Artikkelit jotka sisältää sanan 'Drainage'
Puustobiomassojen määrä ja hyödyntämismahdollisuudet heikkotuottoisilla mäntyvaltaisilla turvemaan ojitusalueilla.
English title: Biomass utilization potential on low-productive Scots pine (Pinus sylvestris) dominated peatlands drained for forestry.
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Tämän tutkimuksen tavoitteena oli selvittää heikkotuottoisten kitumaan metsäojitettujen soiden biomassapotentiaalia, koska mm. energiaturpeen käytön ennakoimattoman nopea ja raju väheneminen aiheuttaa ainakin lyhyellä aikavälillä merkittäviä paineita puuperäisten polttoaineiden käytön lisäämiselle. Heikkotuottoiset metsäojitetut suot voisivat olla yksi mahdollinen puubiomassareservi. Ojituksen jälkeen näille alun perin avoimille tai vähäpuustoisille soille on syntynyt puustoa, josta usein kuitenkin vain osa on hyödyntämiskelpoista jatkokäyttöön puuraaka-aineena. Energiakäyttöön puu sopisi dimensioidensa puolesta kuitenkin hyvin ja korjuusaantoa lisäisi puun korjaaminen kokopuuna siten, että myös kanto- ja juuristobiomassaa korjattaisiin samalla. Tässä tutkimuksessa selvitettiin heikkotuottoisella turvemaakasvupaikalla kasvavan männikön biomassamääriä Lylynnevan suolla Karviassa. Puut korjattiin kokopuukorjuuna eli kokonaisina runkoina kantoineen ja juurineen. Biomassat määritettiin ositteittain koepuista ja niille laadittiin tilastolliset biomassan ennustemallit. Tarkasteltaviin biomassaositteisiin sisältyvät runkopuubiomassan ohella oksa-, kanto- ja juuribiomassat sekä juurakoiden mukana noussutta suon pintakerroksen kasvibiomassaa, kariketta ja pintaturvetta. Näistä määritettiin biomassaositteiset lämpöarvot. Tulokset suhteutettiin Valtakunnan metsien 11:n inventoinnin (VMI 11) puustotietoaineistoon. Tulostemme mukaan heikkotuottoisilta metsäojitetuilta soilta voitaisiin korjata runsaat 30 miljoonaa tonnia kokopuubiomassaa, jonka lisäksi kariketta ja ns. juurakkoturvetta saataisiin noin 9 miljoonaa tonnia. Lämpöarvoltaan kokopuubiomassa-juurakkoturveseos on hyvin lähellä mäntyrunkopuusta tehtyä haketta. Vaikka käytetty korjuutapa on suhteellisen voimaperäinen puuston ja maanpinnan käsittely, sillä voidaan olettaa olevan pidemmällä aikavälillä merkittäviä luonnonhoidollisia ja maankäytön kokonaiskestävyyttä parantavia vaikutuksia, mikäli alueen seuraava käyttömuoto perustuu vedenpinnan nostamiseen. Heikkotuottoisille ojitusalueille syntyneen biomassareservin eduksi voidaan katsoa myös se, että sen hyödyntäminen ei kilpaile ainespuun tuotannon kanssa.
Metsäojitettujen soiden typpi- ja fosforikuormitus Suomessa.
English title: Forestry on drained peatlands as a source of surface water nitrogen and phosphorus in Finland.
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Viime vuosina julkaistujen tutkimusten mukaan metsäojitettujen soiden vesistökuormituksen epäillään olevan moninkertaisesti aiemmin arvioitua suurempaa. Syynä tähän on se, että kuormitusta syntyy aiemmista käsityksistä poiketen silloinkin, kun ojitusalueilla ei ole vuosikausiin tehty mitään toimenpiteitä. Tässä työssä arvioitiin metsäojitusalueilta syntyvä vesistökuormitus ottamalla huomioon sekä tämä nykyisistä metsätaloustoimenpiteistä riippumaton ”ojituslisä” että kunnostusojituksen, lannoituksen ja hakkuiden aiheuttama kuormitus. Tehdyn arvion mukaan metsätaloudesta ojitetuilla soilla syntyy Suomessa vuosittain typpikuormitusta noin 8 500 Mg ja fosforikuormitusta 590 Mg. Kun ojituslisä otetaan huomioon, typpikuormitus on noin 18-kertainen ja fosforikuormitus 6–7-kertainen aiempiin vain eri toimenpiteiden kuormitukset huomioon ottaviin arvioihin verrattuna. Vesiensuojelun kannalta oleellista olisi selvittää, mitkä tekijät ojitusalueilla aiheuttavat ojituslisän muodossa tapahtuvaa pysyvää kuormitusta ja mitä tämän kuormituksen torjumiseksi on tehtävissä.
Vedenpinnan syvyyden spatiaaliseen vaihteluun vaikuttavat tekijät ojitetussa suometsikössä Pohjois-Suomessa.
English title: Factors affecting the spatial variability of water table depth within a drained peatland forest stand in northern Finland.
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Tutkimuksessa selvitettiin pohjaveden syvyyden spatiaaliseen vaihteluun vaikuttavia tekijöitä puustoisella ojitetulla turvekankaalla viiden kasvukauden ajan Pohjois-Suomessa. Tutkimusaineisto kerättiin Rovaniemellä sijaitsevalta Sattasuon pieneltä keinotekoiselta valuma-alueelta (0,53 ha), joka oli muodostettu eristämällä alue ympäristöstään kaksinkertaisella ojituksella. Valuma-alueen puusto oli hoidettua nuorta kasvatusmetsää, jonka pääpuulajina oli mänty ja puuston keskitilavuus oli 93 m3 ha-1. Kasvupaikkatyypiltään alue oli puolukkaturvekangasta. Alueella seurattiin vedenpinnan syvyyttä 50 pohjavesiputkesta viikoittain viiden kasvukauden ajan vuosina 2006–2010. Vedenpinnan syvyyden vaihtelua eri mittauskerroilla selitettiin pohjavesiputken etäisyydellä lähimpään ojaan, puuston määrällä putken ympärillä (ts. puuston vedenkäytöllä) sekä maanpinnan korkeusvaihtelulla. Aineisto käsiteltiin lineaarisella regressioanalyysillä, jossa selittävillä tekijöillä kuvattiin vedenpinnan syvyyttä pohjavesiputkissa kullakin mittaushetkellä. Tulokset osoittivat, että etenkin kasvukauden alussa vedenpinnan syvyyttä suovaluma-alueen sisällä selittävät voimakkaimmin etäisyys lähimpään ojaan sekä maanpinnan topografia. Puuston määrä (pohjapinta-ala 2 m:n etäisyydellä mittauspisteestä) selitti vedenpinnan syvyyden vaihtelua loppukesällä keskimääräistä kuivempina vuosina. Vedenpinnan syvyys lisääntyi keskimäärin 1 cm:llä, kun puuston pohjapinta-ala kasvoi 4,7 m2 ha–1 (mitattuna 2 m säteellä pohjavesiputkesta) tai kun pohjavesiputken etäisyys ojaan pieneni metrillä. Tulokset vahvistavat aiempaa käsitystä, että pohjoisissa olosuhteissa ojilla on tärkeä merkitys vettä poisjohtavina rakenteina ja puuston määrän tulisi olla suurempi kuin Sattasuon puuston määrä, jotta kuivatustilan ylläpitäminen voisi perustua pelkkään puuston vedenkäyttöön.
