Island Plant Adaptations Guide Stop 2

Thousands of years ago the Channel Islands knew a moister climate, as did much of southern California. Different plant communities and different animals, such as the pygmy mammoth, existed on the islands. Island ironwood is a reminder of this earlier environment. Fossil evidence demonstrates that ironwoods once grew on the mainland as far north as Washington and as far east as Nevada.

Today, Santa Cruz Island ironwood grows only in locations where conditions approximate California's earlier, wetter climate. Small groves of these trees are found on Santa Rosa, Santa Cruz, Santa Catalina, and San Clemente Islands, where they grow mostly in north-facing canyons cooled by fog. In fact, fog is an important element in island ironwood's successful adaptation and survival. Moisture from fog collects on the leaves and drips down to the soil surrounding the trunk, thereby increasing the amount of water available to the tree.