Chinese scholar tree (Sophora japonica) / Japanese pagoda tree
槐
=
木
+
鬼
:
Helga Horse (hu) set up a Christmas tree (木) in the airplane's kitchen (ai2), but soon after a demon (鬼) possessed it and morphed it into a Chinese scholar tree (槐).
树
=
对
+
木
:
Sheldon Shrimp cultivates a Christmas tree in the space station's bathroom. He is very happy that he found the right tree, just the one he imagined, and—in his mind—marks of the tree he imagined with a big green check mark.