Hi, Johnny. The tree we have is a Hawthorn but there are others. The blackthorn as you say and the ash are home to fairies as is the oak.
I grew up on stories of folk coming to harm after damaging a fairy tree or fort....mostly in Mayo but also in Kerry. If you google Danny Healy-Rae, one of our TDs, you'll see how important it is not to mess with the fairies...especially if you don't want your roads collapsing.
Much to the dismay of my children...too much time in the UK....I do speak to fairies.
Some years ago the late MrG and I joined my brother and his family in a cottage just along the road from where we are now. We had flown so I hadn't been able to take my scissors with me....I travel with crafting stuff....and there were none in the cottage. I needed scissors. We were about to drive into town and the two young nephews asked if I was going to buy scissors.
Of course not, I said, I'm just going to ask the fairies for some. We stopped at the end of the lane and as we looked to our right hanging on a tree branch was a pair of rusty scissors. God knows what they were doing there and how long they'd been there but I got out of the car...thanked the fairies....and returned to the car with two stunned nephews who still don't know if Auntie Gness is a magical friend of the fairies....or just plain bonkers.... :-)
I also know that when I'm walking in the mountains I never button or zip up my jacket. Sometimes the fairies will take your feet and get you lost. If you quickly turn clothing inside out it defeats the fairies....you can google that one too..... x