Urban Trails East Bay. Alexandra Kenin
the moisture they received in winter (and may stay green until at least the beginning of May). At the same time, wildflowers burst out of the soil, painting the parks with a rainbow of color. Temperatures are ideal for hiking, neither too hot nor too cold. And daylight saving time brings longer days, which means it’s a good time to start hiking longer routes again.
Summer can be challenging for hiking in the East Bay. Visually, it can be argued that the hikes are less scenic because the grasslands have turned from green to brown. While there is little chance of rain affecting your plans, temperatures can be very hot, and shade and water on some routes can be limited. Make sure you and your hiking companions protect yourselves from the sun and that both your human and dog companions have enough water. This is a great time to head into the shade on trails like Huckleberry Botanic Regional Preserve (Hike 15), Redwood Regional Park (Hike 16), and Dimond Park (Hike 19).
Fall can have the same mild weather as spring, but without the blooming wildflowers and green grass. Early in the fall, hot summer temperatures can remain, so bring enough water and sun protection. Starting in October, rain often returns to the area, bringing back green grass and cooler temperatures. When daylight saving time ends in November, it gets dark early, so it’s a good time to do shorter routes that don’t leave you hiking in the dark.
GEOLOGY AND EARTHQUAKES
In many people’s minds, the Bay Area and earthquakes are inextricably linked. In the East Bay, the Hayward Fault (part of the larger San Andreas Fault system) runs 70-plus miles through densely populated cities such as: Richmond, El Cerrito, Berkeley (including directly through Cal’s football stadium), Oakland, San Leandro, Castro Valley, Hayward, Union City, Fremont, and San Jose. The last big earthquake along this fault was a magnitude 6.8 quake that hit in 1868, destroying the city of Hayward, killing five people and injuring thirty. Scientists studying the fault found that the past five major earthquakes affecting it occurred every 140 years or so. Using this data in a model, a large earthquake should have struck this fault around 2008. Many scientists still believe this fault will get a major quake in the next 30 years.
There are also several minor faults in this area. If geology is your thing, check out Las Trampas Regional Wilderness (Hike 33), as the park lies on the Las Trampas and Bollinger Faults.
WILDFIRES
Unfortunately, wildfires are part of life in California, and the East Bay is far from immune to these disasters. In 1991, a catastrophic fire raged through the Oakland Hills, destroying nearly 3500 homes and killing twenty-five people. In recent years, the impact of wildfires has become more severe due to winter rains driving more plant growth in spring. When these plants dry out in the summer and fall due to lack of rainfall, they serve as kindling when a wildfire does break out. Increased temperatures mean that plants are drying out faster, and rainy seasons are starting later than before—both due to climate change. While natural causes (like lightning strikes) can cause wildfires, most wildfires are caused by humans. That’s why it’s more important than ever to leave no trace (see Outdoor Ethics later in this introduction for more information).
FLORA AND FAUNA
The Bay Area’s Mediterranean climate provides an ideal environment for plant life to thrive, including many varieties of native oak trees and redwoods, the tallest trees in the world. An unfortunate side effect of having a near-perfect growing environment, however, is that non-native and invasive plants flourish here too. On the trails in this book, you’ll see non-native eucalyptus reaching into the skies and non-native broom intermingling with the native lupine and California poppies at your feet. This section will help you identify the common trees and plants you’re likely to encounter on your hikes.
Numerous animals also call the Bay Area home. While there are too many species to mention in this short section, I share some information on animals you may see on the trail, from coyotes to cows to ticks to rattlesnakes. The general rule with animals on the trail is to leave them alone. Even a seemingly tranquil cow can charge you and your hiking companions if it feels threatened; be sure to keep dogs on leash near cattle.
COMMON TREES OF THE BAY AREA
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.