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Haahti,
Kersti Haahti, Department of Civil and Environmental Engineering, Aalto University School of Engineering, P.O. Box 15200, FI-00076 Aalto, Finland, e-mail: kersti.haahti@aalto.fi, tel. +358 41 547 5607
Sähköposti:
ei.tietoa@nn.oo
- Koivusalo, Sähköposti: ei.tietoa@nn.oo
- Hökkä, Sähköposti: ei.tietoa@nn.oo
- Nieminen, Sähköposti: ei.tietoa@nn.oo
- Sarkkola, Sähköposti: ei.tietoa@nn.oo
Kasvihuonekaasujen diffuusio kuivatuskanavissa trooppisilla soilla.
English title: Diffusion GHG fluxes at tropical peatland drainage canal water surfaces.
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Data on greenhouse gas (GHG) exchange between water surfaces and the atmosphere above tropical peatland drainage canals are lacking in the literature. We quantified diffusion fluxes of CO2, CH4 and N2O between the water surface and the atmosphere for two typical reclaimed peatland sites. One site was an industrial pulp wood plantation in the Kampar Peninsula (Sumatra) and the other was an abandoned peatland area in Kalimantan (Borneo). Drainage canal fluxes were measured by using floating closed chambers during both the wet and dry seasons. Fluxes at the sites were determined across a range of conditions that were created by varying land use histories, and also by canal biotic environment and hydrological features. Gas fluxes in the canal systems were influenced by their respective surrounding peatland areas, the season, and canal management. Fluxes of all three gases were higher at the more recently reclaimed settled (undisturbed) canals of the Kampar site in comparison to the Kalimantan site. In general, the mean flux from the canals ranged from 9–16, 0.1–1.1 and 0–0.003 g m–2 d–1 for CO2, CH4 and N2O, respectively. A cumulative equivalent annual emission of these three GHGs from canals was nearly three times higher at the Kampar site (13.8 kg CO2 e m–2 y–1) than that at the Kalimantan site (4.8 kg CO2 e m–2 y–1). Mean fluxes of the three gases and the cumulative annual emission at the Kampar site were higher in the settled canals in comparison to the disturbed canals when both dry and wet season fluxes were calculated. The fluxes of CH4 and N2O especially decreased when canals had been recently cleaned (i.e. were in disturbed condition). In terms of their relative global warming potentials (GWP), CO2 was the most important of the three GHG’s both at the Kalimantan site settled canal (69% of the fluxes were attributed to CO2) and at the disturbed canals at the Kampar (82%) site, whereas CH4 dominated in settled canals at the Kampar site at 61% contribution to the total annual emission. CH4 contributed 31% to the total cumulative equivalent annual emission at the Kalimantan settled canal. N2O had only a minor role (0–2% of the cumulative fluxes) at the sites. On a unit area basis, GHG emissions from the drainage canals formed were generally higher emission sources in comparison to the surrounding peatland, and proportional contributions from the three GHG species to the total were more diverse in canals than on land.
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Jauhiainen,
Jyrki Jauhiainen, Department of Forest Sciences, University of Helsinki, P.O. Box 27, 00014 University of Helsinki, Finland, e-mail: jyrki.jauhiainen@helsinki.fi
Sähköposti:
ei.tietoa@nn.oo
- Silvennoinen, Sähköposti: ei.tietoa@nn.oo
Pääravinnesuhteet ja kaliumin riittävyys karujen rämeiden ojitusalueilla.
English title: Macronutrient ratios and sufficiency of soil potassium in drained nutrient-poor Scots pine peatlands.
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Tutkimuksen tavoitteena oli selvittää turpeen ja nykypuuston kaliumvarojen määrä sekä arvioida kaliumvarojen riittävyys puuston kasvulle päätehakkuuvaiheessa ja toisen puusukupolven aikana vanhoilla varputurvekankaan (Vatkg) ojitusalueilla Lounais-Suomessa. Tarkoituksena oli arvioida, voiko osalla karuista varputurvekankaista kalium loppua jo ennen päätehakkuuvaihetta tai viimeistään toisen puusukupolven aikana. Puustoon oli mittaushetkellä sitoutunut kaliumia keskimäärin 62 % (23–106 %) turpeen kaliumvarastoon verrattuna. Jos kiertoajan kokonaistuotokseksi arvioidaan 200 m3 ha–1, eikä turpeen tiivistymisen tai laskeuman mahdollista vaikutusta kaliummäärien muutoksiin huomioida, oli pintaturpeessa keskimäärin 67 % (34–96 %) siitä kaliummäärästä, jonka puusto tarvitsee tuon kokonaistuotoksen maanpäällisen biomassan saavuttamiseksi. Kaliumin riittävyys nykypuuston koko kiertoajalle sekä seuraavan puusukupolven tarpeisiin riippuu paljolti siitä, pystyvätkö ilmasta tuleva kalium ja turpeen tiivistyessä konsentroituva kalium kompensoimaan hakkuun ja huuhtoutumisen aiheuttamat menetykset. Tarkastelu osoittaa, että myös karuilla rämeillä käytettävissä olevan kaliumin määrä saattaa rajoittaa puuston kehitystä. Vähiten kaliumia sisältävien turpeiden kasvupaikoilla ongelmia voi ilmetä jo ensiharvennuksen jälkeen, eikä kalium ehkä riitä edes tavoiteltuun 200 m3 ha–1 kokonaistuotokseen. Kaliumin riittävyyden ongelma lienee pahin niillä varputurvekankailla, jotka ovat lähtöisin runsaasti nevapintaa sisältäneistä lyhytkorsirämeistä (LkR).
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Saarinen,
Markku Saarinen, Metsäntutkimuslaitos, Länsi-Suomen alueyksikkö, Kaironiementie 15, FI-39700 Parkano, email: markku.saarinen@metla.fi
Sähköposti:
ei.tietoa@nn.oo
- Silver, Sähköposti: ei.tietoa@nn.oo
Vedenpinnan muutoksen lyhytaikaiset vaikutukset hiilidioksidi- ja metaanipäästöihin peittosuolla.
English title: The short-term effect of altered water level on carbon dioxide and methane fluxes in a blanket bog.
Avainsanat:
Sphagnum;
Drainage;
peatland;
methane;
flooding;
ecohydrology;
photosynthesis;
respiration;
Racomitrium;
Rhynchospora alba
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Peatlands play an important role in the global carbon (C) cycle, by acting as a large, long-term C sink. The C sink is sustained by a high water level that inhibits decomposition of organic matter. The C gas dynamics are therefore sensitive to changes in water level, and in climatically different years a peatland can vary from a sink to a source of C. We measured carbon dioxide (CO2) and methane (CH4) fluxes from vegetation communities ranging from hummocks to low lawns in a blanket bog. After a one-year calibration period the water level was both lowered and raised experimentally and the changes in vegetation composition and gas fluxes were monitored during a further year. In all vegetation communities the water level drawdown increased the respiration rate and decreased methane emission; rising water level decreased respiration and increased methane emissions. The effect of altered water level on photosynthesis depended on species composition. Water level drawdown decreased photosynthesis in most communities; rising water level decreased the photosynthesis of hummocks species, and increased the photosynthesis of Rhynchospora alba.
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Laine,
Anna M. Laine, Department of Civil and Environmental Engineering, University College Cork, Cork, Ireland; University of Oulu, Oulu, Finland, P.O. Box 3000, 90014 University of Oulu, telephone: +358 8 5531521, email: anna.laine@oulu.fi
Sähköposti:
ei.tietoa@nn.oo
- Byrne, Sähköposti: ei.tietoa@nn.oo
- Kiely, Sähköposti: ei.tietoa@nn.oo
- Tuittila, Sähköposti: ei.tietoa@nn.oo
Pinus sylvestris L. stands in three fertilized and drained peatlands in northern Finland.
