Slang for a Lignadoratist, someone who worships the knots on trees as their Gods. They practice their religion, titled "Lignadoratism", by surrounding themselves in tree heavy areas and holding on to as many knots on the trunks of said trees at once, while pouring all their feelings and worries into the trees. They believe that by doing this, the trees will relieve them and lead them to a less stressful lifestyle.
Tree Horn Worshippers tend to be partial to large trees such as oaks and maples. They prefer these because apparently the larger the tree knot they hold onto, the stronger the connection is. However, Lignadoratists still enjoy and worship all knots on the trunks of trees, including spruce, pine, and cherry.
Please make note that those who practice Lignadoratism do not worship knots on the trunks of elephants, such as tumors or cysts.
Dude, don't hang out with her, I've heard she's a total tree horn worshipper.