For example, if your goal is to make an 8x10 print, use the tree from a 4x5 print to make your dodging tool. You then use the tool about half way between the lens and the paper.
And with respect to burning vs. dodging, I find it useful to try to blend in several small burns along the edge of the detail you are trying to hold back (the tree) rather than trying to do single burns. In essence I build the exposure outside the tree out of several layers.
It is more complex, takes longer and requires some practice, but it gives you great control.