Joe R. McBride – Conservation Sense and Nonsense

Understanding the eucalyptus forest – Professor Joe R. McBride

This article has been republished from the website of Save Mount Sutro Forest, with permission.

Dr. Joe McBride of UC Berkeley spoke at the Commonwealth Club in April 2014 as part of the series “The Science of Conservation and Biodiversity in the 21st Century.” His main message:

Eucalyptus groves in California provide habitat for as many native species as do most ‘native’ habitats.
They grow well at high densities and an average spacing of 8 feet between trees is quite typical.
They have relatively high fuel loads, but the cool and damp dense eucalyptus forests reduce the risk of fire.
Eucalyptus is subject to few diseases or pests, and parasitic wasps provide pest control.
It provides a host of ecosystem services including carbon sequestration, pollution reduction, slope stabilization, windbreaks, wildlife habitat, and recreational value.

Dr. Joe R. McBride was Professor of Landscape Architecture and Environmental Planning, Department of Environmental Science, Policy, and Management, UC Berkeley. (He has since retired.)

Read on for notes from Dr. McBride’s talk. (There are also links to his Powerpoint presentation.)

—————————————

THE HISTORY, ECOLOGY AND FUTURE OF EUCALYPTUS PLANTATIONS IN THE BAY AREA

Notes From a Talk By Dr. Joe R. McBride

Dr McBride’s wide-ranging talk covered a lot of ground. He talked about the ecology of the eucalyptus forest in the Bay Area: its structure, the variety of plants and animals that live within it, its health and the ecological functions it performs; the dynamics within these forest stands; and their invasive potential.

WHY EUCALYPTUS CAME TO CALIFORNIA

Eucalyptus was first planted in California during the Gold Rush, possibly for oil to use in gold-mining and in medicine.

In the 1870s, eucalyptus planting was encouraged for many objectives: to beautify cities, to improve farmland, as windbreaks, and to dry out swamps to combat malaria.

It was grown in woodlots for firewood, but as people switched to natural gas and other fossil fuels this became rare. Later, it was planted for timber – which didn’t work out because the trees were harvested too young; and still later for bio-fuel, which did not become commercially attractive.

By the 1950s, it had become an integral part of the California landscape. Six species were planted, primarily blue gum in Northern California, and red gum and river gum in Southern California. (Worldwide, there are perhaps 640 species.)

Eucalyptus beautifies our cities, and helps stabilize soil on steep hills. The surface area of the leaves, broader than those of conifers, help trap particulate pollution. Unlike deciduous trees, the evergreen foliage of eucalyptus removes pollutants all year long.

HOW DENSE MAKES SENSE?

The density of eucalyptus plantations in Bay Area ranges from 150-160 trees per acre to about 1700 trees per acre. mt davidson understory (The highest density resulted from a freeze in 1970s: trees were cut down because of the perceived fire hazard, but the trees presumed dead later resprouted.) On Angel Island, the normal density was 8ft spacing (about 680 trees per acre) but it ranged to 30 feet between trees.

In the East Bay, 8 ft. x 8 ft. is quite typical eucalyptus plantation density. Left to grow naturally, stands become denser through in-growth, mainly by sprouting and also by sibling establishment.

Is management by thinning necessary for the health of the forest, someone asked, and what density is ideal?

Dr McBride had seen no examples of stands that could be improved by thinning. Eucalyptus grows well with a high density at an average of 8 ft x 8ft spacing between trees. In Australia and New Zealand no one thins; they just harvest the trees and let them regrow from sprouts.

In the US, eucalyptus was not marketable, so there’s no history of managing eucalyptus plantations. Also, until recently there were no diseases or insects. The long-horned borer and the psyllid have now appeared in some places, and thinning is not seen as a solution to these insect problems; they are better controlled by certain predatory wasps.

Logging eucalyptus would mean a lot of ground disturbance and erosion. If the logs are removed, the skid trails can destabilize the soil.

