Browsing by Subject "ojitus"

Sort by: Order: Results:

Now showing items 1-20 of 64
  • Timonen, Erkki (Suomen metsätieteellinen seura, 1971)
  • Rajakallio, Maria; Jyväsjärvi, Jussi; Muotka, Timo; Aroviita, Jukka (Blackwell, 2021)
    Journal of Applied Ecology 58: 7, 1523-1532
    1. Growing bioeconomy is increasing the pressure to clear-cut drained peatland forests. Yet, the cumulative effects of peatland drainage and clear-cutting on the biodiversity of recipient freshwater ecosystems are largely unknown. 2. We studied the isolated and combined effects of peatland drainage and clear-cutting on stream macroinvertebrate communities. We further explored whether the impact of these forestry-driven catchment alterations to benthic invertebrates is related to stream size. We quantified the impact on invertebrate biodiversity by comparing communities in forestry-impacted streams to expected communities modelled with a multi-taxon niche model. 3. The impact of clear-cutting of drained peatland forests exceeded the sum of the independent effects of drainage and clear-cutting, indicating a synergistic interaction between the two disturbances in small streams. Peatland drainage reduced benthic biodiversity in both small and large streams, whereas clear-cutting did the same only in small streams. Small headwater streams were more sensitive to forestry impacts than the larger downstream sites. 4. We found 11 taxa (out of 25 modelled) to respond to forestry disturbances. These taxa were mainly different from those previously reported as sensitive to forestry-driven alterations, indicating the context dependence of taxonomic responses to forestry. In contrast, most of the functional traits previously identified as responsive to agricultural sedimentation also responded to forestry pressures. In particular, taxa that live temporarily in hyporheic habitats, move by crawling, disperse actively in water, live longer than 1 year, use eggs as resistance form and obtain their food by scraping became less abundant than expected, particularly in streams impacted by both drainage and clear-cutting. 5. Synthesis and applications. Drained peatland forests in boreal areas are reaching maturity and will soon be harvested. Clear-cutting of these forests incurs multiple environmental hazards but previous studies have focused on terrestrial ecosystems. Our results show that the combined impacts of peatland drainage and clear-cutting may extend across ecosystem boundaries and cause significant biodiversity loss in recipient freshwater ecosystems. This information supports a paradigm shift in boreal forest management, whereby continuous-cover forestry based on partial harvest may provide the most sustainable approach to peatland forestry.
  • Bhattacharjee, Joy; Marttila, Hannu; Launiainen, Samuli; Lepistö, Ahti; Kløve, Bjørn (Elsevier, 2021)
    Science of The Total Environment 779 (2021), 146419
    Maintaining and improving surface water quality requires knowledge of nutrient and sediment loads due to past and future land-use practices, but historical data on land cover and its changes are often lacking. In this study, we tested whether land-use-specific export coefficients can be used together with satellite images (Landsat) and/or regional land-use statistics to estimate riverine nutrient loads and concentrations of total nitrogen (TN), total phosphorus (TP), and suspended solids (SS). The study area, Simojoki (3160 km2) in northern Finland, has been intensively drained for peatland forestry since the 1960s. We used different approaches at multiple sub-catchment scales to simulate TN, TP, and SS export in the Simojoki catchment. The uncertainty in estimates based on specific export coefficients was quantified based on historical land-use changes (derived from Landsat data), and an uncertainty boundary was established for each land-use. The uncertainty boundary captured at least 60% of measured values of TN, TP, and SS loads or concentrations. However, the uncertainty in estimates compared with measured values ranged from 7% to 20% for TN, 0% to 18% for TP, and 13% to 43% for SS for different catchments. Some discrepancy between predicted and measured loads and concentrations was expected, as the method did not account for inter-annual variability in hydrological conditions or river processes. However, combining historical land-use change estimates with simple export coefficients can be a practical approach for evaluating the influence on water quality of historical land-use changes such as peatland drainage for forest establishment.
  • Cano Bernal, José Enrique; Rankinen, Katri; Thielking, Sophia (Academic Press., 2022)
    Journal of Environmental Management
    The majority of the carbon worldwide is in soil. In a river catchment, the tight relationship between soil, water and climate makes carbon likely to be eroded and transported from the soil to the rivers. There are multiple variables which can trigger and accelerate the process. In order to assess the importance of the factors involved, and their interactions resulting in the changes in the carbon cycle within catchments, we have studied the catchments of 26 Finnish rivers from 2000 to 2019. These catchments are distributed all over Finland, but we have grouped them into three categories: southern, peatland and northern. We have run a boosted regression tree (BRT) analysis on chemical, physical, climatic and anthropogenic factors to determine their influence on the variations of total organic carbon (TOC) concentration. TOC concentration has decreased in Finland between 2000 and 2019 by 0.91 mg/l, driven principally by forest ditching and % old forest in the catchment. Old forest is especially dominant in the northern catchments with an influence on TOC of 40.5%. In southern and peatland catchments, average precipitation is an important factor to explain the changes in TOC whilst in northern catchments, organic fields have more influence.
