“Mulch Madness” and other restoration mistakes

Thanks to Professor Gordon Frankie (UC Berkeley), we have learned a lot about the bees in the Bay Area.  He has been studying our bees for over 20 years and has made a wealth of interesting information available on his website.

Native bee (Anthrophora urbana) approaching nest in ground at Albany Bulb

Unlike the European honeybee, our native bees are usually solitary.  That is, they do not live in social colonies such as the hives of the European honeybee.   Most (60-70%) California native bees live in small nests in the ground.  Although they may produce enough honey to feed their own young, they don’t store an excess of honey like the honeybee.

Professor Frankie has identified one of the biggest challenges to native bees in urban gardens, “Mulch Madness.” 

“[If] you happen to be one of the many ground-nesting bees that looks for garden sites for digging small tunnels where you will lay your eggs in individually-made brood cells that you will provision with pollen and some nectar, [you have a new problem in urban gardens]…Something has happened in recent years to those favored bare dirt sites that makes your task much harder and oftentimes impossible.  MULCH MADNESS has arrived and has become a highly promoted ‘eco-friendly’ method for suppressing weeds, conserving water, and unknowingly discouraging ground-nesting bees!”

Anyone who is familiar with native plant restorations knows that most are covered in a thick layer of mulch.  When tree removals are required for a restoration, the mulch is usually composed of the chips of the trees that have been cut down.  The projects of UC Berkeley for which UC is applying for FEMA funding (based on its claim that the clear-cutting of all non-native trees will reduce fire hazards) say specifically that the clear-cut areas will be covered with 24 inches of mulch composed of the chips of the destroyed trees.

The UC Berkeley projects also claim that native vegetation will return to these clear-cut areas without being planted, based on an assumption that the seeds of native plants are dormant in the soil.  One wonders how these seeds would be able to germinate when covered with 24 inches of mulch, or how the sprouts could penetrate it.  Their proposal contains the fanciful suggestion that squirrels will plant the acorns of oaks in the mulch, which may be true of the oaks, but is an unlikely scenario for the many other native plants and trees which UC claims will populate their “restorations” without being planted.

Accommodating bees in native plant restorations

In the unlikely event that native plants would emerge from this tomb of mulch, they won’t find a population of bees to pollinate them in the future because bees will not be able to populate these projects:  “bees will not dig through a thick layer of mulch.”  Frankie suggests that “about 50% of your garden be left in bare dirt for the bees and other organisms.”  Studies indicate that it will take between 10 and 15 years for 24 inches of mulch to decompose.

Native plant restorations also require the use of herbicides.  A particularly toxic herbicide, Garlon, is used to kill the roots of the non-native trees after they have been cut down.  If the stump isn’t sprayed with this herbicide immediately, the tree will resprout.  The plans for the UC Berkeley projects say that retreatment with this herbicide is required twice per year for 10 years.  Although insecticides are considered one of the primary reasons why bee populations are declining in the United States, less is known about the effect of herbicides on bees and other insects, because testing of these chemicals is minimal. Some scientists believe that all pesticides (both insecticides and herbicides) are more harmful to bees and other animals than we presently know.*  Professor Frankie recommends against the use of all “synthetic chemicals” in a garden in which bees are welcome.

Would native plant restorations benefit from more bees?

The restorations with which we are familiar in the San Francisco Bay Area are often unsuccessful.  That is, they are not usually populated by native plants unless they have been intensively planted, weeded, and irrigated.  Few managers of public lands have the resources for such intensive gardening.  UC Berkeley has been clear-cutting non-native trees on its properties for about 10 years, so we can visit some of those areas to see the results of such projects.  They are now weedy messes, as shown in this photograph.

Results of clear-cutting non-native trees, UC Berkeley project

The use of heavy mulches and herbicides in native plant restorations raises these questions:    Would using less mulch and herbicide attract more bees?  Would more bees benefit the native plants?  Would restorations be more successful if they were more attractive places for bees?  We don’t claim to know the answers to these questions.  However, we don’t think that the managers of these projects know the answers either.

Would scientific methods produce more successful native plant restorations?

What the managers of these projects call “adaptive management,” we call “trial-and-error.”  There is no science involved in these projects.  Control areas are not set up to test questions such as “Will a more bee-friendly environment benefit our projects?”    We think a more methodical approach to these efforts would be less wasteful and more successful.  If we could see more success, perhaps we would be less opposed to what seems like the needless destruction of non-native trees.  As it is, the consistently poor results do not justify the destruction that we witness.