MUCH GROWS UNDER EUCALYPTUS – NATIVE AND NOT

Contrary to popular belief, eucalyptus forests have as many species (or more!) growing in their understory as do oak woodlands. A 1990 survey in Tilden Park found 38 species in the understory of eucalyptus forests (24 native plants; 14 introduced plants), while the oak woodland had 18 species in understory (14 native plants; 5 introduced plants). Only the riparian woodlands in Murray Park are somewhat richer in species than riparian eucalyptus forest (58 species vs 34). In East Bay eucalyptus forests, California Bay, Coast live oak, poison oak, bedstraw, California blackberry, and chickweed were ubiquitous. The amount of light reaching the ground influences which species can be found in the understory.

What about allelopathy? Under experimental conditions, eucalyptus litter inhibited germination and growth of cucumber seeds, so eucalyptus litter may be somewhat allelopathic to some plants. But a study from UC Santa Barbara indicates that if eucalyptus litter is removed, within 2 years there’s no inhibitory effect on other plants germinating. And clearly, it isn’t allelopathic to all the species mentioned earlier.

Someone asked whether it would be advisable to “manage eucalyptus stands that have an invasive understory.”

Dr McBride responded: “I have no prejudice against invasive plants. I am an invasive Californian myself.” (There was amused applause.) He continued that each eucalyptus grove is different, so it’s important to look at it on a stand-by-stand basis and measure the fire hazard of eucalyptus plantations against the value of each stand for wildlife habitation, recreation, and wind break functions.

In response to a question about whether ivy kills eucalyptus trees, Dr McBride said he has not seen evidence the ivy shades the foliage of eucalyptus trees. He’s seen no evidence of ivy killing eucalyptus, although on Mt. Davidson, he did see ivy growing over trees that had been killed by girdling with an axe or chainsaw.

INSIDE A EUCALYPTUS FOREST

Shading and leaf litter changes the microclimate of a eucalyptus grove. As you move in from the edge to the interior of the forest, conditions change. The species change from the edge to the interior of the forest as the amount of light decreases, so there are different species at the edge of the forest and inside it. A 1980s study in the Presidio compared conditions outside a eucalyptus forest and inside it. It showed:

Temperature moderation: Daytime temperature fell an average of 10%, and night-time temperature rose an average of 5%
Windbreak: Wind velocity dropped 40%
Relative humidity was 5% higher (from the edge to the interior).
Shade: Light intensity was 90% lower.
Moisture: Precipitation (rain) decreased 12%; but fog-drip (i.e., moisture precipitated from the fog) increased 300%

EUCALYPTUS STORES CARBON

Eucalyptus increases the carbon content in the soil compared to grasslands (Zinke et al, 1988). Its fast growth and large size means it sequesters a lot of carbon in its trunk and root systems.

EUCALYPUS SUPPORTS WILDLIFE

Again, contrary to belief, eucalyptus provides a good environment for a wide variety of wildlife. A number of studies demonstrate this.

A 1970 study showed many birds make “moderate use” of eucs as habitat and a few birds make “great use” of eucs. (Almost all these species are native.) Birds that make most use: mourning doves; Great Horned Owls, whose range has been extended by CA eucalyptus; Stellar’s jays; yellow-bellied sapsuckers; Allen’s hummingbirds; olive-sided flycatchers; brown creepers; dark-eyed juncos; Audubon warblers.
Some reptiles make great use of eucalyptus groves: Southern Alligator lizard and the slender salamander. Among mammals, deer mice make “heavy” use of eucalyptus.
photo credit: Janet Kessler

Robert Stebbins’ monumental 1978 study on the attractiveness of eucalyptus for habitat in the East Bay found that all species making use of eucalyptus for habitat found eucalyptus about the same as grasslands in attractiveness, but oak/bay woodlands were even more attractive.
Monarch butterflies most commonly use eucalyptus trees in state parks. But some of the insects in eucalyptus hurt the trees. One is the eucalyptus long horned borer – but can be controlled by a parasitic wasp. The red gum lerp psyllid is more of a problem in Southern California, which has more red gum. However, it’s part of the food chain: woodpeckers and other bird species feed on their larvae.
A study showed that eucalyptus in a riverside environment doesn’t impact species diversity of stream insects or pollution tolerance compared with native riparian environments.

