Kubin, E. 1998. Leaching of nitrate nitrogen into the groundwater after clear felling and site preparation. Boreal Env. Res. 3(1): 3–8.
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Nieminen, M. 1998. Changes in nitrogen cycling following the clearcutting of drained peatland forests in southern Finland. Boreal Env. Res. 3(1): 9–21.
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Manninen, P. 1998. Effects of forestry ditch cleaning and supplementary ditching on water quality. Boreal Env. Res. 3(1): 23–32.
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Lepistö, L. & Saura, M. 1998. Effects of forest fertilization on phytoplankton in a boreal brown-water lake. Boreal Env. Res. 3(1): 33–43.
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Turkia, J., Sandman, O. & Huttunen, P. 1998. Palaeolimnological evidence of forestry practices disturbing small lakes in Finland. Boreal Env. Res. 3(1): 45–61.
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Holopainen, A.-L. & Huttunen, P. 1998. Impact of forestry practices on ecology of algal communities in small brooks in the Nurmes experimental forest area, Finland. Boreal Env. Res. 3(1): 63–73.
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Rask, M., Nyberg, K., Markkanen, S.-L. & Ojala, A. 1998. Forestry in catchments: effects on water quality, plankton, zoobenthos and fish in small lakes. Boreal Env. Res. 3(1): 75–86.
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Matero, J. & Saastamoinen, O. 1998. Monetary assessment of the impacts of forestry on water-based benefits in Finland. Boreal Env. Res. 3(1): 87–96.
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Kubin, E. 1998. Leaching of nitrate nitrogen into the groundwater after clear felling and site preparation. Boreal Env. Res. 3(1): 3–8.
The concentration of nitrate nitrogen in the groundwater was investigated one year before and during ten years after clear felling, collecting of logging residues and ploughing that took place in 1986 at the Pahalouhi and Hautala experimental sites at Kivesvaara, located in the middle boreal coniferous forest zone in the central part of Finland (64°28´N, 27°33´E). All the treatments caused a rise in nitrate nitrogen concentrations at both sites. Having been initially virtually zero, the concentrations of nitrate nitrogen continued to rise for 5–7 years, reaching 500–700 ug l–1 at their highest, after which they began to decrease. Concentrations were still high ten years after the treatments, a situation which has not been found earlier.
Nieminen, M. 1998. Changes in nitrogen cycling following the clearcutting of drained peatland forests in southern Finland. Boreal Env. Res. 3(1): 9–21.
The effects of forest clearcutting on the leaching of organic N, NH4+-N and NO3–-N and the processes likely to influence them were studied in two Norway spruce (Picea abies) dominated catchments located on nutrient-rich old peatland drainage areas in southern Finland. The concentrations of NH4+-N in precipitation reaching the ground increased after clearcutting. Those of NO3–-N increased in the area where the atmospheric N deposition was average, but decreased in the area subjected to higher than average N deposition. Ammonium-N concentrations in percolation water passing through the surface peat increased, both under slash-piles and in slash-free areas. Gaseous N2O and N2 emissions or leached amounts of N2O were not influenced by clearcutting. Organic N concentrations in runoff increased immediately after clearcutting, whereas the concentrations of NH4+-N and NO3–-N only increased after the first growing season after cutting. The causes for increased runoff nitrogen concentrations are discussed.
Manninen, P. 1998. Effects of forestry ditch cleaning and supplementary ditching on water quality. Boreal Env. Res. 3(1): 23–32.
The effects of ditch cleaning and additional ditching of forest land were studied at a site in central Finland. The results from the two first years demonstrate that the influence of these measures on water quality is very similar to that of new forest ditching, i.e. the increases in total solids, total phosphorus, total nitrogen, pH and buffering capacity are of the same order of magnitude. On the other hand, the amount of ammonia increased more than in most new ditchings in Finland. Nitrate nitrogen load increased due to the high cocentrations during the snow melt in April–May 1994 and the variability in iron and manganese cocentrations were more pronounced. The amount of total solids deposited on artificial surfaces (plastic plates) in the brook Ruununsuonoja increased four-fold, mineral solids five-fold and organic solids 3.5-fold after ditching. The most striking changes in the microalgal flora in the first year after ditching of the Ruununsuo drainage area were the decline in the mainly acidophilic diatoms of the family Eunotia and in the green algae and the increase in family Euglenophyceae and the diatom genera Nitzschia and Tabellaria, mainly due to the increase in pH, nutrient status and organic matter in the brook.
Lepistö, L. & Saura, M. 1998. Effects of forest fertilization on phytoplankton in a boreal brown-water lake. Boreal Env. Res. 3(1): 33–43.
