to microbes in different years as they take different amounts of time fully decay. Also, different physical specimens attract different creatures, from fungi to ants. Additionally, nitrogen will not be tied up as dramatically at a given time since decomposition is spread out, which will reduce need for supplemental nitrogen additions. Diseased tissue needs to be dealt with, but there are other ways. This leads to the next point:

3. Although not necessarily the case with many commercial operations, chipping, like lawn mowing and sidewalk edging is really about tidiness. I have used chipped mulch and alternatively coarse brush on berries, and man does the chipping look nice. There is nothing wrong with this distinctly human reaction, and we still have a bit of it here, but most of us can get around this tool if we want to. Accessing commercially produced chips may be more sound a practice, since they are produced anyway.

4. Another engine equals another expenditure, routine maintenance, and emotional stamina (when it doesn’t start). Add fuel and oil and health and safety issues. And oh are they loud.

So what do we do? When we prune, all wood larger than an inch gets cut and stacked for the wood stove. Smaller dimensions get pulled into windrows some distance from same species live trees. This often winds up as kindling, but this pile a few years later will be a beautiful crumbly mass. Much of the smaller stuff is actually trimmed and dropped in the dripline while contemplating the next pruning cut. What Todd?! You have time for that?! To answer, the day I do not is the day I have too many trees to take care of in a wholesome manner. Again, this is my deal, and will only make sense to those who have a kinship with such silly ideas. And I enjoy doing it this way. When this is completed, I apply wood ash, and other debris including hay, bramble prunings, you name it to try and smother any erupting pathogen spores and the like. It also keeps the wood moist to improve decomposition. This last point will attract more folks to this method, you can dress up the area by covering the rats nest with a tidy carpet of hay or leaves. (We reserve the nicer piles for the nursery area ). We have a thousand or so trees, and as many bushes of various ages and so far, so good.

So, not the answer, but an answer for those who think in that direction.
Re: Wood Chips
January 14, 2013 09:00PM
" . . . the day I do not is the day I have too many trees to take care of in a wholesome manner"

Amen, brother

Gopher Hill Apples
Zone 8 in California
Re: Wood Chips
April 08, 2013 10:24PM
We have an orchard of apples, pears, pluots, persimmons, figs, almonds, plums and cherries and we did have some apricots but they are dying of something horrible - probably E dieback. Our orchard is very remote and we want to use on-site resources as much as possible. I have been reading about ramial wood chips and want to get a chipper to make our brush into mulch for the fruit trees. Our orchard is in Sonoma County, California. We have alot of California ay, coyote bush, madrone and manzanita, poison oak(!) and non decidious as well as deciduous oak brush which we could use to make ramial wood chips. Would be OK to use Bay and coyote bush and non-decidious oaks and madrones as they are not deciduous plants but not coniferous either? What about poison oak - we have alot of that!. Would that be totally nuts? - probably. Any advice would be very gratefully received.
Thanks, Erica.

Edited 1 time(s). Last edit at 07/09/2014 03:27PM by Michael Phillips.
Don't chip the poison oak
May 12, 2013 10:04PM
As one who has been reacting strongly to poison ivy over the years, and to a Caribbean carrier of the urushiol oil, I can say you do not want to aerosolize the urushiol!

I don't know of a safe way to use your poison oak.
Re: Wood Chips
June 06, 2013 04:48AM
I like the idea of using onsite brush as chippings for the orchard!

I agree with Ed, I would stay away from the poison oak . . . not because it will hurt your orchard in anyway, but it will get the oils from the plant all over your chipper and all the other tools you use to cut and prepare the cuttings for chipping . . . yikes, then as you use your tools, it will almost surely be a skin contact nightmare for years to come.

I like the idea of the coyote brush (a fabulous winter nectar plant for bees!), manzanita (the youngest growth being ramial best as the older wood is very dense and slow to decompose), both types of oak and even the bay laurel being part of your ramial chip strategy. The Bay Laurel may even arguably help with repelling certain over wintering insect foes that might otherwise set up camp within the drip line of your trees . . . and interesting plant medicine experiment in the making.

