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Stebbins Cold Canyon Reserve
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A Natural History Tour of Cold Canyon
By Peter Moyle (with additions by Correigh Greene)
Click Here for an easily printable hiking guide.
A Natural History Hike for All Seasons
This tour describes sights along the Homestead Trail. Enjoy these natural
wonders as you hike up the canyon.
1. Outlet of Cold Creek (unmarked). Start at the parking area 0.2 miles past the bridge over Putah Creek on the right-hand side. In this area you can view the lowermost reaches of Cold Creek, which flows out of Stebbins Cold Canyon Reserve. The channelization here was completed in1995 to enable water to move quickly through the area after floods created huge debris flows. Just upstream of the mouth of Cold Creek is a major spawning area for wild trout in Putah Creek. If you return to this spot in December or January, you may be able to see the shadowy forms of large trout spawning in the riffles.
2. Roadcut (unmarked). As you walk up the road to the trail, observe the exposure of bedrock on the slope to your left. This exposure consists of many layers of sandstone and is part of the Sites Formation, the bedrock forming the entire eastern slope of Cold Canyon.
3. Main Gate. Just inside the gate, the trail forks. The left fork is the Pleasants Ridge trail, which winds up the hill through savanna dominated by blue oaks (Quercus douglasii), to the top of the eastern ridge. The right fork marks the start of the homestead trail.
4. Poison-oak. If you are not familiar with poison oak, use these plants as a standard. In addition to poison oak, look for the large elliptical leaves of mule-ears (Wyethia helenoides) growing here.
5. Redbud (Cercis occidentalis) starts the season with a gorgeous display of magenta blossoms, followed by its heart-shaped leaves. It often sheds these in the heat of the summer, so that by fall, its brown bean-shaped fruits may be all that remain on the branches.
6. Landslide. At the first bend are the remains of a major landslide that resulted from the heavy rains of 1995. The debris flowed out of the dry canyon (on your left as you face upstream). The debris flow eliminated much of the riparian vegetation in the creek below and nearly took out the highway as well.
7. Fork to Blue Ridge Trail. Just after you cross the slide, you will see a large rock on your left that is covered with small circular patches of greenish and rust-colored lichens. Lichens (a fungi-algae symbiotic organism) gradually dissolve rocks, and therefore contribute to the weathering of rock into soil. The trail to the right marks the start of the Blue Ridge Trail.
8. Interior live oak. Proceed along the trail
across a boulder-strewn area, more remains of the 1995 landslide. In the
spring and summer, you can often see western fence lizards (Sceloporus
occidentalis), basking on rocks. In the midst of this area is a large
interior live oak (Quercus wislizenii) that managed to survive the
slide.
9. Coyote brush (Baccharis pilularis) can be found in many
spots along the trail. This species is notable because it is dioecious:
each individual plant is either male or female, just like in humans. In
contrast, most other plants are monoecious, and therefore produce both
seeds and pollen.
10. Sign-in area. This marks the official entrance to the reserve. Please sign in. Just past the sign-in box, a toyon (Heteromeles arbutifolia) grows on the right side of the trail. If you visit in the fall or winter, its bright red fruit will be visible.
11. Slide area. About 100 m up the trail is a flat open space that resulted from another slide.
12. Manzanita. The shrubs with pastel-green leaves and reddish, twisted branches are parry manzanita (Arctostaphylos manzanita). This plant is common in chaparral, along with chamise (Adenostroma fasciculum) and toyon.
13. Yerba santa. In the summer, yerba santa (Eriodictyon californicum) is almost more formidable looking than poison oak; its long dark oily leaves make it appear particularly noxious. While this oil may in fact ward off potential herbivores, it has several medicinal properties for humans.
14. Bay trees. Large bay trees (Umbellularia californica) stand on your left. These have relatively thin, straight limbs and light gray bark. Their leaves are narrow and smooth-edged, and give off a pleasant, pungent smell when rubbed.
15. Rocky peak on right. As the trail starts
to climb, marked by wooden erosion control bars, note the rocky peak
across to the right. Usually, you can see raptors soaring around it.
In the moist areas along the left side of this section of trail, milkmaids
(Cardamine californica), a delicate white four-petaled flowers,
begin blooming starting in February. Look also for ferns and bushes of the
sticky monkeyflower (Mimulus aurantiacus). The bright orange-yellow
tubular flowers that bloom in the spring make this one of the showiest
chaparral shrubs.
16. Old landslide with buckeyes. When the trail starts to climb abruptly with some "stairs," you will know you are crossing a landslide that occurred in 1982. Actually, it was more of a land slump because a good chunk of the hillside slid downwards with much of the vegetation still on top. Numerous California buckeyes (Aesculus calfornica) grow along this section of the trail. They can be identified by their smooth, pale gray bark. In spring, their large compound leaves make this area very lush. In the late spring, their showy flowers bloom-look for large candelabras of small white or pink flowers. Both flowers and leaves wither over the summer, revealing the developing fruits.
17. Intermittent drainage. Just before this
drainage in front of you is an open area that will allow you to see the
steep slope on the opposite side of the creek. A flow from a small
landslide scars this slope. You can follow the scar up to a small
landslide "scarp," the ragged wall of soil exposed by the earth
that tumbled down the slope. Thousands of years ago, a much larger
landslide occurred: the sheer cliff forming the peak above you is the
remains of the much older landslide scarp. The earth that was moved in
this landslide now forms the entire hill slope below the cliff, extending
both to the left and right of the cliff in a relatively flat line along
the hill.
As you cross the drainage, look for several plants of the foothill lupine
(Lupinus albifrons), a round shrub with silvery-gray leaves and
spikes of blue flowers that bloom mid-spring.
