A tall tree would have plenty of trunk visible even in 3/4 view, but the trunk would be foreshortened and the curvature of it would be apparent. The roots would form an arc rather than a straight line along the ground, horizontal features such as cracks in the bark would form arcs, etc.
As for leaves, I think it needs a bit more detail, yes. You don't need to draw individual leaves, but more indication of leafy-shapes rather than vague blobs would be good. In addition, at this size, the fact that the tree has many branches and isn't a leafy lollipop should be apparent - try to suggest gaps in the tree with shadows and highlights instead of shading the whole thing like it's a sphere.