* Schacker, Michael, A Spring without Bees, Lyons Press, Guilford, Connecticut, 2008.

Cultural Lag: Public policy lags behind science regarding “invasion biology”

This is a good-news-bad-news story.  The good news is that the most successful environmental organization devoted to the preservation and conservation of wildlands, The Nature Conservancy, has announced its intention to reorder its priorities in what we hope will be a less destructive direction.  The Conservancy is a science-based environmental organization that is unique in that regard.  It employs over 600 scientists to guide and inform its projects, in contrast to many other organizations that employ more lawyers than scientists.  The scientific orientation of the Conservancy undoubtedly puts it in a position to reflect and respond to the increasingly loud voices of other scientists who are expressing concern about the costs and environmental damage that are the unintended consequences of the “restorations” which have evolved out of invasion biology.

The bad news is that public policy regarding native plant “restorations” lags far behind the developing scientific consensus regarding invasion biology, namely that original theories require revision.  This is the consequence of the cultural lag that is inevitable when science moves forward, but communication of its findings to the general public lags behind. 

The Nature Conservancy redefines its goals

In the past few months, the Chief Scientist of the Nature Conservancy, Peter Kareiva, has written several articles in the Conservancy’s publications expressing his views about the future of conservation.  In “Beyond Man vs Nature,”(1) Kareiva is quoted as saying that species preservation should not be the top priority of the Conservancy.  He admits he is “not a biodiversity guy.”  Rather, he says, “The ultimate goal [should] be better management of nature for human beings.”  He does not agree with those who claim that the earth is fragile and man must be excluded from nature in order to protect it.  He considers nature resilient.  He calls the concept of “biodiversity hot spots” sham science and he rejects the notion that conservation and development are mutually exclusive.  We wants conservation efforts to focus on the things that people need from nature such as clean water and clean air.  If and when people experience the benefits of conservation, they will support and participate in those efforts.  The Conservancy can’t save the world alone.  The active participation of the human population is required to achieve the Conservancy’s conservation goals. 

Golden Gate Park San Francisco. Most plants and trees in GG Park are not native. Creative Commons Attribution - Share Alike

In “Conservation should be a walk in the park, not just in the woods,”(2) Kareiva says that the Conservancy should participate in more urban conservation projects because that’s where most people live and even more will live in the future.  He wants conservation to be more visible to people and he wants people to benefit directly from the projects.

In his most recent publication, “Invasive Species:  Guilty until proven innocent?” Kareiva acknowledges the debate about invasive species.  On the one hand, a few invasive species have done a great deal of harm, particularly on islands.  On the other hand, many invasive species aren’t doing any harm and some are benefitting native species, even endangered species in some cases (e.g., Southwestern Willow Flycatcher in Tamarisk).  He concludes, “Science-based conservation cannot be about knee-jerk platitudes and simple views of good and evil…the fact is we cannot control all invasive species, and in many cases, yesterday’s invaders have become plants and animals that are beloved by local people.” 

There is nothing scientifically new to us in what Kareiva has said recently.  What’s new is that he speaks as a representative of one of the most important environmental organizations in the world.  Therefore, he makes a connection between scientific theory and action.  That is new….very, very, new and very encouraging.

Public policy always lags behind science

Public policy is inherently conservative.  It usually reflects consensus and consensus occurs late in every scientific debate.  Once that consensus is finally reached, changing it is a slow process.  And so, we are not surprised by the most recent example of a local community continuing the crusade to eradicate non-native trees.  Two ordinances were recently passed in the Los Altos Hills on the San Francisco peninsula, to do just that. 

  • Citizens building or expanding buildings on their properties will be required by ordinance 10-2.802 to cut down all eucalypts within 150 feet of any roadway or structure.
  • “Town guidelines concerning restoration action” (5-8.08) “deems certain trees undesirable,” including Monterey pine and cypress, as well as eucalyptus.

We are heartened by the publication which announces these new policies.  The author objects to being dictated to regarding her tree preferences.   She also responds to the usual myths regarding the negative qualities of eucalyptus.  In response to the usual justification for its eradication, that it is not native, the author says, “Who cares?”  Indeed, who cares?  We certainly don’t care and we speculate that the vast majority of people in Los Altos Hills don’t care either.  When we speak up on behalf of our trees, we speed the process of changing public policy to reflect the considerable scientific evidence that non-native trees are not harming anything or anyone.   Indeed, their eradication is causing far more harm to the environment by releasing tons of sequestered carbon and requiring greater herbicide use.    


