Oak has a deep furrowed bark. The wood has a thick outer band of lighter coloured timber called sapwood. The centre called heartwood is much darker. This contrast when looking at the face (rings) of a sawn piece of oak is the most telling.
It takes years to instantly recognise timber so don’t be harsh on yourself.
Ash has almost no sapwood visible, on all but the most huge old trees which it is sometimes seen on the timber from it. The bark is thin, and the flesh of the timber is very light in colour compared to oak. Ash does burn well and gives out the most heat as it is very dense. The aroma of Ash can be bitter, especially if it isn’t well seasoned.
A mix of woods produces the best results and aroma, oak is very aromatic but needs to be very dry and well split to burn well.
Beech burns nicely and is faster burning with a purple-ish flame but doesn’t produce the heat of the above two, again needs lots of seasoning.
I could go on and on but I’ve already probably reached the readers boredom threshold! 😉
Happy learning 🙂