  • Bhattacharjee, Joy; Marttila, Hannu; Haghighi, Ali Torabi; Saarimaa, Miia; Tolvanen, Anne; Lepistö, Ahti; Futter, Martyn N.; Kløve, Bjørn (American Society of Civil Engineers, 2021)
    Journal of Irrigation and Drainage Engineering, 147(4), 04021006
    Spatiotemporal information on historical peatland drainage is needed to relate past land use to observed changes in catchment hydrology. Comprehensive knowledge of historical development of peatland management is largely unknown at the catchment scale. Aerial photos and light detection and ranging (LIDAR) data enlarge the possibilities for identifying past peatland drainage patterns. Here, our objectives are (1) to develop techniques for semiautomatically mapping the location of ditch networks in peat-dominated catchments using aerial photos and LIDAR data, and (2) to generate time series of drainage networks. Our approaches provide open-access techniques to systematically map ditches in peat-dominated catchments through time. We focused on the algorithm in such a way that we can identify the ditch networks from raw aerial images and LIDAR data based on the modification of multiple filters and number of threshold values. Such data are needed to relate spatiotemporal drainage patterns to observed changes in many northern rivers. We demonstrate our approach using data from the Simojoki River catchment (3,160  km2) in northern Finland. The catchment is dominated by forests and peatlands that were almost all drained after 1960. For two representative locations in cultivated peatland (downstream) and peatland forest (upstream) areas of the catchment; we found total ditch length density (km/km2), estimated from aerial images and LIDAR data based on our proposed algorithm, to have varied from 2% to 50% compared with the monitored ditch length available from the National Land survey of Finland (NLSF) in 2018. A different pattern of source variation in ditch network density was observed for whole-catchment estimates and for the available drained-peatland database from Natural Resources Institute Finland (LUKE). Despite such differences, no significant differences were found using the nonparametric Mann-Whitney U test with a 0.05 significance level based on the samples of pixel-identified ditches between (1) aerial images and NLSF vector files and (2) LIDAR data and NLSF vector files.
  • Finér, Leena; Lepistö, Ahti; Karlsson, Kristian; Räike, Antti; Härkönen, Laura; Huttunen, Markus; Joensuu, Samuli; Kortelainen, Pirkko; Mattsson, Tuija; Piirainen, Sirpa; Sallantaus, Tapani; Sarkkola, Sakari; Tattari, Sirkka; Ukonmaanaho, Liisa (Elsevier, 2021)
    Science of The Total Environment 762 (2021), 144098
    More reliable assessments of nutrient export to surface waters and the Baltic Sea are required to achieve good ecological status of all water bodies. Previous nutrient export estimates have recently been questioned since they did not include the long-term impacts of drainage for forestry. We made new estimates of the total nitrogen (N), total phosphorus (P) and total organic carbon (TOC) export from forests to surface waters at different spatial scales in Finland. This was done by formulating statistical equations between streamwater concentrations and climate, soil, forest management and runoff variables and spatial data on catchment characteristics. The equations were based on a large, long-term runoff and streamwater quality dataset, which was collected from 28 pristine and 61 managed boreal forest catchments located around Finland. We found that the concentrations increased with temperature sum (TS), i.e. from north to south. Nitrogen, P and TOC concentrations increased with the proportion of drained areas in the catchment; those of N and TOC also increased with the proportion of peatlands. In contrast, with the increasing concentrations of N and TOC with time, P concentrations showed a decreasing trend over the last few decades. According to our estimates, altogether 47,300 Mg of N, 1780 Mg of P and 1814 Gg of TOC is transported from forest areas to surface waters in Finland. Forest management contributes 17% of the N export, 35% of the P export and 12% of the TOC export. Our new forest management export estimates for N and P are more than two times higher than the old estimates used by the environment authorities. The differences may be explained by the long-term impact of forest drainage. The spatial results indicate that peatland forests are hotspots for N, P and TOC export, especially in the river basins draining to the Gulf of Bothnia.
