erosion – Conservation Sense and Nonsense

Cal Fire grant has created fire hazards in the East Bay Hills

Hoping to get the public’s attention, I will begin this story with its ending. This is the concluding paragraph of my formal complaint to Cal Fire about its grant to UC Berkeley for a project that has increased fire hazards in the East Bay Hills, caused other significant environmental damage, and created conditions for further damage:

“In conclusion, the grant application for this project makes a commitment to reducing greenhouse gas emissions that is based on the assumption that a biofuels plant will generate electricity from the wood debris. Such a plant has not been built and UC Berkeley apparently does not intend to build such a plant. Other claims made in the grant application about carbon storage are based on inaccurate claims about carbon storage. Grant guidelines state, “Failure to meet the agreed upon terms of achieving required GHG reduction may result in project termination and recovery of funds.” In other words, Cal Fire should terminate this project and recover any funds that have been remitted to UC Berkeley. The project is a misuse of grant funds because it will increase fire hazards and increase greenhouse gas emissions. Without imputing motives, on the face of it, the grant application looks fraudulent.”

I published an article about this project last week that I invite you to revisit if you need a reminder of a project that has clear cut all non-native trees 100 feet on the north side of Claremont Ave. in Berkeley, leaving equally flammable native trees in place on the south side. Huge piles of wood chips and logs are stacked along the road that were supposed to have been disposed of by generating electricity in a biofuels plant. No such biofuels plant exists and there are no plans to build it. The disposition of these potential bonfires is at the moment unknown.

The source of the funding for Cal Fire grants is California’s carbon cap-and-trade law that is intended to reduce greenhouse gas emissions, primarily carbon emissions. Therefore, the grant application required the applicant to prove that the project would reduce greenhouse gas emissions to qualify for the grant. The grant application submitted by UC Berkeley claimed to meet this requirement by making a commitment to use the grant to build a biofuels plant. The biofuels plant would have generated electricity by burning wood fuel instead of burning fossil fuels. In fact, the project has significantly increased greenhouse gas emissions by destroying large, mature, healthy trees. The carbon the trees have stored throughout their lifetimes is now being released into the atmosphere as the wood debris decays along the roadside.

UC Berkeley made other inaccurate claims about carbon storage in order to qualify for the grant:

Statements made in the grant application about carbon loss and storage by planting oaks are not accurate:
1. Coast Live Oaks (CLO) do not live for “hundreds of years,” as erroneously claimed by the grant application. USDA plant data base says CLOs live about 250 years in the wild. However, that estimate of longevity does not take into account that Sudden Oak Death has killed over 50 million oaks (CLOs and tan oaks) in California in the past 15 years.
2. Blue Gum eucalyptus lives in its native range 200-400 years. It has lived in California for 160 years, where it has fewer predators than in its native range.
3. The grant application states that carbon storage will be increased by “changing species composition to hardwoods.” In fact, eucalyptus is also a hardwood tree, making this an inaccurate, discriminatory distinction.
4. Above-ground carbon storage in trees is largely a function of biomass of the tree. Therefore, larger trees store more carbon. It follows that carbon storage is not increased by destroying large, mature, healthy trees and replacing them with saplings of smaller trees, such as oaks. The carbon lost by destroying mature trees is never recovered by their smaller replacements with shorter lifespans.
Plans to plant oaks where non-native trees have been clear cut willfully ignore the realities of the accelerating epidemic of Sudden Oak Death (SOD) in the East Bay Hills. According to the press release for the 2020 SOD Blitz, “…overall the rate of SOD infections increased in the wildland urban interface, in spite of reduced rainfall. This is the first time in 13 years of SOD Blitz survey that infection rates increase in spite of reduced rainfall, suggesting SOD is becoming endemic at least on the Central coast of California.” As Cal Fire knows, dead trees are a greater fire hazard than living trees.
The grant budget commits the grantee (UCB) to pay “volunteers” to plant oaks. That budget line item is described in the budget narrative as being funded by volunteer, non-profit organizations over which UC Berkeley has no authority. A “volunteer” is, by definition, not required to perform the assigned task. It follows, that calculations regarding carbon storage resulting from this project are not ensured by the project because the planting of oak trees is not ensured by the project. The “cost” of this line item in the budget seems more theoretical than real.
Planting young trees will require frequent irrigation that is not funded by the grant. Given continuing and worsening drought, planting young trees without making a commitment to irrigating them is throwing good money after bad. Rainfall to date is 26% of the previous year. Rainfall the previous year was less than half the year before that. Oaks are not more drought tolerant than eucalyptus that are native to an equally dry climate.

