while its not uncommon for trees to grow from 2 or more saplings in to a single tree it is a little rare so you do not see it commonly in more civilized areas. the more rural the place the better chance you will find joined plants, i personally had a pinetree outfront of my house that was 2 trunks in 1 as well as seen pine trees and other variants that either grew insanely large or conjoined several trees in to 1.
the only reason trees in salem work as a wall is because the game does not give trees an open hit box around the trunk for you to "walk" through. same is true for drying racks we cant walk through empty ones even though clearly we should beable to.
besides i happen to love my birch tree wall im making its pretty
