Healthy soil and sustainable growing

["D Knoll" <homeschool@iontreasures.com>]

The power company is cutting lots of oaks and a few pines and things out
back along a long stretch. I'm having them dump a bunch of it (at least 6
big loads) and will be using it partly to cover a lot of the grass in the
front yard, and just as general organic matter added in all over.

My questions are:
1. I have noticed how quickly everything breaks down here, but how thick
should we spread the mulch if we want to kill the grass? We're taking back
our lawn. I see quotes like 4" and 6" deep, and am thinking of maybe putting
cardboard or newspaper under parts of it, especially where we want to make
permanent pathways.

2. If I put wood chips on growing beds, will it pull nitrogen from the soil?

Diane