NATURAL SUCCESSION IN EUCALYPTUS?

Over the next 200-300 years, the eucalyptus forests in the East Bay could gradually – and naturally – shift to oak-bay woodlands. In the East Bay (though not at Mt. Davidson or Mt. Sutro), the eucalyptus plantations have California Coast live oaks and California bay trees in the understory, and they are doing well. The live oaks are “tolerant” of shade and the bays are “very tolerant” of shade. If they aren’t disturbed, the oaks and bays regenerate well in the understory, and being even longer-lived than the eucalyptus trees, they will eventually naturally succeed the eucalyptus. The bay tree is higher in regeneration than the Coast live oak in Tilden Park (McBride, 1990).

WHAT ABOUT FIRE HAZARD?

Eucs support considerable fuel load on the ground because of rapid decay of foliage and shredding of its bark. They have a higher fuel load than California bays or Coast live oaks. They release an aromatic compound that can ignite with sparks, and they burn hot.

However, while the tree density of eucalyptus plantations can mean a greater accumulation of fuel in the understory, the higher density means a cooler, wetter understory that might not dry out as fast. Three risk factors in fire risks of any tree: amount of fuel it produces; tissue moisture content; fuel ladder based on presence of other plants in its understory.

IS EUCALYPTUS INVASIVE?

Under certain circumstances, eucalyptus can spread – for instance, on Angel Island, some stands spread through road cuts and prescribed burns (which destroyed competing vegetation). However, in most cases they don’t: aerial photographs show that boundaries are stable. The eucalyptus forests on Mount Davidson and in Tilden Park show stable boundaries.

In the Bay Area, Dr McBride found eucalyptus forest area declined between 1939 and 1997. The natural spread hasn’t increased the area of eucalyptus groves.

DO TREES DEPLETE AQUIFERS?

Someone mentioned attending a talk where the speakers said that tree removal would help to replenish aquifers. Was that true? Dr McBride thought it very unlikely; most aquifers are much deeper than tree roots.

WHAT ABOUT PESTICIDES?

Someone speaking for people with disabilities owing to chemicals said herbicide use in these areas violated their right to access, and wondered how “environmental” organizations – like the Sierra Club – could support this. Dr McBride sympathized, said he was also concerned about toxic herbicide use. He mentioned that the East Bay tree-felling project is on hold owing to a number of unanswered questions that would need further research.

Here are links to his Powerpoint presentation in ppt and pptx formats.
PPT: McBride Presentation – Eucalyptus
PPTX: McBride Presentation – Eucalyptus

Here is a link to the audio notes taken by a member of the audience

2014 Events for your calendar

The year’s winding down, and many of us are making plans for the next few months. An email from the Commonwealth Club told us of an interesting new series of lectures in January, March and April of 2014. It’s the Science of Conservation and Biodiversity in the 21st Century series, from three professors each giving one talk in San Francisco.

According to the email: “This series of lectures will present a new way of looking at public issues in conservation. The things we’ve assumed as facts often are not. Traditional approaches are losing ground as science illuminates new pathways for framing and achieving conservation goals.”

This is important thought leadership that could shift the way San Francisco manages its wild spaces. A good turnout would encourage the Commonwealth Club to have more such talks. Please do attend if you can.

JANUARY 30, 2014, 6 PM: DR SCOTT CARROLL ON CONCILIATION BIOLOGY

bumble bee on strawberry tree — Native bumble-bee on non-native Strawberry Tree

Dr Scott Carroll is the Founding Director, Institute for Contemporary Evolution and Department of Entomology at UC Davis. He will talk about Conciliation Biology: An Approach to Conservation that Reconciles Past, Present and Future Landscapes in Nature.

Here’s what the Commonwealth Club website says: Biologists are now considering the “conciliatory approach.” This approach recognizes that mutual adaptation of native and non-native species is changing best practices for promoting biodiversity. Dr. Carroll investigates how organisms respond to human-caused environmental change. Carroll advocates for interdisciplinary solutions to problems of environmental conservation.