English title: The effect of total peat nitrogen on the height and volume of Scots pine.
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The total peat nitrogen (N) concentration is an important factor when determining stand heights and volumes in areas of poor climate conditions. This study explores the effect of peat nitrogen on the height and volume of Scots pine (Pinus sylvestris L.) stands in drained peatland sites in three temperature sum regions (Susivaara 909, Hepokangas 930, and Haapua 987 dd) in northern Finland. The peat nitrogen concentration ranged from 0.7% to 3.0%. In all experimental fields, the concentrations of foliar nutrients (nitrogen (N), potassium (K), phosphorus (P), and boron (B)) were analyzed. A total of 550 peat samples, 440 foliar samples, and 1687 sample trees were measured. We found nitrogen deficiencies in the foliar samples of all experimental fields. At Haapua, the stands were the highest, about 140 dm, when the peat N-concentration was at its maximum (3.0%). In the areas of Susivaara and Hepokangas, the stand heights were lower than in Haapua, about 90 dm, when N-concentrations of peat were at their maximum (2.5% and 2.8%). The stand volumes were largest at Haapua (about 190 m3/ha, N = 3.0%). At Susivaara (80 m3/ha, N = 2.5%) and Hepokangas (70 m3/ha, N = 2.8%), lower stand volumes were measured. We found a strong positive relationship between peat N-concentration and stand height as well as stand volume at Hepokangas and Haapua. At Susivaara, however, this relationship was weak. The results show that the total peat nitrogen concentration strongly affects stand height and volume on drained peatlands. The information of this study can be utilized, for example, when assessing the feasibility of forest management practices, such as the profitability of ditch network maintenance and fertilizations on peatlands.
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Korkalainen,
University of Joensuu, Department of Geography, P.O. Box 111, 80101 Joensuu, Finland
Sähköposti:
ei.tietoa@nn.oo
- Pietiläinen, Sähköposti: ei.tietoa@nn.oo
- Colpaert, Sähköposti: ei.tietoa@nn.oo
Fosforin ainekierto rämemännikön puustossa ja pintakasvillisuudessa ojituksen jälkeen.
English title: Post-drainage dynamics of P uptake by trees and ground vegetation in Scots pine dominated peatlands.
Avainsanat:
mire;
secondary succession;
ecosystem functioning;
drainage for forestry;
nutrient cycling;
nutrient upatake;
Pinus sylvstris
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We investigated long-term dynamics of phosphorus (P) in ground vegetation, tree stand biomass and litterf all in two undrained and four drained oligotrophic pine fens in southern Finland. The study sites, which encompassed observation periods up to six decades after drainage, were chosen to form a chronosequcncc of sites initially similar floristically, showing different stages of the forest succession induced by drainage. The pattern of P allocation to above- and below-ground plant biomass followed the changes in growth form dominance from mosses, graminoids and shrubs to trees. Overall, net vascular plant uptake of P increased after drainage and remained on a higher level compared to that in the pristine fen. The amount of P in the drained ecosystem seems to remain high enough to support the uptake and continuing forest succession.
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Laiho,
Peatland Ecology Group, Department of Forest Ecology, University of Helsinki, P.O. Box 27, FI-00014 Helsinki University, Finland
Sähköposti:
ei.tietoa@nn.oo
- Penttilä, Sähköposti: ei.tietoa@nn.oo
- Vasander, Sähköposti: ei.tietoa@nn.oo
- Laine, Sähköposti: ei.tietoa@nn.oo
Kavillisuus puutomana pidetyllä metsäojitusalueella.
English title: Vegetation on an artificially treeless drained mire.
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In this study the vegetation composition of a drained mire that was partly forested and partly kept treeless was compared. The study site was a low sedge fen near the town Oulu in west central Finland. Drainage was carried out in the 1930s. A power transmission line was drawn through the fen in 1956. The area under the line was kept treeless through repeated cleanings. In summer 2004 the vegetation was inventoried on a study area half of which was on the treeless and half on the forested part. The forested and treeless parts were similar with respect to mire site type, depth of peat layer and efficiency of drainage. Therefore the effect of the tree stand on the vegetation on the forested part was obvious. The secondary succession of the vegetation had been significantly slower on the treeless part. Practically no forest moss species, but also fewer Sphagnum moss species were found on the treeless part. On the other hand, a number of sedge-like plants were found only there. With regard to species number and coverage, the largest group was dwarf shrubs, especially on the forested part.
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Silfverberg,
Metsäntutkimuslaitos, Vantaan toimintayksikkö (Finnish Forest Research Institute, P.O. Box 18) PL 18, FIN- 01301 Vantaa, Finland
Sähköposti:
ei.tietoa@nn.oo
- Seväkivi, Sähköposti: ei.tietoa@nn.oo
Vedenpinnan nousu avohakkuun jälkeen ojitetulla puustoisella suolla.
English title: Water table rise after harvesting in treed fen previously drained for forestry.
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Water table measurements were obtained in a treed fen that was drained in 1987 and harvested for timber in 1997. The water table level was quantified at five different distances from the ditch for three ditch spacing. Water table levels were compared between pre-drainage, post-drainage and post-removal of the canopy. The phenomenon of watering-up after clear-cutting did not occur where a drawdown of at least 10 cm was caused by the drainage. This lowering was observed across the 20 m ditch spacing and within the first 6 m from the ditch, in the 40 and the 60 m spacing. The water table fluctuations were also reduced after harvesting.
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Jutras,
Forest Biology Research Centre, Université Laval, Sainte-Foy, QC G1K7P4 Canada
Sähköposti:
ei.tietoa@nn.oo
- Plamondon, Sähköposti: ei.tietoa@nn.oo
Pitääkö kaikkein happamimmat sulfaattimaat poistaa viljelystä?
English title: Should the cultivation of the most acidic sulphate soils be stopped?
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Estimates of the area of cultivated acid sulphate soils in Finland range from 50,000 ha to 336,000 ha. In these soils, sulfides are oxidized to sulphuric acid upon aeration, which is promoted by drainage. Agricultural use of these soils requires abundant liming. Acidic drainage waters impact the aquatic life negatively. Early research concentrated on the agricultural utilization of acid sulphate soils while more recently environmental aspects have been emphasized. Controlled drainage, aiming at a high water table, is considered an option for the management of acidity. Owing to evapotranspiration, however, sulfidic layers may be exposed to oxidation every summer in spite of controlled drainage. Successful submerging of sulfidic layers may require pumping of water to the field from outside sources. Abandoning the most acidic sulphate soils and stop draining them would prevent further oxidation of sulfides. This is a sensitive issue, because the farmland is private property. Moreover, it is not exactly known where the most acidic sulphate soils are located and how their abandonment would impact the quality of water in recipient rivers.
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Yli-Halla,
MTT Agrifood Research Finland, Environmental research, FIN-31600 Jokioinen, Finland
Sähköposti:
ei.tietoa@nn.oo
Kasvillisuuden ja maanmuokkauksen vaikutus männyn ja koivun taimettumiseen varpu- ja puolukkaturvekankaille.
English title: Effect of vegetation and site preparation on the restocking of Scots pine and birch in dwarf-schrub and Vaccinium vitis-idaea type peatland forests.
