Except for my time in the Navy, I've been heated with wood nearly my entire life. I grew up burning coal and wood.
For the last 35 years, I've generally had enough of my own firewood. We burn 5-6 cord per year. Some years I'm a little short and I have to buy a cord or two. Some years I have an excess. Most years, a number of friends plus me, deliver or cut/split firewood for the local elderly for free.
I've got several friends who sell hundreds of cords per year. To sell year after year, they are careful to sell seasoned wood that properly fits the customer's stove or fireplace.
It sounds like the wood you are getting is coming from the spoils of arborists who are taking down trees.
People selling wood for burning, at least around here, typically cut it in 16-18 and 20-22 inch lengths. If they know you, and you call ahead in late summer, they will cut it to the length you want. Short lengths cost more than long lengths.
If you aren't getting that service, find another supplier. I wish you were near here. I could recommend several really good suppliers who sell only oak, gum, hickory, and maple.
Please be careful with the sassafras. I have a lot of it on some other property we own nearby. It burns like dried pine soaked in gasoline. We use it only for starting fires.
Keep Warm,
Ken
