I'll take the job of building a treefarm again if nobody minds.
There's a bunch of new trees, but from what I can gather the wood isn't craftable into any new colored planks. The Fir, Redwood and Acacia blocks are kind've neat looking if used as a building block though. I am curious what color planks each will generate.
I like the concept of the trashcan, but I think I may adapt it a bit and go square instead of circular (maybe), plus I'm going to start the farm at bedrock level so the first 7 tiers are underground. Still open in the center for tall jungle trees, and possibly a second center level for redwoods. It'll still probably stick up above the ground ~30 blocks or so, but at least it won't be so looming.
The 4 autumn trees I think I'll just give one level (or two). The wood looks to be the same as oak so the only value of those would be saplings for people that wanted to plant some colorful trees around their house or grab the leaves for some nicely colored shrubbery. I'll probably take the Oak down from 3 to 2 levels too, depending on how close together the Autumn trees are able to be planted.
[edit]: So I just did a couple of quick sketches and I think by expanding the farming rows by 6 blocks I can actually decrease the size of the structure (slightly) if I go with a square-ish build. So instead of 19 plantable blocks per planting strip I'm going with 25, and that way I can decrease the amount of levels for each tree. In an ideal world everything would be below ground except for the Redwoods and fir (and maybe a center giant rubber tree), so I'm hoping that I can do that. I may have to build on a hill.
I think I may even do only 1 level (4 planting strips) of Oak. That's 100 trees, and at a minimum of 4 tree-blocks a pop that's a shit-ton of potentially craftable loot. I'll probably make that the level closest to bedrock though, as it's more of a harvesting-resource than the more valuable trees for crafting colored planks.
It'll take some testing to see how Autumn trees grow, but I assume they'll grow as tightly together as Oak given that they're just Oak trees with fancy leaves. Acacia I'm assuming needs 1 space between plantings like Birch does.