Sending hugs because I know how scary it can be.
Yes, I have had various types of paranoia during manias and depressions. They were often also accompanied by delusions, which frequently went hand in hand. One major example, that lasted over a year, was a fear I had that the devil lived in my husband's dark room in our basement. That was sort of odd, because deep down I don't believe in the devil, but the unhealthy mind can do crazy things. I had had hallucinations twice in my life before that where I saw the devil, when psychotic. The second time the devil was in my garage. Then I had some odd notion that he moved into the basement. That worked out better, in the end, because I really needed to go to the garage. For one full year, I would not go down into our basement. Not even to get supplies, which we kept down there. My husband always had to go. For some reason, I didn't fear that the devil would go after my husband.
My psychologist worked with me a lot on the devil/basement, suggesting exposure therapy. One time (half-way into the paranoid notion), I tried to go down and sit on my stationary bike. I started peddling, but less than one minute later, I heard a loud sound as if a whole nest full of hatched chicks were cheeping. That scared the living heck out of me. I basically fell off the bike and ran upstairs, as fast as I could, and slammed the door. As irrational as it seems, I thought that was a sign from the devil.
When I initially told my psychiatrist about the above, he was a bit obnoxious about it, asking me to describe the devil. “Did he have a tail?” and crap like that. He later stopped that.
At the same time I had the above fear, I was also afraid I would choke on meat. For weeks, I would either avoid certain meats, especially steak or pork chops, or would chew teeny pieces for a long time before swallowing.
I did get passed the above.
I have had several delusions during psychosis that I believed 100%. The odd thing about the devil in the basement, was that intellectually, I would acknowledge its absurdity, but I still had that extreme fear. That’s what I’m assuming is the case with you and those trees.