Shiloh Ranch Regional County Park is a great choice for a nature hike that offers viewing of many native trees and shrubs of Sonoma County.
The park is located just south of the intersection of Shiloh Road and Faught Road on the southern edge of Windsor. From Highway 101 go east on Shiloh Road. Go straight through the stop light at Old Redwood Highway for a few miles until you reach a stop sign at Faught Road. Turn south (right) and the park is located on the left about 100 yards down at 5750 Faught Road. There is some parking available along the roadside and a parking area that requires paying a fee inside the park area.
The hiking trails are open to hikers, cyclists and horseback riding but dogs are limited to the picnic area and must be kept on a leash of six feet maximum in length.
There are several loop routes available. The elevation change from the parking area to the upper ridge areas is approximately 650 feet. The Ridge Trail is quite steep in some areas. The Big Leaf Trail and Creekside Trail are less steep and can be hiked up and back the same route to reduce the need for hiking up and down steep areas.
A good loop trail for viewing a wide variety of native trees and shrubs is a loop that utilizes the Ridge Trail, the South Ridge Trail and the Big Leaf Trail. If you prefer going up a steeper trail and down a less steep trail I would recommend starting at the Ridge Trail area. If you prefer a less steep climb upward and a steep down hill hike start at the Big Leaf Trail side. To find either of these trail heads go past the bathrooms and the group picnic area to the north. The Ridge Trail starts on the north side of a small creek area behind a chain link fence. The Big Leaf Trail heads up hill to the right towards the south.
I recommend visiting the Sonoma County Parks website and printing out a map of the park with the different trails indicated. The Ridge Trail to the South Ridge Trail is a 0.6 mile leg. The South Ridge Trail to Big Lead Trail is a 0.9 mile leg and the Big Leaf Trail back to the parking area is a 1.0 mile leg. This 2.5 mile loop takes you through grassy meadows, oak woodlands, mixed and chamise chaparrals, and fir forest areas.
Along the Ridge Trail are California Bays, California Buckeyes, Madrones, Douglas Firs, and Coast Live Oaks. About 0.4 miles up the Ridge Trail is a very large Douglas Fir located above the trail on the east side. This tree is approximately four to five feet in diameter. Toyon and madrones can be viewed as you continue up the hill.
As you reach the ridge area take the South Ridge Trail 0.4 miles to the Look Out Point which provides panoramic views to the north and south of the 101 Corridor. Proceed 0.5 miles along the South Ridge Trail to Big Leaf Trail. Along this area are White oaks, grasslands and Coast Live Oaks. As you descend the 1.0 mile to the parking area on Big Leaf Trail you will view some large and majestic Big Leaf Maples along the trail. These moss covered trees have trunks of three to four feet in diameter with a spread of over 60 feet.
A good resource book for identifying native trees and shrubs in Sonoma County is the National Audubon Society Field Guide to American Trees Western Region. This book provides color plates with bark, foliage and seed references. It's small in size, easy to carry and lists for $19.95 or as little as $3 to $4 used from Amazon.