soupy1957 said:
I'd be hard pressed to be able to call around and see if I could buy exclusively one preferred type of wood (say "Black Birch" for example, that has a very high BTU rating).
Soupy, you might be surprised. I just got more black birch in one year than I've burned in the previous 25 years.
Since I never had a lot at once, I never noticed just how powerfully it burns is a straight load. One of our members here, Gyrfalcon, said he got a lot more heat out of his little stove with black birch than with sugar maple, and I paid attention. When I asked what woods my guy was cutting, he said it was a mostly oak woodlot, red and white. "Any white ash?" "Not a stick. There's some cherry, a bit of beech... I got quite a few black birch if you like that stuff." Ding, ding! Ordered several cord. That's a big bargaining chip, a lot of these guys are hard pressed to find somebody who wants even one whole cord. I got two cord delivered, then the guy told me he didn't want to cut anymore because the black birch on this woodlot was super stringy and hard to split. I told him that was too bad, because I really wanted all black birch like he said. Well, don't I get a call the other day telling me that the guy has another load of black birch ready for me. If the black birch availability stops... well, he still has that beech, ya know? ;-)
Wood is a commodity, just like any other. Supply and demand dictate the price and the quality. The supply is always there, but the demand for green wood peaks in late summer/early fall. These guys need to put shoes on the kids and food on the table all year round. If they know you are ahead on your wood supply, they will often jump through a few hoops to get the business during slack time. Always ask what they are cutting, you just might get what you want. Most of these guys have picky customers that they don't want to lose. Learn to be one of them and let them deliver the sopping wet red oak to someone else.
As far as the charts go, they are calculated by using the average density of each species when it is dry, then using the amount of chemical energy in a cord of wood at that density. Nobody is out there actually measuring the heat output from a wood stove using these woods. I feel that the charts are only a rough guide. How each wood burns in the stove is the final determinant of heat output.
For example, black birch is right about up there with black locust and shagbark hickory. Of the three, the black birch burns fastest, the hickory is second, and the locust burns for a very long time... at least in my stove. What that means is that the birch will put out more heat in a given time than will the locust, even though they all have close to the same BTUs in a cord. Sure, that also means I use more of it in a given time, but the extra heat output per hour can make the difference between a comfortable home and a chilly one.