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The study deals with the natural regeneration of Scots pine (Pinus sylvestris) and birch (Betula pendula & B. pubescens) on ten experimental fields on peatland sites drained for forestry, mainly during the 1930s. The principal goal of the study was to investigate the effect of different types of natural ground vegetation on the restocking of pine and birch following site preparation (rotavation and mounding) on old drainage areas. Rotavation, which corresponds to disc trenching on upland forest soils, is capable of producing fully-stocked pine stands. The effect of surface treatments such as rotavation depends, however, on the predominant ground vegetation. Sphagnum moss patches are often well restocked even when not prepared, which means that site preparation often only has an effect on transformed Pleurozium and Dicranum vegetation. The success of rotavation has also encouraged forest owners to use other alternative methods of surface treatment such as mounding. The tree seedlings tend to be concentrated on the surface of the furrows produced by rotavation, which means that restricting digger-scarification to the topmost surface of the soil on well-drained regeneration sites can produce the same result; the required machinery is usually already present at the site for ditch network maintenance.
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Saarinen,
The Finnish Forest Research Institute, Parkano Research Station, Kaironiementie 54, 39700 Parkano, Finland
Sähköposti:
ei.tietoa@nn.oo
Kunnostusojituksen vaikutus rämemänniköiden kehitykseen.
English title: Effects of maintaining ditch networks on the development of Scots pine stands.
Avainsanat:
forest drainage;
peatland;
ditch cleaning;
complementary ditching;
tree stand;
Pinus sylvestris L.;
volume growth
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This study aimed at finding out the effects of maintaining ditch systems by ditch cleaning and complementary ditching on volume growth of drained Scots pine (Pinus sylvestris L.) stands. Volume growth during the first ten post-treatment years was increased by 0.16 m3 ha-1 a-1 after ditch cleaning, 0.36 m3 ha-1 a-1 after complementary ditching, and 0.48 m3 ha-1 a-1 after the combined treatment. The average growth reactions during the second five-year period were considerably higher than during the first one. No drastic reductions in stand growth, however, occurred in the untreated plots during the post-treatment period of ten years.
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Lauhanen,
The Finnish Forest Research Institute, Kaironiementie 54, FIN-39700 Parkano, Finland
Sähköposti:
ei.tietoa@nn.oo
- Ahti, Sähköposti: ei.tietoa@nn.oo
Raakahumuksen ja kasvillisuuden yhteisvaihtelu Pohjois-Hämeen vanhoilla ojitusalueilla.
English title: Covariation between raw humus layer and vegetation on peatlands drained for forestry in western Finland.
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The occurrence of raw humus layer and its relationship to the structure of the vegetation and the environmental variables were studied on 501 sample plots located systematically in drained peatland forests. The drainage had been done in the 1930s – 60s. The correlation between the amount of raw humus and the two-dimensional GNMDS (global nonmetric multidimensional scaling) ordination space was 0.57. The thickness of the raw humus layer increased in the direction of the drainage succession gradient. The correlations between the thickness of the raw humus and the measured environmental variables were weak. The strongest correlation was with the stand volume (0.31) and the drainage age (0.21). Weakness of these correlations was most probably due to the regressive succession on many plots. On average, the raw humus layer was thickest , 6.5 cm, in Vaccinium vitis-idaea transformed type I (developed from genuine forested mires) and 5.4 cm in type II (developed from treeless or composite types). In Vaccinium myrtillus types the corresponding mean thickness was 5.2 cm (I) and 3.2 cm (II) and in dwarf-shrub types 3.3 cm (I) and 4.6 cm (II). The secondary succession is slower and the amount of the needle litter (of Pinus sylvestris) smaller in the dwarf-shrub type than in the V. vitis-idaea type. In the V. myrtillus type the origin of the litter is more dominated by deciduous trees, the decomposition faster and the coverage of Pleurozium schreberi clearly smaller than in the nutrient-poorer types. P. schreberi tolerates the litterfall well and together with especially conifer litter, and maybe with slow decaying fine roots, too, it forms a loose raw humus layer on old drained peatlands. Being a poor germination bed, the raw humus makes successful stand regeneration difficult.
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Saarinen,
The Finnish Forest Research Institute, Parkano Research Station, Kaironiementie 54, FIN-39700 Parkano, Finland
Sähköposti:
ei.tietoa@nn.oo
- Hotanen, Sähköposti: ei.tietoa@nn.oo
The effect of thinning and ditch network maintenance on the water table level in a Scots pine stand on peat soil.
Avainsanat:
forest drainage;
peatland;
hydrology;
ditch cleaning;
complementary ditching;
tree harvesting
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The effect of tree stand thinning and ditch network maintenance on the water table level was studied in an uneven-aged Scots pine (Pinus sylvestris L.) stand growing on a drained dwarf shrub pine bog in southern Finland. The water table level was monitored once a week during the growing seasons (May–September) of 1991–1999. This time span is divided into the following treatment periods: calibration (1991–1992), thinning (1993–1994), ditch cleaning (1995), and proper ditch network maintenance (1996–1999). The growing season of 1995 was not included in the calculations because the ditch cleaning treatment failed. The layout included three thinning intensities (9.5, 15.0, and 28.1% removal of the initial stand volume) and an unthinned control. For the ditch maintenance treatment there was an additional control sample plot. The effect of the treatments on the water table level was evaluated both by a graphical approach and linear regression analysis. Only a slight, ecologically insignificant rise in the water table level was caused by the thinning cuttings. Ditch maintenance seemed to eliminate this change. It was concluded that in the planning stage, a careful evaluation of the real need of maintaining the ditch network (ditch cleaning or complementary ditching) should be done in connection with the first commercial thinning in order to avoid unnecessary costs.
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Päivänen,
Department of Forest Ecology, Box 24, FIN-00014 Helsinki University, Finland
Sähköposti:
ei.tietoa@nn.oo
- Sarkkola, Sähköposti: ei.tietoa@nn.oo
Effect of peat harvesting on peat hydraulic properties and runoff generation.
Avainsanat:
peatlands;
Drainage;
runoff generation;
hydrological pathways;
hydraulic conductivity;
shear strength;
soil loss;
subsidence;
peak runoff
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Peat hydraulic conductivity, shear strength, plant composition and runoff at seven peat harvesting sites in Central Finland were measured. A large variation in hydraulic conductivity (10–8–10–6 m s–1 ), peat shear strength (302–413 kPa), and peak runoff (97–898 l s–1 km–2 ) was observed between different harvesting sites. The hydraulic conductivity showed a clear correlation with peat shear strength (r = –0.89), which has not been previously observed. The correlation between hydraulic conductivity and degree of humification was weak (r = 0.60). Soil lowering decreased the hydraulic conductivity and the peat shear strength. These reductions, with reduced drainage depths, increased peak flow and changed runoff generation patterns by increasing the possibility of Horton and saturation excess overland flow.
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Kløve,
Jordforsk, Norwegian Centre for Soil and Environmental Research, 1432 Ås, Norway
Sähköposti:
ei.tietoa@nn.oo
Kunnostusojitustarpeen ennustaminen ojitusalueilla.
English title: Predicting the need for ditch network maintenance in drained peatland sites in Finland.
