UC Berkeley expert talks about hillside tree removal plan

Eucalyptus
Eucalyptus is one of the non-native tree species that would be cut down under UC Berkeley’s fire risk reduction plan. Photo: Tracey Taylor

UC Berkeley has sought federal funds to cut down 22,000 non-native trees in Strawberry Canyon and Claremont Canyon with the goal of reducing the risk of fires. The project is a continuation of work the university has been doing for the last decade on its land. There has been some opposition to the proposal, including from the Hills Conservation Network, who believe the scheme, while restoring native species, might actually increase fire risk. The proposed use of certain herbicides is also being debated.

The Hills Conservation Network is holding a public forum to discuss UC Berkeley’s plans on Wednesday June 12 at 7:30 pm at The Hillside Club, 2286 Cedar Street (at Arch).

Public comment to FEMA has been invited through June 17. As the public considers the project, UC Berkeley’s Tom Klatt, campus environmental manager and a member of the UC Fire Mitigation Committee, answered questions about the plan.

Why does UC Berkeley want to cut down trees in the hills?


In 1973, H.H. Biswell, professor of forestry and conservation at UC Berkeley, made this prophetic statement: “When eucalyptus waste catches fire, an updraft is created and strong winds may blow flaming bark for a great distance. I think the eucalyptus is the worst tree anywhere as far as fire hazard is concerned. If some of that flaming bark should be blown on to shake roofs in the hills we might have a firestorm that would literally suck the roofs off the houses. People might be trapped.”

Biswell was absolutely right. Eucalyptus, planted by land speculators, along with equally flammable Monterey pines, have been implicated in several disastrous conflagrations in the East Bay hills, especially the deadly 1991 firestorm that took 25 lives, destroyed more than 3,000 homes and cost $1.5 billion.

Reducing this risk means removing high-risk trees and vegetation.

Eucalyptus are a special risk because they drop tons of dead leaves and branches on the forest floor, litter that provides excessive fuel to fires. Their low branches serve as fuel ladders up to their high crowns, and their volatile oils burn hot and fast. When eucalyptus catch fire, flames shoot up to the crowns, which send embers flying. High winds can carry the embers across firebreaks and clearings and into residential areas.

Eucalyptus groves on steep hillsides — like those in the East Bay hills — are extremely flammable when hot Diablo winds of late summer and fall start blowing and make control of a moving flame front impossible until the winds stop.

As a result, CalFIRE (the state firefighting agency) has categorized the East Bay hills, particularly Berkeley and Oakland, as a Very High Fire Hazard Severity Zone.

klatt300
Tom Klatt, manager of Emergency Services, at work clearing trail and brush in Strawberry Canyon in December 2005. Photo: UC Berkeley NewsCenter/Jeffery Kahn

Is cutting down trees the only option for reducing the hazard?

Australia, where eucalyptus are native, uses prescribed burns to keep fuel loads below six tons per acre in wildland areas and two tons per acre near homes. Mechanical methods can also be used to remove large amounts of vegetation. But the practicability, costs and environmental impacts of doing so — and repeating the removal every five years — remains mind-boggling, especially on steep hillsides.

Reluctance to use prescribed burns in the Oakland/Berkeley Hills starts from the risk that a fire could escape near a residential area. Also, there is a lack of fire crews trained and experienced in the use of this technique near residential areas, and the climate window for prescribed fire on steep hillsides is narrow.  Prescribed fire also has an impact on air quality, and carries significant costs.

Furthermore, the blue gum eucalyptus groves in the Oakland/Berkeley Hills are significantly different and apparently more flammable than groves of the same or similar varieties of eucalyptus near cities in Australia, according to recent research.

Will more trees be planted to replace the eucalyptus?

Yes. In similar projects over the last 12 years, the university has found that native trees such as bay laurel, coast live oak, buckeye and willow readily colonize areas suitable for tree growth.  Some areas will convert to native scrub or grassland, depending upon the slope, aspect and soil conditions. Historically, the hills have not been as heavily forested as we now find them. Rather, grassland and scrubland was much more common, with tree growth following the creeks, riparian zones and north-facing slopes.

Don’t oaks and other native trees burn too?

Yes, all vegetation will burn, given the right conditions. However, our native plants produce less litter and live biomass (fuel) and don’t have the extreme ember-casting characteristics of the blue gum eucalyptus.

And what about all those wood chips. Why leave them there, and aren’t they a fire hazard too?

