Near the beginning of what is likely to be an intense fire season, the area north of Cold Canyon that has burned twice before over the past four years was in flames again. A total of 2,269 acres burned north of Highway 128 near Winters over three days in early July:
This map shows all of the fires in the area between 2014 and 2016:
While fire is a necessary component of a healthy ecosystem, when the same area burns repeatedly with only short intervals between fires, seed banks are destroyed and trees that might have survived a single fire are unable to recover enough to withstand the next fire. We still have a couple of months or more of hot dry weather, and plenty of extra fuel this year as a result of the wet winter. I will be surprised if there are not more fires in this area this year.
Approximately a year and six months after the fire, it is apparent that the crowns of many of the trees near the trailhead have filled in considerably. There is also a lot more vegetation on the ground than there was in March a year ago. Chaparral shrubs are resprouting from their bases, but I have noticed this winter and spring that vines (wild cucumber, wild grape) are responsible for a lot of the newest greenery on the hillsides, growing up the trunks of the burned shrubs.
The view September 2016:
Having established a pattern of drawing the view at the trailhead every six months, I am posting the drawing for September 2016, just a over a year after the fire. Although plenty of charred tree and shrub branches are still in evidence, new growth in tree crowns and from the bases of both trees and shrubs stands out starkly against the summer-yellowed hillsides.
The view in March 2016:
The view in September 2015:
John De Benedictis, a Research Fellow at the Richard M. Bohart Museum of Entomology, has been collecting moths twice a month at dusk in Cold Canyon since 1989. I accompanied him for the first part of his visit on May 18. John sets up a sheet across the path at the entrance to the Reserve, and sometimes a second sheet parallel to the path (and perpendicular to the first sheet), when accompanied by Greg Kareofelas, a Research Affiliate at the Bohart Museum. John hangs a fluorescent light against the sheet, which transmits unfiltered UV light, a mixture of UV and white light.
John collects the moths that land on the sheet for later identification. John started his work in Cold Canyon three years after the last major wildfire and is watching closely to see how moth populations respond after the Wragg Fire. May is the month in which he has recorded the most moth species over the years; on a good night, he collects about a third of the species known to fly at that time of year. The numbers collected this May will be a good indication of how depleted the populations are after the fire.
When John first started collecting in 1989, not long after the previous fire at the Reserve, he observed that Sparganothis senecionana was numerous. S. senecionana is a tortricid that prefers to feed on low-growing plants. Over time, as fire recovery progressed, the numbers of S. senecionana decreased, while those of Archips argyrospila, the fruit tree leafroller (also Tortricidae), increased. A. argryrospila feeds on a number of plants including oaks, but seems more abundant in areas with oaks, and their numbers seem to have followed oak regrowth in the Reserve. This pattern now appears to be repeating after the Wragg Fire: John has observed that Archips numbers are considerable lower since the fire, along with the numbers of other oak-associated moths, indicating that they have been hard-hit by the fire and the loss of oaks.
Because the green hills will not last long, I wanted to capture the great difference in the view at the trailhead in March compared to last September. The charred trees and shrubs stand out starkly against the vibrant green new growth. Here is the view March 23:
And here is the view from last September 11:
The Wragg Fire started just over the ridge to the west of Cold Canyon, rushing quickly over the hill and down into the canyon. Once there, it remained in the canyon, generating winds that caused it to cycle within the canyon, according to Jeffrey Clary, Stebbins Cold Canyon Reserve Manager. This greatly increased the intensity of burning in the canyon. The differences in fire intensity across the landscape burned will lead to interesting opportunities to compare rates and types of regrowth in the coming years.
Between July 22 and August 5, 2015, the Wragg Fire burned over 8,000 acres in Napa and Solano Counties, including the entirety of the Stebbins Cold Canyon Reserve near Lake Berryessa.
On July 28, driving home in Davis, I happened to notice a new large plume of smoke, further south than where I had seen smoke previously. This was the day the fire reignited, after having been at 80% containment. It took another seven days to reach full containment.
As I stood at the side of the road watching, an air tanker flew overhead, heading away from the fire.
A couple of days earlier, I had seen the completely burned hillside west of Winters, making a stark contrast with the hills in their usual summer gold and green to the north.