Nitrogen, Phosphorus, Carbon, and Suspended Solids Loads from Forest Clear-Cutting and Site Preparation: Long-Term Paired Catchment Studies from Eastern Finland

• Published in: AMBIO
• Main Authors: Palviainen, Marjo, Finér, Leena, Laurén, Ari, Launiainen, Samuli, Piirainen, Sirpa, Mattsson, Tuija, Starr, Mike
• Format: Text
• Language: English
• Published: Springer Netherlands 2013
• Subjects: Report; Fennoscandia
• Online Access: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3906482; http://www.ncbi.nlm.nih.gov/pubmed/24046144; https://doi.org/10.1007/s13280-013-0439-x

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 (NH4-N), nitrate (NO3-N), total phosphorus (total P), phosphate (PO4-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, NO3-N, PO4-P, and SS loads, except for SS, only in C34. Runoff increased by 16 % and the annual exports of total N, TON, NO3-N, and PO4-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, NO3-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.