The grant application also displays ignorance of trees and the functions they perform in the environment.

The trees that remain on the north side of the road are now more vulnerable to windthrow because they have lost protection from their neighbors on their windward side. Trees develop their defenses against the wind while they grow in response to the wind to which they are exposed. In California, most wildfire events are associated with high winds, making windthrow and wildfire probable simultaneous events.
The run off from the eroded hillside will undoubtedly pollute the creek on the south side of the road with sediment and road run off.

Claremont Ave. west of Grizzly Peak Blvd, December 2020. Photo by Doug Prose.

The project is not a suitable evacuation route

Claremont Ave, west of the Cal Fire/UCB project is a residential neighborhood, heavily wooded with native trees that overhang the road. Source Google Earth.

The justification for this project was to provide an evacuation route. It is a premise that makes little sense. There are no residences east of Grizzly Peak Blvd, where the project begins. The residential community on Claremont Ave. is downhill, west of the project. If the residential community needs to evacuate, it won’t be fleeing up hill. Residents will need to flee downhill, through a tunnel of native trees. The roadside through the residential community is heavily wooded in native oaks, bays, and buckeyes. High voltage power lines overhang the road. Nothing has been done to clear that road for possible evacuation. This residential community would benefit from the creation of a safe evacuation route, not the pointless project that was done.

Claremont Ave, west of Cal Fire/UCB project is heavily wooded with native trees that overhang the road. There are also high-voltage power lines hanging over the road. Source Google Earth.

What’s next?

I received the following promising reply from Cal Fire by the end of the day I sent the complaint: “We are in receipt of your email dated 1/14/2021 in regards to a Fire Prevention Grant awarded to the University of California Berkeley (UCB). We will promptly begin investigating your concerns and allegations of UCB non-compliance with the grant’s guidelines and contractual agreement. I will respond to you within 30 days with the results of our findings. CAL FIRE takes the grant assistance programs very seriously so we will investigate thoroughly.”

What’s done cannot be undone. The best we can hope for is that the strategy used to reduce fuel loads on Claremont Ave. won’t be used elsewhere. My primary goal is to prevent this destructive approach from being used on 300 miles of roadside in Oakland, as the supporters of the UCB project on less than one mile on Claremont Ave are demanding.

Governor Newsom has proposed that the State budget should invest an additional $1 billion in reducing fire hazards in California. The proposal includes $512 million for landscape-scale vegetation projects. Cal Fire will probably administer those grants. It is critically important that Cal Fire improve its evaluation of grant applications to avoid funding disastrous projects such as the project done by UC Berkeley on Claremont Ave. There are many worthwhile projects that deserve funding, such as providing the residential community on Claremont Ave a safe evacuation route.

A retired university planner critiques the FEMA projects in the East Bay Hills

We recently finished reading all of the 13,000 public comments on the FEMA draft EIS. FEMA says that about 90% of the comments are opposed to the project and having read the comments that seems about right.

It was a very rewarding experience to read the comments and we recommend it to anyone who is discouraged or doubtful that we can prevent the destruction of our urban forest in the East Bay (available HERE).

There were many excellent comments, many from people with specific expertise and knowledge of the issues that inform our opposition to these projects. We plan to publish a few of them, as we obtain permission from their authors. Today, we publish the public comment of Christopher Adams, with his permission. We hope you are as impressed with his astute analysis as we are.

Comments on Hazardous Fire Risk Reduction, East Bay Hills, CA,

Draft EIS

Prepared by Christopher Adams

Introduction:

My comments here are made solely in my capacity as a private citizen, but I think it is germane to state my background. I am a retired university planner, and for several years I directed the office which was responsible for review of every environmental document prepared by all the campuses and other facilities of the University of California. In addition, I was directly involved with the drafting, the public hearings, and the response to comments and preparation of two major Environmental Impact Reports, prepared under the California Environmental Quality Act for a UC campus. I also live near the EB Hills in an area subject to wild fires and share the concerns of others about the risk of fire.

