Adding compost and wood chips around trees

I am about to add a lot of homemade compost and wood chips around all my fruit trees.  I have Asian Pears, Asian Persimmons, Plums, Pluots, Jujube and Hardy and Fuzzy Kiwi.
Some of the trees are young (under 2 to 3 years since planting) but others are over 6 to 8 years old.  

I have put hardware cloth (1/4 inch) around each of the trees/vines to keep everything at least 3 inches away so I won't have problems with root rot.

I will remove the old concrete tree rings and put down a thick layer of compost, then covered by thin layer of sand and dirt and then a thick layer of wood chips on top.  

Questions.  How far out from the tree should I go with compost? I have a lot so 3 or 4 feet is not a big deal.  I also have access to all the wood chips I can desire. Don't want to waste compost since it can be used elsewhere.

I will then try to make guilds around the trees with borage, Nasturnums, Yard Long beans

I read where Dr. Redhawk recommended not planting tree guilds closer than 3 feet for young trees.  But for older trees can I get within 6 inches if it is on top of the compost layer?

Also I seem to recall that burying tree roots under too much soil can suffocate the tree.  Is this true?  Should I stop adding this compost and wood chip layers after a couple years or will the roots grow upward to find the air they need?

I recently saw an interesting presentation by this guy not long ago.  robertkourik.com  He has a book on understanding root systems.  I haven't seen the book but a lot of his presentation was from his book.  He has collected root studies done a long time ago by universities. He has some different views on what is typically done on mulching trees.  You might want to check out his website and see if the book is worth buying.

Here is a picture of how I am keeping the chips and compost away from the trunk.  

Mike Schroer wrote:I recently saw an interesting presentation by this guy not long ago.  robertkourik.com  He has a book on understanding root systems.  I haven't seen the book but a lot of his presentation was from his book.  He has collected root studies done a long time ago by universities. He has some different views on what is typically done on mulching trees.  You might want to check out his website and see if the book is worth buying.

I own this book. It's really neat, and there are tons of drawings depicting root systems of various trees, shrubs and plants. One thing I took away from reading this book is tree roots can grow way out horizontally past a trees drip line, like double or more the distance from the tree trunk in some instances. A lot of roots tend to stay shallow in the first few feet of soil, some venture deeper into sub soils, and only a handful of trees have a taproot going deep.

Dennis Bangham wrote: How far out from the tree should I go with compost? I have a lot so 3 or 4 feet is not a big deal.  I also have access to all the wood chips I can desire. Don't want to waste compost since it can be used elsewhere.

If they were my fruit trees, I myself would spread wood chips and compost 6 or 8 or 12 feet radius, or farther from the tree. Putting the wood chips and compost down, even if the tree's roots aren't there, will increase bacterial and fungal populations creating helping create awesome soil, which the trees roots will find and move into, building a huge complex of feeder roots.

Also I seem to recall that burying tree roots under too much soil can suffocate the tree.  Is this true?  Should I stop adding this compost and wood chip layers after a couple years or will the roots grow upward to find the air they need?

It can be true, sometimes. If it's a hard, poor draining soil, then it's possible. If it's a loose soil with a thriving soil food web, then it won't. Adding the compost and wood chips will, with time, help loosen the soil beneath as bacterial and fungal life move downward. Bugs and earthworms move in, creating little tunnels and voids that not only allow rainwater to infiltrate better, they also give a place for oxygen to come in and stay. Rain drops pick up a lot of oxygen falling through the atmosphere, so each time it rains, oxygenated water can migrate deep into soils, and nice crumbly loose soils will let this happen and help get this water down to the subsoil.

Those roots can grow upward and into an added layer of compost and wood chips. The trees roots aren't really dictated by gravity, and will seek out and find the microbial friends and nutrients hanging out together in the compost.

Dennis,

I am NOT Dr Redhawk, and hopefully he will pop in. I can tell you what I have done, and good and bad aspects. First, I made windrow swales just off contour- small amount of soil, 18-24" of chips. Basically I wanted to define a fungal strip. The chips were unfortunately fresh, as I got them I laid them out. I didn't know any better and planted in the chips with tree tubes preventing chips against the trunks. Some trees took off like rockets, others died, some just got stunted. The common thread was N-fixers did well. My honeylocust whips grew 10' in a year, to the point that I cut them back because when I took the tubes off they were lying all over the ground. I was hesitant to remove the tubes but I figured better with a 10' tree than a 20' tree. Redbud did well.

Anything grafted hated me. When stuff looked sickly I figured the roots were too wet or starved of nitrogen. I replanted them higher and moved the chips away at least six inches from the trunk (most didn't have roots beyond that, these are bare-roots). I used urine on the remaining chips (just a thin layer for water retention/sun/weeds). Some came back well. A few I had to replant. The ones that died at a really high rate were fig and persimmon, which should be about the easiest thing to grow. After replanting in what was now 2nd year chips, life is good, but always with about a 12" diameter for air to reach roots. By the time the roots have extended outside that radius the mulch is 1/3 of the original height in this climate, and they send out roots into the grassy strips if they want (strips are about 4' wide).

Stuff that took off-
Legumes
Pawpaw (grew 4' on one year- slow growing my backside)
Mulberry - probably would grow anywhere so no evidence there
vibernum
gooseberry
asparagus
elderberry
goumi
ginko
Che
Grapes


Stuff that looked sad
jujube
apple/pear
raspberry (surprising)
hazels

Stuff that did poorly
Persimmon
fig
cherry (it's marginal here anyway)
citrus

I was really surprised by the persimmon issues. I think a big part was the fresh chips and the huge amount of rain that year. I replanted and they did well even though we had historic rain. I replanted the figs from cuttings and they did great. Over time several have gotten chips pushed up against the trunks- your little wire things should be really helpful- I lost an apple to something boring into it. Now I go back and recreate the tree "pot" a couple times a year after kids or whatever wreck them. Everything did fine with this method- 2 year old chips and areas they can have air-exposed roots. Thats how I plan on the larger planting- chips go down with only legumes planted the first year in tree tubes. Second year the rows get filled in with the other stuff that haven't shown pickiness. Then third year they get the picky stuff and also the herb layer. The advantage to this system is that I root hardwood cuttings in the second-year chips, in place- just stick in goumi or elderberry or honeylocust and they will mostly root (this year looks like about 75%). Super cheap. Third year chips will root even more stuff- my che and some wild hazels and raspberry and honestly about anything seem to take. No on figs and blueberry but still a great way to expand your plantings.  

Thanks Tj.  Most of my trees are older and the ones that are new (2 Asian Persimmon and 1 Asian Pear) seem to handle being in fresh wood chips.  At least since last summer when I put fresh ships down.  I will uncover around the base of all my trees and put down some compost and seal off the compost with sand and dirt.  Then replace the wood chips on top. I have a buried drip irrigation system that I deep water 2 times a week.
I think I may have really good soil because of the Pawpaw that I transplanted.  They all seem to have survived (3 out of 3 doing good).  I was under impression that Pawpaw were hard to transplant.  It is still early so time will tell.  I transplanted a mulberry that I found in the lot next door and it seems to have survived also. Eager to see what kind it is.
About the only things that did not do well was some jujube root suckers that i dug up and put in some air pruning buckets.  
I have been thinking of controlling water by the use of raised beds. I use cement blocks with soil and wood chips and after the root system is in place and the chips degraded I remove the blocks and relocate.   I will soon have a raised bed swale if I do a couple more raised beds. I live on a minor slope so most of the water goes downhill to my neighbor but I live in an area that normally gets 60 inches of rain a year.