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Logistic regression models were developed to predict the condition of ditch networks in drained peatland sites in Finland. The data consisted of observations from two forest inventories in which the need for ditch network maintenance had been assessed in the field by classifying the condition of the ditches in the sample stands. In the analysis an indicator variable which referred to one of two condition categories (in need of repair – not in need of repair) was used as the response variable. According to the results, the probability of being in the poor condition category was higher in sites where the time elapsed since drainage was longer, the geographic location was more northern, peat thickness was greater, and plot inclination was smaller. At a probability level of 0.5, the models predicted the category correctly in 69% of the sites in the modeling data, on average. The models were applied to a growth simulator to study the effect of poor drainage conditions on stand-level growth forecasts.
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Hökkä,
Finnish Forest Research Institute, Rovaniemi Research Station, P.O. Box 16, FIN-96301 Rovaniemi, Finland
Sähköposti:
ei.tietoa@nn.oo
- Alenius, Sähköposti: ei.tietoa@nn.oo
- Salminen, Sähköposti: ei.tietoa@nn.oo
Kunnostusojituksen vaikutus rämeiden ravinnetilaan.
English title: Effect of drainage maintenance on the nutrient status on drained Scots pine mires.
Avainsanat:
forest drainage;
peat;
Scots pine;
ditch cleaning;
complementary ditching;
nutrients;
needles
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The effects of drainage maintenance on the nutrient contents in peat and Scots pine needles on drained pine mires were studied. The material consisted of twelve Finnish field experiments. Drainage maintenance (increasing ditching intensity; no treatment at all, mere ditch cleaning, mere complementary ditching, and both of them together) was carried out in 1982-1985. The needles were sampled in 1994-1995 and peat in 1996. There were great differences in the site types and consequently also in the peat and needle nutrient concentrations between the experiments. The needle Mn concentrations demonstrated a fairly good drainage status in all the treatments. Drainage maintenance had only minor effects on the nutrient status of peat and needles. Ditch cleaning decreased magnesium, manganese and zink amounts in the surface peat. Increasing the intensity of drainage maintenance increased the 100-needle dry mass, but decreased the needle boron concentrations. Peat and needle nitrogen concentrations increased slightly (not significantly) along with the increased intensity in drainage maintenance. The peat nutrients classified correctly 83.7% of the fertility classes for drained peatlands.
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Lauhanen,
The Finnish Forest Research Institute, Kaironiementie 54, FIN-39700, Parkano, Finland
Sähköposti:
ei.tietoa@nn.oo
- Kaunisto, Sähköposti: ei.tietoa@nn.oo
Karttoja suo-ojitusten vaikutuksesta Suomen ilmastoon.
English title: Charts of the climatic impact of the drainage of mires in Finland.
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Widespread drainage measures, which were carried out mainly in the period 1950-
1990 on Finnish mires, have had significant climatic consequences, part of them being
temporary, part permanent. The aim of this study was to prepare charts of these climatic
effects by combining three sources of knowledge: (I) the climatic effect of drainage (e, °C),
as given by (Solantie 1994, 1998) for a 100% mire area in the climatically most affecting
stage, (2) fresh grid-square statistics of the proportion of drained mires compared
with the total area, and (3) annual statistics of the proportion of drained mires in various
stages having characteristic climatic effects, compiled by the Finnish Forest Research
Institute. Three charts show the maximum cooling effect of peatland drainage in Finland
during the first 15 years after the drainage in the period 1973-1982, as drained
mires in such a stage of drainage were then most common. Two charts show the warming
effect after successful afforestation and canopy closure; the canopy acts as a radiation
shelter and a mixing generator for the air beneath. In the middle boreal natural
zone, that most heavily drained, the mean monthly minimum temperatures in the period
1973-1982 were reduced by 1.5°C and the yearly frost-free period was shortened by 17
days. As a result of successful afforestation, the annual minimum temperature in the
middle boreal zone will be raised by 2°C to 3°C by the year 2005.
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Solantie,
The Finnish Meteorological Institute, P.O. Box 503, FIN-00101 Helsinki, Finland
Sähköposti:
ei.tietoa@nn.oo
Metsätalouden vesistöhaittojen torjuminen ojitetuista soista muodostettujen puskurivyöhykkeiden avulla.
English title: Prevention of detrimental impacts of forestry operations on water bodies using buffer zones created from drained peatlands.
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Before large-scale drainage, the outflowing water from forests was naturally filtered through peatlands. The even topography, dense moss cover and the favourable physical, chemical and biological properties of surface peat facilitate versatile buffering functions in these systems. In addition to retaining suspended solids, peatlands may act as traps for nutrients or harmful metals.
Major part of these buffering systems have been lost as a result of forestry drainage. Restoring drained peatlands, being potentially well suited to act as a buffer zone between forestry land and a watercourse, is the major reason for rewetting outside nature reserves. Potentially each drainage area should include a restored part through which waters both from the drainage area itself and from the surrounding upland forest catchment would be filtered.
Preliminary results from three experimental catchments show that buffer zones restored from drained peatlands may be succesfully used in decreasing the detrimental impacts forestry operations may have on adjacent water courses. Long-term monitoring is, however, required for the quantitative assessment of the buffer efficiency.
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Sallantaus,
Pirkanmaa Regional Environment Centre, P.O.Box 297, FIN-33101 Tampere, Finland
Sähköposti:
ei.tietoa@nn.oo
- Vasander, Sähköposti: ei.tietoa@nn.oo
- Laine, Sähköposti: ei.tietoa@nn.oo
Kunnostusojitustarpeen arviointi Pohjois-Suomessa.
English title: Evaluation of the need for ditch network maintenance in northern Finland.
Avainsanat:
forest drainage;
ditch cleaning;
complementary drainage;
tree stand;
stand growth;
decision making
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Factors affecting the need for ditch network maintenance in northern Finland were studied. In addition, the effect of ditch network maintenance on stand growth was estimated. A dataset containing ditch, tree stand, site type and climate variables was built up on the basis of the permanent sample plots (SINKA) on peatlands. Regression analysis as well as discriminant analysis were used to identify factors and criteria that could be used to identify sites that would respond to ditch network maintenance. Instead of the ditch condition class, ditch age and depth proved to be the variables reflecting the need for ditch network maintenance. The volume of the tree stand was influenced the most by the temperature sum and age of ditching. Stand volume growth was influenced the most by the volume of the tree stand. The site type index or the volume of the tree stand did not give useful information for the planning of ditch network maintenance. When ditch age was 10-40 years, complementary ditching increased annual stand growth of pine mires by 0.6-1.0 and 1.5-1.9 m3 ha-1 a-1 on spruce-birch swamps.
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Lauhanen,
The Finnish Forest Research Institute, Parkano Research Station, FIN-39700 Parkano, Finland
Sähköposti:
ei.tietoa@nn.oo
- Piiroinen, Sähköposti: ei.tietoa@nn.oo
- Penttilä, Sähköposti: ei.tietoa@nn.oo
- Kolehmainen, Sähköposti: ei.tietoa@nn.oo
Kunnostusojituksen erilliskannattavuus muutamilla karuhkoilla rämeillä.
English title: Profitability of ditch-network maintenance on some oligotrophic pine mires.
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The paper presents the results of a study to assess the profitability of ditch-network maintenance on some oligotrophic pine mires. The alternative ditch-network maintenance methods compared were: ditch cleaning, complementary ditching, and ditch cleaning and complementrary ditching combined. Nine drained pine-dominated mires were chosen for investigation. Only the ditch-network maintenance costs were included in the calculations. Profitability was calculated for two cases: 1) the forest owner pays all the costs and 2) he obtains the maximum state grant. Without the state grant ditch-network maintenance provided a net present value of 870 FIM ha-1 with a 3 % rate of interest, of 220 FIM ha-1 with the 5 % rate of interest, and on internal rate of return of 5 %. With the state grant the results were: 1620 FIM ha-1, 970 FIM ha-1 and 10%, respectively. The conclusions were that in most cases ditch-network maintenance is profitable even without state grant. By using 3 % and 5 % interest rates, the complementary ditching and combination provided similar profitability, specially when the state grants were provided. Using the IRR criterion, the complementary ditching provided the best profit.
