NPSのDaily Reportが、Tuolumne Meadows周辺で、「 lodgepole needle miner（松葉の鉱夫）」と呼ばれる小さなガ（蛾）によってロッジポールパイン林の変色が進んでいると報じています。
みなさまもこれはと思うエリアがありましたら、ご報告ください。
Many have noticed discoloration of lodgepole pine forests in the greater Tuolumne Meadows area. This is due to a tiny moth called the lodgepole needle miner. The larvae live inside pine needles, eating them from the inside out, and only emerging in the late summer as small gray moths for a few weeks in the late summer of odd-numbered years. The lodgepole needle miner has few effective natural predators, as not many creatures can make a good living eating something that's only out a few weeks every other year. Repeated defoliation slowly starves trees, and makes them vulnerable to mountain pine beetle colonization. Needle miner populations generally keep rising until the overstory trees in an infested area die, then start building slowly again. Historically, large areas of lodgepole overstory die and leave isolated California red fir or mountain hemlock exposed to snow damage and wind throw. Approximately 50,000 acres of defoliation was mapped last year, and this is the fourth major episode since 1900. Many previously described "Ghost Forests" of lodgepole skeletons have since failed, and are the bane of many cross-country hikers. Small trees with foliage below the depth of the winter snow pack (ok, maybe not so small this season) are generally spared defoliation because melting snow wicks into the mined leaves by capillary action and drowns the larvae. This native, and nearly endemic forest insect is not likely to ever extirpate lodgepole from Yosemite, and may serve as a fire surrogate. Previous attempts to control lodgepole needle miners proved effective but several broad-spectrum chemicals would not be proposed with current knowledge of non-target effects. Lots more in the needle miner file, so contact Park Forester Brian Mattos for additional information. (B. Mattos - 7/14/05)
投稿者 nishimura : 2005年07月15日 22:57