Before I can start putting seasonal leaves onto the trees, I need to have something there for when the leaves are not, which is why I spent the last few days making bare branches for the trees.
In my initial attempt, I tried to make floor-thickness cylinders for the thicker branches that are shown in the game as ┴, ├, ┌, etc, which taper off into the neighboring tiles, where I would put a small + shape for the smaller branches, that the game shows as ¼ symbols. It… did not work. very few of the smaller branches actually connected to the larger ones, while most of them were simply standing on their own, and all looked exactly the same as well, so the result was a floating grid around each tree, that was the same at every level, mostly, and did not look natural at all.
First thing I had to do to fix this was to allow some tiles to have random rotations, to get rid of the most obvious tiling.
Then I modified the small branch tiles so that they connect to all of their neighbors, offset the center intersection along some diagonal, and made them use the random rotation, and made a similarly shaped and thinner version for the twigs.
The result is something that looks decent both in a zoomed-out areal view, as well as in a first-person perspective, and can provide a decent base for adding leaves to the tree.
As a bit of fun, since I have wintery-looking trees anyway, I tried out adding some shader-based snow onto the landscape. I think it looks pretty nice, personally.