In many cases, native plants such as Douglas fir, western red cedar, vine maple, and a diverse array of understory shrubs and ground covers have been removed, allowing common offenders like blackberries, knotweed, scotch broom, English ivy, and reed canary grass to take over. These species often create a monoculture, reducing diversity, preventing native plants to germinate, providing little to no wildlife value, and sometimes contributing to erosion or depletion of soil nutrients.