Pine Beetles Pose Serious Threat to the Environment
Pine Beetles Pose Serious Threat to the Environment
06 November 2010
published by www.theepochtimes.com
USA — Governor Mike Rounds of South Dakota put it plainly: The Mountain Pine Beetle is one of the biggest threats to forests in the U.S. In the Black Hills they are running rampant. They have not been properly managed. The U.S. Forest Service has taken out some trees, some people say take no trees. This is a major fire hazard. We were fortunate this year that we had a lot of rain and didnt lose this forest to fire. We will lose it.
This was a dire prediction from the man who is ultimately responsible for the largest state park in the United States. Custer State Parks 74,000 acres, its wilderness areas, lakes, and game make it one of the worlds most important heritage sites.
State foresters are doing what they can, but the park is surrounded by 1.5 million acres of federal land and that is where the controversy comes in. Governor Rounds and others have been urging the U.S. Forest Service to do more to cull infected trees and remove them from public lands to prevent the spread of the Mountain Pine Beetle.
Its biology is fascinating. The pine beetle is always present in forests. It is when it gets out of control that it endangers trees on a grand scale. The beetles kill the trees. The trees stand for four to five years and fall over on the forest floor. They add to the deadfall all around that accumulates to make tinder for forest fires.
Lightning strikes occur all the time in the forests, especially those in the Black Hills. This accounts for natural fires. There is also some degree of careless activity by smokers and campers. Lookout towers and modern firefighting techniques have kept forest fires under control in the Black Hills.
With the great mass of tinder from fallen and dead treesthe result of pine beetle infestationthe fires will have lots to burn. When a fire gets going and is fueled by so much dead matter, it cannot be easily controlled.
Adam Gahagan is the state forester assigned to Custer State Park. Its going on the 11th year. The basic science in the Black Hills is that Ponderosa Pine is disturbance-driven. That ecology has developed over thousands of years.
The primary value of fire is that it kills small trees, burns up fuel, kills pockets of trees, and creates a mosaic landscape. When you remove fire from the Black Hills, you end up with trees the same age creating very dense and continuous forest. The beetle needs to eat lots of trees fast.
Two main factors create a perfect environment for that: When trees grow at high density, trees become stressed. Think of your garden. People plant five tomato seeds in a pot. If they all grow, the gardener has to pluck out four. The same with trees. Pine needles are a bank account. They can capture more sunlight if the trees are spaced out. A healthy, strong tree in the open can push the pine beetle out, Gahagan explained.
Beetles are poor flyers. It is hard for them to fly in wind that is over 5 miles per hour. They need to find a new tree. In a dense stand with stagnant air, the beetles have an easier time to pick out a stressed tree to attack, the forester said.
August is the peak adult flight of pine beetles. They go out, find a stressed tree, and emit a pheromone, which is a scent that tells other beetles to attack.
It takes a hundred beetles to kill a tree. The adult beetle goes under the bark and feeds on cambrium. That is the layer under the bark that the tree uses to transport materials. They chomp on the tree and lay eggs. This first activity kills the tree. The pine beetles carry on their feet a blue stain fungus. The fungus plugs up the channels and does not allow the tree to take up water and nutrients.
The pine logs retain a blue stain from the fungus, making the lumber desirable and decorative. The tree, after the main attack in August, is dead by the next spring.
Once attacked, the tree is pretty much gone. An infested tree has zero chances of survival. It is treated only to prevent the fly-out. That is one form of mitigation; the other is thinning trees and forest management, Gahagan explained.
Commercial thinning is the most cost-effective way of stopping infestation. The options are limited: Treating trees is difficult and costly, and The Wilderness Act proscribes spraying. Removal of infested trees by logging is feasible in some accessible forest areas. When the sawmill takes the bark off the logs, the beetles die.
Weve used helicopters to get in where the ground is inaccessible. It makes it very expensive, Gahagan said. Another tactic is to take infested trees and cut them into 2-foot sections. Solar radiation dries the layer and prevents beetle larvae from living.
When a tree is full, the beetles send out a verbanone. The scent tells other beetles not to come. Artificial verbanones have been developed and work in Colorado, Wyoming, and Montana but not here in South Dakota, Gahagan said. Chemistry still has to be done to find the right chemical imitator of the verbanone specific to Black Hills pine beetles.
About placing blame, Gahagan said: I hate to get into the blame game with the U.S. Forest Service. This forest around us is 1.5 million acres and it produces more saw timber than any other forest. They are active and do a lot of thinning.
What gets them is the bureaucratic process, so they cant move very fast. Weve been more aggressive but we have 74,000 acres; they have 1.5 million acres. They are doing a lot of forest management now, the forester added.
Then he became philosophical: The Mountain Pine Beetle is not the most terrible thing. The forest will open up. There is a fuel risk and fire hazard from all those dead trees. In four to five years, a dead tree will fall over. It becomes like a big jack straw pile.
Humans have disrupted the natural cycle for the last hundred years. We are good at preventing forest fires. We are trying to manage this resource for us. We are trying to mimic the natural process, he reflected. In the end, this is a public place for people to enjoy.
Theyve canceled the fireworks display at Mt. Rushmore National Monument this year and next. The fear is that there will be a major fire that we will not be able to put out, Governor Mike Rounds said. Custer State Park is green. The federal forest area is brown.
Governor Rounds is concerned that the elements created by late management of beetle infestation has created both a fire and environmental hazard that will have telling effect on wilderness forest lands in his state for years to come.