Summary:

The Hazardous Fire Risk Reduction, East Bay Hills, CA, Draft EIS is a deficient document, beginning with its basic premise. While purportedly for the purposes of fire management, the proposed actions appear to be mostly motivated by a dream of a restoring the EB Hills to some imagined Eden prior to the European and American colonization of California. Instead of applying scientific and policy analysis to the impacts of the proposed actions the DEIS authors appear to have decided that the proposed clear cutting and herbicide measures are the right ones for fire protection and then cherry‐picked evidence, whether in the description of existing conditions or the possible alternatives solutions, which supports this conclusion. The DEIS rejects out of hand fire management alternatives that do not involve clear cutting and massive application of herbicides. In so doing the DEIS is a classic example of post hoc rationalization. Unless the DEIS is re‐issued with corrections and additions responding to the comments below, I believe that FEMA is seriously exposed to potential litigation. More significantly, if FEMA does not consider other less draconian and less expensive fire management measures, it will not be serving the interests of the citizens most impacted by fire danger, not to mention the taxpayers who will ultimately foot the bill.

Specific Comments:

The DEIS fails to note the existence of native trees which are specifically susceptible to the effects of one of the herbicides proposed for use. Section 4.2.2.2.1 notes that the native trees in the woodlands include madrone (Arbutus menziesii). However, in Section 3.4.2.1.1 Strawberry Canyon‐PDM there is no mention of madrones in the list of trees in the “native forest” (first paragraph of section). This is a significant omission, because there are madrones in Strawberry Canyon, yet in the third paragraph of this same section one of the two herbicides proposed for use to stifle stump regeneration is Stalker (imazapyr) which has been identified elsewhere as being used specifically to eliminate madrones. According to the EPA Reregistration Eligibility Decision for Imazapyr: “Imazapyr use at the labeled rates on non‐crop areas when applied as a spray or as a granular to forestry areas present risks to non‐target plants located adjacent to treated areas.” (1)

The DEIS fails to acknowledge the growing threat of French broom in the UCB area.

While the presence of eucalyptus, Monterey pine, and acacia is repeatedly discussed, there is almost no mention of the rapid invasion of French broom. It is mentioned only in passing and without its scientific name in the discussion in Section 4.2.2.2.3 under “Northern Coastal Scrub.” While French broom has been rapidly increasing in the upper slopes of the Strawberry Canyon PDM and Claremont PDM areas, there is no mention of it at these locations in the DEIS. This plant is an active pyrophyte which chokes out native vegetation, can be poisonous to livestock, and is of limited benefit to native animals. The increase in sunlight from the proposed removal of large amounts of eucalyptus will encourage its spread. There is no mention of the fire risk from French broom in the discussion of fire risk in Northern Coastal Scrub, Section 4.3.3.2.5, and I could find no mention of its removal anywhere in the document.

The UCB project description does not explain if a fuel break is planned in the UCB areas and if so to describe it.

Section 1.1.1 UCB states that it will follow the “same general approach…which is included in Oakland’s grant application (see Section 1.1.2 below).” In Section 1.1.2 it is stated there the Oakland PDM would “create a fuel break on the west side of Grizzly Peak Boulevard north and east of the Caldecott Tunnel [presumably this means the west entrance to the tunnel].” UCB Strawberry Canyon properties also abut Grizzly Peak Boulevard, so the statement of “the same general approach” implies that UCB also proposes a “fuel break,” but none is described. Since the term “fuel break” implies clearing to the bare soil, with potential significant environmental impacts, this is a serious omission.

The DEIS fails to consider the impact on global climate change by the wholesale destruction of trees. The DEIS states that for UCB Strawberry Canyon alone 12,000 trees will be destroyed. Because trees absorb CO2 at an average rate of 13 pounds per year, this represents a potential loss in CO2 absorption of 78 tons per year. Given the growth patterns of native trees in Berkeley, which tend to be riparian or to grow on north facing slopes in a widely scattered pattern, the number of replacement trees will not come close to compensating for those destroyed. The difference should be estimated and calculated.

The DEIS fails to consider an actual and accomplished fuel management program when dismissing the alternative described in Section 3.3.1.1.

The Lawrence Berkeley National Laboratory (LBNL) is located on 175 acres on the north side of Strawberry Canyon immediately adjacent to the UCB and EBRPD areas described in the DEIS. LBNL, which is managed by the University of California, employs more than 4,000 persons on this site in laboratory buildings and with equipment that is worth several billion dollars. LBNL has recently completed a fire management program which is essentially what is described in Section 3.3.1.1 of the DEIS, Removal of Brush, Surface Fuels, Lower Limbs and Small Trees. The entire project was completed within the LBNL maintenance budget without special grants and has given the laboratory a great deal of fire security, according to its professional fire personnel. Yet there is no reference to this in the DEIS. The LBNL program is further described in the following links. This first links to a powerpoint slides; the second to a video discussion of the slides. http://www.lbnl‐cag.org/docManager/1000000159/Berkeley%20Lab%20Fire%20Safe%20Vegetati on%2C%20Lab%20Fire%20Marshal.pdf

http://www.lbnl‐cag.org/Content/10024/preview.html

The links convey much more effectively than my comments how an alternative to massive clear cutting and massive application of herbicides will effectively accomplish the goal of managing fire in the East Bay Hills.