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Hytönen,
Finnish Forest Research Institute, Kannus Research Station, P.O. Box 44, FIN-69101 Kannus, Finland
Sähköposti:
ei.tietoa@nn.oo
- Aarnio, Sähköposti: ei.tietoa@nn.oo
Ojien mitoitus kunnostusojituksessa. Kirjallisuustarkastelu.
English title: Ditch dimensioning in ditch-network-maintenance areas. A literature review.
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Drainage of pristine mires has been discontinued in Finland and now drainage activity focuses on remedial treatment of old ditch networks on transformed drained mires. In the era of first-time drainage, uniform regulations were applied in the dimensioning of ditches. Also the current national recommendations pertaining to remedial drainage and the dimensioning of ditches corresponds to the old regulations applied in first-time drainage. However, regional organizations have their own directives, and accordingly ditch depths show considerable regional variation. The purpose of this paper is to look for answers to questions which have arisen already some years ago, especially among practitioners responsible for forest-improvement works in non-industrial, private woodlots: Can the service life of ditch networks be increased by means of ditches which are deeper than those implemented at the time of first-time drainage and will this also result in a reduced impact on water ecosystems by reducing the number of remedial actions needed ? Is ditch depth in old, well-stocked drainage areas a more important factor than ditch spacing in controlling the drainage depth?
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Saarinen,
The Finnish Forest Research Institute, Parkano Research Station, Kaironiementie 54, FIN-39700 Parkano, Finland
Sähköposti:
ei.tietoa@nn.oo
- Silver, Sähköposti: ei.tietoa@nn.oo
- Joensuu, Sähköposti: ei.tietoa@nn.oo
Kasvupaikkatekijöiden vaikutus vanhojen ojitusalueiden taimettumiseen Kirjallisuuteen perustuva tarkastelu.
English title: Effect of site factors on restocking of old drainage areas. A literature review.
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The rate of renewal of forests on drained peatlands in Finland will undergo a rapid rise in the near future as a large amount of these forests is approaching their renewal age. Indeed, forest renewal increasingly calls for familiarity with the special characteristics of peatland habitats. These special characteristics making them different from upland sites are primarily connected to hydrology, temperature conditions, nutrient status, and to changes in the composition of the ground vegetation. This literature review is focused on the effects of these site factors on the germination of tree seeds and the initial development of seedlings on different seedbeds.
Key words: drainage areas, natural regeneration, peatlands
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Saarinen,
Finnish Forest Research Institute, Parkano Research Station, Kaironiementie 54, FIN-39700 Parkano, Finland
Sähköposti:
ei.tietoa@nn.oo
Suometsien rakenne-erot keskisessä Suomessa.
English title: The structure of virgin and managed peatland forest stands in central Finland.
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The structure of peatland forests were compared between different site quality classes, drainage phases, and different forest ownership groups. The comparisons and statistical tests were made in terms of the number of tree species, range of diameter distribution and the estimated number of tree storeys, separately for spruce- and pine-dominated mires. The statistical tests were performed with multivariate analysis of variance and covariance. Tree storeys were estimated with objective rules from the peaks of continuous diameter distribution smoothed by the non-parametric kernel-estimation. The data used from the 8th National Forest Inventory of Finland.
On average the mean values of the chosen stand structure characteristics differed significantly between the site quality classes. The stands had a more diverse structure the more fertile the site was. When examining the differences between the post-drainage succession phases, a decrease of the stand structure diversity was observed in the recently drained peatlands. After this, the mean values of the stand structure characteristics increased and exceeded the values of undrained peatlands at latest in the transformed post-drainage succession stage.
Statistically significant differences in the means of stand structure characteristics between the forest ownership groups were not observed. It seems that drainage and possible cleaning cuttings have been made with the same intensity regardless of the particular forest ownership group. It is also possible that drainage causes so drastic change in growing conditions that small differences in the intensity of cleaning cuttings between forest ownership groups are disappeared.
The results correspond to the results of previous studies which have examined different stand structure characteristics. The forest on drained peatlands maintains an uneven-sized structure for quite a long period after drainage. In order to preserve habitat diversity this structure of the peatland forests should be maintained in subsequent forest management practices.
Key words: drainage, habitat diversity, peatland forest management, structure of forest stand.
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Uuttera,
The European Forest Institute, Torikatu 34, FIN-80100 Joensuu, Finland
Sähköposti:
ei.tietoa@nn.oo
- Maltamo, Sähköposti: ei.tietoa@nn.oo
- Hotanen, Sähköposti: ei.tietoa@nn.oo
Vedenpinnan alenemisen vaikutus sararämeen pintakasvillisuuden biomassaan ja lajistoon.
English title: Changes in understorey biomass and species composition after water level drawdown on pine mires in southern Finland.
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Abstract: Understorey biomass and species composition were analyzed on six sites representing tall sedge pine fen at different stages of secondary succession caused by drainage for forestry. Two of the sites were undrained controls and the other sites had been drained 8 - 55 years earlier. Cyperaceous and herbaceous field layer was found to diminish permanently after drainage, whereas shrub and moss layers survived in the drainage succession in terms of biomass allocation although the species composition changed almost completely. On the oldest drained site the ground vegetation was dominated by typical upland forest species with the exception of Sphagnum russowii. Total understorey biomass varied from 260 g m-2 on sites drained 22-30 years earlier to 990 g m-2 on a site drained 8 years earlier.
Key words: drainage, field layer, ground vegetation, moss layer, peatland, succession
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Laiho,
Department of Forest Ecology, P.O.Box 24, FIN-00014 University of Helsinki, Finland
Sähköposti:
ei.tietoa@nn.oo
Pituusboniteettisovellus ojitusalueiden metsille.
English title: Site index model approach for drained peatland forest stands.
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The site index system presented is intended as support for the idea of developing a more hierarchical and integrated forest classification system in Finland. The data used were obtained from stands growing on old permanent experimental plots laid out in drainage areas in southern Finland. The model, describing the post-drainage development of stand dominant height as a function of drainage age (time elapsed since drainage), is based on successive measurement data (465 observations), collected from 89 plots, each representing a single stand. The site indices H40dr are post-drainage dominant height values 40 years since drainage, given in 2-meter classes. Post-drainage dominant height is defined as the difference between the current dominant height and the dominant height at the time of drainage. In classification work, one needs to know (or measure) the two aforementioned height characteristics, together with age since drainage. If the dominant height at the time of drainage is not known, it can be estimated from a function presented herein and based on current dominant height and drainage age. The mean annual volume increments at 40 years since drainage (MAI40) are also presented. There is still a need for examining separately the accuracy of the model with new data from spruce-, pine- and birch-dominated stands, collected for numerical constructions of site index curves. Therefore, the site index model and its characteristics must be seen more as outlines than as a final system for practical application. A well-functioning ditch network is a default when applying the site index curves.
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Gustavsen,
The Finnish Forest Research Institute, Joensuu Research Station, P.O.Box 68, FIN-80101 Joensuu, Finland
Sähköposti:
ei.tietoa@nn.oo
Sekakoivikon reaktio ensiharvennukseen mustikkaturvekankaalla Lapissa.
