|Mountain area infested by MPB, showing three years of mortality. Old, dead trees are gray; newly killed trees are straw yellow or orange. Some trees may also be infested but do not turn color until nine months or so under attack.|
During years of adequate precipitation, it will be normal to see an isolated tree here and there that might be losing the battle with Mountain Pine Beetle (Dendroctonus ponderosae), the most common and most destructive insect on the ranch. But after last year's acute drought, the drought weakened pines are being victimized right and left. Unless there is significant human intervention, we could easily have a beetle plague similar to what has been observed in other parts of the west in recent years where huge tracts of forest have been lost. Forest wildfire is only one of the heartbreaking ways we can lose a forest.
Mountain Pine Beetle (MPB) attacks mainly ponderosa, lodgepole, Scotch, and limber pine. Pinyons are susceptable to a lesser degree. Usually, MPB singles out weakened trees, whether from construction damage, root disease, fire damage, or old age. But the MPB populations have now increased to such an alarming degree, we can expect even healthy stands of trees to be under attack.
Examine the tree trunks for "popcorn" shaped masses of resin, brown, pink, or white in color. Sometimes, if the tree is hardy, this process of secreting resin in response to a beetle boring into the bark, will result in a beetle being trapped in a "pitch tube". The beetle will be 1/8 to 1/3 inch long.
Look for boring dust in bark crevices or on the ground at the tree base.
If you notice a sudden flurry of woodpecker activity, you may have have beetles. Look for missing patches of bark on the tree and bark flakes on the ground.
If you observe any of these symptoms, peal back a piece of bark with a hatchet and look for the eggs, larvae, pupae or adult beetles.
The solar method is a popular one, involving no chemicals. You can do it with or without wrapping the wood in clear plastic sheeting but you need to water the logs before wrapping. Seal the edges with soil or duck tape. You must place the wood, wrapped or unwrapped, in a sunny location for a minimum of two months of warm weather without stacking it. The logs need to be rotated every three weeks.
I favor using carbaryl (SEVIN) solution, spraying the downed wood, and getting it overwith. You can also use plain diesel oil for an impressive kill rate. (See my previous article on Fighting the Pine Beetle.) After exposure to the sun over the summer, the chemicals will have been neutralized so the wood will be completely safe to burn.
|Large, uninfested pine being preventively sprayed. This protects high-value trees and should be done annually between April 1 and July 1.|
Or you can call in the pros. It happens that C.K. Morey will be on the ranch this coming first week of May, and he will have with him a commercial sprayer that fits in the bed of a truck. He'll be working at Will Potter's, and the Johnsons on Owen Baldwin. And then he will be at the Obreys up on Alpine Meadows. For infrmation call C.K. at work: 719-742-3588 or at home: 719-742-3492. C. K. wants to help us any way he can to save our forest.
A good long range plan of prevention is to thin out the tree population, thus ensuring that the remaining trees have enough moisture and nutrients to be healthy enough to stave off future pine beetle attacks. This also helps the forest resist the ravaging effects of wildfire.
Complacency in the presence of this potentially devasting insect is like deciding to ignore the wild fire that is roaring up the slope toward you. The time to do something about the problem is RIGHT NOW!
For more information on the Mountain Pine Beetle, see the Colorado State University Cooperative Extension page at www.ext.colostate.edu/pubs/insect/05528.html
For more information on diseases and insects of the Pinon Pine, see the Colorado State University Cooperative Extension page at www.ext.colostate.edu/pubs/garden/02948.html