Explore Lopez Canyon, a serene minor member of the canyon system in Los Peñasquitos Canyon Preserve.

A sparrow hawk alights upon a sycamore limb, then launches with outstretched wings to catch a puff of sea breeze moving up the canyon. A mule deer bounces across the pathway, pausing to take your measure with a wary stare. The yellow-brown, desiccated leaves of the sycamores of Lopez Canyon chafe and break free of their moorings and spin toward the gravelly canyon floor.

As a minor member of the canyon system in Los Peñasquitos Canyon Preserve, Lopez Canyon is serene compared to the main Los Peñasquitos Canyon. The sights and smells of sage and chaparral and the stately sycamores down along the creek bed echo the long period when vaqueros herded cattle through this and many other San Diego canyons. Cattle grazed this canyon until the late 1980s, a tradition that stretched back to the Spanish and Mexican periods.

Today, the Los Peñasquitos Preserve serves as a buffer between the speading suburbs of north San Diego and as a place for self-propelled visitors to "recreate." Although mountain-bike travel is allowed on the popular, six-mile-long dirt roadway through Los Peñasquitos Canyon, Lopez Canyon itself is reserved for travel on foot only.

From Los Peñasquitos Preserve's west-side parking lot, off Sorrento Valley Boulevard a mile east of the I-5/I-805 merge, start walking east on a former dirt road following Lopez Canyon's broad floor. On the scenic stretch ahead, you'll spot an enormous, multitrunked sycamore tree on the right covering an area about 100 feet across. Make your way along the cobbled canyon bottom, which will harbor a shallow stream if and when the winter rains arrive.

A short mile east from the parking lot, the Old Lopez Road (now a trail), descending from Pacific Center Boulevard, intersects on the right. The Lopez family homesteaded this section of the canyon a century ago and built a cabin on a little flat just north of the canyon's stream. You can look for the cabin's remains next to an old pepper tree and, higher up, discover an old concrete cistern.

After traveling about 1.7 miles up Lopez Canyon, you'll reach the last of the scattered trees -- just short of the towering Camino Santa Fe concrete bridge. This is a good place to turn around. Beyond, the going gets rougher on a cobble-strewn stretch of canyon bottom.

Whenever heavy rains come, muddy trails are the result. In this instance, Los Peñasquitos Preserve closes until the trails become firm again. For more information, call the preserve at 858-538-8066.