Recovery Plan for the Northern Spotted Owl - DRAFT

* Opening the canopy in small patches and preparing the site for seeding orplanting probably will be needed to maintain ponderosa pine and Douglasfirin the forests, if fire is to be excluded to provide owl habitat.SummaryThese silvicultural systems, developed for common types of stands throughoutthe range of the owl, indicate that multilayered stands can be developed ormaintained. Where stands are well stocked with young conifers, thinningthese stands provides space for development of large trees with full crowns,while providing light and moisture for growth of understory trees into multiplelayers. The structure and species composition of multistoried stands can bedeveloped and maintained by opening the overstory to favor establishedseedlings and saplings or to establish new ones.Fire, wind, insects, pathogens, soils, and other environmental variables areimportant within forests throughout the owl's range. They must be evaluatedon a stand by stand basis to determine how they affect stand development.Their potential effects often will be a key in determining the silviculture systememployed. Also, the structure of stands must be considered. Are there hardwoodsor conifers present in the understory which will form multiple layers?Are there shrubs which will prevent or delay the establishment of trees neededto form multilayers? Will the stand produce large snags or only small ones?What will costs or returns be? Therefore, the cases presented are examples ofsystems which might be used to produce owl habitat. In practice,multidisciplinary professional input is needed on the ground to develop andimplement silvicultural systems.Careful implementation, monitoring, and evaluation of treatment effects arealso essential. They indicate the willingness and commitment to ensure thatthe system will produce the desired structure and habitat.As with all silviculture activities, there is an important linkage between planningand implementation. Silviculture systems and practices that are feasibleecologically may be difficult and expensive to carry out. The prescriptionsoutlined here call for thinning, encouraging the growth of advance regenerationof hardwoods and conifers, and establishment of regeneration during thecourse of stand development. All of these practices require care and need to beclosely monitored during and after implementation. Natural disturbances suchas fire, insect outbreaks, and windthrow affect managed and unmanagedstands. These events occur at random, and the timing and nature of theireffects cannot be predicted. After such events occur, managed andunmanaged stands must be evaluated to determine their effects on standdevelopment. In some stands, the effects might be beneficial, in that theywould aid stand development toward old-growth characteristics. In othercases, disturbance might prevent or delay development of desired standstructures.518