MARCH 24, 2014, 12 NOON: DR. ARTHUR SHAPIRO ON ECOLOGICAL COMMUNITIES

Dr. Arthur M. Shapiro is Distinguished Professor in the Department of Evolution and Ecology, College of Biological Sciences, at UC Davis. He’s speaking on Ecological Communities and the March of Time.

Gulf Fritillary Butterfly emerges on passiflora plant — Gulf Fritillary butterfly breeds on non-native passionflower – wikimedia

From the website: “Ecological communities as we know them are similar to freeze-frames from a long movie. Associations among species are very dynamic on millennial scales, as demonstrated by the evidence since deglaciation 15,000 years ago. Coevolution of species occurs locally in geographic mosaics, and can be extremely dynamic as well. Frederic Clements, the father of American community ecology, had a holistic vision. He saw communities as super-organisms. He was wrong.”

WEDNESDAY APRIL 9, 12 NOON: DR JOE MCBRIDE ON EUCALYPTUS IN THE BAY AREA

ferns and blackberry and poison oak — Eucalyptus forest understory on Mt Sutro

Dr. Joe R. McBride is Professor of Landscape Architecture and Environmental Planning, Department of Environmental Science, Policy, and Management, UC Berkeley. His talk is about The History, Ecology and Future of Eucalyptus Plantations in the Bay Area.

The website says: “McBride will explain the ecology of the eucalyptus forest in the Bay Area. He will discuss its structure, the variety of plants and animals that live within it, its health and the ecological functions it performs. There will be a description of the dynamics within these forest stands (such as whether they are successional or a climax-species that replace themselves over time without human input) and about their invasive potential.”

Register at: www.commonwealthclub.org/events/2014-04-09/joe-r-mcbride-history-ecology-and-future-eucalyptus-plantations-bay-area

WHERE AND HOW MUCH

All lectures are at the San Francisco Club Office, 595 Market St.
The tickets cost $20 to the general public, $8 for members of the Commonwealth Club, and $7 for students carrying appropiate ID.
You can register to attend at the links we gave, or call 415.597.6705

********************************

This is reprinted from Save Mount Sutro Forest with permission.

Professor Joe McBride defends the forest on Mount Davidson

With great pleasure we share with our readers the following letter from Professor Joe R. McBride to Phil Ginsburg, the General Manager of San Francisco’s Recreation and Park Department, expressing his criticism of the plans of the Natural Areas Program to destroy 1,600 trees on Mount Davidson.

Joe McBride is Professor of Environmental Science in the College of Natural Resources at University of California, Berkeley and an expert on urban forestry in the San Francisco Bay Area and around the world. He is the author of many studies of urban forests, several of which he cites in his letter to the General Manager. He is particularly expert on the failure of trees caused by extreme wind conditions.

Professor McBride kindly accepted the invitation of several neighbors of Mount Davidson to read the plans of the Natural Areas Program (SNRAMP) for Mount Davidson and tour the mountain with them to evaluate those plans within the context of the actual conditions there. The neighbors and all lovers of the urban forest are extremely grateful to him for his time and willingness to share his expertise and decades of experience with us to help us save this beautiful forest from being needlessly destroyed.

*************************

June 29, 2013

Mr. Phil Ginsburg
General Manager
San Francisco Recreation and Park Dept.
San Francisco, CA 94117

Re: Significant Natural Resource Areas Management Plan for Mt. Davidson Park

Dear Mr. Ginsburg,

I am writing to express my concern over the plan for removal of trees on Mt. Davidson. This concern is based on the historical importance of the trees, their contribution to San Francisco landscape, and several specific aspects of the Significant Natural Resource Areas Management Plan for San Francisco. As a Professor of Urban Forestry at the University of California I have for many years studied plantations of trees in the city and compiled several reports for the U.S. Army, National Park Service, Presidio Trusts, and the Golden Gate Conservancy concerning the condition and management of eucalyptus, Monterey pine, and Monterey cypress stands. My concern over the proposed management plan for Mt. Davidson is based both on my experience in urban forestry and on my experience as a citizen of the Bay Area who has enjoyed the urban forests of San Francisco for many years. These concerns are elaborated in the following paragraphs.

