Bees and Blue Gum Eucalyptus and Herbicides

We saw this interesting letter to the Editor in the Pulitzer Prize winning Pt Reyes Light newspaper. It’s reproduced here with permission from the edition of 6 Jan 2011. It makes reference to the two-part article Myth of the Eucalyptus Blight, linked here and here, which were discussed in our recent post.

Painting by Brian Stewart; click to go to artist's website

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, ceanothus, 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 with foraging bees (Photo: Susan Walter)

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
Point Reyes Station

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Meanwhile, Robert MacKimmie of City Bees, an outfit that promotes urban bee-keeping, and harvests San Francisco honey, commented on our post Twin Peaks: Fall Weather, Roundup and Garlon. In it, he linked to  an article in EcoSalon, (for which he was interviewed), that describes a number of sudden bee-colony collapses in San Francisco.

glyphosate and triclopyr

Could the herbicides being used in “Natural Areas” in the Fall have a role? Garlon 4 Ultra is supposed to be very mildly toxic to adult bees — but we couldn’t find any research on bee larvae. The herbicide is very poisonous to aquatic creatures, including invertebrates. Also,  Triclopyr (its technical name) falls into the class of pyridines — which also include “insect growth regulators” or insecticides that work by interfering with larval growth.

Could the Garlon and the Roundup (glyphosate) be working together to have an impact that neither has individually? We found no research on that, either. San Francisco’s Recreation and Parks Department frequently uses the two pesticides together at the same site. [Edited to Add: RPD have decided not to use combinations of Roundup and Garlon going forward.]

We’re concerned. If the planned UCSF project goes through, we expect the same mix of Roundup and Garlon to be used in the Mount Sutro Forest for the same reasons — preventing regrowth of undesired plants.

In addition to felling thousands of the eucalyptus trees that flower through the winter.

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4 Responses to Bees and Blue Gum Eucalyptus and Herbicides

  1. Alicia snow says:

    We need to make sure the pertinent administrative people at UCSF see this, and then discuss it with them tonight. Do we know if they check this website?

  2. Pingback: Sutro Forest Ecosystem and Wildlife Habitat | Save Mount Sutro Forest

  3. Manjiri Subhash says:

    I’m a Palo Alto resident and I came across your blog as I was searching for ways to save Eucalytpus trees in a neighborhood park. The city wants to remove ten magnificent trees because a limb drop. There is a pressure group who wants all of them removed while some of us would like to to save them.
    We’d greatly appreciate your help and tips.
    Thanks.

  4. Pingback: Fact Check: Nothing Grows Under Eucalyptus? (Allelopathy) | Save Mount Sutro Forest

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