Category Archives: nature|wildfire

New Growth on Bigcone Douglas-Fir

New growth on bigcone Douglas-fir

These young-appearing bigcone Douglas-firs along the Valley Forge Trail are probably older than they look. According to the Forest Service Silvics Manual, Volume 1: Conifers, saplings may be only 2 ft. tall when 40-50 years old and as old as 70 years when they break through the oak overstory.

The bigcone Douglas-fir is a very resilient tree that is remarkably fire tolerant. It can lose virtually all of it foliage to a fire, appear to be beyond the point of recovery, yet survive and regenerate its foliage. Fire-scarred bigcone Douglas-firs have been used to analyze fire history and regimes.

The photograph on the left is of a bigcone Douglas-fir along the Valley Forge Trail that was burned in the 2009 Station Fire. Here is a closer view of the same tree showing how new foliage sprouts from buds along its limbs and trunk.

The Valley Forge Trail is in the canyon of the West Fork San Gabriel River in the San Gabriel Mountains near Los Angeles. It connects the Gabrielino Trail to Eaton Saddle on Mt. Wilson Road. The trailhead for Mt. Lowe Truck Trail is at Eaton Saddle.

The photographs are from a trail run in May 2012.

Related post: Red Box – Bear Canyon Loop

Where Are We Running Next?

A rabbit waits at the top of Cheeseboro Canyon

I don’t think I’ve ever seen as many rabbits on a run. It seemed that every few strides another rabbit, or two or three rabbits, would pop up on the trail.

Cottontails have a peculiar behavior when people approach. When one sees me running toward it, it will often watch and wait…, watch and wait… It’s almost like the rabbit is waiting to see just how close I’ll approach. Usually when I’m about 10-12 feet away — sometimes closer — it will break for an established escape path. Then just a foot or two into the brush, it will stop again. If you stop and stand very still, many times a rabbit “on pause” will just sit there, 3 to 4 feet away.

Rabbits aren’t always so calm. One time I was running down Las Virgenes Canyon and a ground squirrel and rabbit were on the road about 25 yards ahead of me. They must have been preoccupied with each other because when the squirrel finally noticed me, it panicked and bolted toward the rabbit. That caused the rabbit to freak. The rabbit launched like a rocket, just as the squirrel collided with it. The resulting visual was of a rabbit eight feet in the air with a ground squirrel spinning off-kilter below it!

From this morning’s Cheeseboro Canyon Loop from the Victory Trailhead of Ahmanson Ranch (Upper Las Virgenes Canyon Open Space Preserve).

Related post: Classic Cheeseboro Canyon

Angeles National Forest Reforestation, the Natural Way

Area near Mt. Islip burned in the 2002 Curve Fire

The photograph above is of an area on the Pacific Crest Trail near Mt. Islip that was burned ten years ago in the 2002 Curve Fire. Here’s another photograph of an area along the PCT near Throop Peak that was also burned in the Curve Fire. These are from last weekend’s trail run.

The forest conditions are quite a bit different in each case. The Mt. Islip trees are on a cooler northeast-facing slope that was densely forested, and the Throop Peak trees are on a warmer, more open, south-facing slope. But in both cases you can see numerous pines, from small seedlings to young trees two to three feet tall.

Reforestation doesn’t happen overnight, but nature is remarkably resilient, and as long as an area is not burned too frequently, many forests are able to recover from fire with minimal intervention.

However, the process of recovery is multi-faceted and complex. It may involve varying degrees of regrowth and succession. In some cases, such as in the blast zone of Mt. St. Helens, the ecosystem has to be effectively bootstrapped, and seemingly restored from scratch.

Ultimately the mature forest that results from these processes will be comprised of an ecosystem — and vegetation — suitable for the array of climatic and other factors present at the time.

Attempts to shortcut this process are not often successful — such as the recent attempt to plant nearly one million seedlings in the Station Fire burn area. An Angeles National Forest official is quoted in an April 7, 2012 Los Angeles Times story as saying, “When we planted seedlings, conditions were ideal in terms of soil composition and temperature, rainfall and weather trends.” Beyond the criticisms outlined in the story did anyone in the Forest Service consider that La Nina conditions were present, and there was a good chance La Nina conditions would be present during the 2011-2012 rain season — along with a likelihood of below normal precipitation?

Tree 75

Valley oak at Ahmanson Ranch killed by 2005 Topanga Fire

The collapsed tree above is number 75 of 80 dead oaks counted on a 7.5 mile loop encompassing much of Ahmanson Ranch. The trees were burned in the 2005 Topanga Fire. Most of the trees were valley oaks, but some coast live oaks were also burned.

Most of the oaks in the Ahmanson Ranch area survived the fire, but perhaps as many as one in 20 trees were killed or severely injured. Of those that were severely burned, a small number, such as the valley oak above, attempted to replace its foliage through the process of epicormic sprouting.

Oaks that lost all of their foliage generally survived in proportion to the number of epicormic sprouts they were able to produce. Those that produced only a few epicormic sprouts generally succumbed after 3-4 years. Oaks with numerous epicormic sprouts generally survived.

Although Tree 75 didn’t make it, most of the surrounding trees survived the fire. And if you look next to Tree 75 you’ll see that its progeny, a young valley oak, appears to be doing well.

Stem fasciation in Eriodictyon parryi (Poodle-dog bush)

The photograph above is of an example of a bizarre malformation in plants known as stem fasciation — in this case in Eriodictyon parryi (Poodle-dog bush). The normally round stem of the plant has been transformed into a thick ribbon-like structure, many times the size of a normal stem. The photo is from a recent trail run in an area burned by the 2009 Station Fire.

This is the second time I’ve found a plant with a fasciated stem in a burn area. The first was at Sage Ranch following the 2005 Topanga Fire. In this case the fasciated stem of a wreath plant (Stephanomeria) was a contorted spiral several feet tall.

There are many mechanisms which are reported to cause fasciation; among them a bacterium, stress, chemical or mechanical damage, and inheritance. It may or may not be coincidence that both of these examples were found in burn areas — about two and a half years into recovery in the case of the Turricula, and a year in the case of the wreath plant.

The Problem with Mustard

Brassica nigra in Upper Las Virgenes Canyon Open Space Preserve

The problem with mustard is that it is prolific. It out-competes native annuals, and native and non-native grasses. In oak grasslands this can produce brush conditions that should a fire occur, it is likely to kill more trees.

A heavy growth of mustard was probably a factor in the death of the valley oak pictured above. It was burned in the 2005 Topanga Fire.

From this afternoon’s run at Ahmanson Ranch.