The eucalyptus and Monterey cypress on Mt. Davidson were planted under the direction of the former Mayor of San Francisco, Adolph Sutro. He was also responsible for planting other areas in the city that have subsequently become city parks. The plantations he established have served to protect park users from the wind, provide wildlife habitat, and in some cases define the visual character of the San Francisco landscape. They present an important historical heritage that I think should not be discarded lightly. I found no mention of the historical significance of the Mt. Davidson forest in justification for the proposed management in the Natural Areas Resource Management Plan for San Francisco. San Francisco might review the vegetation management plan developed by the Presidio Trust for the National Park Service to see the approach taken at the Presidio to maintain and manage historically significant forest plantations.

From a number of vantage points in San Francisco one can see several of the city’s hilltops covered in plantations of eucalyptus and Monterey cypress. These plantations stand in contrast to the architecture that surrounds them. They have been part of the San Francisco landscape for over one hundred years. Eucalyptus plantations are as much a part of the California landscape as the coastal grassland, chaparral, and oak woodland plant communities for many people growing up in the Bay Area. I did not find the visual value of the eucalyptus and Monterey cypress plantations on Mt. Davidson addressed in the plan. I was, however, alarmed by the use of the term ”invasive forest” in reference to eucalyptus plantations. This is a pejorative term that should not be applied to eucalyptus plantations. I have found little evidence of eucalyptus invading adjacent areas of grassland or other native vegetation types in the San Francisco Bay areas in studies I conducted in open space areas (McBride, Sugihara, and Amme, 1987; McBride, Cheng, and Chorover, 1989; Cheng and McBride, 1992; Russell and McBride, 2003). Comparison of photographs of Mt Davidson taken in the 1920s and 1950s show no evidence of the eucalyptus invading the adjacent grassland area (Proctor, 2006). These photographs indicate that a stable boundary exists between the eucalyptus plantation and the adjacent grassland. I see no justification for the establishment of a stable boundary between the eucalyptus and grassland habitats as called for in the “Site Improvements” section of the Significant Natural Resource Areas Management Plan.

My concerns over the management plan for the eucalyptus and Monterey cypress plantation on Mt. Davidson are based on portions of the Significant Natural Resources Areas Management Plan : 5. General Recommendations, 6.2 Mount Davidson, Appendix F Urban Forestry Statements. I am concerned with the justification for tree removal and the proposed levels (%) of trees to be removed.

Justification for Tree Removal

The primary justification for tree removal in the documents is the restoration of native habitat. Various statements are made concerning the minimal amount of habitat within the eucalyptus urban forest. This assumption is not supported by any data or reference to publications on this topic. Stebbins (1976) concluded that eucalyptus plantations in the East Bay were far richer habitats for vertebrates than either redwood or Monterey forest and that they vie with ‘dry’ chaparral and grasslands in species diversity and ’attractiveness’ to vertebrate species.

The general recommendation to maintain a basal area between 200 and 600 square feet per acre is appropriate. However, a conflict exists at Mt. Davidson where some stands (MA-1c) within the plantation currently have basal areas less than 200 square feet yet the plan proposes the removal of 82% of the trees. I think there is a problem with the use of tree density measured in eucalyptus stands in Glen Canyon Park in developing the proposed cutting of trees at Mt. Davidson. The point-quarter survey mentioned in Appendix F (Urban Forest Statements) of the Significant Natural Resources Areas Management Plan indicates a tree density of 353 trees per acre. Three eucalyptus plantations measured in the Golden Gate National Recreation Area had tree densities of 50, 98, and 726 trees per acre (McBride, Cheng, and Clausen, 2004). These numbers demonstrate the wide range of tree densities found within eucalyptus plantations in San Francisco. I estimated the tree density in stand MA-1c from Google Earth images of Mt. Davidson to range from 24 to 33 trees per acre. Trees in this stand average about 24 inches in diameter. Trees of this size with a density of 33 trees per acre would have a basal area of a little over 100 square feet per acre (103.6 square feet). No trees from the area designated MA-1c could be removed if the basal area recommendation was followed. The same would apply to stands MA-2e and MA-2c where recommendations are for removal of 23% and 31% respectively. I think a major shortcoming of the Plan is that lack of stand-specific tree density data.

