title: Nitrogen, phosphorus, carbon, and suspended solids loads from forest clear-cutting and site preparation: long-term paired catchment studies from eastern Finland.
abstract: The long-term impacts of current forest management methods on surface water quality in Fennoscandia are largely unexplored. We studied the long-term effects of clear-cutting and site preparation on runoff and the export of total nitrogen (total N), total organic nitrogen (TON), ammonium (NH(4)-N), nitrate (NO(3)-N), total phosphorus (total P), phosphate (PO(4)-P), total organic carbon, and suspended solids (SS) in three paired-catchments in Eastern Finland. Clear-cutting and soil preparation were carried out on 34 % (C34), 11 % (C11), and 8 % (C8) of the area of the treated catchments and wide buffer zones were left along the streams. Clear-cutting and soil preparation increased annual runoff and total N, TON, NO(3)-N, PO(4)-P, and SS loads, except for SS, only in C34. Runoff increased by 16 % and the annual exports of total N, TON, NO(3)-N, and PO(4)-P by 18, 12, 270, and 12 %, respectively, during the 14-year period after clear-cutting. SS export increased by 291 % in C34, 134 % in C11, and 16 % in C8 during the 14, 6, and 11-year periods after clear-cutting. In the C11 catchment, NO(3)-N export decreased by 12 %. The results indicate that while current forest management practices can increase the export of N, P and SS from boreal catchments for many years (>10 years), the increases are only significant when the area of clear cutting exceeds 30 % of catchment area.
authors.affiliation: Department of Forest Sciences, University of Helsinki, P.O. Box 27, 00014, Helsinki, Finland, marjo.palviainen@helsinki.fi.
authors.forename: Marjo
authors.initials: M
authors.lastname: Palviainen
authors.forename: Leena
authors.initials: L
authors.lastname: Finér
authors.forename: Ari
authors.initials: A
authors.lastname: Laurén
authors.forename: Samuli
authors.initials: S
authors.lastname: Launiainen
authors.forename: Sirpa
authors.initials: S
authors.lastname: Piirainen
authors.forename: Tuija
authors.initials: T
authors.lastname: Mattsson
authors.forename: Mike
authors.initials: M
authors.lastname: Starr
mesh_terms: D002244:Carbon / Q000032:analysis; D005387:Finland; D016468:Forestry; D009584:Nitrogen / Q000032:analysis; D010758:Phosphorus / Q000032:analysis; D014867:Water / Q000032:analysis*; D014876:Water Pollution / Q000032:analysis*
chemical_list: D014867:Water; D010758:Phosphorus; D002244:Carbon; D009584:Nitrogen
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