English title: Thinning response of a young, birch-dominated mixed stand on Vaccinium myrtillus peatland forest type in Lapland.
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The five-year response of a birch-dominated mixed stand (80% Betula pubescens, 14% Betula pendula) to thinning was studied in a thinning experiment in a mesotrophic, shallow-peated site in Ylitornio, northern Finland. Four thinning intensities (0%, 47%, 57% and 71 % removal of the initial stem number, i.e. 0%, 17%, 27% and 52% removal of the initial basal area), with three replications, were arranged in a randomized block design. At the time of thinning, the stand age was 30 a, and the dominant height was 11.5 m. Light (15%) and normal (27%) thinning decreased the rates of stand-level basal area growth by 12 and 15%, respectively. Thinning resulted in a significant increase in the growth of mean height and a subsequent increase in volume growth in the normally-thinned plots. Following heavy thinning, the volume and basal area growth rates were 35% and 32% less than those in the control treatment. The relative basal area increment, as well as the increase in mean diameter, was at its maximum in the heavily-thinned plots.
Keywords: Betula pubescens, forest drainage, growth, thinning
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Hökkä,
The Finnish Forest Research Institute, Rovaniemi Research Station, P.O.Box 16, FIN-96301 Rovaniemi, Finland
Sähköposti:
ei.tietoa@nn.oo
- Penttilä, Sähköposti: ei.tietoa@nn.oo
Väri-infrakuvat kunnostusojituksen kohdevalinnan tukena.
English title: Usability of infra red imagery in the planning of ditch network maintenance.
Avainsanat:
forest drainage;
biodiversity;
ditch cleaning;
environmental protection;
complementary ditching;
IR imagery;
decision making system
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The purpose of the study was to determine the usability of infra red imagery in evaluating the need for ditch network maintenance on nutrient-poor Scots pine mires. After interpreting a total of 75 tree stands in six peatland areas from the IR imagery, the stands were inventoried in the field. Site type, growing stock and ditch condition were determined. In addition, possible silvicultural treatments were suggested. Sphagnum fuscum, reddish-brown in the imagery indicated ditching areas unsuitable for ditch cleaning or complementary ditching. The estimated mean volumes of the tree stands were -37-+11% of the mean ground inventory values. The true proportions of tree species were in good agreement with the estimations based on the TR imagery. All in all, it was concluded that IR imagery is suitable in evaluating the need for ditch network maintenance on nutrient-poor mires. However, the validity of the method depended on the quality of the imagery and the skill of the interpreter.
Keywords: forest drainage, ditch cleaning, complementary ditching, IR imagery, decision making system, environmental protection, biodiversity
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Lauhanen,
The Finnish Forest Research Institute, Kannus Research Station,FIN-69101 Kannus, Finland
Sähköposti:
ei.tietoa@nn.oo
- Pietiläinen, Sähköposti: ei.tietoa@nn.oo
- Saarinen, Sähköposti: ei.tietoa@nn.oo
- Heikkinen, Sähköposti: ei.tietoa@nn.oo
Harvennushakkuun vaikutus pohjavedenpinnan syvyyteen ojitusalueilla Pohjois-Suomessa.
English title: Effect of thinning on groundwater table depth in drained peatlands in northern Finland.
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The effect of thinning on the groundwater table level was studied in four stands of Scots pine (Pinus sylvestris) on drained peatlands in northern Finland. Four thinning intensities (0-50% removal of the initial stocking), with three replications arranged using a randomized block design, were used in each experiment. If found to be in an unsatisfactory condition, the ditch networks were repaired at the time of thinning. Data from nine groundwater wells on each plot were used to determine the average depth of the groundwater table. The wells were monitored at two-week intervals during the latter parts of the growing seasons in 1991-1993. The mean groundwater table depth was used as the dependent variable in ANOVA with repeated measurements. In most cases, the groundwater table depth was lowest in the control plots, but significant differences between the treatments were found only in 1993 in two experiments. It was concluded that thinning caused no rise, or only a slight rise, in the groundwater table level.
Keywords: Forest drainage, groundwater table, Pinus sylvestris, thinning
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Hökkä,
The Finnish Forest Research Institute, Rovaniemi Research Station, P.O.Box 16, FIN-96301 Rovaniemi, Finland
Sähköposti:
ei.tietoa@nn.oo
- Penttilä, Sähköposti: ei.tietoa@nn.oo
Kaivukaluston aiheuttamat puustovauriot kunnostusojituksessa.
English title: Tree damage caused by excavating machines in ditch network maintenance.
Avainsanat:
forest drainage;
excavator;
ditch cleaning;
work studies;
backhoe;
ditch digging;
environmental protection
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An inventory of tree damage caused by five excavators, four backhoes and one small-size single-track backhoe was carried out in western Finland during the frost free season. The proportion of damaged trees was 1.1-2.4 % in tree stands ditched using backhoes and excavators, if the ditch lines had been opened in advance. The corresponding proportion caused by the single-track backhoe was 0.9%, if the ditch lines had not been opened in advance. The damage to tree stands was affected by the machine type, the work type and the width of the opened ditch line. Excavators caused more stem damage in the ditch cleaning than backhoes did (p<0.02). The mean distances of the damaged trees from the center line of the ditch were 226-264 cm on the work sites ditched using backhoes and excavators. The mean DBH of the damaged trees was 8-10 cm depending on work and machine type. The optimum width of the ditch line for the different machine types was assumed to be 400-500 cm when considering the growth losses of tree stand, the tree damage and the work productivity.
Keywords: backhoe, ditch cleaning, ditch digging, environmental protection, excavator, forest drainage, work studies
R. Lauhanen, The Finnish Forest Research Institute, Kannus Research Station, FIN-69101 Kannus, Finland
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Lauhanen,
The Finnish Forest Research Institute, Kannus Research Station, FIN-69101 Kannus, Finland
Sähköposti:
ei.tietoa@nn.oo
Kaivukaluston tuottavuus, työnjalki ja kustannukset kunnostusojituksessa.
English title: The productivity, work quality and the costs of employing backhoes and excavators in ditch network maintenance.
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Four backhoes and four excavators were studied in different excavation difficulty classes (1-5) during the unfrozen period in the western part of Finland. The productivity (per effective hour) of the backhoes in ditch digging (additional ditching) was 54-172 m/h and 68-202 m/h in ditch cleaning. The productivity of the excavators was 114-289 m/h and 88-250 m/h, respectively. Productivity decreased as the difficulty class increased. It was affected by the width of the ditch line opening, the stoniness, and ditch depth. Productivity seemed to be affected by the machine operator, too. The work quality was acceptable. The operating costs were 268-388 FIM per hour for the machines costing 400 000-1000 000 FIM.
Key words: additional ditching, ditch cleaning, excavating machines, forest drainage, work studies
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Lauhanen,
The Finnish Forest Research Institute, Kannus Research Station, FIN-69100 Kannus, Finland
Sähköposti:
ei.tietoa@nn.oo
Soiden luokittelu metsätaloutta varten entisessä Neuvostoliitossa.
English title: Classification of mires in the forestry in the former USSR.
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Peatlands and paludified forests have been regarded and classified as forests on peat soil in the former USSR. Treeless mires and sparsely forested mires with poor-quality tree stands have considered to be real mires. That is why in Russia, the term of forest type is traditionally used instead of mire type. The dominant tree species has the indicator role of the site type and this is also reflected in the name of the forest type. Besides the nationwide classification based on Sukachev's works, there are also some interesting regional (now national) classification systems especially in Latvia and Lithuania.