The quantity and composition of phytoplankton in a brown-water lake was studied from 1988 to 1994 after forest fertilization in its catchment area. The following spring after fertilization, phosphorus concentrations were high (in average 18 ug l–1), and an evident vernal maximum of phytoplankton (chrysophytes and diatoms) was observed, but no further signs of trophicity changes could be observed. The extra nutrients must have been quickly utilized by bacteria or transported out of the lake through the out-flowing brook during the spring high-flow. Mixotrophic algae, like e.g. Cryptomonas spp. and Gonyostomum semen, were the ones to mostly benefit from the increased amounts of organic compounds and nutrient concentrations. The typical brown-water lake phytoplankton composition, in general did not change during the study period.
Turkia, J., Sandman, O. & Huttunen, P. 1998. Palaeolimnological evidence of forestry practices disturbing small lakes in Finland. Boreal Env. Res. 3(1): 45–61.
The effects of forestry practices on lake water quality were traced in the sediments of six small lakes in Finland by studying the physical and chemical properties and the diatom composition of the sediments. Weighted averaging and a calibration data set of 89 lakes was used to reconstruct lake water pH, conductivity and concentration of total phosphorus on the basis of the sedimentary diatom assemblages. Palaeolimnological changes that can be connected with forest ditchings and fertilizations were detected, and a sudden eutrophication is shown in one case. The effects of clear cuttings seem to be dependent on the subsequent soil treatments (e.g. harrowing or screefing). Some changes in the diatom floras suggest an increase of humic matter in lake water. The links between forestry operations and Aulacoseira distans var. tenella (Nygaard) R. Ross as well as Asterionella ralfsii var. americana Körn. are discussed.
Holopainen, A.-L. & Huttunen, P. 1998. Impact of forestry practices on ecology of algal communities in small brooks in the Nurmes experimental forest area, Finland. Boreal Env. Res. 3(1): 63–73.
The effects of clear felling, ditching and site preparation on the species composition, biomass and production of algae in forest brooks have been studied in 1982–93 as a part of the Nurmes Project in Finland. After clear felling and site preparation the primary factors causing change in species composition of algae were the increased nutrient content and colour of water. As the effects of site preparation started to wear off the nutrient content and temperature of the water returned towards the original level, a new response was seen in species of algae. Immediately after ditching and clear felling the biomasses of Volvocales and Cryptophyceae rose and reached their maximum in the following open water season, while the proportion of diatoms in the biomass decreased. A protective forest zone between the brook and the area affected by the intervention appeared to be highly effective in preventing changes in the water quality.
Rask, M., Nyberg, K., Markkanen, S.-L. & Ojala, A. 1998. Forestry in catchments: effects on water quality, plankton, zoobenthos and fish in small lakes. Boreal Env. Res. 3(1): 75–86.
Limnological responses of three small forest lakes in eastern Finland to forest clear cutting and soil scarification (in 15–33% of their catchments) were studied in 1991–1994, and compared with one reference lake. Increases in the concentrations of total phosphorus and iron indicated an increased inorganic load whereas the increase in water colour and chemical oxygen demand suggested an increased load of organic matter. No such changes were recorded in the reference lake. No clear response in phytoplankton biomass to catchment forestry was recorded. However, the changes in species composition, e.g. a bloom of cyanobacteria in one of the lakes in autumn 1993, indicated a slight eutrophication. Periphyton growth increased after the forestry operations resulting in increased concentrations of chlorophyll a. Zooplankton densities, both cladocerans and copepods, increased slightly in two of the lakes. Zoobenthos abundance increased in all the study lakes but increased biomass was recorded in only one. Population structure and growth of perch (Perca fluviatilis) remained unchanged in all the experimental lakes and in the reference lake, suggesting that there were no dramatic changes in the habitat of fish. Observed changes in zooplankton and zoobenthos community composition were also reflected in the diet of perch. The maximum Hg concentration in perch, 1.6 mg kg–1 (ww), was measured in a 19-year-old fish of 16.9 cm in total length. Otherwise, the mean Hg contents of 15 cm long perch were 0.4–0.8 mg kg–1 (ww), except in the reference lake where the mean concentrations were 0.1–0.2 mg kg–1. After the clear cutting and soil scarification a slightly decreasing trend in Hg concentrations in perch was recorded. Generally, the limnological responses to catchment forestry were modest, partly due to the protective zones of ca. 50 m in width left at the shores of the lakes according to the recent recommendations of forest management in Finland.
Matero, J. & Saastamoinen, O. 1998. Monetary assessment of the impacts of forestry on water-based benefits in Finland. Boreal Env. Res. 3(1): 87–96.
This paper identifies the major impacts of forestry on watercourses, introduces methods and calculation approaches for valuing these impacts in monetary terms and presents some preliminary estimates of the economic value (order of magnitude) of damages to different water-based values. Using a variety of calculation approaches, the range of aggregated damages was estimated to be 17–93 million FIM per year if even the more uncertain (guess-estimate type) figures of general recreation, biodiversity and crayfish fisheries were included. The main components in this estimate were the impacts on flood protection and water-based recreation. The range of aggregated damage estimates corresponds to 0.2–1.0% of the GDP of forestry in Finland in 1992. However, due to data and methodological problems in some specific impact estimations, and those related to individual valuation and summation procedure in general, even the total range remains tentative.