It certainly will affect everything growing
there as the pine tree
will absorb much of the water and nutrients from the soil where the roots are. Your plants
will be competing with the tree
for needed nutrients and water. tree
roots extend out as much as three times farther then the diameter of the tree
's dripline. They really don't have a "taproot". Most plants
don't. Their root systems are located mostly
in the top couple feet of soil where most of the water and nutrients come from. You really won't hurt a mature tree
by taking out some of the roots, but the tree
will relentlessly continue to send roots out into your planting bed. When a root is cut, say with a shovel, it will begin to branch out at the cut.
This is not to say that your plants
cannot sustain themselves in the shadow of a large tree
. The tree
will not take ALL nutrients, but you can make it easier on them by making up for the lack of nutrients with more fertilizer or compost.