(1) Nature Conservancy, Spring 2011

(2) Nature Conservancy, Issue 2, 2011

Facts about carbon storage in grasses do not support assumptions of native plant advocates

We have received many comments from native plant advocates regarding carbon storage.  These comments defend projects in the Bay Area to destroy non-native forests and “restore” native plants by claiming that native plants will actually sequester more carbon than the forest that they propose to destroy.  As always, we are grateful for comments that give us the opportunity to research the issues and report what we have learned about this complex and important subject.

Carbon cycling in a terrestrial plant-soil system

The storage of carbon in plants and soil occurs as plants and soil exchange carbon dioxide (CO₂) with the atmosphere as a part of natural processes, as shown in the following diagram (1):

Green Arrow:  CO₂ uptake by plants through photosynthesis

Orange Arrows:  Incorporation of Carbon into biomass and Carbon inputs into soil from death of plant parts

Yellow Arrows:  Carbon returns to the atmosphere through plant respiration and decomposition of litter and soil Carbon.  Carbon in plant tissues ultimately returns to atmosphere during combustion or eventual decomposition.

Rates of carbon uptake and emissions are influenced by many factors, but most factors are related to temperature and precipitation:

  • Higher temperatures are associated with faster plant growth, which accelerates photosynthesis and carbon uptake.
  • Higher temperatures also accelerate decomposition of plant materials, thereby accelerating the return of stored carbon into the atmosphere.
  • The effect of moisture in the soil on decomposition can be graphed as a “hump.”  In extremely dry soils, decomposition is slow because the organisms that decompose vegetation are under desiccation stress.  Conditions for decomposition improve as moisture in the soil increases until the soil is very wet when lack of oxygen in the soil impedes decomposition.

Although temperature and precipitation are important factors in carbon storage, they don’t change appreciably when one type of vegetation is replaced with another.  Therefore, these factors aren’t helpful in addressing the fundamental question we are considering in this post, which is “Does native vegetation store more carbon than the forests that presently occupy the land in question?”

Where is carbon stored?

Source: U.S. EPA, 2018

Much of the carbon stored in the forest is in the soil.  It is therefore important to our analysis to determine if carbon stored in the soil in native vegetation is greater than that stored in non-native forests.  The answer to that question is definitely NO!  The carbon stored in the soil of native vegetation in Oakland, California is a fraction (5.7 kilograms of carbon per square meter of soil) of the carbon stored in residential soil (14.4 kilograms in per square meter of soil). (9)  Residential soil is defined by this study as “residential grass, park use and grass, and clean fill.”  This study (9) reports that the amount of carbon stored in the soil in Oakland is greater after urbanization than prior to urbanization because Oakland’s “wildland cover” is associated with “low SOC [soil organic carbon] densities characteristic of native soils in the region.”

Native plant advocates have also argued that the carbon stored in the soil of perennial native grasslands is greater than non-native trees because their roots are deeper.  In fact, studies consistently inform us that most carbon is found in the top 10 centimeters of soil and almost none is found beyond a meter (100 centimeters) deep. (1, 4) In any case, we do not assume that the roots of perennial grasses are longer than the roots of a large tree.

Another argument that native plant advocates use to support their claim that native perennial grasslands store more carbon in the soil than non-native trees is that native grasses are long-lived and continue to add carbon to the soil throughout their lives.  In fact, carbon stored in the soil reaches a steady state, i.e., it is not capable of storing additional carbon once it has reached its maximum capacity. (1)

It is pointless to theorize about why grassland soils should store more carbon than forest soils.  The fact is they don’t.  In all regions of the United States forest soils store more carbon than either grassland or shrubland soils.  (9, Table 5)

We should also describe Oakland’s native vegetation before moving on:  “Vegetation before urbanization in Oakland was dominated by grass, shrub, and marshlands that occupied approximately 98% of the area.  Trees in riparian woodlands covered approximately 1.1% of Oakland’s preurbanized lands…”  (5)  In other words, native vegetation in Oakland is composed of shrub and grassland.  When non-native forests are destroyed, they will not be replaced by native trees, especially in view of the fact that replanting is not planned for any of the “restoration” projects in the East Bay.

