Acorn Shortage Drives Scientists Nutty
(Dec. 12) - Up and down the East Coast, residents and naturalists alike have been
scratching their heads this autumn over a simple question: Where are all the acorns?
Oak trees have shed their leaves, but the usual carpet of acorns is not crunching
underfoot. In far-flung pockets of northern Virginia, Maryland, Pennsylvania, West Virginia and other states, scientists have found no acorns whatsoever.
"I can’t think of any other year like this,” said Alonso Abugattas, director of the
Long Branch Nature Center in Arlington, Virginia. Louise Garris, who lives in the Oakcrest neighborhood of Arlington, Virginia, first noticed the mysterious phenomenon early this fall when doing yardwork beneath a canopy of large oak trees.
“I have lived in the area my entire life and have never not seen any acorns!” she
said. Garris checked with some local plant nurseries and they confirmed her
observation. The mystery has found its way to the Internet, where a “No acorns this year”
discussion on Topix.com yielded more than 180 comments from people reporting
acorn disappearances as far away as Connecticut and North Carolina. “WHAT IS GOING ON?” posted a resident of Maplewood, New Jersey.
“Now we are finding dead squirrels! SHOULD WE ALL BE CONCERNED?” Not necessarily, naturalists say. Last year Garris reported a bumper crop of acorns,
which scientists say may be one clue to this year’s scarcity. Virginia extension agent Adam Downing said acorn production runs in cycles, so a lean year is normal after a year with a big crop.
“It fits with the physiology of seed reproduction. The trees are exhausted, energy wise, from last year,” Downing said. But even he is surprised at the complete absence of nuts in parts of Virginia.
“There are plenty of acorns in most of the state, but zero acorns in some pockets,” he said. Downing said recovery from last year’s big crop, combined with a much wetter than- usual spring, probably accounts for the acorn absence. Meteorologists say the Washington-Baltimore area saw about twice as much precipitation last May as normal.
Kate McNamee, who runs a Washington area, volunteer tree-planting project called “Growing Native,” lends specific numbers to the acorn shortage. Her group collects hardwood seeds and plants trees to protect rivers and streams in the Potomac River watershed.
“Last year we collected 25,000 pounds of seeds, most from a bumper crop of acorns,” said McNamee. “This year we only collected 10,000 pounds, and 90 percent of that was walnuts.”
Even though this acorn shortage has not risen to the level of a crisis, scientists say
it is important to watch closely. If the shortage continues for several years, other forces might be at work.
Garris said her observations got her thinking about other recent environmental issues.
“I had read about the collapse of the bee colonies, and it made me wonder, is something else going on here? Could this be affecting other systems?” At the Long Branch Nature Center, calls and e-mails have been pouring in from people who want to donate acorns they’ve gathered in areas where they are plentiful.
It’s also hard to think of acorns without thinking about squirrels. What happens to
them when their favorite food disappears? Some Eastern Seaboard residents have
reported seeing skinny, aggressive squirrels devouring bird feed. “Especially in the depths of winter, there’s not much else for the squirrels to eat. Some may switch their diet, many others probably won’t make it,” said Abugattas.
“Squirrel and deer numbers will almost certainly go down.” But Doug Inkley, senior scientist at the National Wildlife Federation, said that wild animals can be resilient when their usual food sources go away. Inkley cited a blight that destroyed 3.5
billion American chestnuts from 1900-1940, wiping out a common food source for squirrels, deer, mice and wild turkeys. But those animals adapted and survived,
he said.
Barbara Prescott, a wildlife rehabilitation expert, agreed that squirrels are not fussy
about their diet. She suggested that residents leave whole (not crushed) corn,
peanuts and sunflowers in the seed as backyard treats. John Rohm, wildlife biologist for Prince William, Loudoun, Fairfax, and Arlington counties in northern Virginia, has faith in the furry population.
“Animals are resourceful,” he said. “If they’re hungry, they’re gonna find something to eat.”
CNN.com’s Brandon Griggs contributed to this story.
As California continues to respond to an outbreak of swine flu – plant biologists are dealing with a deadly epidemic of a different kind. Sudden Oak Death is devastating oak forests along the coast, killing trees that are key to the ecology of the coastal hills. Researchers have found a way to inoculate individual trees from the disease, but are struggling in their search to find a more sweeping answer to the threat.
Since 1995, native oaks have been dying inCalifornia’s coastal counties due to a diseaseknown as Sudden Oak Death. This disease iscaused by the pathogen Phytophthora ramorum. The pathogen can also infect a number of other plants, referred to as hosts of the disease.Confirmed cases of Sudden Oak Death havebeen reported in the coastal counties of central and northern California. Sudden Oak Deathinfections are often fatal on tanoak, coast live oak,California black oak, canyon live oak, and Shreveoak. Phytophthora ramorum primarily attacks the tree’s vascular system just below the bark, girdling the tree. The vascular system is the “plumbing” that transports nutrients and water throughout the tree. A tree infected with the pathogen is weakened and may also be attacked by other tree pests, such as bark beetles and decay fungi.
