Water quality, biodiversity and codes of practice in relation to harvesting forest plantations in streamside management zones

摘要

This report examines important streamside management zone processes and illustrates them with examples from forest management operations and agriculture.Streamside management zones (SMZs) are special landscape units that include riparian areas and adjacent lands that mitigate the movement of sediment, nutrients and other chemicals from upland forest and agricultural management areas into streams. The size, shape, and management of SMZs are governed by various combinations of economic, ecological, and regulatory factors. Although SMZs used around the world have a wide range of widths, in many cases they are similar at 5-20 m.Streamside management zones are important barriers or treatment areas that protect water resources from non-point source pollution. Vegetation and the geomorphic characteristics of SMZs result in infiltration, filtering, and deposition from sediment- and nutrient-laden water flowing off intensively managed forestry, agriculture, and urban lands. The effectiveness of SMZs for trapping sediment depends upon the velocity of water flow, size distribution of sediments, slope and length of slope above the SMZ, slope and length of the SMZ itself, depth of water flow into the SMZ, and vegetation characteristics such as type, density, and height. Nutrient removal is a function of SMZ width, runoff water residence time in the SMZ, the vigor of SMZ vegetation, and the amount of runoff water infiltrated into the soil during its transit of the SMZ.Authored by Daniel G. Neary, Philip J. Smethurst, Brenda Baillie, and Kevin C. Petrone.