Various sections of the Significant Natural Resource Areas Management Plan justify tree removal as a means of allowing re-vegetation with native understory vegetation. Species commonly found in the understories of native forests and woodlands of the Bay Area are adapted to the low light intensity of these forests and woodlands. Removing the eucalyptus overstory up to 82% as proposed for area MA-1c will expose the ground surface to light levels that most native understory plants will not be able to tolerate. The management plan also points out that removal of eucalyptus will result in the promotion of growth of existing exotic understory species. These will no doubt, compete with any native species for the site. The suggestion that these exotic species will be controlled by manual removal and the use of herbicides indicates the City is prepared for a large investment of time and labor to combat these plants. Projects to eliminate exotic understory plants at the Presidio after overstories of Eucalyptus and Monterey cypress have been removed have proved to be very expensive and only partially successful.

The Significant Natural Resource Areas Management Plan states that the proposed forest management will not result in long-term changes in recreational use of the natural areas. I cannot agree with this conclusion. The proposed cutting of trees will increase the windthrow and wind breakage of the remaining trees. Trees that have grown up together in a plantation have buffered each other from the wind. When individuals are exposed by the removal of surrounding trees they are very vulnerable to the wind. This is well documented in studies of native forests and forests which have been thinned or opened for subdivision development (Franklin and Forman, 1987; McBride, 1999, 2002, 2003; Sinton et al, 2000). The tree fall and wind breakage hazard to walkers using the Mt. Davidson area after the proposed tree removal and thinning would, I believe, seriously compromise the use of the area for recreational purposes. The existing forest plantations currently contribute to the use of Mt. Davidson by walkers because of the reduction in wind velocity by the trees. Forest plantations studied at the Presidio and at Lands End significantly reduce wind velocity and protect people walking from uncomfortable wind chill effects (McBride, 2002; McBride and Leffingwell, 2003). Choice of coastal bluff trails at the Sea Ranch made by walkers is often dependent on the amount of protective cover from the wind provided by areas planted with Monterey cypress. The exposure of Mt. Davidson to winds from the ocean will result in a less pleasant recreational experience if trees are removed.

There is an assumption in the Significant Natural Resource Areas Management Plan that minimal impact will occur to species such as hawks and owls as a result of tree removal because the overall acreage of the forest will remain high. This is not a valid assumption for two reasons. First, hawks and owls choose specific trees for nesting and perching. These trees are chosen on the basis of their position in a forest stand and the structure of the tree. Nests are used by some species year after year so that the removal of a nesting tree can present a major problem for the specific bird using the tree. Avoiding the cutting of nest trees during the nesting season, but felling of these trees after the nesting season is a major impact that should not be part of the management plan. It is also important to not remove trees surrounding nesting trees. Most recovery plans for rare and threatened tree nesting birds require a protected area with a minimum radius of 300’ around a nesting tree. No trees can be removed within this zone.