Federated Indians of Graton Rancheria
ENVIRONMENTAL PROTECTION DEPARTMENT
Sudden Oak Death
S U D D E N O A K D E A T H
Mendocino
Sonoma
Napa
Solano
Marin
Alameda
San Mateo
Santa Clara
Monterey
Humbolt
Contra Costa
Lake
San Francisco
* Almost all of these are physically within the fog belt. They are all in the central ,coast counties which have an access to water either from the ocean or the bay. Which again suggests that when you have mild weather it is favorable for the disease.
Lethally affected hostsEpidemiologically important hosts
Epidemiologically important hosts (e.g. killed in large numbers) (e.g. they spread the disease)
(e.g. they spread the disease)Coast Live oakCa bay laurel
Ca bay laurelCa black oak Tanoak
TanoakShreve's oak Rhododendron
RhododendronCanyon live oak Redwoods
RedwoodsThe best defense against Sudden Oak Death is to use good management and sanitary practices:
- Clean and disinfect all pruning, cutting, and chipping tools with a household disinfectant (such as Lysol, ethanol, or diluted bleach) after pruning host plants.
- Monitor oaks for bleeding symptoms year round. If bleeding symptoms are detected, seek confirmation that the cause is Phytophthora ramorum by contacting your County Agricultural Commissioner or UCCE.
- If you are in an infested county, do not move host material to uninfested areas. If host material must be removed from your property, it should be disposed of at a local landfill or transported to an approved collection facility.
Current information shows that there is a dual type of issues.
This disease is an exoctic organism which can develop into an epidemic.
WE CANNOT GET RID OF IT.
What can we do?
We can learn in the future is how to make things worse for the microbe which is the cause of the disease,. so that the level of tree mortality and level of infestation is not as prevelant.
The Tan Oak is the most seriously attacked plant species in the state of California. There is a risk that is some parts of the state that populations of this particular tree will become very very small, especially where climates are favorable to the disease.
The difference between animal and plant diseases is the fact that plant diseases are driven by the weather, by climatic conditions and that is unique. In the case of forest diseases, the diseases remain permanent in the site but the effect of the disease will be more or less apparant depending on the weather conditions. If the weather is more favorable for the disease you will see more trees dying and if the weather is unfavorable you will see less trees dying.
This will go on until all of the trees are gone. If you have a lot of trees being killed, in the end you will not see the disease anymore not because the disease is gone, but potentially because all of the trees have been killed.
Phytopthora is a water based organism, which means that in order for the disease to thrive, in order for trees to die, you will need a wet period during the year.
During the wet period is when the pathogen is active. It will infect trees and spread throughout the landscape. You can understand immediately that the consequences are that we live in a wet area which is why the disease can reach epidemic levels.
The pathogen can infect literally hundreds of plant species and it can create different types of diseases. The trees that are of major concern are ones that die because of the disease or are the host of the disease which help to spread the pathogen.
Oaks and Tanoaks - An early symptom on oaks may be the “bleeding” of a thick sap that appears on the bark surface. Other diseases and injuries may also cause similar symptoms. Underneath the bleeding bark there is a canker with dark patches of infected tissue surrounded by healthy tissue. Cankers and bleeding usually occur on the trunk within ten feet from the ground.
Foliar Hosts - Other than the oaks, plants infected with Phytophthora ramorum most often show symptoms of leaf spots and twig dieback, and are considered foliar hosts. Pathogen spores can build up rapidly on the leaves of these hosts. California bay laurel (Umbellularia californica) is a foliar host that appears to play a significant role in the distribution of Phytophthora ramorum spores.
Laboratory culture of Phytophthora ramorum is needed to confirm the diagnosis of Sudden Oak Death since many other agents* cause similar symptoms. For diagnostic assistance, please contact your local County Agricultural Commissioner or University of California Cooperative Extension (UCCE). *Not all bleeding on oak trunks is indicative of Sudden Oak Death. Other causal agents such as Phytophthora cinnamomi, wet wood, Armillaria, or insects may be responsible and cause similar symptoms.
For more information go to the California Oak Mortality Task Force website.
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M A N A G E M E N T
H O S T S B Y T Y P E O F D I S E A S E:
C O U N T I E S W I T H C O N F I R M E D S O D*
R E L A T E D N E W S
S U D D E N O A K D E A T H O N Q U E S T
Duration: 05:30
Original Air Date: Monday, May 11, 2009
Devastating over 1 million oak trees across Northern California in the past 10 years, Sudden Oak Death is a killer with no cure. But biologists now are looking to the trees' genetics for a solution.
P L A N T P L A G U E: S U D D E N O A K D E A T H O N Q U E S T
Duration: 8:00
Original Air Date: Tuesday, Apr 24, 2007
S U D D E N O A K D E A T H