18. Wild grapes. Soon you will step out of the wooded area into a section of the trail bordered on either side by shrubs. This is typical chaparral habitat, although the proximity of the creek provides moisture for other plants to grow. Among them is the California wild grape (Vitis californica), a vine that can be seen covering much of the vegetation on the right side of the trail. These plants produce their fruits in late summer, and are a very important food source for birds and other animals. Look past the wild grapes to the creek, where you can see young cottonwoods (Populus fremontii) and willows (Salix spp.) that rooted after the major storm-generated rock slides and floods of 1995.
19. Spicebush. Several spicebush (Calycanthus occidentalis) plants grow here. True to their name, spicebush leaves are quite pungent. In the spring, these trees produce large deep red flowers with many petals.
20. Signs of fire. This section of the trail is bordered by extensive chaparral. In a few places on the left side of the trail you can see dead limbs of bushes sticking out of thick growth. These are one of the few reminders of the fire that burned throughout the canyon in 1988. The chaparral plants are adapted to fire, and new branches and foliage sprouted from the old rootstocks. Chief among these plants are chamise, the wiry bushes with tiny leaves dominating this area.
21. Side trail. A scrub oak (Quercus berberidifolia) marks a fork in the path. The left fork is the main trail, and a side trail on the right will take you to toward the creek. In the spring, the flowing creek forms a pool here. This is a great place to look for aquatic insects, foothill yellow-legged frogs (Rana boylei), and other animals. On a large boulder at the end of the trail is a rounded hole in the rock. This is a mortar made by the Patwin Native Americans who lived here until the 1800s. They used this mortar to grind acorns into flour, which formed the staple of their diet.
22. Cold Creek. Return to the main trail. The trail next crosses the bed of Cold Creek. In most years, this stream flows for about seven months (November-May). When it starts flowing, it is quickly colonized by aquatic insects such as water striders (Gerris remigis), and stringy algae. In the summer, pools of water are left behind when the stream stops flowing and are important sources of water for wildlife. The creek crossing is also a good place to look at plants. The plants growing in and along the stream course are mule-fat (Baccharis salicifolia), which looks like willow, but is a completely different species of plant. On the steep left side of the creek, blue larspur (Delphinium hesperium) makes a showy display in the spring. Just after the creek crossing, the vertical slope on the right yields a colorful display of red larkspur (Delphinium nudicaule) in early spring.
23. Foothill pine tree. As you hike up the trail from the creek crossing, the first large tree you see on your left is a tall foothill pine (Pinus sabiniana), Cold Canyon's only species of conifer.
24. Bedrock underlying Cold Creek. As the trail continues upstream, look for a side trail on the left leading down to the creek. At this point in the canyon, the shale bedrock underlying the canyon makes its appearance. In the spring, the gray layers of the Yolo Formation form the bottom of the pools in this section of the creek. In the summer and fall, these pools have dried up, allowing you to inspect the bedrock. Shale is easily eroded by the action of water, so outcrops of the Yolo Formation are difficult to find in Cold Canyon.
25. Cottonwood tree. As you cross the small bridge on the trail, you will have a good view of a cottonwood tree growing right in the stream channel. Cottonwoods are important riparian ("riverside") trees, requiring water around the roots. This is a good spot to watch birds, such as Black Phoebes (Sayornis nigricans) and Bewick's Wrens (Thyromanes bewickii).
26. Scrub oak. The trail now climbs through chaparral, and this spot marks the location of a large scrub oak growing up and over you. Nearby grow buck brush (Ceanothus cuneatus), parry manzanita, and toyon. The shade of the chapparal keeps this area relatively cool and moist, enabling maidenhair ferns (Adiantum jordanii) and mushrooms to thrive even after the spring rains have ceased.
27. Tunnel of brush. The chaparral now has become a veritable tunnel of buck brush. As you pass through, birds and small mammals can be heard skittering about just out of sight on either side of you.
28. Wildhorse canyon. At this marker is a good view of the southern section of Cold Canyon Reserve. Cold Canyon continues flowing south parallel to the trail, and joins with Wildhorse Canyon to the left in the distance. This wild area is owned partly by the University and partly by the Bureau of Land Management.
29. No entry fence. This fence was constructed to keep people from climbing this tempting open hillside. Even a small trail in this fragile land could start a major landslide.
30. Homestead. A short distance further the trail crosses the Vlahos homestead. The open area around you was probably cleared by Vlahos and the soil compacted by livestock, mainly goats. One indication of this is star thistle (Centaurea solstitialis), a native of Asia that thrives on poor, overgrazed soils. The grassland is currently being treated to control this invasive pest, and to restore the native grassland vegetation that used to grow here.
31. Homestead foundations. The stone wall on the left is about all that remains of the Vlahos' former farmhouse. Walk around the foundations and you can find the former site of a well, some rusted metal, and a few rotted wood boards, but little else remains to remind us that this site was once a bustling household.
32. Cold storage area. Beyond the homestead, the trail continues into a shady glen. In the spring, look for the large white and purple blossoms of the iris (Iris macrosiphon) and the faded-red flowers of the Indian warrior (Pedicularis densiflora) on the right side of the trail here. Cross the creek to the foundations of the old cold storage shed and the end of the Homestead Trail. This area is delightfully cool and moist all summer long. The trees here include California bay and spicebush, but several large bigleaf maples (Acer macrophyllum) provide most of the shade. In the fall, the leaves of the maples turn color and bathe the glen in a wonderful orange light. In the spring, follow the creek up from the cold storage foundation to a small waterfall. Here Cold creek pours over some boulders into a small pool that often contains a variety of aquatic wildlife.
Have a great hike back down the trail!
Last Updated 03/09/06