Best wood under audio components?


I am just about finishing my DIY audio rack and wondering about what type of wood would be the best directly under the components? 
I am from Norway and don`t have access to North American maple. Baltic birch plywood is rare also, because we have Norwegian. I would rather have other solid type of wood under my components than plywood, but the efficiency is the major consern, not the outlook.

What type of wood would you recommend?

Thank you! :)
128x128korakotta
Himalayan salt lamps have a nice warm glow and provide low level light in the space. Other than that I doubt they do anything although they were and maybe still are msrketed as producing negative ions since salt is a pyroelectric material, I.e., produces negative ions when heat or voltage is applied. In the case of the Himalayan salt lamp the wattage of the bulb supplied is not suffientky high to produce anywhere near enough heat to produce negative ions and replacing the bulb with a higher wattage bulb doesn’t help. But they are pretty, I’ll give them that.
Thank you for all of your helpful comments!

I have a chance to choose between Norwegian maple, Ash, White Oak, Red Oak, Walnut, Elm, Ceder, Mahogany, Pine, Norwegian Birch, Elm, Siberian Larch.