For trail riding, I wear what maybe are yoga pants in summer. (I buy them second hand at thrift stores). Maybe they are cycling pants? Anyway, they are light, have no zippers , somewhat stretchy, and very cool and comfortable.
When it gets colder, I ride in sweat pants. I find jeans way to hot in summer, plus a pain, when you need those 'tree breaks, LOL!
I also don't trail ride in regular western or English boots., although when it gets really cold, I ride with winter riding boots, like the the ones Muck boot makes (hate the ones with zippers, as I had one zipper fail, when boots were not that old, and might as well buy a new pair , as try and get that zipper re placed ) I also found them too tight, if you tried to wear thick socks
Yes, I have ridden many many trail miles in jeans, just found what works better over the years!
And, a flash from the past-how about those red jeans!