  • Silvola, Jouko; Välijoki, Jukka; Aaltonen, Heikki (Suomen metsätieteellinen seura, 1985)
    At sites in SE Finland, hourly respiration varied mainly in the range 100-500 mg CO2/msuperscript 2 with changes following those in soil surface temp. with a time lag of 3 h. After groundwater table was reduced by about 0.5 m, respiration increased 2.5-fold (resulting in a rate of peat decomposition considerably in excess of the rate of production of new organic matter in the peat). Application of fast-dissolving PK or urea rapidly increased soil respiration at the site poorest in nutrients. Ash gave the greatest steady increase. At sites rich in nutrients, fertilizer treatment reduced soil respiration for 1-2 yr. Treatment with micronutrients caused an intial reduction in respiration followed by a pronounced increase.
  • Kinnunen, Oona; Hjerppe, Turo; Väisänen, Sari (Suomen ympäristökeskus, Samassa Vedessä -hanke, 2021)
  • Hynninen, Pekka; Sepponen, Pentti (Suomen metsätieteellinen seura, 1983)
  • Heikurainen, Leo; Päivänen, Juhani; Sarasto, Juhani (Suomen metsätieteellinen seura, 1964)
  • Heikurainen, Leo (Suomen metsätieteellinen seura, 1967)
  • Tertsunen, Jermi; Martinmäki, Kati; Heikkinen, Kaisa; Marttila, Hannu; Saukkoriipi, Jaakko; Tammela, Simo; Saarinen, Tuomas; Tolkkinen, Mikko; Hyvärinen, Marja; Ihme, Raimo; Yrjänä, Timo; Klöve, Björn (Suomen ympäristökeskus, 2012)
    Suomen ympäristö 37/2012
    Sanginjoki, Oulujoen alin sivujoki, on Oulun seudun tärkeimpiä virkistysalueita ja Merikosken kalatietä lähin potentiaalinen vaelluskalojen nousualue. Joen ajoittainen happamuus kuitenkin heikentää Sanginjoen virkistyskäytöllistä ja ekologista arvoa. Kaupunki ja vesi – Sanginjoen virkistyskäyttöarvon parantaminen ja ekologinen kunnostus (2008-2011) -hankkeessa selvitettiin Sanginjoen happamuuden alkuperää, seurattiin laajasti eri alueilta jokeen laskevien valumavesien pH:n muutoksia sekä testattiin menetelmiä happamien huuhtoumien ennaltaehkäisyyn ja neutralointiin. Tulosten perusteella laadittiin toimenpidesuunnitelma happamuuden ehkäisemiseksi sekä happamuuden aiheuttamien haittojen lieventämiseksi. Julkaisussa on myös esitetty tietoa Sanginjoen ja sen valuma-alueen ominaisuuksista, joen ekologisesta tilasta, vedenlaadun kehityksestä sekä happamuuden ehkäisemiseen soveltuvista menetelmistä. Tulosten perusteella Sanginjoen veden happamuus usein voimistuu virtaamien kasvaessa. Etenkin kesä- ja syyssateiden yhteydessä havaittiin alhaisia pH-lukemia, joihin vaikuttivat maaperä, kasvillisuus ja maankäyttö. Hapan huuhtouma on pääosin peräisin turvepitoisten maiden orgaanisesta huuhtoumasta, mutta paikallisesti vedenlaatuun voivat vaikuttaa alueella esiintyvät happamat sulfaattimaat ja mustaliuskealueet. Sanginjoen vesi on ollut myös luontaisesti hapanta lähinnä suo- ja turvemaiden happamien valumavesien johdosta, mutta happamuus on todennäköisesti lisääntynyt ihmistoiminnan vaikutuksesta. Sanginjoen valuma-alueella testattujen vesiensuojelu- ja kunnostusmenetelmien vaikutukset happamien valumavesien neutraloinnissa vaihtelivat, mutta osa menetelmistä osoittautui käyttökelpoiseksi ja niitä voidaan suositella käytettävän jatkossa niin Sanginjoella kuin vastaavilla happamuudesta kärsivillä kohteilla. Menetelmien kehittämistä ja erityisesti vaikutusten seurantaa tulee kuitenkin edelleen jatkaa. Hankkeessa testatut menetelmät ovat keinoja ihmistoiminnasta aiheutuvan happamuuden lisääntymisen torjunnassa. Parhaiten Sanginjoen ja muiden happamuudesta kärsivien vesistöjen hapanta kuormitusta ehkäistään huomioimalla maankäytössä happamuuden kannalta kriittisten turve- ja sulfidipitoisten alueiden ominaisuudet ja sijoittuminen jo ennen maankäytön toimenpiteitä ja kuormituksen syntymistä.
  • Päivänen, Juhani (Suomen metsätieteellinen seura, 1973)
  • Metsänheimo, U. (Suomen metsätieteellinen seura, 1934)
  • Mälkönen, Eino; Paavilainen, Eero (Suomen metsätieteellinen seura, 1985)
  • Rantonen, Harri; Päivänen, Juhani (Suomen metsätieteellinen seura, 1989)