Turning my mini orchard into a mini food forest?

Ok, first of all, I'll pre-apologize if I have my terms all messed up. I am extremely new to growing anything. Let's just say, I used to own more than 1 fake ficus tree in previous years!

We just purchased a home and I have had long time dreams of homesteading, which now have pretty much just morphed into growing as much food as (lazily) possible. So far, it hasn't been so lazy! But we're growing mostly perennials, so I have future hopes. We presently live on 1/3 acre in a small town (neighbors are veeeeery close) on a lot that already had plenty of mature trees - none of them fruit (with the exception of some very old, yet producing grape vines and two of those mini plum trees...and we like those, so that's cool!).

I'm trying to focus on one little area at a time and have been reading a lot about tree guilds to allow for more organic gardening (we really don't want to spray chemicals if avoidable).

Basically, I planted 6 fruit trees (semi-dwarf that we plan to keep pruned to just over arms reach) in 2 rows - 3 trees per row. We did a layer of "kill mulch" under each tree, and between the spaces of mulch is just grass to mow. Well, weeds to mow. I noticed I can put a 4x4 bed (with room to spare) between each tree, and at the ends, forming a rectangle. That would give us 6 4x4 boxes to plant in. I was wondering if that's a good idea instead of planting directly under the trees? I would love to have that whole area planted so we don't need to mow it (then start working on other areas of my yard).

Opinions? Advice? What would be best to plant directly in the dirt next to the tree vs. in the planter boxes between?

I'm going to attach a sloppily done "paint" drawing just in case this post is a little jumbled! (the land the trees is on is pretty much level, with a slope and mound behind it. That ugly looking yellow brown "bush" is my newly planted forsynthia...couldn't resist. The yellow blooms made me happy!).

P.S.
Now that I've "drawn" this it doesn't seem a fit for forest garden, but I'm not sure were to put it. Sorry about that!

Which way is north?  You'll want to know which plants are mostly sunny, partially sunny and shade tolerant and plant accordingly.

To save work in the future of cutting grass, I would extend my garden between the trees as it would be so annoying to cut grass between your trees and the garden box. Unless you have a really good reason to have a raised garden box between the trees, I would not put in a raised boxes between the trees.

You can plant some plants directly under the trees.  You will need to evaluate how much sun they will get.  There are more types of plants to plant on the sunny side of the trees compared to the north shady side of the trees.  You might like to make a list of all the plants you would like to plant then plant them accordingly with taller plants behind shorter sun loving plants.  I would also try to get as much mulch as you can get your hands on.  

In the fall, gather up all the leaves you can get for mulch. Or straw and wood chips are other good mulches.   Just make sure that there is no residue chemicals on them, so pick your sources wisely.  

You can do the lasagna technic for your layers of mulch over the grass.  Or some prefer to turn their grass over first to minimize the weed / grass pressure before laying the mulch.   I would not get hung up trying to do the perfect method.  Find what works for you.  Over time your methods will likely evolve.  

Concerning your mature trees the traditional thing to do with the slash or fallen branches is to burn it because it's a waste stream that shrinks in fire.  But I'd propose it's a resource as fungi food.  If you chop it up and get it to make good contact with your forest soil it won't be a fire liability or as bulky after the soil food web works it over.  Oregon commercial orchards are regulated by states laws (like deq or something--I aint an expert)  I assume because of what they use for inputs.  But what do forests have for inputs other than light air and water?  Fungi recycled plant food big time, and bacteria and animal recycled matter too.  I'm pretty sure one of the winning facets of hugelculture is the fungi working in the background.  

So some things to think about for your big picture context.  Do you have loam or clay soil?  The loam meets that description pretty much every fruit tree for sale wants "well drained" and it warms up a little faster than clay in the spring.  Both types of soil benefit from fungi but what you have to work with will inform what you do to improve it over the years. For instance if you are in clay there are fruit tree rootstocks that will do better than others there.   If you're in mixed douglas fir hardwoods you might have the acidic ph already to grow blueberries easy-mode.  But if you read about it on the internet and skipped getting a soil test before you start then you might think you need to supplement Sulphur, wait a year, ph test, then plant them, then buy acid-loving plant fertilizer.  Maybe, but maybe not the way to go.  My soil test recommended I do dolomitic lime.  I have; not at the blueberries, but at pretty much everything else.  My soil was very low N and K and low P, 38 inches of rain a year so I suppose the more water soluble stuff is lost to the water cycle.  I've added lots of woodchips and goat manure because I think it will address and help what I have to work with.  Looking forward to my second soil test this fall.

