If you're growing for firewood, you also want to consider which woods burn well, how long they take to season, etc.
Sycamore and field maple need good seasoning and aren't the best burners, in my experience.
Sitka and other softwoods burn hot but fast; brash is great for firelighting, but still needs seasoning. My memory is telling me that larch needs seasoning for two years... is that right?
Ash is the prince of woods, will burn green and burns very very hot, for ages, leaving only... ash, hence its name. But ash can be hard to get hold of these days, due to the ash dieback disease, so please don't bring ash in from otherwhere; either find a reputable local supplier who is using only locally-sourced and grown trees, or take your own cuttings from trees nearby.
Beech and hornbeam are good, but I don't know if they'll grow where you are. And are not the fastest growers.
Hedgerows are a lovely way to grow firewood for harvesting; usually on a ten year cycle. And the plants protect each other, provide shelter for livestock, habitat for wildlife, etc. Hawthorn, blackthorn, hollies, and other such natives are the usual components.
In Wales you find a lot of laburnum hedging, which is harvested on a ten year cycle for firewood. It's a grand burning wood, but I never did establish how come the livestock aren't poisoned by the flowers and seeds

In Cumbria we used to use
Trees Please - their website is full of useful information about the various ways of using trees and the habitats created. I imagine there's at least one Scottish equivalent.