The blade that you have was used for carpentry, cabinet building or general woodworking use.
A "buck" saw, as everyone else has insisted that it is, which would be used for cutting firewood, has a much greater aggressive tooth pattern, like a traditional cross cut saw would have.
Use a Google search for bow saw, and click on the images. Then do the same for a buck saw. Look at the vast differences between the blades. The saw that you have was meant for more fine and precise cutting, where as a buck saw is meant for aggressive cutting where it wouldn't matter, as with firewood.
I reckon a guy could cut firewood with your saw blade, but it is going to give you a workout, and take 20 times longer than it should.