The Oak Nature Trail - Folsom Lake State Recreation Area

After you drive through the park entrance stay left on Rattlesnake Bar Road after the first fork. Soon you will see a parking lot on your right where the trail begins. You can also enjoy a nice picnic at one of the picnic tables under the trees looking out onto beautiful Folsom Lake.

When you are ready to start the hike, walk towards the large blue sign which gives an overview of the area. The trail is 0.75 miles each way, and is flat the entire hike.

As the lake levels change throughout the seasons, so does the wildlife associated with the open water and lakeshore. The constantly changing lake levels favor plants and animals that can rapidly adjust to these fluctuations. Non-native annual grasses and weedly plants quickly grow on exposed banks and set seed before the next high water. Many bird species come and go with the water as they follow their favorite foods. When water levels are high, fish-eating birds such as the great blue heron, egret, and kingfisher can be seen from the trail. During low water, grazing Canada geese, seed-eating finches and blackbirds, and ground-nesting killdeers move into the area.

Try This:
Watch quietly, look for movement and listen for calling birds. Compare the types of birds you see. Water and shorebirds are shaped differently and act differently than birds living in trees, but be ready for an occasional surprise. Watch for great blue herons roosting in shoreline oak trees.

Red candy kisses, pink cups, green golf balls, yellow marbles, fuchsia urchins; all the work of tiny wasps. Cynipid wasps are smaller than fruit flies, yet they produce these unusual and beautiful galls on oak trees. The female cynipid wasp first stings the leaf, bud, stem, or acorn of the oak and then lays an egg on the wound. The oak reacts by growing a protective layer around the egg, which provides nutrition and protection to the young wasp larvae and protects the tree from damage. The chemicals produced by the sting and larvae determine the shape and color of the gall. Each gall is unique to a single species of wasp.

Try This:
Closely examine the leaves, stems, branches, and buds of the valley oak above you. You should be able to spot at least three different types of calls. LOOK, BUT DON'T PICK! Now look at a nearby blue oak to see a different set of galls. Often, one tree like the valley oak above you will be covered with galls, but a neighboring tree will have just a few.

A hunk of fur, a pile of dung, a dusty footprint…tell tale signs of the nightly dance between predator and prey. While you sleep, the oak woodland comes alive with a nocturnal feeding procession; from acorn to deer mouse to ringtale, from acorn to beetle to skunk to great horned owl, from accorn to field mouse to house cat to coyote. A harsh, but necessary balance amid the oaks.

Try This:
Walk the trail early in the morning when the sounds of the wild replace the noise of boats and people. Look for the three P's: Prints, Poop, and owl Pellets, signs of the park's nighttime hunters.

Acorns are a nutritious source of food, rich in carbohydrates, proteins, and lipids. But, acorns ripen and fall only during a few months in the fall, so animals must quickly harvest this seasonal bounty. Many animals utilize a wide variety of plant foods and feed on acorns when they are available. Others, like ground squirrels, scrub jays, and acorn woodpeckers, collect and store acorns for use throughout the year. Mule deer and band-tailed pigeons follow the ripening crop from high elevations to low, extending their harvest period. These animals, together with non-native turkeys and wild pigs, gorge on the accords to build up the supply of fat to cover winter and prepare for spring births.

Try This:
Pick out two or three oak trees and check them for acorns. Most trees produce large crops of acorns in two- or three-year cycles, but usually a number of trees in a grove will have a good crop each year.

Winter rains and underground springs feed these year-round pools, providing wildlife with a critical water supply during the parched summer and fall. While Folsom Lake now provides summer water for animals that can follow the changing water levels, the springs provide sustenance to plants and animals unable to migrate. Generations of frogs, salamanders, insects and plants call these pools home. Even mobile animals such as California quail and coyotes come to the pools to drink, especially when the lake's edge has receded in the late summer.

