What affect if any would "pine needles" have on a 50yd stretch of evergreen trees if the needles were blown under them ? Customer wants me to blow 6 pine trees worth under a fence line of 15 evergreens within about 30 feet of the pine trees. I blew about 5 minutes worth under the evergreens to see how it would hold the large amount of needles. Looked like a 18" mulch bed of pine needles under the evergreen tree which are larger trees, 14'. Be easy to do the clean up this way, but do not want to bring harm to the evergreen trees.