Gouty Pitch Midge Damage to Ponderosa Pines Planted on Fertile and Infertile Soils in the Western Sierra Nevada

摘要

Crown damage caused by gouty pitch midge (GPM) and its effects on tree growth were assessed in two 14-year-old ponderosa pine plantations, one on a shallow, infertile soil derived from serpentine and other on a deeper, more fertile nonserpentine soil of marine parent material. Seed sources for each marine parent material. Seed sources for each plantation were nearby indigenous stands on the same soil. Tree in both plantations had either viscid (resinous) or nonviscid surfaces on spring shoots. Light to moderate GPM damage was found in both plantations. Trees of both seed sources grew much faster in the nonserpentine than in the serpentine plantation. And in the serpentine seed source grew faster than the nonserpentine seed source. But both fast and slow-growing trees had similar levels of GPM damage.