I recommend blueberries in your wettest location if it gets enough light and you have naturally acidic soil.  It is the most water dependent bush we grow at 2" per week, but the berries are a super food.  A rhubarb maybe two if you really like them in your future drip line in other words centered between fruit trees future bigger shade.  Picture them taking up a little less than 3'x'3'x2' each.  Hybrid comfrey in similar spaces a couple feet away from your trees *if* you are sure you won't need to relocate it.  They get taller but not as broad as the rhubarb. You will be mad at me if you plant comfrey and then need to dig it up and try to remove it.  But it's compost activator, strawberry mulch, medicinal, animal fodder.   I recommend asparagus in a drier place that you can leave it for 25 years.  It has deep roots tall ferns low labor early season yield after the 3 year investment. Spring mushrooms, rhubarb, and asparagus are first yields here.  And strawberries if you can provide them enough southern exposure so they can get full light despite the nearby trees or maybe in a damp spot with more than half light so they get plenty of water.  They like 1 1/2" per week.  Companion to strawberry is borage and marigold.  A friend of ours has hardi kiwi trellise it's gorgeous up above head height and productive.  I went copy it and lost two female vines to voles.   I would also add daffodils if you like their looks.  Might help with gophers and voles, might not.  Thick mulch, watered happy plants, compost  and vibrant earthworm populations unfortunately draw in these things from the wild as part of the system.

If you have 100 day drought summers like I do then I would invest in a serious drip system with buried pvc.  It fits your easier goal after the initial pain in the lower back investment.  They make special narrow shovels for trenching, and reject sand for protecting the buried pipes before backfilling is cheap insurance against rock damage.  We had a thrown together drip irrigation last summer, and haven't gotten around to fixing it this year.  And I'm out of town on a trip and my wife has an emergency to deal with.  The trees and deep tap rooted perennials  will be fine until she gets to them, but there is a real life case to be made for the easy-mode plants.

I have a similar goal of taking a mini orchard and make it into suburban food forest.  I have an area with about 5 Asian Pears, 5 Asian Persimmons and two apples.  Outside of this little center orchard is 6 plums/pluots and a Kiwi Pergola.  

I am thinking of getting some cement blocks and building little square 8ft by 8ft wood chip beds where I will try a buried log technique for growing Mushrooms.  Garden Giants, Black Poplar, Hen of the Woods and Oysters (Yellow, Blue and Grey).

To do this I will put down cardboard and a thin layer of wood chips and then plug the logs and then completely bury them with more chips.  After a year of production, I put down more chips on top.  And when nothing grows anymore I have mushroom compost.

I will have to make a shade cloth tent for the mushroom beds and I find EMT (Metal Conduit) works great.  A secret:  the 1/2 inch conduit fits neatly inside 3/4 inch conduit, so this means with a little hammering and some bolts I can make Tees to give the frame more structure.

I will then find berries and some greens (Mustard, Collard) to grow outside the beds and will include some of the plants that will keep insects away.  I can use ideas for this part.

My neighbors don't get to see what I am doing since I have an Elaeagnus hedge bordering the yard that is maintained around 6 foot tall.  The neighbors do get rewarded with fresh fruit, veggies and mushrooms that are in overabundance.   Have had no complaints so far.

Thanks all for the advice and opinions.

I've since abandoned this idea, but now I'm thinking of putting the raised beds around/directly under my trees. I would then plant typical companions (some flowers, herbs, alliums, berries that can tolerate shade and some of my greens - chard, kale, etc).

I have clay soil, I don't know much about soil, but I am pretty sure it's "mega-clay". Mushy mud baths/totally unworkable in the rainy season and giant cracks (not over all the yard, but in certain areas) in the summer. I think, perhaps, putting the beds around the trees (not above the graft lines) may help with the water run off. The reason for the beds vs. just heaping more dirt, compost and mulch is just to make mowing easier for my husband...and because he brought home enough precut free cedar to make beds, and I want them out of my garage.

I stupidly put two raised beds about 2ft from my house when we first moved in, and I'm working hard to get all my edibles out of them and into new beds (I'm mostly done). The fruit trees are at least 70ft from my house. We spray our home due to roaches (me and roaches cannot coexist, so not spraying is not optional in my world) and I don't want to get the chemicals in my food or have to keep covering my plants each month when the bug guy comes. Kind of a shameful thing to confess on a permies forum I'm sure, but it's the truth, so yeah. Anyway!