Fresh wood chips have a lower C:N ratio then aged and dry wood chips would have, but that is not easy to find since apparently most researchers don't make a distinction. But a pile of fresh wood chips will get quite warm with nothing else mixed in indicating there is considerable bacterial activity there.
Leaves, especially green leaves, would be a high N source and I have seen piles of wood chips with green leaves mixed in producing large volumes of steam on a hot summer morning. How well the proposed mix will work out depends not only on what the layers are made of but the ratio of each layer to the other, ie. 3 parts wood chips to 1 part manure?

Can I use them to build lasagna bed? Definitely! And mulch your garden paths, and anything else that needs mulching.

The chipped branches are brown? and the leafs are green? Nope ... thin branches and twigs have a lot of moisture and nitrogen in their bark and cambium.

I consider chipper/shredder stuff (unless I am shredding deadwood) to be an ideal ingredient for composting just as it is - it heats up fast, sitting in the pile of shreddings, and quickly degrades to a coarse granular compost that makes a good topping for veggie beds.

Proportion of brown to green are obviously uncertain and they are mixed together unevenly. True, but if you shovel them in and shovel them out and rake them onto the bed they will mix pretty well. Don't worry about it. It averages out.

Eucalyptus can excrete poisons that can be toxic to other plants, don't they? Not that I have read in any reputable source.

Newspaper - Steer manure - mix-chips - steer manure - mix-chips - steer manure - straw. About 24" tall. If you are using fresh cow manure, good. Dried commercial "steer manure" ... not so good. It's over-rated and often high in salt content (as well as stinky).

A couple layers of high-clay dirt would improve the mix and improve the water retention.

Thanks guys for helping. Sounded like mix-chips may be high on green instead of brown? May be I should do my layering by adding another layer of straw in between and become something like:

Paper>steer manure>chips>steer manure>dirt>straw>chips>steer manure>straw

I need something to hold them down though as winter can be windy here.

toffee, in my experience, wood chips take a long time (years) to break down and tie up nitrogen in the process. Maybe California woodchips--and climate--make it different. I would build a small bed with them and see what kind of plants you get in that mix. There are some threads about mixing wood chips into soil. From those, I learned that wood contains lignin which slows the breakdown process.

From my own experience in the mid Atlantic, I made one bed with very fine chips mixed with grass clippings, compost and soil. That bed, a year later, is just beginning to produce, and not nearly as vigorously as the beds with no wood chips, made at the same time. Even peas and beans did not grow well in that bed.

hepatica
hepatica

I built a lasagna bed much as you are talking about, except I had a layer or two of grass clippings and a layer of shredded office paper. I topped it off with a thin layer of soil and grew veggies in it. Amazing growth, moisture retention and now 3 years later, the soil is still good. The chips do take a long time to break down though and there are big chunks showing still.

The eucalyptus has such a bad reputation ... unfairly given. Probably because of the aromatic nature of their leaves, it is assumed that the leaves/wood chips are toxic to plants. I can only speak from personal experience with two varieties - Silver Dollar and Lemon -- all parts of these trees compost very quickly and I grow roses, plumbago, geraniums, philodendron,nasturtiums, ...well, dozens of different plants either right under these trees or heavily mulched by their trimmings, or grown in compost from these tree trimmings. [and ALL of my vegetable beds get compost or mulch derived from eucs]

Re: how quickly the freshly cut tree chips break down .. in my experience, the smaller the chips, the more quickly they morph into compost. The chips used in my pathways [which might be similar to a lasagna type situation?] break down VERY quickly ... except for the larger [4-6"] seem to last quite a while. The next quickest composting situation is material used as a mulch in my well-watered garden, and the slowest decomposition is in a part of my yard that only gets watered by rain ... they perform the task of supressing weeds. As to how quickly they compost within my compost pile .. I don't know how quickly, because I don't turn and only harvest once a year. It's all composted down by then, except for the occasional larger piece.

As one poster said, our climate may have a bearing on my experience with fresh wood chips. I think the operative word is FRESH.

Fresh wood chippings from the branches less than 3" in diameter are known as 'ramial' mulch. From what I've heard, agricultural stations have done research that shows that you can prepare farmland by tilling fresh ramial mulch into the soil.

But I think that tree services have the entire tree in the truck, including the wood from the trunk. I would not till that sort of mulch into the soil nor layer it into a lasagna bed. I would either compost it or use is as a mulch on top of soil.

I have a nice chipper and in my situation I would re-chip the wood chips to a smaller chip size and then use it.

Searched online, ramial mulch are good stuff. By using ramial mulch, are there any merit in adding manure, straw or more green?

I would not use wood chips in the bed. Put them in a pile and let them rot; use them for paths. They will inhibit the growth of your plants instead of helping them.

