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.