On the whole, the shore land protection act is more concerned with what you take away, not what you decide to plant. A good summary about the act can be found here <
http://des.nh.gov/organization/commi...ments/sp-5.pdf > . If you root around the DES site, you can also find another fact sheet that lists acceptable trees and shrubs and other greenery <
http://des.nh.gov/organization/commi..._plantings.pdf >
I don't think I answered your question directly but at least you'll have more information.