Читать книгу Urban Trails East Bay - Alexandra Kenin - Страница 16

The East Bay is filled with such a wide variety of trees—both native and non-native—that it can be hard to feel like an expert. However, if you can identify the three types of trees listed below, you’ll enjoy seeing them again and again as you hike throughout the region.

Oak. There are more than twenty species of oaks native to California, many of which thrive across the East Bay. One of the most common varieties is the coast live oak—the one that Oakland is named for. Oaks were an important part of life for the Native population, the Ohlone, who used the acorns to make flour for bread, soup, and more. In addition to the oaks you'll see throughout the parks I describe, you can see what remains of Oakland’s oldest oak (cut down due to disease in 2005) in Dimond Park (Hike 19), and you can see the tall Jack London Oak in front of Oakland’s City Hall on the Oakland Ale Trail route (Hike 24).

Green grass and oak trees line a trail in Mount Diablo State Park (Hike 39).

Redwood. Redwoods, which draw their name from their red bark, are native to the Bay Area and are some of the tallest trees in the world—growing up to 380 feet high and 24 feet wide. For their size, they have a surprisingly shallow root system. Their roots grow outward (as far as one hundred feet from the base) instead of downward, and they intertwine with the roots of neighboring redwoods to increase their stability. Redwood bark has evolved for survival: it grows up to one foot thick to protect the trees against fire damage, and the bark’s tannins prevent insect damage.

Many of the area’s original redwoods were logged to build homes in the gold rush era. A second generation of redwoods grew in their place, but these second-growth redwoods were logged to rebuild after the 1906 earthquake. Many of the redwoods you see in the area today are third-growth trees. Though you can find small groves of redwoods in many parks throughout the East Bay, check out Redwood Regional Park (Hike 16) for the most impressive display.

Eucalyptus. Eucalyptus trees first came to California on Australian ships heading into the bay during the gold rush. At that time, trees were sparse in the Bay Area and settlers knew they’d need wood for building homes, for firewood, and to create windbreaks. People brought more eucalyptus into the area over the following decades as they began to fear a timber shortage.

At first, eucalyptus seemed like the perfect solution, as it grows fast, creating forests in years instead of decades. However, people soon discovered that the trees really were only good for firewood: they were too weak for large-scale structures like homes, and they cracked even on a smaller scale when made into railroad ties. There is an ongoing debate on just how flammable the trees are, but one thing seems to be true—eucalyptus trees grow back quickly after fires. Some people even think that eucalyptus trees like fires because fires let them crowd out other species. They do shade out other species with their canopy, and their leaves emit chemicals that suppress growth of native plants—even after the leaves and trees are removed. Eucalyptus is a contentious species in the Bay Area, and many people have strong opinions about whether they should be saved or chopped down to prevent fires and allow native plants to return.