Question
We have a ~60-foot pine in the front yard (northwest exposure) that's all by itself - just the one pine surrounded by lawn.  We'd like to plant another, smaller tree (probably white birch) about 25-30 feet away from  it.  Shade is not a problem - the pine provides some but not too much.    

But I wonder about the root system of the pine - will it and the birch compete for water and/or nourishment, or will planting another tree that close damage the pine's roots?

Thanks,
Larry

Answer
A pines root system extends about 1 1/2 the width of the branches. Planting 25-30 feet away from a pine will not be a problem. They will compete for water and food but this will not be a problem for either tree. I see no problem with this planting.
When you plant the new tree make sure the new hole is about twice the size of the rootball of the tree and fill the hole with good top soil, water and mulch around the tree with not more than 3 inches deep of mulch.