Larch or Aspen trees

Aspen is a type of poplar tree, with white bark, pale wood (shade falling between the current birch and pale oak), with (seasonally) vibrant gold, and sometimes red, leaves.

Larch is a deciduous conifer (very unique!), with reddish undertones to its bark, a golden light-brown hue to its wood (warmer in tone than current oak wood), and (seasonally) vibrant gold needles. 

The tree(s) would have merit in the game, as yellow (or red) leaves would be introduced, adding color and variety in building, as well as the natural environment. Even if new wood types were not added, and the aspen trees were merely a variant of birch, or the larch trees variants of spruce, the new leaves would be a wonderful addition.

As for biome, both trees thrive in high altitudes, and in cool-to-cold temperatures. They would be great transition trees between taigas and mountain forests.