posted 6 years ago
I grow nearly all of my fruit trees in raised beds (to elevate the rootball above the water level in a spot that floods twice annually), but most aren't far enough along where I can tell you if it was a bad idea. I have about 20 beds like that (half my trees), so I hope it works. =D
They are about 3 years old and doing great, but haven't grown so large yet that I know for sure whether the boxes are a problem.
I made my beds out of 2x10" pressure treated lumber (2.5 x 2.5 feet square), and I dug below the bed so as to not make a hard division between the normal soil and the supplemented soil. I also mixed the normal local soil (a tad too clay-ish for my liking) with the supplemented soil in the box, so the tree gets used to the natural soil. It's about 80% soil from the area.
And I bury fish corpses, cow manure, vegetables, egg shells, turkey intestines, chicken entrails and corpses, chicken bones, etc... whatever I can get my hands on to gradually break down underneath the trees. I usually put it down a decent ways, so it'll break down quite a bit before the tree roots reach it.
After three years, the trees haven't been in any way hindered by the raised beds, but I figure if they ever are, I'll just come along and unscrew the boards, or - worst case - use a chainsaw to cut the boards off. I suspect the tree roots will just burst the beds on their own if I did nothing - I mean, tree roots crack through concrete...
But taking the boards off is basically my plan irregardless of if they need it or not. Being more into hugelkulture now, I intend to eventually cut the boards off, stack tree logs around the beds and form a hugelkultural mound in place of the raised box, and grow something on the mound to help it not get eroded.
My newer trees (5 of them) are just using logs as a plantbox to raise up the soil hoping the logs will eventually break down and provide a hugelkultural benefit.
(I fix the logs in-place with weedblock fabric and chicken wire, with bricks holding it all down so the water doesn't wash the logs away - again, flood zone)
To my (ignorant inexperienced eyes) nothing about your mound looks bad, assuming you're going to mulch it like crazy to improve soil and keep weeds down.