How to join two tree species into one? For example, a spruce with a birch. Any that won't mix. Thnx.?

Answer 1

you'll never mix [in *any* way] a spruce (a conifer) with a birch (a flowering plant) because they are fundamentally different.

Answer 2

By the definition of species, you can not mix two different kinds (except in some cases ie. liger or tigon, mule etc. but those are anomalies). You can, however graft two trees together. One website that has info is: http://www.oreworld.org/grafting.htm

Answer 3

This process is called grafting. I'm sure some trees wont take but if they both grow in you area it will probably work. If i planned to attempt this i would contact Home and garden.com