Growing threat of diseased trees - Democratic Underground

grantcart

(1000+ posts) Send PM | Profile | Ignore

Tue Aug-03-10 03:58 PM
Original message

Growing threat of diseased trees

I recently returned from doing a benefits seminar for Federal Employees working in Federal forrests (bizarre fact - federal employees are unionized by forrests. Some forrests have unionized forrest service employees and other forrests are non unionized. )

One of the speakers had an extensive slide showing the effects of diseased trees.

Having spent my teenage summers in the Cascades and the Rockies I found these pictures really horrifying.

Here is an example but what I saw was much much worse:

From a distance the trees seem to have a normal form and are healthy but when you examine them up closely they are dead.

I visited areas where I recognized trees that I had seen only a couple of years ago and were healthy and vibrant but now are mere skeletons.

Sudden Oak Death Syndrome was first discovered in 1995 but has now become endemic and threatens huge swatches of forrest:

http://www.forestdata.com/sod2.htm

It was first noticed in upper end suburban neighborhoods and was called the "Political Tree Disease".

http://www.forestdata.com/sod03.htm

It was thought that the culprit was SOD, Sudden Oak Disease, caused by a parasitical type fungus

http://en.wikipedia.org/wiki/Phytophthora

http://en.wikipedia.org/wiki/Sudden_oak_disease

It was first discovered in California in 1995 when large numbers of tanoaks (Lithocarpus densiflorus) died mysteriously, and was described as a new species of Phytophthora in 2000. It has subsequently been found in many other areas including Britain, Germany, and some other U.S. states, either accidentally introduced in nursery stock, or already present undetected.

In tanoaks, the disease may be recognized by wilting new shoots, older leaves becoming pale green, and after a period of two to three weeks, foliage turns brown while clinging to the branches. Dark brown sap may stain the lower trunk's bark. Bark may split and exude gum, with visible discoloration. After the tree dies, the suckers will try sprout next year, but their tips soon bend and die. Ambrosia beetles (Monarthrum scutellare) will most likely infest a dying tree during midsummer, producing piles of fine white dust near tiny holes. Later, bark beetles (Pseudopityophthorus pubipennis) produce fine red boring dust. Small black domes, the fruiting bodies of the Hypoxylon fungus, may also be present on the bark. Leaf death may occur more than a year after the initial infection and months after the tree has been girdled by beetles.

It spreads from one healthy tree to another until trees lined up next to each other all looking like the same dead corpse sharing a common agony.

Many California Redwood Trees across wide areas are dying or showing signs of severe stress. Greg Guisti, the University of California forest advisor for Mendocino County noted in a Ukiah Daily Journal Article dated May 8, 2002: â€œâ€¦There are also many redwood trees in town that are showing signs of widespread diseaseâ€¦â€ The questions remain unanswered: Why?

Trees are being cut down in record numbers across the United States without anyone doing the studies to determine why these trees are dying and what is causing this problem. Fires are burning hotter and are more devastating since the late 1980s, and the dying of the trees is certainly aggravating this situation.

Mr. Buckman noted: â€œI think we are in for big changes, and I think we should be on this â€˜like a duck on a June bugâ€™. I think this is as serious as it gets, and we need to act quickly to document the facts and take corrective actionsâ€¦â€

Sudden Oak Death, now blamed for many tree problems, is found rarely or not at all in some counties, and SOD diagnosis does not explain the widespread decline in Oak tree health in trees and counties not infected with SOD, nor does it explain the broad decline and die-off response in trees across the United States.

In a recent article in the Ukiah Daily Journal written by Mark Hedges, titled â€œFir Trees Under Attackâ€, some of the tree symptoms are listed. In an interview with Jack Marshall, a forest pathologist for the California Department of Forestry, he noted â€œâ€¦a few common things going on with the Douglas Fir relative to dry portions of this county, maybe Lake County and southern Humboldtâ€¦â€ However, it should be noted that the impacts are also found throughout these counties not just in the â€œdryâ€ areas. Marshall, according to the Ukiah Daily Journal article also stated: â€œâ€¦tree-killing insects do not usually attack a healthy stand of trees unless individual trees are somehow stressed or some other pathogen is degrading the health of the treeâ€¦â€

There is a major concern that all of this dead wood will become fuel for destructive wild fires that will effect healthy forrests

http://nature.berkeley.edu/comtf/pdf/Fire_and_P%20ramorum_update_2009_v3.pdf

Now similar problems are being found in Europe. Given how devistating Dutch Elm Disease was this sounds ominous.

Disease ravaging oak trees 'could be worse for UK than Dutch elm'

Read more: http://www.dailymail.co.uk/sciencetech/article-1279628/Disease-ravaging-oak-trees-worse-UK-Dutch-elm.html#ixzz0vZpEvKu6

A 'very serious' new disease is killing native oak trees across a wide swathe of Britain. Experts have warned could alter the British landscape more than Dutch elm disease.

The Forestry Commission said the condition acute oak decline (AOD) is hitting both native species of oak, which show black bleeding on the trunks and stems.

The trees can suffer rapid dieback and death within three to five years, experts are warning.
Acute Oak Decline causes black bleeding on the trunks and stems on affected trees (as shown)

Acute Oak Decline causes black bleeding on the trunks and stems on affected trees (as shown)

The practice note from the Forestry Commission, whose research arm Forest Research recently identified bacteria thought to be involved in the disease, is urging woodland managers to be vigilant about the health of their oak trees.

Roddie Burgess, head of the Forestry Commission's plant health service, said: 'It's one where I think they need to take this very seriously.

'We tend to be cautious about what might be seen as scare-mongering, but the signs here are that we are dealing with something that has the markings that it could become something very serious indeed.'

He added: 'We've 200 million oaks in the UK, so if this thing did really take off in the same way as Dutch elm disease, the impact on the landscape and biodiversity would be very significant.'

Read more: http://www.dailymail.co.uk/sciencetech/article-1279628/Disease-ravaging-oak-trees-worse-UK-Dutch-elm.html#ixzz0vZolmWrX

When you take time to look at the actual devistation it is somewhat overwhelming to see so much lifeless matter where healthy vibrant trees cast such a beautiful image just a few short months ago.

A friend of mine who is an expert on parasites say that usually the most effective way to stop a parasite is to find a natural parasite that can attach to the offending parasite "on the inside". Rather than going from tree to tree and trying to combat each parasite it is more effective to get inside the parasitical ecosystem. He is sure that such an entry exists it just takes time for it to spread the infection to the rest of the parasites.