By Michelle Werts

Mangroves in Koh Hong, Thailand
Mangroves in Koh Hong, Thailand. Credit: Jim Winstead (jimw)/Flickr

When I hear the word ocean, I picture sparkling blue waters, colorful fish and wide open sky. Having been accused of being able to swim better than I walk, I have a natural affection for all types of water, including oceans. So today’s celebration of World Oceans Day is near to my heart. The idea of a day celebrating oceans was first proposed back in 1992 at the Earth Summit and was then unofficially celebrated for almost two decades until the United Nations officially declared June 8th as World Oceans Day in 2008. Wondering why I’m talking about oceans on a tree blog? Beyond being near to my heart, oceans are also dear to a certain tree species.

Meet the mangroves.

These trees include 80 different species that grow along tropical coastlines — most within 30 degrees of the equator — with oxygen-poor soils and slow-moving water. Actually, they don’t grow along the coastline: They grow in the water itself. Their roots act like stilts, holding their branches above the wake. This unique structure allows them to withstand the ebb and flow of the tides. They also have an ultrafiltration system to regulate the amount of salt in their system.

Beyond being fascinating to view and contemplate, mangroves provide crucial benefits to the tropical and subtropical ecosystems that they call home:

  • They provide shelter underwater for schools of fish, oysters, crabs and other aquatic life, and their branches provide shelter and food for birds, monkeys, bats, bees and more.
  • Their complex roots slow the water lapping the shore, helping control sediment buildup and reducing erosion from the shore.
  • They protect shoreline communities, acting as a buffer against powerful waves and storms.

Despite their important contributions to these ecosystems, though, mangroves are disappearing, thanks to activities like industrial shrimp farming and house/community building — beachfront property is always sought after. In the last 50 years, the world has lost about 50 percent of its mangroves. As a result, groups like American Forests have been working over the years to restore mangrove forests. For more on mangroves and the difficulties they face, check out the American Forests feature “Mangroves in the Mist.” And while celebrating the oceans today, give a thought to the trees who love the oceans, too.

Credit: Senorhorst Jahnsen (rabanito)/Flickr