The total amount of carbon stored within the plant or tree is proportional to its biomass, both above ground (trunk, foliage, leaf litter, etc.) and below ground (roots).  Since the grass and shrubs that are native to the Bay Area are a small fraction of the size of any tree, the carbon stored within native plants will not be as great as that stored in the trees that are being destroyed.

Whether we consider the carbon stored in soil or within the plant, the non-native forest contains more carbon than the shrub and grassland that is native to the Bay Area.

Converting forests to grassland

If we were starting with bare ground, it might be relevant to compare carbon sequestration in various types of vegetation, but we’re not.  We’re talking about specific projects which will require the destruction of millions of non-native trees.  Therefore, we must consider the loss of carbon associated with destroying those trees.  It doesn’t matter what is planted after the destruction of those trees, nothing will compensate for that loss because of how the trees will be disposed of.

The fate of the wood in trees that are destroyed determines how much carbon is released into the atmosphere.  For example, if the wood is used to build houses the loss of carbon is less than if the wood is allowed to decompose on the forest floor.  And that is exactly what all the projects we are discussing propose to do:  chip the wood from the trees and distribute it on the forest floor, also known as “mulching.”  As the wood decomposes, the carbon stored in the wood is released into the atmosphere:  “Two common tree disposal/utilization scenarios were modeled:  1) mulching and 2) landfill.  Although no mulch decomposition studies could be found, studies on decomposition of tree roots and twigs reveal that 50% of the carbon is lost within the first 3 years.  The remaining carbon is estimated to be lost within 20 years of mulching.  Belowground biomass was modeled to decompose at the same rate as mulch regardless of how the aboveground biomass was disposed” (8)

Furthermore, the process of removing trees releases stored carbon into the atmosphere, regardless of the fate of the destroyed trees:  “Even in forests harvested for long-term storage wood, more than 50% of the harvested biomass is released to the atmosphere in a short period after harvest.”  (1)

Will thinning trees result in greater carbon storage?

Native plant advocates claim that thinning the non-native forest will result in improved forest health and therefore greater carbon storage.  In fact, the more open canopy of an urban forest with less tree density results in greater growth rates.  (3)  Although more rapid growth is associated with greater rates of carbon sequestration, rates of storage have little effect on the net carbon storage over the life of the tree.  (6)  Net carbon storage over the life of the tree is determined by how long the species lives and how big the tree is at maturity.  These characteristics are inherent in the species of tree and are little influenced by forest management practices such as thinning. (6)

More importantly, even if there were some small increase in carbon storage of individual trees associated with thinning, this increase would be swamped by the fact that over 90% of the urban forest will be destroyed by the proposed projects we are evaluating in the East Bay.  The projects of UC Berkeley and the City of Oakland propose to destroy all non-native trees in the project areas.  The project of the East Bay Regional Park District proposes to destroy all non-native trees in some areas and thin in other areas from 25 to 35 feet between each tree, reducing tree density per acre by at least 90%.  No amount of “forest health” will compensate for the loss of carbon of that magnitude.   

Responding to native plant advocates

  • The vegetation that is native to the Bay Area does not store more carbon above or below the ground than the non-native forest.
  • Chipping the trees that are destroyed and distributing the chips on the ground will not prevent the release of carbon from the trees that are destroyed.
  • Thinning the trees in our public lands will not increase the capacity of the trees that remain to store carbon.

 ————————————————————————————————–

Bibliography

  1.  Anderson, J., et. al., “The Potential for Terrestrial Carbon Sequestration in Minnesota, A Report to the Department of Natural Resources from the Minnesota Terrestrial Carbon Sequestration Initiative, February 2008.
  2. Birdsey, Richard, “Carbon storage and accumulation in United States Forest Ecosystems,” USDA Forest Service, General Technical Report WO-59, 1992
  3. Environmental Protection Agency, “Inventory of U.S. Greenhouse Gas Emissions and Sinks: 1990-2008,” April 15, 2010., EPA 430-R-10-006
  4. Fissore, C.,  et.al., “Limited potential for terrestrial carbon sequestration to offset fossil-fuel emissions in the upper Midwestern US,” Frontiers in Ecology and the Environment, 2009, 10.1890/090059
  5. Nowak, David, “Historical vegetation change in Oakland and its implication for urban forest management,” Journal of Arboriculture, 19(5): September 1993
  6. Nowak, David, “Atmospheric Carbon Reduction by Urban Trees,” Journal of Environmental Management, (1993) 37, 207-217
  7. Nowak, David. Crane, Daniel, “Carbon storage and sequestration by urban trees in the U.S.A.,” Environmental Pollution, 116 (2002) 381-389
  8. Nowak, David, et.al., “Effects of urban tree management and species selection on atmospheric carbon dioxide,” Journal of Arboriculture 28(3) May 2002
  9. Pouyat, R.V. (US Forest Service)., et.al., “Carbon Storage by Urban Soils in the United States,” Journal of Environmental Quality, 35:1566-1575 (2006)

