A downed tree is actually how I fell in total love with pecan. My brother in law had 6 big ones in his property, but old old old trees. One night, the wind came up and a big one came down.
We cut it up and stacked it and from a long dead limb in it I took home about 6-7 nice 3-4 inch diameter rounds. I split them and started using them in my pit. I was in love. I took a load of that wood home everytime I went out to his place. Used it about 3 years.
I'm in SC where you can't sneeze without hitting a hickory tree, so everyone uses hickory. It's a very regional thing, hickory smoked pulled pork.
Me...I didn't grow up here. I was a Louisiana kid who spent a lot of time in Arkansas (moved there at 13) but my family used mostly post oak (Texas influence). Hickory was very available in Arkansas, but it wasn't our thing.
After I moved to SC, I kept oak in my heart but discovered adding fruit (cherry is my favorite) made it twice as nice. People here love my pulled pork because it's different. And the oak here is way different than the oak from "back home"
After finding pecan, I left oak forever. The oak in SC runs mostly red oak and I just can't get post oak here. Red isn't the same, it is weird to me. Kinda like if post oak had a mesquite great grandpappy in it's family tree. I can get white, but pecan reminds me of post oak from the ArkLaTex region.
Now I use a pellet, but if I ever build another pit, I'll be on the hunt for another load of pecan.
But to India's point, absolutely look at a downed tree as a resource.