Trees fascinate me as well. I love the connections of trees with folklore. Did you know that the Druids worshipped Oak trees? Of course you did. But did you also know that word Dru is Ancient Greek for tree. Just love those connections, unfortunately with this one I have never been able to track down why??? This is one explanation I just found. Search for dru greek.
"Many scholars, who have endeavored in the past to solve word derivations, have concluded the meaning of the word Druid comes from a contraction of two Indo-European, i.e. two Sanskrit words. The two Sanskrit words Druid is said to derive from are deru meaning oak, and vid meaning wisdom. The first person to postulate this was the ancient-Roman scholar, Pliny the Elder. He made this assumption while, ostensibly, endeavoring to explain Druidism to his contemporaries. In Pliny's descriptions of the beliefs and actions of Druids, among other things, he noted they had a reverence for oaks and proposed the title of Druid derived from the word oak. Just as Stoicism was a current Greek and Roman Phenomenon in Pliny's time, Druidism was a current Celtic phenomenon.
It should be pointed out, however, that it was the ancient-Greek word for both tree and oak which was dru. This was not the word for oak in the languages of the Gaels, the Gauls, the Galicians, or the Galatians. Considering this, Pliny’s explanation seems convenient, and a little near-sighted. Pliny the Elder, as a learned Roman, would have been very familiar with the Greek language. Dru was the word for tree and oak to the Greeks, but not to the Celts. Perhaps Pliny was misinformed, and guessing to some extent, about Druids."
Footnote: You may have heard the word "torc" used by Celts to describe a bracelet or neckpiece with animal finials such as horses, rams, lions etc. The Greek were wearing these long before the Celts. I actually have one - it is my favourite piece and I plan to be buried with it - it is a 18kt gold hand-made twisted bracelet torc with ram's heads. I bought it in Olympia.