Fall color is not as widespread in chaparral as in some other plant communities. This vividly colored poison oak is along the Garapito Trail in Topanga State Park.

From a run of the Trippet Ranch Loop from Marvin Braude Mulholland Gateway Park at the southern end of Reseda Blvd., in the San Fernando Valley.

Related post: Poison Oak, Ferns Along the Garapito Trail

Following are brief descriptions, Google Earth images, and a Google Earth KMZ file of several trail runs at Ahmanson Ranch -- now Upper Las Virgenes Canyon Open Space Preserve. These are shorter courses, generally on dirt roads, that extend as far west as Las Virgenes Canyon. Some longer runs in this area are listed in the Santa Monica Mountain Conservancy Open Space section of my Google Earth KMZ Files of Trail Runs page.

Sometimes growing as large as a supermarket cherry, the sweetish, thin-pulped fruit of hollyleaf cherry (Prunus ilicifolia) is a favorite snack of coyotes.

These are on the Chumash Trail in Rocky Peak Park. This is the first year since the 2003 Simi Fire that there has been a sizable hollyleaf cherry crop along the trail.

It is commonly reported that an "acid treatment" in the digestive tract of a coyote or bird is required for germination. However, according to the University of Texas Native Plant Information Network Native Plant Database, fresh seeds require no treatment.

Related post: Holly-leaved Cherry

Ka-ree... Ka-ree... Ka-ree...

I heard the angry cries at least a quarter-mile away. The screams were incessant. Running along the dirt road, I emerged from a grove of oaks and turned west -- running down a short hill and then up another. Cresting the rise, I paused to search the parched terrain.

The Winter rain season had been the driest on record, and Summer heat was now oppressive, abusing the animals and desiccating the chaparral. A few clouds cluttered the sky, but they would bring no rain. The cries continued.

Ka-ree... Ka-ree... Ka-ree...

The screams seemed to be coming from a group of rocks and oak trees near the campground. I left the road and slowly walked through the brush in the direction of the shrill shrieks. As I approached, the intensity and urgency of the screams increased. Intimidated, I stopped.

KA-REE... KA-REE... KA-REE...

There was not only fury in those cries, but a warning.

To my left, something stirred. Slowly I turned and looked down. For a moment I just stared. Rabbit lay face-down against a rock, twitching. Up in the oak tree, Hawk continued his irate cries.

KA-REE... KA-REE... KA-REE...

Suddenly, there was motion to my right, and Bobcat bolted from the brush. Hawk swooped in pursuit. His broad tail flared and wings twisted one direction and then another, as he followed the abrupt zigs and zags of Bobcat through the rocks, up the hill, and out of view.

KA-REE... KA-REE... Ka-ree... ka-ree...

Afterward: This encounter occurred during a run at Sage Ranch Park in July of 2002. I continued my run, and when I returned about 30-40 minutes later, the rabbit was gone. The photographs were taken during the encounter.

Adjacent to Las Virgenes Creek, not far from the cattails of Linear Green, is a sizable plot of western ragweed. On a recent run I noticed several tufts of fluff caught on the ragweed and backlit by the afternoon sun.

Investigating, I found the source of the tufts about 15 yards away -- a patch of bull thistle -- an invasive weed that is found throughout the U.S.

Like a dandelion, bull thistle seeds are attached to a downy pappus, and can be dispersed by wind. The rate at which these plumed seeds fall through still air is quite low -- less than 1.5 ft/sec. This is slower than the minimum sink rate of a high performance sailplane. For a given plant height, the lower the sink rate, the farther the seed can potentially be dispersed from the parent plant.

Even though the plumed seed of bull thistle (Cirsium vulgare) is much larger and heavier than a dandelion's familiar tuft, it is reported to have about the same ratio of plume area to seed weight. This is a key factor affecting the sink rate. However, the bull thistle's seed is reported to sink at about a 15% slower rate than the dandelion's. This may be attributable to aerodynamic and structural advantages of the secondary branches found in the plume of the bull thistle, but not in the dandelion's.

Related technical papers:

Diaspore Size, Shape, and Fall Behavior in Wind-Dispersed Plant Species
Glenn R. Matlack
American Journal of Botany, Vol. 74, No. 8 (Aug., 1987), pp. 1150-1160
Botanical Society of America

The Aerodynamics of Plumed Seeds
D. F. Greene and E. A. Johnson
Functional Ecology, Vol. 4, No. 1 (1990), pp. 117-125
British Ecological Society

One hundred degrees
A willowed stream
Late afternoon sun
And linear green.

Study of cattail leaves in afternoon sun.

From a run to Las Virgenes Creek from the Victory trailhead of Upper Las Virgenes Canyon Open Space Preserve (formerly Ahmanson Ranch).

