ABSTRACT
This chapter discusses sewage sludge applications to forest land for three common situations: cleared forest land that has not been planted, young plantations, and established forest stands. Microorganisms present in the sewage sludge are initially filtered out by the soil and forest floor and then replaced by the native organisms of the soil. Seedlings of deciduous species and many conifers, including Douglas fir and Sitka spruce, have shown excellent tolerance to sewage sludge in demonstration projects. There are four general types of methods for applying sewage sludge to forests: direct spreading; spray irrigation with either a set system or a traveling gun; spray application by an application vehicle with a spray cannon; and application by a manure-type spreader. Scheduling sewage sludge application also requires a consideration of climatic conditions and the age of the forest. High rainfall periods and/or freezing conditions can limit sewage sludge applications in almost all situations.
