Within-stream factors affecting nutrient transport from forested and logged watersheds.

Nutrient concentrations in stream water are the result not only of inputs from the adjacent forest but also of instream modifications of these inputs. Important instream process include autotrophic and heterotrophic uptake, macroinvertebrate particle generation, and retention of dissolved and particulate nutrients by woody debris. Major changes in these processes occur following forest logging. As a result of these changes, streams in the southern Appalachian Mountains may have their lowest ability to retain nutrients 20 to 30 years after logging.