Based on experience shared by Tom Robert on his blog: in praise of ramial wood chips. Building a Lasagna bed with ramial chips may not be a good idea:

Quote++
Simply piled alone they store well, and in five years will look almost the same as they day they were piled. Summer chips (with green leaves) will heat up and rot down a bit, but there is so much more carbon in the chips than nitrogen in their leaves, that the brief period of initial heating soon subsides. Of course this depends somewhat on the type of woods being chipped, but getting more chips than you can use in a year or two is no real problem if you have a place to store them. Piles of chips are very porous, so they naturally tend to dry out quickly on their own unless covered with a tarp, straw or hay, etc. Since drying is preserving, simple piles of chips don't compost, they keep.
End quote++

So using them along, they don't decompose much. Then if you add manure or more green matter, they compose very hot. Is that desirable in a lasagna bed?

Quote++
All of the work done on building soils with ramial chipped wood recommends tilling the chips directly into the soil. I have done this sometimes, usually followed by a cover crop. When tilling in two inches of popple chips, I have found that there are temporary (one year) signs of nitrogen deficiency (poor crop growth, small plants with yellowing of leaves). By the second year these signs disappear. This may have been due to the large amount used, and the fact that some of the branches chipped were rather large. In future, I will be doing more direct tilling of chips into the soil using popple, alder and other mixed woods in separate sections, and chipping smaller diameter wood. The research quoted above has shown that ramial chips from climax trees (oak, maple, yellow birch, beech) produce the best quality soils, while ramial chips from conifers are the least beneficial.

Mixed with cow manure, chips take more than a year to digest, so we no longer use them this way. However, over the past two years we have discovered that grass clippings have the necessary nitrogen to make chips "disappear" within a year when mixed at the rate of one grass to two chips and turned a few times. Such piles get VERY HOT very quickly. This past summer's pile is six feet high and thirty feet long and could be seen emiting warm vapor in the cool of morning and evening.
End quote++

I am back to square one :)

Here is a link that might be useful: This is from:

They are still useful just not in a bed. You can put them on top of the ground as a mulch for shrubs after they have broken down, they will look like peat moss. I still think they inhibit growth and are best for a mulch on top or paths. I think this because I made a path of rotten wood chips over some ground that had daffodils. In the spring the bulbs that came up in the path were not as healthy as the ones in soil. I have a big supply of wood chips from the electric utility work trimming trees away from power lines. I said I wanted them and this nice young man left me a mountain of them. Mine are from a valley so there would be some walnut in there which is not good.

Several factors influence the digestion rate of wood chips, freshness, size, as well as type of wood. Hardwoods will take longer than softwoods. Aspen digests faster than
Catalpa which digests faster than Oak or Maple (depending on the species of Maple).

Yup, mulch and even tilt into soil as amendment but not as main material for a lasagna bed. Sounded like I may have to buy alfalfa hay and straw to do it.

If you're going to make it 24" deep, you don't need to lay newspaper down first. Trust me, everything will be smothered. Freshly chipped trees will heat up a lot. I wouldn't plant in it any time soon.

Deanna

From what i have read on composting, the compost pile needs to be 3' by 3' "minimum" before it can start to "cook" (get hot).

yet, websites for lasagna gardening state that you can plant into a layered bed immediately. I assume it's because it doesn't reach the mass (height) to "cook", it is more like "cold composting".

basically, i think the OP is safe to plant whenever they are ready.

"From what i have read on composting, the compost pile needs to be 3' by 3' "minimum" before it can start to "cook" (get hot). "

I've read the same claim, but personal experience contradicts it. I've got a much smaller bin and have had it get to 180F when I've managed it carefully.

They would make a good mulch on TOP of a lasagne bed to keep moisture in. In case no one mentioned that.

I took down a poplar tree a few years back, in spring. We cut all the wood down to about 1" dia. for firewood, so only the smaller stuff and leaves went into the chipper. That stuff did heat up and decompose pretty fast. But I agree the tree service truck is going to have much bigger stuff in it. More's the pity.

Why can't you pile it, mix it with manure and greens to make the wood pile compost faster and then use the following the next year in the bed?

Is the lasagna bed method so that you get plants in faster? Just get a load of topsoil and fill the beds with that, then when your big pile of compost is ready, amend the topsoil beds with that.

Around here a load of topsoil is relatively cheap. I got three yards this spring for $105. It's good but not great, I mean I grew most of my veggies this year in that dirt alone and had pretty good crops. I can't wait to amend it with my compost that i'm doing this year as the soil is a little tight and doesn't drain well.

Next year besides building 6-8 more raised beds, I plan on screening all my topsoil (including the pile I dug out for my sunken patio area) and then screen and mix my compost with that to amend it and then put it into my beds. I am hoping I have enough compost to really get a good OM mix into the dirt, but I have 4 large maples (60ft trees) which will be giving me quite a supply of leaves to add into the mix this fall.

If you have the space, I think you could make a better soil faster by making a big compost pile and really cooking those woodchips down fast. A big enough pile with enough green will nuke those things down in record time. It sounds like putting them uncomposted into a growing medium might not be quite as beneficial in the short term.

i have recently started reading about lasagna gardening but haven't actually done it. but as i understand, the ingredients are cheap or free ($105 is a lot money for some of us).

the lasagna garden can either be used immediately or prepared in fall and used in spring. but this is where it gets hazy... the exact ingredients/layers to use (ratio of c:n) on every web page I read differs... even here on gardenweb.