Читать книгу 101 Hikes in Northern California. Exploring Mountains, Valleys, and Seashore онлайн

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Description The hike begins from the visitor center on the paved River Walk (0.0/20') and quickly proceeds into shady woods of young valley oak. Also present are prime examples of the many massive poison oak shrubs that grow throughout the preserve.

Recognize valley oak by its distinctive deeply lobed and rounded leaves. Once common throughout the central Valley, its population has been dramatically reduced by agricultural development. Today only a handful of locations still harbor portions of undisturbed valley oak habitat—this preserve is one of the best remaining examples.

You next cross a bridge over the Willow Slough floodplain, where a sign highlights the remarkable fact that here, more than 60 miles from San Francisco Bay, the elevation is a mere five feet above sea level and that tides cause the water here to rise and fall as much as five feet each day.

The path reaches a junction by wetlands (0.1/10'), where you turn right. The path winds by the edge of a pond and alongside wetlands thick with willow and oaks. It then travels atop a berm with wetlands on both sides, where you can see abundant “balls” hanging from many oak trees. These are striking examples of galls, which are created when insects lay their eggs on oak trees. This stimulates the tree to produce distinctive structures in response, which protect the young insects as they hatch. Hundreds of different types of gall-producing insects exist, each of which generates a different structure. A careful eye will find other varieties on leaves and branches throughout the preserve.