Among the Old Oaks of Los Osos

Antiquarian California live oaks, estimated to be 600 to 800 years old, are the highlight of Los Osos Oaks State Reserve in Los Osos Valley near San Luis Obispo. Two miles of trail meander through the old oaks, which have--during their long life span--contorted into some unusual shapes.

Botanists say the oak woodland is a culmination of thousands of years of plant succession that has transformed the area from sparsely vegetated sand dunes into this lovely landscape of live oaks. A small remnant of the sand dunes remains, the crest of which is dotted with dwarf oaks. These aged little trees, draped with lichen, add a magical, fairy-tale dimension to your walk in the woods.

The majority of the reserve’s Quercus agrifolia are large-limbed specimens that form a truly enchanted community. Oaks don’t much like wind, so you’ll find the bigger ones hugging the lower, east-facing slopes and the smaller ones stuck higher up in the face of the prevailing west winds.

The oaks have some arboreal company. Bay laurel, sycamore and even some cottonwoods line Los Osos Creek, which meanders along the eastern boundary of the reserve.

The oaks are full of bird life. Several species perch in the crowns of the trees, others hunt bugs and grubs in the piles of leaves beneath. The chaparral that makes up one-fourth of the reserve is home to quail and many more birds.

Those piles of sticks you see, some several feet high, are wood rat nests. Judging by all those nests, the rarely seen rodent may be the most common animal in the reserve.

Docent-led walks are scheduled frequently from the Museum of Natural History in Morro Bay. While walking in the reserve, stay on the trail; poison oak is abundant.

*

Directions to trail head: From U.S. 101 on the southern outskirts of San Luis Obispo, exit on Los Osos Valley Road and travel eight miles to Los Osos Oaks State Reserve on the left side of the road.

*

The hike: The path crosses a bridge over a trickling creek; passes a plaque thanking, among others, the California State Parks Foundation for preserving this place, then begins a clockwise loop through the reserve.

The main path winds through the old oaks, wanders near Los Osos Creek, then leads to an overlook of a still-pastoral part of Los Osos Valley.

The path crests a low hill and leads into a drier area. Here you’ll encounter some wind-blown six- to 10-foot-high pygmy oaks which sport “beards” that look a lot like Spanish moss, but are actually a combination of lichen.

The trail passes through a chaparral community of ceanothus, chamise and sage. Brightening this area of the reserve in the springtime are bush lupine and California poppies.

The trail re-enters the oak forest and circles back to the trail head.

Oak Trail

WHERE: Los Osos Oaks State Reserve.

DISTANCE: About 2 miles round trip.

TERRAIN: Classic California oak woodland, grassland, chaparral.

HIGHLIGHTS: Magnificent ancient oaks.

DEGREE OF DIFFICULTY: Easy.

PRECAUTIONS: Plenty of poison oak, so exercise care.

FOR MORE INFORMATION: Call the Museum of Natural History in Morro Bay at (805)772-2694 for information on docent-led walks.