If each block is a meter cubed, then each side of the cube is a meter. The tree is about 95 blocks tall = 95 meters. The tree may look skinny from far away because it's so tall relative to its diameter. If you see it in person, you can get a better idea of how massive it is. The diameter at the base is about 8 blocks I think. If you cut a hole in the base, you could easily fit a car through it.