Try This:
Sit back and quietly watch the area surrounding the pools. In the summer, many types of wildlife will come to drink. Dawn and dusk provide the best times for watching wildlife around the pools.

The hot summer sun bakes the surrounding hills to a golden brown by early June. The first areas to dry are the hills facing south, exposed to the direct rays of the sun. Only seasonal wildflowers and grasses, and blue oaks can survive on these slopes. Here on the north-facing hillside, additional soil moisture and cooler ground temperatures support other types of plants. An overstory of interior live oaks, blue oaks, and California buckeyes shade the twining vines of the Dutchman's pipeline and clematis. Poison oak, Himalaya berry and even ferns thrive on these cooler slopes.

Try This:
Compare the oak woodlands on the south-facing slope across the ravine to the surrounding area. Notice the differences in plant varieties, space between trees and luckiness of plant growth. Is there a difference in the types and numbers of wildlife species as well?

As acorns ripen in the fall, a single scrub jay can collect and bury over 5,000 acorns. Biologists have clocked jays collecting more than 400 acorns per hour! Only about half of the buried acorns are retrieved and eaten by the jay, leaving the rest for other animals or to sprout into new trees. In this way, the jays provide an important service to the oaks, distributing the acorns throughout the woodland and planting the acorns point-side down so they have the best chance of sprouting. What a good friend to oak has in the jay.

Try This:
Count all the oak trees shorter than you. Where are all of the young trees? Despite the efforts of the scrub jays, almost every acorn and seedling dies from drought, disease, or predation in its first few years of life.

This old live oak may have fed generations of Nisenan Indians and sheltered a gold miner during its long life. When alive, it provided food and cover for a variety of plants and animals. But even in death the oak tree continues to support a host of wildlife and plants. Tangles of Himalaya berry and two young live oaks grow from between the protective branches of the oak, out of reach of browsing deer. Fungus and insects slowly consume the wood, returning nutrients to the soil for the next generation of oaks.

Try This:
Compare the young live oaks growing in the tangle of berry vines to those struggling to survive on the other side of the trail. Mule deer feed on the tender young leaves and twigs of the oaks in the spring, sometimes stunting the young oak's growth for decades until the trees funnily frown above the animals' reach.

Two hundred years ago, this valley supported many Nisenan families. Salmon, deer and small game, and a multitude of berries, seeds, and bulbs provided the Nisenan with a varied and rich diet. But it was the acorn and oaks that provided the year-round foundation of their diet. In great part, the bounty of California's oak forests supported over 300,000 people living in 100 separate tribal groups within the state, the greatest density and diversity of epode north of Mexico prior to European contact. Today our relationship with the oak has changed. While California still supports the greatest number of diversity of people in North America, it is at the cost of our oak forests. Houses are rapidly replacing the oak forests here in El Dorado and Placer Counties. What is the value of oak woodlands to our state, to our local communities and to us as individuals?

Try This:
Take a moment to consider how important this oak woodland and its wildlife was to the Native Americans who once stood where you are. Is it any different for us living today? Aren't open space, oaks, and wildlife important to you and your family, just like they were for the Nisenan families?

"Waka, aka, aka", the scolding call of the acorn woodpecker fills the oak woodlands with sound. These communal birds constantly call to members of their extended family and to warn off competing clans. Territories are established around granary trees where the woodpeckers store their food and share nest cavities. Aptly named, acorn woodpeckers collect acorns and store them in soft-barked trees in this area, the foothills pine is their favorite granary free. The woodpeckers excavate a hole in the bark, and then hammer in a single acorn. One tree can contain thousands of holes, the work of generations of woodpeckers. Each fall, the communal family fills the empty holes with the current crop of acorns and feeds on the supply throughout the year.

Try This:
Listen for the characteristic call of the acorn woodpecker and follow the sounds to their granary tree. The foothills pine is too young to be used by the birds, but look for the tall, lanky mature pines in the surrounding oak woodland.