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Facing a Future of Runaway Wildfires in Southern California

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A group of Jeffrey pines on Mt. Waterman killed by the Bobcat Fire with smoke from the Bridge Fire in the distance.

It was a sobering sight. I had stopped at a point on Mt. Waterman burned by the Station Fire in 2009 and the Bobcat Fire in 2020.

To the east, smoke from the Bridge Fire filled the canyons and clung to the ridges between Mt. Baldy and the East Fork San Gabriel River. A group of skeletal Jeffrey pines, once full and green, stood starkly in the foreground.

Another devastating fire had stormed through the San Gabriel Mountains, destroying homes and ravaging the forest and all that lives within. Not far away, the Line and Airport Fires were also burning, the extent of the three fires totaling over 117,500 acres.

Conventional methods of land and fire management usually do not prevent the rapid spread of a fire when forest or weather conditions are extreme — and extreme conditions are now the norm.

Incremental changes to long-established policies will not be enough to prevent runaway wildfires. Novel approaches must be considered, researched and evaluated. New tools and technology, including AI, need to be more widely applied. The hesitancy to spend money proactively must be overcome.

Today, it is difficult to do a hike or run of more than a few miles in the foothills or mountains of Southern California without passing through an area that has been burned in the past 25 years. In 50, 100, or 200 years what will the outdoor experience be? Will conifers only exist in widely scattered stands? Will the ecology be forever compromised?

Every effort must be made to mitigate the impacts of runaway wildfires and preserve the nature and ecology of our open space areas and wildlands.

Some related posts:
– Bridge Fire Perimeter and Some Area Trails
– After the Bobcat and Station Fires: Three Points Loop Around Mt. Waterman
– After the Station Fire: Pine Seedling Along the Mt. Waterman Trail
– Waterman Mountain: Fallen Trees, Forest and Ferns
– After the Station Fire: Three Points – Mt. Waterman Loop

ahmanson ranch, climate change, nature|trees, photography, trails, trees, upper las virgenes canyon open space preserve

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

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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

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Ahmanson Blue Oak Succumbs to Climate Change

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Rare at this latitude, this blue oak at Upper Las Virgenes Canyon Open Space preserve succumbed to drought, fire, and above average temperatures.

When I rounded the corner on the Lasky Mesa Trail, I could hardly believe my eyes. The Ahmanson Blue Oak was gone. Where there had been a sprawling oak, there was nothing.

Crossing an eroded section of trail and walking over to the edge of the old roadbed, I looked down the slope. Much like this valley oak along Rocky Peak Road, the entire Ahmanson blue oak  had fallen from its hillside perch near the bottom of the canyon.

Oaks in the oak-grasslands of Upper Las Virgenes Canyon Open Space Preserve have had a tough time with climate change. The five-year drought from July 2011 to October 2016, increasing temperature, and the 2018 Woolsey Fire have combined to kill a large number of trees.

This blue oak was one of very few found at the southern extent of its range.

Related posts: Ahmanson Blue Oak, Ahmanson Valley Oaks Battling Drought, After the Woolsey Fire: Ahmanson Ranch, Fallen Oak, Valley Oak Savanna