mangrove trees, tropical oceans


bark


rainbow eucalyptus, Indonesia


Not All Alike


All trees have the same characteristics, like bark, roots, and trunks. But these can be very diff erent, depending on where the tree is and what its environment is like.


Rainbow Bark


Bark protects trees. It acts like a shield against weather and insects. It can be dark and craggy, like an oak tree’s, or pale and papery, like a birch tree’s. In the case of the rainbow eucalyptus tree, it can look like someone painted it with a brush. Unlike oak trees, which grow new layers of


thick bark every year, the rainbow eucalyptus has layers of very thin bark that shed year round. Papery, brown bark peels away to reveal shades of tender, bright green bark beneath. Over time, the sun and the air turn the green bark purple, blue, then orange, pink, red, and yellow. T e bark turns brown just before it sheds. Because the bark is shedding at diff erent times, the tree looks like a living rainbow. T e colors are always changing. No two trees have the same pattern. It’s more than just pretty. T e bright colors may be a good defense. T e colors send signals to insects and other animals that it is poisonous.


16 NATIONAL GEOGRAPHIC EXPLORER Snorkel Roots


Twice a day, the salty tides rise and cover the roots of the mangrove trees living along the shore. T ese trees are tough. Hurricanes and storms batter them, but they stand tall. It’s their roots that help them live where most plants could not. Roots suck up water and nutrients from the soil. T ey also help anchor the tree so it can stay upright. Most roots grow underground, but not mangrove roots. Saltwater kills most trees, but a mangrove


has special roots that fi lter out the salt in the water it lives in. T ese roots arch high over the water and anchor deep into the muddy soils. Some mangroves have pencil-shaped tubes that grow straight up from the roots and reach above the water when the tides rise. T ey act as snorkels to cope with daily fl ooding by ocean tides.


roots


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