Gopher Hill Apples
Zone 8 in California

Edited 1 time(s). Last edit at 07/09/2014 03:29PM by Michael Phillips.
Re: Wood Chips
July 07, 2014 11:45PM
I'd like to revive this thread if I may. We have taken stewardship of a neglected 300 tree dwarf apple orchard recently here on the Olympic Peninsula.

We began mulching a month ago with free moldy hay and will continue doing that with our own freshly cut hay. Basically I've come to the conclusion that "haphazard mulching" isn't the way to go for us - our trees are planted 2-3' apart in long rows on trellis and mowing is a huge task (when we took over some of it hadn't been mowed in years).. We have a very dry summer clime (also only 20 inches/year total mostly in the winter) and I although I have jury rigged a soaker hose system off passive pressure water coming down from the mountains in our irrigation ditch, I do still feel a need to mulch it all to retain moisture and to curb the mowing we have to do. Isn't much diversity anyway in the understory and we plan to plant small flowering plants into the mulched understory.

Now to the chips part. Deciduous trees here are alder and big leaf maple primarily and I've called around but haven't found a source for ramial chips. But we are in luck! On site we have massive English Laurel (about 30' tall and across) which is a great windbreak and bee forage but I've been taking quite a bit back on it as a coppice. From what I've read on the Permies forum - it contains cyanide that shouldn't harm the apples but may help scorch back the grass. It's not all ramial (some 6+ inches diameter) but mostly is.

My question: should I mulch the hay first then the chips or vice versa? Above it was commented that if the chips/stems are below they will break down better but the trees have been neglected for 5+ years and I think they could use the nutrient shot of the quickly rotting hay below the chips in that scenario. We will begin holistic sprays and minerals this fall (making comfrey, nettle and horsetail tea to spray as we speak though).

Let me know what you think we dove right in to this holistic orchard thing and our neglected trees thank you for any tips smiling smiley

Nick Segner
Re: Wood Chips
July 08, 2014 01:59AM
What is the distance between the rows?

Hydrogen cyanide conversion is normally what happens when an animal ingests cyanogenic glycosides (the body makes the transformation). Keep in mind many plants have the latter, including most tree fruits like apple and cherry.

As for speed of breaking things down, hay on top will keep the woodier material moist and facilitate breakdown..but..I have never understood the rush to do so. Material will become available to your trees eventually, so it should not matter if that is in year 2 or 5 or 7 or whatever, as long as quicker composting things are in the soup as well. Like your hay, or weeds, and the leaves if they are put down green in a coppice/pollard system cut for summer mulch.
Re: Wood Chips
July 08, 2014 02:40AM

Thanks for the reply.

The distance between rows is unfortunately inconsistent but out of the 22 rows the average distance between them is somewhere on the order of 10'.. And just narrow enough that our compact 32hp Yanmar doesn't fit between the rows :/

Please elaborate on the cyanide - sounds like once ingested is when it becomes toxic to animals and humans? What of whether or not the tree (and then fruit) takes this up? It will be our primary mulch for now until we add other coppice hedges.. but we plan to keep using the laurel as coppice for ramial chips indefinitely (unless the cyanide thing is indeed an issue..)

I understand what you mean on the mulch breakdown timeline. I just wanted this first round to break down more quickly as the trees have been neglected of late and maybe need that boost. Also, the fall sprays should help break it down more quickly and help with our primary disease problem (scab).

Nick Segner

Wildcat Valley Farm
Zone 8b
Olympic Peninsula Rainshadow
Port Angeles, Washington
Re: Wood Chips
July 08, 2014 04:27AM
It turns out that all higher plants produce HCN as part of their normal metabolism, or more than 2600 plant species. Also, soil fauna break it down in a couple of weeks anyway, into benign substances. It is also unlikely the tree would absorb it, and apples synthesizes these compounds anyway. (I am mentioning this more for folks that might read things and then cart all their cherry leaves off to the landfill). If it does indeed harm the grass, please let us know, I am sure a lot of readers would love to kill some grass, present company included.

