Cloning Lab

Cloning Lab can combine two saplings (one with foliage A, another with stem B) into two saplings, both of which have foliage A and stem B.

This is used to improve drops from trees, and also for decorative purposes (resulting trees can look very unique and/or weird).

The only tree part that isn't accepted by the Cloning Lab is Geode Foliage. One of the reasons for that is combination of Geode Foliage and Redwood Stem being way overpowered. This makes Geode Saplings one of the most valuable in the game - each Geode Tree only drops 1 Sapling, so you cannot multiply them as most other trees.

There is a working Cloning Lab at the Science Outpost.