A survey of Douglas-fir dwarf mistletoe brooms used for nests by northern spotted owls on the applegate ranger district and ashland resource area in southwest oregon

Abstract

A survey was done to provide forest managers in southwest Oregon with information about characteristics of Douglas-fir dwarf mistletoe (Arceuthobium douglasii) brooms used for nests by northern spotted owls (Strix occidentalis var. caurina). Data were collected on 35 nest brooms and nest trees. Site, stand, and mistletoe data were collected in variable-radius plots in a 20 ac area around 11 of the nest trees. On average, half the nest trees' crowns were occupied by brooms. Douglas-fir trees in variable radius plots immediately surrounding the nest trees were more heavily infected than trees in neighboring plots. The majority of owl nests were in Type 2 and 3 brooms. Few nests were in Type 1 brooms even though they were the most common broom type. The majority of nests were in brooms in the lower third of the tree crowns and on the lower to middle third of the slope. Survey results were used to make recommendations for managing infected trees and stands for current and replacement spotted owl nest habitat in the survey area.