From a run at Ahmanson Ranch (now Upper Las Virgenes Canyon Open Space Preserve).

An unusual, offset lightning scar on a Jeffrey pine in the San Gabriel Mountains, near Los Angeles. The tree is located at an elevation of about 8750', on the ridge east of Mt. Hawkins.

The offset scar is not easily explained. Either the scar was offset when created, became offset as the tree aged, or perhaps multiple strikes have somehow created the appearance of an offset. None of these explanations seem completely satisfactory.

The lightning scar on the Mt. Hawkins tree appears to be older than the scar on the Jeffrey pine on the Three Points - Twin Peaks Saddle trail, and quite a bit older than the scar on the Jeffrey pine on Mt. Baldy's North Backbone Trail.

Technorati Tags: lightning

Mt. San Jacinto (10,804') from the Mt. Wilson pavilion parking lot, just before sunrise, the morning of the 2008 Mt. Disappointment 50K and 50 mile Endurance Runs. San Jacinto -- the large peak left of center -- is 84 miles distant.

Related posts: Mt. Disappointment 50K 2008 Notes, Room with a View

Updated 8/20/08. Added Split Rank listings (PDF) for 2007 50K and 50M, and related comments.

Winding down the precipitous Mt. Wilson road, I thought about the run ahead. To my left granite and pine glowed golden in the morning sun, and to my right the mountain plunged in long shadows, 2000' into the canyon of the West Fork San Gabriel River.

In a few hours I would be somewhere down in that canyon, plodding along sun-baked Red Box road. By then the temperature would be in the mid-eighties, but in the full sun it would feel like a hundred. That would be around mile 23. I kicked a pebble and winced as it almost hit the heel of the runner in front of me. Only at mile 1-something, there were a lot of miles to go.

There are some imperfections, but generally the unopened disk florets comprising the head of this immature sneezeweed blossom are arranged so that each floret is surrounded by six other florets. This is an example of hexagonal close packing, and is probably the most dense arrangement of florets that can be achieved in this spherical flower head.

The photograph of the Bigelow's sneezeweed (Helenium bigelovii) was taken on an out and back run on the Pacific Crest Trail from Vincent Gap to Little Jimmy Spring during July 2007.

Related post: Bigelow's Sneezeweed & Bee

Or did the Curve Fire trigger a lightning strike?

These trees -- on a section of the Pacific Crest Trail east of Windy Gap -- were burned almost six years ago in the 20,857 acre Curve Fire. According to the Curve Fire Burned Area Emergency Report Implementation Plan, the source of ignition for the devastating fire was "a ritual involving the use of fire (candles) and animal sacrifices." The fire started the afternoon of September 1, 2002.

However, in the document An Exercise Involving Flash Flood and Lightning Potential Forecasts, an alternative ignition source was suggested -- an "out of the blue" lightning strike. Forecasters observed a "single positive lightning strike northeast of the Mount Wilson Observatory" about 1:00 PM PDT (2000Z), near the time the Curve Fire started. According to NWS Lightning Safety Outdoors, such bolts from the blue have been documented to travel more than 25 miles from a thunderstorm cloud.

While there is compelling evidence that the blue sky lightning strike occurred, the time of the strike suggests that it was not the initial source of ignition of the Curve Fire. This UCLA Solar Towercam image is time-stamped at 12:58:58, about the time of the strike. It shows the Curve Fire already underway, with a well-developed smoke column. The photograph also shows the cloud development over the San Gabriel Mountains.

An intriguing question comes to mind. Was the lightning strike a coincidence, or was it somehow triggered by the fire, or the smoke?

According to "Forest Fires: Behavior and Ecological Effects" By Edward A. Johnson, Kiyoko Miyanishi (Academic Press, 2001) large scale lightning detection networks have revealed an association between forest fires and the electrification of thunderstorms. Further, "a shift from negative to positive ground flash prevalence in association with fires and forest fire smoke" has been documented.

So it looks like lightning did not start the Curve Fire, but the Curve Fire may have triggered the positive lightning strike observed by the NWS!

The photograph of trees burned in the Curve Fire is from Sunday's Islip Saddle - Mt. Baden-Powell South Fork run.

Technical papers:

CLOUD-TO-GROUND LIGHTNING DOWNWIND OF THE 2002 HAYMAN FOREST FIRE IN COLORADO
Timothy J. Lang* and Steven A. Rutledge
Colorado State University, Fort Collins, Colorado

Enhanced Positive Cloud-to-Ground Lightning in Thunderstorms Ingesting Smoke from Fires
Walter A. Lyons, Thomas E. Nelson, Earle R. Williams, John A. Cramer, and Tommy R. Turner
Science 2 October 1998 282: 77-80 [DOI: 10.1126/science.282.5386.77] (in Reports)

Technorati Tags: lightning, forest fires, San Gabriel Mountains