Well im not very familiar with all the different kinds of trees I have cut this past spring. So im wondering is the weight of the splits is a good way to figure out the available btu's. Like I noticed that the white birch I cut seems heavier then some other kinda trees I cut at the same time in april. Im thinking the lighter splits would be better for burning now while its not so cold then save the heavier birch and unknown species for the colder weather. Or maybee the heavier species just haven't shed as much water. I dunno.