The DEIS is incomplete and verging on the dishonest about the use of herbicides.

“Management of resprouts without herbicides is expensive….and thus was removed from further study.” This ignores the management of resprouts used successfully by LBNL as described in the above referenced powerpoint and video. There is no study about the use of herbicides at the scale proposed, e.g. 12,000 trees in Strawberry Canyon alone, on human populations, let alone native plants and animals.

The DEIS fails completely to discuss the realities of encouraging native plants after the clear cutting and heavy and repeated application of herbicides.

1) Restoration ecology is barely in its infancy, yet this DEIS expects us to accept on faith alone that when the clear cutting is done and the slopes sprayed with herbicides the native vegetation will miraculously reappear.

2) At the present time live oaks and bays are common on the north side (south facing side) of Strawberry Canyon under eucalyptus. This is probably because the fog drip from the eucalyptus and the shade encourage their growth in what would otherwise be a very dry area. Compare, for example, on slopes of similar aspect in portions of the EB Hills behind El Cerrito or Fremont. There is nothing in the DEIS to explain how native trees will increase or survive after the clear cutting has destroyed their source of water and shade.

3) Because of the abundance of deer in Strawberry Canyon and adjacent areas, small trees need to be protected against browsing. (See the LBNL powerpoint for an illustration of wire protective cages. http://www.lbnl‐ cag.org/docManager/1000000159/Berkeley%20Lab%20Fire%20Safe%20Vegetati on%2C%20Lab%20Fire%20Marshal.pdf) The DEIS says nothing about preventing deer browsing.

4) California native oaks of several species, including Quercus agrifolia are subject to the fungal disease Sudden Oak Death Syndrome (SODS), which has been found in the East Bay Hills. The DEIS fails to discuss the existence of SODS or its impact on replacement vegetation after the clear cutting and application of herbicides.

5) The DEIS states that “alleopathic oils” in the leaves and bark of eucalyptus suppress the growth of other vegetation. Yet the DEIS fails to state how covering slopes two feet deep with eucalyptus slash will not inhibit growth of new “native” plants.

6) Native California bunch grasses have largely been supplanted by European annual grasses, many of which form mats which choke out other plants. Similarly native shrubs such as coyote bush (Baccharis species) are being supplanted by invasive plants such as broom. The DEIS fails to explain how native plants will succeed in competition for sun and water with these plants.

The DEIS fails to consider the aesthetic impact to views from the trails and roads within the canyon and from houses near it after the clear cutting.

Section 4.12.2 of the DEIS states that a goal of the UCB LRDP (2005) is to “Maintain the visual primacy of the natural landscape in the hill campus” but there is no mention of the impact of clear cutting on this natural landscape. The north side of the lower portion of Strawberry Canyon forms the main campus of Lawrence Berkeley National Laboratory (LBNL). While individual buildings at LBNL are attractive in design, the overall effect of the site is essentially industrial, similar to an office park one might see along a freeway. The views of LBNL from the fire road that winds through the canyon are now largely screened by the large trees which will be destroyed by clear cutting. The trees also offer cooling shade to those using the area for recreation. The fire road is a major recreation amenity for UCB students, employees, and neighbors, used daily by hundreds of hikers, joggers, dog walkers, and mountain bikers. Removal of most of the trees as proposed will completely change the views enjoyed from the fire road. The DEIR provides absolutely no analysis of this impact either verbally or by providing illustrations of any viewing point in Strawberry Canyon. Most of the discussion of Section 5.8 is oriented to views over the hills from high points to the bay, which indeed may be improved by clear cutting. There is no discussion of views from within the areas to be clear cut and no reference to Strawberry Canyon.

The DEIS bases its list of plant species slated for destruction on incomplete and inaccurate botanical and fire danger information.

