Evergreen bagworm in forested areas are rare. With scarce predators in urban areas, evergreen bagworms often thrive in urban habitats. When disturbed, the larva will retract its head into its case and hold the front opening closed. Mature larva may remain in the host tree or drag its case nearby before attaching itself for the pupa stage. Arborvitae and red cedar are the favored host trees of the evergreen bagworm, but cypress, juniper, pine, spruce, apple, birch, black locust, elm, maple, poplar, oak, sycamore, willow, and over 100 other species are also attacked. Leaves and buds are both fair game for food.
California mixed evergreen forest forests, and Sierra Nevada lower montane forest. The forests of each ecoregion have a somewhat different plant community composition. The mixed evergreen forests of the Klamath Mountains-Siskiyou Mountains occur above 300 meters (1000 ft) elevation, and are of four main types. Douglas-fir forests are found on gentle slopes, north-facing slopes, ridges with deep soil, and river terraces with deep sediments, usually underlain with sedimentary rocks. Coast Douglas-fir ("Pseudotsuga menziesii" ssp. "menziesii") is the predominant tree, occupying up to 70% of the forest cover. Broadleaf evergreen trees are relatively few. Tree species of secondary importance are: On granite soils, a similar