The valley oak pictured above — one of the larger oaks along Rocky Peak fire road — toppled over in the summer of 2016 following five years of drought.
Fire and drought are a natural part of the valley oak’s habitat and the trees have evolved to withstand ordinary variations in their environment. However, severe fires or extended droughts, or fire in combination with drought can overcome the tree’s defenses.
The drought may have been the culminating factor in the felling of this oak, but fire and other factors may have also played a role.
According to the Fire Effects Information System (FEIS), the heart-rot fungus Armillaria mellea is usually present in valley oaks and larger oaks tend to be hollow or rotten in the center. The toppled oak was hollow near its base and its interior appears to have been blackened by fire. The FEIS describes instances where the decaying wood in the interior of older valley oaks could ignite in a fire, but leave the exterior bark uncharred.
While much of the country shivers in the cold climes of Winter, the muted colors of the changing season have finally reached the lower elevation areas of Southern California.
In this area the leaves of Valley Oaks usually begin to turn around mid-December and the trees lose their leaves around the beginning of the new year. About a month and a half later trees begin to sprout new leaves, usually in mid to late February. From year to year the time frame can vary by as much as 2-3 weeks.
The photo of Valley Oak leaves was taken December 28, 2017 in Upper Las Virgenes Canyon Open Space Preserve (formerly Ahmanson Ranch). This willow in East Las Virgenes Canyon was also showing some nice color.
The sand was compact, the breeze cool, the surf up and the running oh so pleasant. Brett and I were running south along Kelham Beach, an idyllic stretch of sand between Point Resistance and Miller’s Point within Point Reyes National Seashore. If the tide was not too high we hoped to reach an area of dramatically folded strata along the 150′ tall sea cliffs.
It is the San Andreas Fault that makes the story of the Point Reyes Peninsula so unusual. A glance at a geologic map shows the rocks of the peninsula to be geologically distinct from those on the other side of the San Andreas. Essentially the Point Reyes Peninsula is an island on the margin of the Pacific Plate that is sitting against the North American Plate. The San Andreas Fault is the boundary between the two plates.
The core of the Point Reyes Peninsula is a granite similar to a granite found in Southern California. Over many millions of years the chunk of crust was propelled northward along the San Andreas Fault by the movement of the Pacific Plate. The story is not a simple one, involving a combination of faults. At some point — perhaps near current day Point Lobos — the granite core was overlain by the sedimentary rocks we see on the peninsula today.
It seems likely that at times during its 10 million year journey northward from Monterey, the Point Reyes Peninsula may have been separated from the coast. With more than 80% of its perimeter currently bounded by water, it may once again become an island.
After visiting the fault zone we ran across the Point Reyes Peninsula to the coast using the Bear Valley, Mt. Wittenberg, Sky and Coast Trails. For the most part the trails were duff-covered, tree-lined, shaded and cool. For someone that runs mostly in Southern California this was practically nirvana. The previous Saturday I’d run a 50K race on a rocky, exposed course near Los Angeles in 90 degree temps and gusty Santa Ana winds. In the West San Fernando Valley the temperature this year has reached at least 95 °F every month from March through October. In July, August and September the highest temp each month was over 110 °F!
It was not 110 °F now. It was about 60 ocean-conditioned degrees. Brett and I had reached the first point where the beach narrowed. There was still room to run, but the beach narrowed even more ahead. We watched as a large wave broke and washed up to the rocks. It looked like the tide was going out, but we weren’t sure. Although the surf wasn’t huge, there was a consistent swell of maybe 6′-8′.
In between sets we took a look around the next corner and it looked sketchy. Debating, we watched as more waves washed up to the base of the cliffs. That part of the exploration would have to wait until another day with a lower tide!