The wood chips do not pose a fire hazard. Composted wood chips produce only incidental flaming with smoldering as the primary form of combustion, according to research by the University of Nevada Cooperative Extension. Retaining the wood chips also controls erosion, recycles nutrients and suppresses the germination of the millions of eucalyptus seeds that have accumulated beneath the trees.  These seeds are viable for up to 10 to 12 years, but covering the heaviest seed accumulations with chips kills these potential trees without the use of herbicide. Lastly, retaining biomass on site avoids thousands of truck trips needed to haul the material 100 miles to a waste-reuse facility and saves substantial taxpayer dollars.

Why is herbicide necessary?

The eucalyptus trees on UC land are not killed by felling alone. Virtually all of UC’s eucalyptus trees have been cut at least once, many of them twice prior to 2001.  It is estimated that more than 95 percent of the trees re-grew from their cut stumps. Had herbicide been used effectively in earlier work, this project would not be needed. However, the eucalyptus trees did re-grow, and instead of a single trunk, they grew as clusters of trunks, a far more hazardous condition from a fire-management perspective.

How will the environment be protected during application of a herbicide?

The U.S. Fish and Wildlife Service concluded that the use of herbicides is not likely to adversely affect either the endangered Alameda whipsnake nor the California red legged frog, and the National Marine Fisheries Services concluded there would be no adverse impact to fish or aquatic life proximate to the project areas. Strict best-management practices, rules and regulations will be followed at all times to ensure the application of herbicide is consistent with the hundreds of rules that regulate their use. These measures are fully outlined in the Draft Environmental Impact Statement. (LINK) http://ebheis.cdmims.com

Some people are upset about this. What do you tell them?

There should be absolutely no confusion or argument about the serious nature of fire risks in the East Bay hills.

Under normal weather conditions, fires that start in the hills are efficiently controlled by firefighters, and do not usually reach residential areas. During most of the year, temperatures are moderate and vegetation is relatively moist and fire-safe. Summers bring overnight and morning fog along the hills until noon, with moist midday winds blowing westerly in from the coast.  Westerly winds can fan flames in a fire almost anytime during the year, but embers, if they are created, will be carried in an easterly direction away from East Bay hills’ residential areas.

However, there are a few red-flag days each year when all of the conditions are in place for extreme wildfire, usually during August through November. On these days, vegetation will experience a “perfect firestorm condition” with unusually hot temperatures above 90 degrees, humidity below 10 percent and strong Diablo winds blowing from the east, over the high ridge tops and down leeward slopes into densely populated residential areas. Any eucalyptus grove fire that occurred under these conditions could produce millions of burning embers and firebrands that could blow over fuel breaks and other cleared areas and then drop to ignite homes and landscapes.

Three official reports — the 1995 Hills Emergency Forum Vegetation Management Consortium Plan, the 2010 Park District Fire Mitigation Plan EIR, and the 2013 FEMA East Bay Hills Hazardous Fire Risk Reduction EIS — clearly document the problem and identify eucalyptus and pine groves as contributors to this area’s high-risk fire hazard potential.

As a responsible agency, UC is fulfilling its obligation to mitigate this risk on land under its control.

How will the tree-management project affect wildlife?

The project should be beneficial to many species of wildlife, resulting in both greater diversity and abundance of native plants and animals. The U.S. Fish and Wildlife Service has concluded that the UC project will remove zero acres of habitat suitable for the endangered whipsnake and will result in over 120 acres of new snake habitat, as well as reversing the ongoing loss of habitat as the eucalyptus groves expand over time.

Has this been done before, and if so, what were the effects?

While the earliest UC efforts were not successful in eliminating the eucalyptus, projects undertaken using the FEMA-proposed methodology have resulted in the removal of over 19,000 re-sprouted trees on 185 acres in the UC hill area over the past 12 years. Not only have the eucalyptus and pine been effectively extirpated, native plant and animal communities have grown phenomenally without the competition from the large, tall, invasive trees.

A demonstration forest is growing at the top of Claremont Canyon; the south side of the road was cleared of eucalyptus and pine, while the north side has a dense eucalyptus overstory. The treated side has achieved a substantial biodiversity in just over a decade, and is on the path to becoming a sustainable, native-plant community that is thriving and teeming with life. Of course, these plants can burn, but are expected to burn with far less intensity, with lower frequency and in smaller fire footprints. Most importantly, eucalyptus trees and the potential for their shooting “roman candle” embers has been eliminated, successfully mitigating the fire risk to many thousands of Berkeley and Oakland residents.

More information about the project is available on a UC Berkeley fact sheet and on the the project website.

Written comments may be sent to FEMA before midnight on June 17, 2013 by email at EBH-EIS-FEMA-RIX@fema.dhs.gov, by FAX at (510) 627-7147, or by mail to P.O. Box 72379, Oakland, CA 94612-8579.

This article was first published by UC Berkeley News Center on May 31.

Related:
UC Berkeley seeks funds to cut down 22,000 non-native trees [05.17.13]

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