The authors of the DEIS seem not to understand the difference between “native” and “endemic” and they seem to have arbitrarily selected some “native” plants to extirpate while keeping others based on criteria having little or no relationship to fire hazards. Section 3.4.2.1.1 states that “Non native trees, including all eucalyptus, Monterey pine, and acacia would be cut down.” The Jepson Manual (2), which is the definitive source for California plants divides the state into geographic areas. According to Jepson Monterey pines (Pinus radiata) are native to California, and while not endemic to the EB Hills, they are native in the geographic area CCo, which includes both portions of Monterey County and the EB Hills with similar climatic conditions. Coast redwoods (Sequoia sempervirens) are also found in Strawberry Canyon but not as an endemic. They are also native to the geographic area (CCo). In contrast to Monterey pines, however, Coast Redwoods appear to escape destruction by clear cutting; at least there is no mention of such action in the DEIS. Another native and Strawberry Canyon endemic, California Bay (Umbellularia californica), is specifically listed in the DEIS to be retained. But in a publication of the University of California Cooperative Extension (3) it is listed as a “High Fire Hazard Native Tree.” Note that these comments are not meant to imply favoring destruction of redwoods or bay trees but to further illustrate the inaccurate information and the arbitrary nature of the DEIS conclusions. Similarly cypress species which grow in parts of Strawberry Canyon are also listed as pyrophites in this UC document, but the DEIS does not propose their extirpation.

The DEIS fails to consider the impact on Strawberry Creek of run‐off from the predicted massive amounts of slash, from the standpoint of hydrology and flood control or the impact on the biota of the creek.

Section 3.4.2.1 of the DEIS states within Strawberry Canyon there will be clear cutting on 56 acres and that the downed trees will be chipped and left on 20% of the site at a depth of 2 feet. Based on these numbers the cumulative amount of material on the ground will be 975,744 cubic feet (.2 x 56 x 43,560 x 2). If merely 1% of this material is washed away in a storm, which seems a very conservative estimate considering the slopes where the material would be placed, there could be more than 1,000 cubic yards of slash material washed into Strawberry Creek. The DEIS does not discuss the impact on the biota of the creek of this potential massive amount of new material. Nor does the DEIS discuss the impact of this material on stream flow in storm conditions. Given that the culverts in the lower levels of the creek, near the Haas Clubhouse and the University Botanic Garden, are only about 9.5 square feet in cross section (See Figure 1.), there is a strong likelihood that the slash material would block the culverts and cause flooding. Section 3.4.2.1 states that “if the site yields a large number of large tree trunks,” some “may” be removed or used for other purposes than left on the site; however, the DEIS fails to state the criteria for determining what the “large number” is that would trigger such action. The hydrologic and ecological impacts are presumably left to the loggers to evaluate.

Figure 1, Culvert on lower fire trail, near Botanic Garden

The DEIS implies that trees other than eucalyptus, Monterey pines, and acacias will not be cut, but current actions in Strawberry Canyon suggest that UCB will cut anything at any time regardless of environmental regulations. The DEIS must be amended and re‐issued to include other UCB actions as part of cumulative impacts.

During the past week (June 6‐13, 2013) I have personally observed the cutting of at least six healthy, mature California live oaks, bays, and cypresses in Strawberry Canyon. (See Figures 2 and 3.) The oaks were particularly magnificent, and their destruction is tragic. I am familiar with the needs for passage of fire trucks as I own woodland property on a narrow privately maintained road. None of the trees just cut would have prevented passage of trucks, but I was told by one of the tree cutters that the excuse was “Fireman.” To my knowledge this cutting was done without any compliance with the California Environmental Quality Act (CEQA), which is the state equivalent of NEPA and applies to all UCB actions. This cutting constitutes a violation of the CEQA Guidelines Section 15304, which states that exemptions from CEQA apply only to actions “which do not involve the removal of healthy, mature, scenic trees.” If UCB is flagrantly cutting trees now, while the DEIS is out for public comment, what can we expect once the NEPA process is completed?

Figure 2. Bay stump on lower fire trail, cut on or about June 11 2013, diameter +/‐42”

Figure 3. Live oak stump on lower fire trail, cut on June 10, 2013, diameter +/‐ 38”

(1) EPA 738‐R‐06‐007, 2006

(2) The Jepson Manual of Vascular Plants of California, 2nd Edition, UC Press, 2012

(3) Pyrophytic vs. Fire Resistant Plants, FireSafe Marin in Cooperation with University of California Cooperative Extension, October 1998

Thank you, Mr. Adams, for taking the time and trouble to write this excellent public comment on the FEMA draft EIS.

Destroying trees causes erosion and landslide risk

We are republishing with permission a post from the Save Mount Sutro Forest blog. At the end of the Save Sutro post we add an example of erosion in the East Bay caused by tree removals by UC Berkeley.

