Tag Archives: upper las virgenes canyon open space preserve

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Searching For Another Blue Oak In Upper Las Virgenes Canyon Open Space Preserve

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Blue oak-like leaves of an unusual oak in in Upper Las Virgenes Canyon Open Space Preserve (Ahmanson Ranch).

After the Ahmanson Blue Oak in East Las Virgenes Canyon died this Winter, I started to search for another blue oak (Quercus douglasii) in Upper Las Virgenes Canyon Open Space Preserve (aka Ahmanson Ranch). Blue oaks are rare at the southern limit of their range, but I was hopeful that if there was one blue oak at Ahmanson, there might be another.

Valley oak leaves in Upper Las Virgenes Canyon Open Space Preserve (Ahmanson Ranch).
Valley oak leaves.

Typically, blue oak leaves are noticeably different than valley oak leaves. The Jepson eFlora describes the leaf margins of blue oak as being more or less entire, wavy, or more or less lobed. The leaves of the Ahmanson Blue Oak fit this description. Valley oak leaves are usually much more deeply lobed and readily identified.

Recently, while on a run, I noticed an unusual oak near the top of a service road on the western margin of Lasky Mesa. Its leaves are not deeply-lobed and are a bit more dusky than the usual valley oak leaf. But the tree doesn’t look quite the same as the Ahmanson Blue Oak. One difference is that the shape of the leaves is not as uniform as those of the Ahmanson Blue Oak. This might be due to the wet 2022-2023 rain season and the flourish of leaves that resulted. And, as with the Ahmanson Blue Oak, this oak was burned in the 2018 Woolsey Fire, and its trunk is partially hollow.

Blue oak-like leaves of the unusual oak on the western margin of Lasky Mesa.
Blue oak-like leaves of an oak on the western margin of Lasky Mesa.

Based on its leaves, the “West Lasky Mesa Oak” could be a blue oak, blue oak hybrid, or valley oak hybrid. A 2002 study of a mixed stand of blue and valley oaks found that appearance can be misleading. When DNA tested, four of the five hybrid-appearing oaks in the study were not classified as hybrids. Of the four trees deemed most likely to be hybrids, only one oak was intermediate in appearance.

Although it seems unlikely this tree would have been overlooked, I could find no specific reference to the oak in the various studies and surveys done of Ahmanson Ranch. Please get in touch with me if you can provide additional information about this tree or how a DNA analysis can be arranged.

Some related posts: Ahmanson Blue Oak, Ahmanson Blue Oak Succumbs to Climate Change

ahmanson ranch, nature, photography, trails, upper las virgenes canyon open space preserve, wildflowers, wildflowers

Farewell-to-Spring in Upper Las Virgenes Canyon Open Space Preserve

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Farewell-to-Spring found in Upper Las Virgenes Canyon Open Space Preserve in June 2023

An unusually wet rain season not only increases the population of many wildflowers, it can produce wildflowers not usually seen in an area.

The Farewell to Spring (Clarkia amoena) pictured above was one of very small population found in Upper Las Virgenes Canyon Open Space Preserve (aka Ahmanson Ranch) in June 2023. The California native is much more common in the Bay Area and coastal Northern California. It probably found its way to Ahmanson by way of a local garden.

ahmanson ranch, photography|wildflowers, trails, upper las virgenes canyon open space preserve

Elegant Clarkia in Las Virgenes Canyon

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Hillside of Elegant Clarkia in Upper Las Virgenes Canyon Open Space Preserve (aka Ahmanson Ranch)

This year’s bloom of Elegant Clarkia (Clarkia unguiculata) in Upper Las Virgenes Canyon Open Space Preserve (aka Ahmanson Ranch) is even more widespread and lavish than it was in Spring 2020. It’s virtually impossible to do a hike, run, or ride at Ahmanson Ranch and not see the stalks of the oddly-shaped, 4-petaled, pink-purple flowers.

As in 2020, Purple Clarkia (Clarkia purpurea) is also widespread. Not as common at Ahmanson Ranch is another member of the Evening Primrose Family, Shredding Primrose (Eremothera boothii). It can be found along the Edison service road near the Las Virgenes Trailhead.

ahmanson ranch, running, trails, upper las virgenes canyon open space preserve

Running, Hiking and Riding Just Got a Little Easier in Some Parts of Ahmanson Ranch

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Equipment used to scrape and grade dirt roads in the area of upper Las Virgenes Canyon.
Upper Las Virgenes Canyon

Dirt roads used to service gas pipelines that pass through Ahmanson Ranch have recently been scraped and graded.

Scraped and graded section of East Las Virgenes Canyon Road at Ahmanson Ranch. May 23,2023.
Scraped and graded section of East Las Virgenes Canyon Rd about two miles west of the Victory Trailhead.

The work was sorely needed. In the wake of our very wet rain season, in some areas the mustard was 8 feet tall and roads were rutted and damaged.

All of the scraped roads are in the western part of Ahmanson, primarily in and near upper Las Virgenes Canyon. Some very welcome weed-cutting was previously done along the roads in other parts of the open space area.

(Officially named Upper Las Virgenes Canyon Open Space Preserve, most users refer to the open space area as Ahmanson Ranch or simply Ahmanson.)

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Upper Las Virgenes Canyon Trailhead Valley Oak

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Large valley oak near the Upper Las Virgenes Canyon Trailhead of Upper Las Virgenes Canyon Open Space Preserve (aka Ahmanson Ranch)

This large valley oak lives near the Upper Las Virgenes Canyon Trailhead of Upper Las Virgenes Canyon Open Space Preserve (aka Ahmanson Ranch). There used to be several large valley oaks near the trailhead, but they were killed in the 2018 Woolsey Fire.

The trunk of the Upper Las Virgenes Canyon Trailhead valley oak.
The brim of the cap is about 7 inches wide.

This tree is as large as any of the valley oaks I see along the trails at Ahmanson. I estimate it’s diameter to be a little under four feet. That’s not large by Northern California standards, but it is still a sizable tree. Valley oaks have a tougher time here.

Along with coast live oak, the valley oak is one of the iconic species of oak-grasslands at Ahmanson Ranch. In the past 20 years, valley oaks at Ahmanson Ranch have been more severely impacted by drought, fire, and rising temperatures than live oaks. In the not too distant future, the valley oak may become a relic at Ahmanson, much like the blue oak that died earlier this year.

Some related posts: Ahmanson Valley Oaks Finally Get Their Leaves, Ahmanson Valley Oaks Battling Drought, Ahmanson Blue Oak Succumbs to Climate Change, and Many More

ahmanson ranch, photography|landscape, photography|trail running, running, smmc open space, trails, upper las virgenes canyon open space preserve, weather|southern california

Lasky Mesa Runner, Grassland, and Clouds

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Lasky Mesa Runner, Grassland, and Clouds

Brett was down for a few days, and as an initial run we did a loop from the Victory Trailhead of Ahmanson Ranch, through part of Las Virgenes Canyon, up onto Lasky Mesa, and then back to the trailhead.

Upper Las Virgenes Creek still flowed. Valley oaks were full with new leaves. The green grasses of the rain season had finally turned, and rare May cumulus clouds were painted on postcard skies.

It was an outstanding run!