Destruction of eucalyptus threatens bees

The Pt Reyes Light received a Letter to the Editor in response to its series about the destruction of eucalyptus trees.  The author of the letter explains that eucalypts are one of the few sources of nectar during the winter, that the nectar is vital to the survival of bees over the winter, and that the bees are essential to California agriculture.  The letter was published in the Light on January 6th and is reprinted here with permission:

Think before you cut

Dear Editor,

The recent articles in the Light regarding the Park’s and other’s plans to eradicate eucalyptus from California fail to take into consideration one critical aspect of the need for eucalyptus in the continuation of agriculture in the state.

The common honeybee was introduced to California in the mid-19th century, around the same time as Blue Gum Eucalyptus. Each spring and summer, honeybees gather huge amounts of nectar from flowers and store it in the form of honey so they will have enough food to make it through the winter, when the weather is too cold and rainy and flowers are too few to provide food for the bees. 

In autumn, each hive greatly reduces its number of bees in order to survive the winter on the honey they stored. This is done by the queen laying fewer eggs and thus not replacing the bees that naturally die. Hives of 40,000 to 50,000 bees in summer drop to 10,000 bees in winter.

During December and early January, bees hover in a tight cluster, keeping each other warm and living off the stored honey.  In early January the Queen again lays eggs in ever-increasing numbers each day; larvae and then newly-hatched bees must be fed huge amounts of honey to support rapid growth. The demand for honey increases exponentially and if honey stores are not enough, the hive can starve to death just before warmer, drier weather and its tons of flowering plants arrives. 

But in California we have periods of sunny, warm days, in January and especially February. These allow bees to forage for nectar to supplement depleted stores in their hives and insure their continuation.  But what is blooming in January and February, when bees are in desperate need of nectar plants? Acacia, almond, ceonothus, manzanita, mustard, rosemary and some fruit trees bloom for short periods of time, but their small number and smaller sizes do not always guarantee enough blossoms. And any hard rain or wind can destroy whatever blossoms there are. 

Eucalyptus, on average 100-feet high and 30 to 50-feet wide, has tens of thousands of nectar-filled blossoms per tree.  It blooms throughout California from late January through mid-May, ensuring an abundant supply of nectar for hives at the time of their most critical need.

Prior to the arrival of the honeybee in California, the state population was 1 million people and agriculture consisted of wheat, barley, cattle and sheep, all of which could easily survive without honeybees.  Today, with California growing much of the fruits, nuts and vegetables for the U.S., the honeybee is an intricate part of the continuation of agriculture. With the current problem of Colony Collapse Disorder, the fate of the honeybee is already precarious. Cut down all these Eucalyptus trees and the fate of thousands of hives of bees, and thus the continued pollination of our food crops, may be in serious jeopardy.  Think before you cut them down.

Cathleen Dorinson, Pt Reyes Station

Eucalyptus and Bee, painting by Brian Stewart
Research on Colony Collapse Disorder has identified reduced supplies of nectar as one of many factors in the failure of about 30% of commercial hives per year in the past few years.  Bees, already weakened by chronic exposure to pesticides and reduced food supplies, are unable to recover from the fungi, viruses, and parasites that are rampant in the “global diaspora of organisms.”

eucalyptus honey

Because of the role of pesticides in the death of bees, the eradication of eucalyptus exposes bees to  double jeopardy:  the loss of a major food source during the winter and exposure to the pesticides that are used to kill the roots of the eucalyptus trees.

Garlon with the active ingredient triclopyr, is the pesticide used by most managers of public lands to kill the roots of the eucalyptus after the trees are cut down.  Eucalyptus is a vigorous resprouter.   Unless the stump is poisoned immediately with a toxic pesticide, it will return ten-fold after it is cut down, or in the unlikely event that it burns down, or after a freeze deep and long enough to cause the tree to die back.