The question about the pathway is to consider using this as the mulch area. You probably are looking for a weed suppression option in the row, but at that spacing I do not see how that is possible with mulches- you may wind up rotting your trunks. Path mulching will keep compaction down, and feed the tree if it finds the root zone. If you are mowing anyway, the coarser debris will be continually pulverized and help with the faster decomposition. I do try to speed up decomposition with apple prunings and leaves in the spring by burying them under those first mowings and hay.
Re: Wood Chips
July 09, 2014 09:58PM

Thanks again. That's good to know that those organic chemicals will break down quickly anyway. Makes sense. I will see what happens with the grass - though the laurel leaves may not be fresh enough anymore by the time we chip/shred it all (end of the month and most of the laurel is already cut and piled)..

That's an interesting way to do it - mulch the pathways. However, we do intend to back the mulch up from the trunks during our rainy season (winter) and use pea gravel rings around each tree per Michael. Hope that would prevent any rot. Other concern is vole damage with all that hay habitat but I bet the gravel will prevent that too. I left fields fallow around the orchard for snake and owl habitat of which we have seen many. The pathway is largely just out of the drip zone but I bet you're right that feeder roots do extend into this grass..

Nick Segner

Wildcat Valley Farm
Zone 8b
Olympic Peninsula Rainshadow
Port Angeles, Washington
Re: Wood Chips
November 13, 2014 07:55PM
Organic farmer across the pond from me has been using ramial chips in enormous amounts on many things besides apple trees. Like to share what I saw in September at his farm and his comments: Ramial chips inoculated with black trumpet spores gave him crops of sellable mushrooms amidst the squash and sweet corn. But the kicker: unbelievable levels of worms and even more unbelievable (3" thick) worm castings on top of soil and the worms were making the ramial chips disappear fast. Nitrogen depletion? Not possible! Not sure this was in the study Michael quotes....
Now back to the holy grail--a reasonable and reliable source of ramial deciduous chips without standing drone-like in front of a chipper when the other chores need doing. One tree guy here has been chipping on this fellows farm and when he did some tree work for me he was pre-educated as to what ramial chips are. Worth cultivating a tree guy--maybe give some apples or cider. smiling smiley Enormous chippers are fast but dear...
Re: Wood Chips
November 14, 2014 02:22AM
There are plenty of mills using hardwood, and many chip their residue (typically a hammer mill). The fuel and carbon footprint of trucking this to the site I bet is a good deal less than slaving over a smaller chipper. Also, this is another reminder that every last one of us does not need to own every last piece of equipment in earth's arsenal. Although most of us succumb to gear greed (especially us guys), sharing has been known to work. This sharing can also take its form in having someone else share in the work. We could probably all collectively own haying equipment, chicken pluckers, and even wood chippers. Better yet, having a load of otherwise waste material delivered to your doorstep and helping a logger, lumberman, or truck driver put his kid through school works pretty well too.

Incidentally, anyone obtaining or creating a load of fresh chippings should really consider harnessing the energy. The center of a sizable pile can generate a goodly amount of heat (as in burn your hand heat) to warm buildings and greenhouses using a pumped water system, similar to "pain mounds". In this era of energy talk, it seems sinful to waste such a resource. When it is done cooking, you have a beautiful partially decomposed dressing for the orchard. Elegant.

Walden Heights Nursery & Orchard
Zone 3 in Vermont
Re: Wood Chips
June 24, 2018 07:39AM
As I understand it, the main argument against using wood chips from coniferous trees is due to their lacking something called syringyl units (which I think is a molecular structure) in their lignin. Lignin is defined as a "recalcitrant biopolymer", which means that it resists decomposition. Saprophytic filamentous basidiomycete fungi (white and brown rot) are not able to completely break down this material as they are with deciduous hardwoods rich in syringyl. The intact lignin polymers of coniferous trees retain sequestered carbon and this material goes on to form an acidic strata of peat.