In the “Site Improvements” section of the Significant Natural Resource Areas Management Plan it is suggested that the management proposals will improve the health of the eucalyptus forest. It is suggested that tree thinning will promote a more healthy forest. This certainly is true in densely stocked forest stands, but I did not observe conditions in the eucalyptus plantations where tree density required thinning. Several standing dead eucalyptus trees are present at Mt. Davidson, but the standing dead trees I examined had all been girdled. It was evident that some individual or individuals have had a vendetta against eucalyptus trees and had girdled trees in the past. I did not see any indication of natural mortality in the overstory of the plantations. Concern has been raised over the potential for ivy to grow up the trunks and eventually smother the eucalyptus trees. I have not observed this taking place in eucalyptus plantations in the East Bay. Ivy (English and Algerian) may climb the trunks of trees, but in my experience it does not have the capacity to grow over the smaller limbs and branches. There were a couple of eucalyptus snags completely covered by ivy at Mt. Davidson, but these snags were the result of girdling of the trees snags, not the growth of ivy. The ivy, Cape ivy, and the Himalayan blackberry in the under story of the eucalyptus plantation are restricting establishment of eucalyptus seedlings. I do not see this as a problem at the current age of the plantation. Perhaps in another hundred years an examination of the plantation could establish the need for regeneration. At this time in the life of the Mt. Davidson plantation I do not consider the lack of regeneration a problem. Removal of the exotic understory species at this time would reduce the habitat quality of the plantation, especially the removal of Himalayan blackberry that provides a valuable food source for many species.

I conclude that the Significant Natural Resource Areas Management Plan for the removal and thinning of different portions of the eucalyptus plantation on Mt. Davidson is not justified. The plantation serves an important role in the history and visual characteristics of the city. Trees and the existing understory provide habitat for wildlife and wind protection for walkers. The justifications for the management prescriptions have not been properly developed. Furthermore, the cost of removal of the trees seems unjustified in view of other priorities in the San Francisco budget.

Sincerely,

Joe R. McBride
Professor

CC: Mayor Edwin M. Lee
City and County of San Francisco Board of Supervisors
San Francisco Recreation and Park Commission
San Francisco Planning Commission
San Francisco Urban Forestry Council
Park, Recreation and Open Space Advisory Committee
Bill Wycko, Environmental Review Officer (Case No. 005.1912E)

Literature Cited

Cheng, S. and J.R. McBride. 1992. Biological Assessment of Mills Creek Riparian Corridor. Report to the California Department of Parks and Recreation. Monterey Co., CA 89p.

Franklin, J. and R.T.T. Forman. 1987. Creating landscape patterns by forest cutting: ecological consequences and principles. Landscape ecology 1:5-18.

McBride, J. R. 1999. Identification of areas of high windthrow potential at the Sea Ranch. McBride and McBride. Consulting Landscape Ecologists. Berkeley, CA.

McBride, J. R. 2002. Presidio of San Francisco Wind Study, First Phase. Report to the Presidio Trust. San Francisco, CA. 35 p.

McBride, J. R. 2003. Re-evaluation of the windthrow problem at The Sea Ranch. Report to the Planning Department. The Sea Ranch, CA. 6 p.

McBride, J. R. and J. Leffingwell. 2003. Effects of Forest Stands on the Microclimates of the Presidio. Report to the Presidio Trust. San Francisco, CA. 27 p.

McBride, J.R., N. Sugihara and D. Amme. 1987. Vegetation Assessment. In: D. Boyd (Ed.) Environmental assessment for Eucalyptus Removal on Angel Island. California Dept. Parks and Recreation, Sacramento, CA. pp 23-45

McBride, J.R., S. Cheng and J. Chorover. 1989. Natural Resources Assessment – Jack London State Park. Calif. Dept. Parks and Recreation. Sacramento, CA. 432 p.

Proctor, J. 2006. San Francisco’s West of Twin Peaks. Charleston, SC: Arcadia Publishing.

Russell, W. H. and J. R. McBride. 2003. Landscape scale vegetation-type conversion and fire hazard in the San Francisco Bay Area open spaces. Landscape and Urban Planning 64:201-208.

McBride, J. R. , S. Cheng, and J. Clausen. 2004. Vegetation management Strategy for Lands End, GGNRA. Report to the Golden Gate National Park Conservancy. San Francisco, CA

Sinton, D. S. et al. 2000. Windthrow disturbance, forest composition, and structure in the Bull Run Basin, Oregon. Ecology 81(9): 2539-2556.

Stebbins, R. 1976. Use of habitats in the East Bay Regional Parks by free-living vertebrate animals. August 1975. In “Vegetation Management Principles and Policies for the East Bay Regional Park District”. East Bay Regional Parks District. Oakland, CA.