Garlon is known to be toxic to bees.  The Marin Municipal Water District quit using all pesticides on its properties in 2005 in response to public protests.  It hired a consultant to evaluate 5 pesticides for potential use in the future.  The risk assessment published in 2008  stated that Garlon was the most toxic of the 5 pesticides studied and that it was the most toxic to bees. The Marin Municipal Water District is presently seeking approval to begin using Roundup again.  It does not propose to use Garlon.

The so-called Natural Areas Program in San Francisco, which is responsible for the care of approximately 1,000 acres of park land ironically called “natural areas” uses Garlon heavily.  About 75% of its pesticide applications (by volume and frequency) are of Garlon.  Could this be a factor in the collapse of several beehives recently reported in San Francisco?

The East Bay Regional Park District used 34 gallons of Garlon in 2008.  How many more gallons of Garlon will be used by these managers of public lands when they cut down the hundreds of thousands of eucalyptus trees which they have proposed to destroy in their official plans?

Once again, we can’t make sense of the destructive actions of those who are damaging nature in the name of “restoring” nature.  In our view, it is a fundamental contradiction.

Pt Reyes Light sheds light on eucalyptus myths and an arborist adds context

The Pt Reyes Light is one of the last bastions of investigative reporting in the Bay Area.  Following its tradition of digging deep into the actions of its biggest neighbor, the Pt Reyes National Seashore (PRNS), it has recently published two hard hitting articles about the massive destruction of eucalyptus on the properties of the National Park Service in Marin County.  This two-part article, “Myth of the eucalyptus blight,” is available here and here.

The Light reports that the Pt Reyes National Seashore is destroying between 400 and 600 eucalypts per year.  Its neighbor, the Golden Gate National Recreation Area, is engaged in the same eradication effort.  The Light repeats the PRNS justification for this destruction and reports the evidence that the justification is fabricated.  This justification is based on myths propagated by native plant advocates to frighten the public into supporting the destruction.  The myths and their negative impact on our environment are reported and refuted elsewhere on the Million Trees blog:

 There is also much new information in the Light articles, particularly in the quotes of a certified arborist from Berkeley, California, Mark Bowman.  Mr. Bowman adds context and clarification to the Light article for the readers of Million Trees.*

In response to the claims that the “shreddy” bark of the Blue Gum eucalyptus provides a fire ladder to its canopy and casts embers long distances from its great height, Mr. Bowman says,

“There are many mitigating factors such as the age and the amount of wind the trees receive which would determine how much bark litter would remain on the tree or be scattered on the ground.  In general, the bark that sheds doesn’t reach all the way to the top.  It usually tapers off before it reaches the first branches.  As a rule of thumb it tends to be most noticeable on the lower 20 feet or so of the trunk and collects around the tree base, which makes it rather easy to pick up if you are worried about fire safety.  This may be news to some folks, but there is no such thing as a maintenance free tree unless it is made out of plastic.  If you are going to purchase a home in or next to the forest, then you shouldn’t assume you have the right to cut it down; after all you do have a choice to live elsewhere if you consider that environment too extreme for one reason or another.”

Eucalyptus, shreddy bark low on the trunk, smooth bark higher on the trunk, Mosswood Park, Oakland, CA
 
As an arborist working in that neighborhood, Mr. Bowman is familiar with the area of the 1991 fire in the Oakland-Berkeley hills.  He says that the eucalypts were a casualty of that fire, not the cause of it:

“I took care of a property next door to where the fire started and, as I recall, that neighborhood on Charing Cross and Buckingham was comprised predominantly of pine and native oaks, not eucalyptus.  If my memory is accurate, then it appears the fire department could not halt the burning of native oaks, dry grass and pines located in that steep terrain in the beginning, before the fire became that inferno, so I don’t understand why eucalyptus is getting this bad rap as a fire starter.  There was plenty of blame for that tragedy to go around:  the homeowners who failed to maintain their properties; the city, county and state who failed to maintain theirs; and the fire department who failed to put out the blaze the day before.  When a fire ignites due to low humidity, hot dry Santa Ana winds, massive amounts of dry grass, shrubs and trees coupled with the steep terrain, there is nothing that is going to stop it but luck.  The fuel for that inferno had been obviously accumulating for years on both public and private lands.  I saw the smoke that day when I was driving along Grizzly Peak Blvd., and the first thing that came to mind was that ‘it finally happened.’  Anyone who worked in that area in the aboriculture and landscaping fields knew it was inevitable, and never once did I think that the eucalyptus trees were the issue; 20 years later I still don’t.  I want to state that I have no expertise in fighting fires; however  when a fire gets to the point that even homes being saturated with water burn, then obviously the trees burn too.  The fire could care less what species of tree is in its path or whether it was here before 1750 or not. The simplest and cheapest solution to this problem is for:  (1) owners of both public and private lands to maintain and clean their properties of dry grass, shrubs and leaf litter and; (2) insist that public agencies in charge of fire prevention use the laws and enforcement codes already on the books for those who fail to comply.  Let’s use a little common sense, that way the trees won’t burn.   This “native plant is superior” mentality is going to end up being a big taxpayer and/or rate payer fraud with no significant benefits and (more to the point) many guaranteed unintended consequences if this movement is allowed to come to fruition.  Grab a hold of your wallet folks.”

Mr. Bowman says that eucalyptus is no more likely to uproot or shed its branches than any other tree of comparable size:

“From a structural standpoint, Blue Gum eucalyptus has no inherent weakness on any below ground or above ground parts endemic to the species which would make it more prone to failure than any other large tree.  I have seen no scientific proof, nor do I have any hands on evidence that would lead me to believe that the cellular structure of this species is any more prone to failure from tension, torsion or compression forces than any other species.  Just because a large tree may look intimidating in the eyes of some people doesn’t mean it is dangerous, yet there are plenty of tree industry people all too happy to take advantage of that fear.  Every tree has its own individual and unique characteristics.  It is imperative when you are looking for advice to not take the word of the “Free Estimate” people you talk to without getting a second opinion.  Obtain a consultation from someone who has no conflict of interest in that they are not there to try and sell you on their service.  Removing eucalyptus or any other tree can be very expensive and sometimes completely unnecessary.  I’ve been in business for over 30 years and that experience has proved to me repeatedly that there is an awful lot of hopefully well intentioned but all too often misinformed people giving advice.  The best advice would be to consult with an arborist who does not have a vested interest in performing tree work.”

In fact, thinning the eucalypts can in some instances make those that remain more dangerous than they would otherwise be:

“Here again, there are many mitigating factors and situations which have to be taken into account but sometimes leaving them alone can be the best option.  There is no doubt that selective thinning of any tree species will reduce the fuel load in case of fire, but at the same time there is a myriad of potential unintended consequences when you undertake this approach:  (1) exposing the trees left behind to wind forces their root systems haven’t developed a resistance to, thus making them more prone to blow down; (2) introduction of wood decay organisms and parasitic fungi; (3) invasion of grasses and small understory plants that are more easily ignited, and (4) erosion of steep slopes previously stabilized by the roots of the trees.   Since I have mentioned unintended consequences a number of times, perhaps we should learn something from that old adage, ‘If it ain’t broke, don’t fix it.’”

Ironically, the PRNS staff interviewed by the Light actually agrees with Mr. Bowman that destroying the eucalyptus may not accomplish anything.  He observes that areas cleared of eucalypts are populated with shrubs that can be equally flammable:  “Just getting rid of them doesn’t necessarily solve anything.  It’s like swapping one problem for another…Even if it’s a native component, it might be less desirable.” 

So, why are we destroying these trees?  Clearly we are doing more harm than good.  The results are not less flammable.  The trees that remain are more dangerous than they were before their neighbors were removed.  And the landscape is doused with toxic herbicides. 

 Perhaps the answer to that question is in the answer to this question:  Who benefits from the eradication of non-native trees?  The chemical companies that manufacture the pesticides used to kill the trees.  The people who make their living destroying trees.  The people making their living “restoring” native plants.  The employees of the California Invasive Plant Council.  etc., etc. 

It’s a growth industry, funded by your tax dollars.  In the past two years tree destruction on federal lands (GGNRA and PRNS) has been funded by the federal economic stimulus program.  How does destroying trees stimulate the economy?  Might this money have made a more lasting contribution to our economy if it had been spent  repairing or improving our infrastructure?  


* Quotes from Mr. Bowman were made directly to Million Trees.  Not all these quotes appear in the Light articles.  Quotes of PRNS staff are from the Light.