On managing California bay laurels to improve oak health

Removing young bay laurels and burning the remains. Photo by Lee Klinger.

Several friends and tree professionals have contacted me about my thoughts on the following article by Peter Femrite that recently appeared in the San Francisco Chronicle:

Saving oak trees by chopping down bay trees

Workers began chopping down 250 California bay laurels this week in the Santa Cruz Mountains so that 49 signature oak trees might be saved from the infectious scourge known as sudden oak death.

The tree-removal project is an attempt by the Midpeninsula Regional Open Space District to prevent the spread of the tree-killing pathogen, which uses bay trees to scatter spores in the forest.

(h/t to R Zingaro for alerting me to this article)

First, there are important points here with which I agree. The bays are clearly major vectors for sudden oak death disease. I do believe that selective removal of bays will lower the incidence of sudden oak death (SOD). However, I am bothered by the singular focus on the disease. I would rather the focus of efforts be made toward promoting the overall health of the forest ecosystem.

Six-year results of fire mimicry treatments on California buckeyes

Six years ago these California buckeyes in Mill Valley were suffering from early leaf senescence. The owner wisely followed my fire mimicry protocol in treating the buckeyes, and six years later we see that the buckeyes are no longer experiencing early leaf senescence. As can be seen in results from these same trees posted from year 4 and year 5, these buckeyes have not been experiencing early leaf senescence for the past 3 years.

More results are shown below:

New study with implications for fire management of oak woodlands

Managed fire in a California oak woodland. Photo by Lee Klinger.

A recent study reported at Science Daily on the fire history of post oaks in Illinois reads like page from the history of California oak woodlands:

Old-Growth Tree Stumps Tell the Story of Fire in the Upper Midwest

The new study, in the journal Castanea, confirms that the people who lived in Illinois before European settlers arrived [Native Americans] were in the habit of setting fires in the region nearly every year, with fires in the Hamilton County woodland occurring at least every two or three years, McClain said. This repeated burning actually stabilized the prairies and open woodlands that dominated the region until the late 19th century, when the fire-suppression efforts of the new settlers allowed different plant species to take over, the researchers said.

The study was conducted by William McClain, a botanist with the Illinois State Museum along with researchers John Ebinger and Greg Spyreas, of the Illinois Natural History Survey at the University of Illinois. They also report:

“For hundreds, maybe thousands of years, this was a stable post oak woodland,” Spyreas said. “And then you have a gap of a couple of decades where there were no fires and suddenly the whole system is completely different. It’s amazing how, from Kansas to Ohio, these ecosystems completely depend on fire to be stable.”

See the full report here.

To all you Californian’s concerned about the oaks, this study is highly relevant.