When UCSF (or SF Recreation and Parks Department) discusses “Safety” in the forests on Mt Sutro and Mt Davidson, they generally focus on fire hazard (relatively low in these damp cloud forests), or on the risk of being hit by a falling tree (about half the risk of being hit by lightning). Tree removal could actually increase both those risks, by drying out the forest and by increasing windthrow – the risk of the remaining trees being blown over.

But what we want to talk about in this post is landslide risk.

Two weeks ago, a horrible mudslide in Washington State engulfed homes and took lives. Some scientists think logging trees in the area contributed to the tragedy. This has implications for Sutro Forest, which grows on a steep hill – and also for the other San Francisco forest, Mount Davidson. Tree removal, ongoing and planned, could destabilize the mountainsides.

LOGGING AND LANDSLIDES

On March 22, 2014, a huge landslide destroyed the small Washington community of Oso. Rain was of course a factor, as was erosion at the base of the slope. But it’s probable that tree-cutting above the slide area was an important factor too. An article in the Seattle Times quotes a report from Lee Benda, a University of Washington geologist. It said tree removal could increase soil water “on the order of 20 to 35 percent” — and that the impact could last 16-27 years, until new trees matured. Benda looked at past slides on the hill and found they occurred within five to 10 years of harvests [i.e. felling trees for timber].

There had been red flags before. The area was second growth forest, grown back from logging in the 1920s/30s. Over 300 acres were again logged in the late 1980s.

The first time regulators tried to stop logging on the hill was in 1988. But the owner of the timber successfully argued that measures could be taken to mitigate the risk. Eventually, the state only blocked it from logging some 48 acres, and the owners gave in on that.
In 2004, new owners applied to cut 15 acres; when the Department of Natural Resources (DNR) objected, they halved the area and re-located the cut. DNR gave approval, subject to no work during heavy rain and for a day afterward. The tree-cutting finished in August 2005.
In January 2006, there was a major landslide 600 feet from the cut zone. The state built a log wall to shore up the slope.
The owners continued logging. In 2009, they removed 20% of the trees. In 2011, they removed another 15%. In 2014, the hillside collapsed.

The regulators were aware of the risk; they thought they were mitigating it with their restrictions and reaching a compromise with the owners. But it wasn’t enough. Destabilizing the mountainside is a long-term thing; the effects can show up in months, but it’s more likely to take years.

THE LESSON FOR SAN FRANCISCO

We know our hills are prone to slides. Here’s a geological map of Mt Sutro and surrounding areas. The blue zones show where there’s a potential landslide risk:

Blue areas show "potential for permanent ground displacements..." — Blue areas show “potential for permanent ground displacements…”

This next map is from a UCSF document. The pink areas and wiggly arrows indicate landslide risk. The double-arrows show where actual landslides seem to have occurred in the past.

Pink areas and wiggly arrows show landslide risk; double line arrows show past landslides.

Landslide under blue tarp. South Ridge at top left.

This slope in the Forest Knolls neighborhood was covered in a blue tarp for months after the slope became destabilized by tree removal…

This other blue tarp is on the hillside above Medical Center Way. It was installed soon after some extensive work on the trail in that area, with undergrowth being cleared and trails realigned. When we enquired why it was there, UCSF said there had been some rock slides, and this was a temporary solution.

This photograph was taken in March 2013. A year later, the blue tarp is still there.

For more evidence, there’s the ongoing situation in Twin Peaks, where erosion and rockfalls in rainy weather are ongoing. There, it matters less, because it’s not falling on homes. Landslides on Mt Sutro or Mt Davidson have the potential to damage homes.

YEARS OF INCREASED RISK

While it’s possible that a slide could happen within months of the tree-felling, it could also happen 6-8 years later as the root systems rot away. It could happen in any year until the trees grow back and conditions are right for water-logging. On that fateful Washington slope, the average was 5-10 years. No one wants to find out the average for San Francisco slopes.

We ask the land managers for these forests to stop removing trees and large shrubs that have successfully stabilized our hillsides for decades.

Addendum: About 10 years ago, UC Berkeley removed about 18,000 trees on 150 acres of its property. This is a photo of erosion that resulted from that tree removal on Grizzly Peak Blvd close to the intersection with Claremont Ave. This erosion has been getting steadily worse for at least 5 years. The only remediation has been plastic and sandbags, which are clearly not capable of preventing further erosion.

Grizzly Peak Blvd, south of Claremont Ave. Berkeley, California