At first glance, this is strange as the old growth forests of the Pacific Northwest are dominated by conifer trees and the fungal activity in them is unbelievable and extremely diverse. You can sink up to your neck in a dead tree trunk being devoured by fungi... A part of me feels that there is more to the story. Perhaps other non fungal biology plays a vital role in digesting these recalcitrant linkages...I don't know.

In dry areas without consistent or cumulatively abundant rainfall, the ability to select choice tree species might be more limited than in areas situated in abundant deciduous biomass. Most municipalities have waste transfer stations with sections devoted to wood chips from a large spectrum of tree species that are free for the taking. If you contact a local independent trucking business, they will transport dozens of cubic yards at a time for an affordable fee contingent on proximity.

The concern with wood chips sourced in such a way might be centered on contamination issues, but my inquiries into organic certification leads me to understand that organic mulches are not mandated (although we will strive to employ them). It is important to exclude all construction debris, yard waste, and manures. Here in New Mexico, the piles are organized so that this criteria is easily met. We obviously want to bar all herbicides and insecticides from our matrix. I think that a mulch derived from ramial tree waste is far less likely to be heavily contaminated than a mulch of non organic roundup ready alfalfa or straw unknowingly treated with atrazine. The primary tree species in the transfer station wastes seem to be juniper, pinyon, various locusts (psuedo robinia & glenditsia triacanthos), elms, fruit & nut trees, ponderosa, and things of this nature. We utilize the older, more decomposed piles as much as we can.

There is a dimension of time and fleeting human mortality that forms a component of interacting with trees and attempting to establish them in an environment. Our approach to establishing trees here has focused upon building a soil biome and establishing a system of earthworks to bank the large amounts of intermittent storm runoff that sheets over the hydrophobic soil in violent torrential storms. In the course of moving hundreds of wheelbarrows of dirt, I did not see a single earthworm. It was a fine dry powder without any aggregation. To the naked eye, it was lifeless. From a mineral perspective we have a deep strata of silty clay loam over volcanic conglomerate composed of a wide lithic diversity. I don't have a microscope yet, but I think it's possible to infer that our alkaline soil was almost exclusively bacterial in barren areas and that there was a higher ratio of fungi in the pinyon juniper and native clumping grass rhizomes. Our weeds have tended to be invasives such as koschia (Koschia scoparia) and Russian thistle (Salsola tragus), species of Locoweed (Astragalus), and others.

We have brought in many cubic yards of wood chips and put them over our earthworks and throughout the trees so that everything is linked up and protected from the sun, wind, and temperature fluctuations. The chips break down quickly and begin to transform into a deep black humic material full of mycelial hyphea. I have added worms, pill bugs, and millipedes and these are present and their populations seem to be growing. We are identifying insects we encounter and most of those we see are beneficials and predators. We have an army of native lizards which devour insects and dig up larvae.

To summarize, I don't think we would have been able to accomplish what we have and feel like it were going to survive if we hadn't extensively built upon wood chips. For us, the idea of chopping and dropping enough mulch from a self produced biomass would not be possible in this environment as anything left exposed to the elements here seems to close stoma, dwarf, shrivel, and die. Shade is crucial.

Karn Piana
Zone 7 Semi-Arid Steppe
Northern New Mexico
Re: Wood Chips
August 11, 2019 11:12AM
We use Fir. No cedar. Have a close friend who is an arbourist and I've had a couple dump truck loads of fresh chippings. That pile is hot hot hot for a while but we spread it one after about a month onto the orchard in spring to about 2' thick. The mushrooms we had this spring was amazing. I wish I had innoculated with morels!!

Anyways, the pile remains are slowly getting smaller and smaller via breakdown and some of the trellis line hardly looks like we have any chips left. Those areas need more and definitely have the most weeds.

I'm in pacific northwest and I will use this mulch again and I trust the source quality which makes me feel better.
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