3 ideas
Kilogram for kilogram, dry wood of almost any species releases nearly the same energy. Species differ mainly in density, so hardwoods such as birch or oak pack more heat into each stacked cubic metre. The factor that matters most is moisture, because water in the wood must be boiled off before it gives heat, and wet wood burns cool, smoky and sooty.
Fell trees in late winter, when sap is low and snow makes the logs easier to move. Split them soon afterward, because wood loses water mostly through cut ends and split faces, not through bark. Stack the wood where sun and wind can reach it during the dry spring months, when most of the year's drying happens, and cover only the top so air still moves through the pile.
A stack of firewood is readable evidence of the person who built it. Its straightness, tightness, and choice of site show how patient and foresighted the builder is, and how much they care about how things look. Because a woodpile is built long before the cold it answers, it displays character through accumulated effort rather than through stated intentions.