Question
Please advise...our trees are about 13 feet tall now and we are not sure what is best for the tree.  We prefer to trim bottom branches....trees are planted in clay soil on a hill in Oakland,
California...they are in sunlight and have ivy growing in the yard around them.  Previously, there were Monterey Pines which we cut down at a neighbors request.

Answer
You can prune the lower limbs from a redwood without harming the tree. Make the cut about 1/4 inch from the trunk. There is a area flush with the trunk that is called the branch collar and this should not be cut--the wound will heal over if it is left in tact. As long as you do not cut more than 1/3 of the limbs off the tree will be fine.