Afoot and Afield: San Francisco Bay Area. David Weintraub

follow a paved path beside noisy Presidio Blvd. into the park. After about 100 feet you reach a four-way junction, where you go straight through the park’s lovely Rose Garden. Crossing John F. Kennedy Dr., you turn right on a paved path, and after about 150 feet veer left and climb past some tall eucalyptus trees. The path soon levels and curves left beside the Japanese Tea Garden, well worth a visit. Its entrance is ahead and then left about 100 yards on Hagiwara Tea Garden Dr.; there is a fee for admission.

      Opposite the Tea Garden exit is a paved path going right and uphill to Stow Lake. Ahead, across Martin Luther King Jr. Dr., is Friend Gate and the entrance to the Strybing Arboretum and Botanical Gardens (free admission).

      The Arboretum

      The 70-acre Strybing Arboretum and Botanical Gardens contains plants from around the world, including Asia, South America, Australia, New Zealand, South Africa, and, of course, California. You can explore the John Muir Nature Trail, walk through a garden with plants mentioned in the Bible, and experience the Garden of Fragrance. There is a small pond here, and the water, combined with the variety of flowering plants, attracts many species of birds. An information board near the entrance lists guided walks and classes that are available.

      To visit Stow Lake, go uphill on the paved path and then climb a set of steps. When you reach the lake, turn left and follow the paved path that circles the lake, which is actually a narrow body of water surrounding an island. Paddleboats ply the lake’s placid waters, which are fringed by Monterey pine, eucalyptus, and Monterey cypress. On the southwest side is Rustic Bridge, an 1893 stone span that leads to the island. Continuing clockwise around the lake, you come to the Boathouse, where you can buy snacks and drinks and rent boats and bicycles. Restrooms are downhill and across a parking area, left.

      Stow Lake is a favorite birding destination — from its shore you may spot great blue herons, black-crowned night herons, egrets, gulls, ducks, geese, and songbirds. Sometimes a rare bird shows up and creates a stir among local birders.

      Passing the Boathouse and ambling beside the lake, you come to Roman Bridge. To visit the island, turn right and cross the bridge. At a four-way junction, you turn right again and now begin to circle the island counter clockwise on a dirt path. A hillside rises steeply left, and after about 100 yards you come to a fork; the branches soon rejoin, so you can take either. Passing Rustic Bridge, you soon come to the colorful and elaborate Chinese Pavilion, a gift from San Francisco’s sister city, Taipei.

      On the east side of the island is Huntington Falls, fed by the outflow from a reservoir atop the island. A series of stone steps allows you to cross the rushing water, which flows unimpeded into the lake. Just past the falls are steps leading to the reservoir. Now back at Roman Bridge, turn right to cross it, then right again when you reach the paved path to continue around the lake. At the northeast corner of the lake you close the loop. From here, retrace your route to the trailhead, or spend more time exploring the park and its many other attractions.

      TRIP 3 Presidio of San Francisco: Ecology Trail

Distance		2.2 miles, Loop
Hiking Time		1 to 2 hours
Elevation Gain/Loss		±400 feet
Difficulty		Easy
Trail Use		Leashed dogs, Good for kids
Best Times		All year
Agency		GGNRA
Recommended Map		Golden Gate National Recreation Area Presidio of San Francisco (GGNRA)

      HIGHLIGHTS The Presidio was established in 1776 as a Spanish colonial outpost on a windy sand dune near San Francisco Bay. It later served as a Mexican fort and a U.S. military base before being turned over in 1994 to the National Park Service. The Americans built forts, housing, and coastal gun batteries, and planted trees that transformed the landscape. The Ecology Trail loops through the southeastern corner of the Presidio, providing a look at what human intervention has wrought, and also what conservation efforts have managed to preserve and restore, including native wildflowers and grasses, some of them rare, threatened, or endangered.

      DIRECTIONS From the Presidio’s Arguello Gate entrance, just north of Arguello Blvd. and Jackson St., go 0.1 mile northeast to the large paved parking area at Inspiration Point, on the right.

      FACILITIES/TRAILHEAD There are no facilities at the trailhead, which is on the east side of the parking area.

      Walk southeast down a set of wooden steps and after several hundred feet join the Ecology Trail, a wide, dirt path, by turning left. An outcrop of serpentine rock in the midst of a grassy, wildflower-filled meadow is right, behind a fence, in an area that is being restored.

      The trail skirts Inspiration Point and descends on a gentle grade. At a junction with a trail heading right, you continue straight, now in forest. Several unofficial trails branch right and left; ignore them. Soon the red brick buildings of the Presidio’s Main Post are visible ahead. Now on a paved path, you descend to a gate, and pass it on the left. With Pershing Hall on your left, you follow a sidewalk to Moraga Ave., which you cross. A sidewalk along Funston Ave. takes you past part of Officers Row, built in 1862 to house commissioned officers and their families.

      Presidio Flora

      Grasslands are a threatened ecosystem, and this serpentine grassland is unique in the Golden Gate National Recreation Area. Serpentine soil, high in magnesium and low in calcium, is toxic to many plants, but some have adapted to it, including ones that are rare, threatened, or endangered.

      Among the wildflowers that grow beside the trail are goldfields, coastal tidytips, California buttercups, blue-eyed grass, and California poppies.

      At the corner of Funston Ave. and Presidio Blvd., get on the left side of Presidio and follow the sidewalk gently downhill to a crosswalk just past Barnard Ave. Turn right, cross Presidio, and then follow a paved path through a corridor of eucalyptus trees and berry vines. A footbridge, built around 1865, takes you over a watercourse. When you reach MacArthur Ave., cross it and continue on Lovers’ Lane, a paved path that is part of the Ecology Trail.

      You walk moderately uphill, past stands of Monterey cypress and eucalyptus. At the intersection of Liggett Ave. and Clarke St., you continue straight, now on a sidewalk. Passing a row of brick houses, you turn right onto a dirt path, which almost immediately merges with another coming sharply from the left. Now you pass a fenced area that has been planted with trees, and soon reach a four-way junction, not shown on the park map.

      Here you turn right and descend over loose sand to a fork, where you bear right. With Paul Goode Field on your right, you come to a large dirt parking area and a junction with a trail going left. Turn right, cross the parking area, and then follow a trail past some white buildings with red roofs. The trail bends left and descends steeply into forest.

      Rare, threatened, or endangered plants are found in the Presidio, and, at the time of research, there was a controversial plan in the works to remove some of the Presidio’s planted trees, such as eucalyptus, Monterey pine, and Monterey cypress, and to restore the original dune habitat.

      Inspiration Point is the trailhead for the Ecology Trail, a loop through the Presidio.

      When you reach a loop of paved road with a grassy area in its middle, go straight across, passing El Polin Spring. Your trail continues from the northwest side of the