Green Roofs on Guam–How Vegetation Survives Typhoons?

Guam, a tropical island located in the “typhoon alley” of the Western Pacific is populated by 180,000 people and visited by 1.5 million tourists annually. Frequent damaging winds and occasional strong typhoons (hurricanes) discourage farmers from the production of fresh fruits and vegetables. Over the last decade, documented benefits of green roofs and their increasing popularity has convinced some home owners to establish roof vegetation on existing solid concrete roofs to conserve exceedingly expensive energy and at the same time to grow a small garden for personal enjoyment. A major challenge is the survival of these gardens during tropical storms when over 200 km h^-1 winds blow for several hours. It has been determined that only dense turf rooted to wire mesh that is attached to the concrete roof can be fully typhoon proof. Other plants need to be grown in their own soil inside flat porous rings inserted within the turf mat. In the event of wind damage and even complete soil loss, the rings can be easily filled with new soil, the green roof becomes fully functional within a few days and the garden can be reestablished. Information presenting the survivability of different types of vegetation under conditions of heavy rain and winds ranging from 142 km h^-1 to 378 km•h^-1will be presented and discussed.