You have to remove the sapling from the tree spreader. I would recommend putting it kind of far from your base so you don't get locked out by foliage. Edit for spelling

You can just take the tree seed out of the planter, and they will all disappear and re-grow differently. Or, you could move the seeder further away. It doesn't have to be close to your base for it to be useful.

I like this better. I want to build a massive power station and surround it with trees

No way to deconstruct the trees, but you can deconstruct the planter and rebuild it somewhere out of the way.

remove the tree seed and deconstruct the spreader. Move the spreader away from your base and then reconstruct it along with any optimizers.

Deconstruct the tree planter and put it somewhere else.

You can by taking the tree seed out of the planter. Then you can deconstruct and move it to another location if you want.

Remove the seed from the tree spreader, then build Foundations around and in front of your base. Then replace the seed in the Tree Spreader. Plants doesn't grow through foundations. At least they didn't when I last played. The 'naturally occuring' trees, though... nothing can stop those.

I love this...I've just run onto this exact issue and was about to ask what to do. I was groaning thinking I would need to reconfigure my entire base because trees were invading my lab.

After a while, trees just start growing all over. No planting involved. I was unlucky enough that one grew up right in from of my base door.