If this is the case, then we recommend that those plantings have irrigation provided for those periods that are very hot and dry. No routine irrigation - only based on need. But keep in mind that no mature pines seem to enjoy this environment. Pitch Pine is interesting for its ability to withstand the fires which gave our island its name. It has thick bark to protect the living tissue underneath.
Fire actually stimulates dormant buds to grow, which they do by means of epicormic branching.
Another potential threat to trees is the Asian Longhorn Beetle . It has not hit Fire Island yet, but the pest has been found in nearby Amityville. Anyway, your best bet is native plants. There are only a few shrubs that deer do not eat. It likes lots of sunlight.