Key words: forest drainage, Latvia, Lithuania, Russia, Siberia
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Vompersky,
Institute of Forest Research, Russian Academy of Sciences, Uspenskoye, Moscow Region, 143030 Russia
Sähköposti:
ei.tietoa@nn.oo
- Anatolij, Sähköposti: ei.tietoa@nn.oo
Metsäojien jatkuvan kunnossapidon vaikutus ojitusalueiden tilaan Keski-Pohjanmaalla.
English title: Effects of continuous ditch network maintenance on the condition of forest drainage areas in Central Ostrobothnia district.
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The estimated annual need for ditch network maintenance in Finnish peatland forests is over 100 000 hectares, most of it consisting of ditch cleaning. However, there are not enough funds available for the needs of remedial ditching. In addition, environmental aspects in peatland forestry must be considered more than in the past. Thus, it is necessary to evaluate alternative work methods of ditch network maintenance. This paper presents the effects of continuous ditch network maintenance on the dimensions and the condition of ditches, as well as on the development of the tree stands on ditched sites.
Key words: Alternative excavating methods, ditch maintenance, forest drainage, stand volume
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Isoaho,
The Finnish Forest Research Institute, Kannus Research Station, FIN-69100 Kannus, Finland
Sähköposti:
ei.tietoa@nn.oo
- Lauhanen, Sähköposti: ei.tietoa@nn.oo
- Saarinen, Sähköposti: ei.tietoa@nn.oo
The effect of changing water table on methane fluxes at two Finnish mire sites.
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Methane fluxes were measured using a static chamber technique on a minerotrophic fen and an ombrotrophic peat bog site located on the Lak-kasuo mire complex in central Finland. Both sites consisted of a virgin area and an area drained in 1961 by ditching. The measurements in 1991 were made biweekly from spring thaw to winter freezing. During this period, the mean CH4 emission from the virgin minerotrophic site and virgin ombrotrophic site was 98 mg m-2 d-1 and 40 mg m-2 d-1 , respectively. The mean emission of CH4 from the drained ombrotrophic site was 18 mg m-2 d-1. The drained minerotrophic site consumed methane during most of the measuring period, the average uptake was 0.13 mg m-2 d-1. Draining had lowered the average water table by 4 cm at the ombrotrophic site and by 20 cm at minerotrophic site. The possible reasons for the different development of the water table and methane fluxes at ombrotrophic and minerotrophic sites after draining are discussed.
Keywords: Drainage, methane flux, methane oxidation, nutrient status, peat soil
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Martikainen,
Department of Environmental Microbiology, National Public Health Institute, P.O. Box 95, FIN-70701 Kuopio, Finland
Sähköposti:
ei.tietoa@nn.oo
- Nykänen, Sähköposti: ei.tietoa@nn.oo
- Crill, Sähköposti: ei.tietoa@nn.oo
- Silvola, Sähköposti: ei.tietoa@nn.oo
Fine root dynamics on two drained peatland sites.
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Total fine root biomass was 397 g/m2 at an afforested and fertilized tall sedge fen (VSN), and 529 g/m2 at a tall sedge pine fen (VSR). The studied sites were located on the Lakkasuo mire complex in central Finland. The greater biomass on the VSR site could be a result of its lower nutrient status compared to that of the fertilized VSN site. Total root production during May-September 1991 was 178 g/m2 at the VSN site and 242 g/m2 at the VSR site when all significant increments in the living and dead root biomasses were summed up. Almost half of the fine root biomass was renewed during the summer.
Keywords: Biomass, drainage, ground vegetation, necromass, Pinus sylvestris, production
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Finér,
Finnish Forest Research Institute, Joensuu Research Station, P.O. Box 68, FIN-80101 Joensuu, Finland
Sähköposti:
ei.tietoa@nn.oo
- Laine, Sähköposti: ei.tietoa@nn.oo
- Halko, Sähköposti: ei.tietoa@nn.oo
Karujen rämeiden kunnostusojituskelpoisuus.
English title: Evaluation of ditch network maintenance on drained poor pine mires.
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In the southern part of Finland there are over 400 000 hectares of old drainage areas which are on very poor pine mires. This paper presents their problematic site type classification, growing stock variation and some criteria to evaluate the profitability of the ditch network maintenance.
Keywords: Classification, drainage, peatlands, profitability
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Saarinen,
The Finnish Forest Research Institute, Parkano Research Station, SF-39700 Parkano, Finland
Sähköposti:
ei.tietoa@nn.oo
- Silver, Sähköposti: ei.tietoa@nn.oo
Lannoituksen vaikutus rämemännikon kasvuun ja rakenteeseen.
English title: Effect of fertilization on the growth and structure of a Scots pine stand growing on an ombrotrophic bog.
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NPK fertilization increased volume growth by 6.3 m3 ha-1 and PK fertilization by 4.3 m3 ha-1 within six years after nutrient application. The results indicate that dominant and co-dominant trees respond to fertilization better than suppressed ones, and that the trees close to the ditches benefit almost as much from fertilization as those in the middle of the strip. NPK fertilization also increased the mortality of the intermediate trees.
Keywords: bog, drainage, increment, Pinus sylvestris, tree class
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Finér,
Finnish Forest Research Institute, Joensuu Research Station, P. O. Box 68, SF-80101 Joensuu, Finland
Sähköposti:
ei.tietoa@nn.oo
Suometsät ja niiden tutkimus Virossa ja Latviassa.
English title: Peatland forestry research in Estonia and Latvia.
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The authors visited Estonia and Latvia on 20-25.8.1990 in order to get acquainted with peatland forestry research and methods for increasing tree growth on cultivated peatlands, especially by using fertilization. The paper describes peatland forestry in general, paying special attention to the activities in the field of fertilization research on Estonian and Latvian peatlands.
Keywords: Drainage, fertilization, peatland forestry
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Kaunisto,
The Finnish Forest Research Institute, Parkano ResearchStation, SF-39700 Parkano, Finland.
Sähköposti:
ei.tietoa@nn.oo
- Ferm, Sähköposti: ei.tietoa@nn.oo
- Kokkonen, Sähköposti: ei.tietoa@nn.oo
Suometsätieteellinen tutkimus Ruotsissa.
English title: Peatland forestry research in Sweden.
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Former and present peatland forestry studies by the Department of Forest Soils of the Swedish University of Agricultural Sciences (Umeå) are presented, based on a tour to field experiments in north, mid and south Sweden. Up to the 1970s, major interest was paid to the nutrition of drained, originally treeless or sparsely treed fens and bogs. Several fertilization experiments since the first wood ash trials in Norra Hällmyren have indicated the necessity of P and K application to ensure afforestation and satisfactory growth of Scots pine on such sites. Silvicultural problems on drained peatlands, such as regeneration on highly productive peatlands, planting techniques, commercial thinnings, as well as gas exchange in peat and the distribution of nutrients in a peatland forest ecosystem are the focus of a large-scale project started in 1985. The preliminary results of the regeneration experiments, i.e. the effectiviness of spruce shelter wood (140-200 trees per ha) against frost damage during the growing season, are discussed. A brief description of the present classification and post-drainage site index system for peatlands is also given.
Keywords: Classification, drainage, nutrient status, regeneration
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Hökkä,
Finnish Forest Research Institute, Rovaniemi Research Station, P.O. Box 16, SF-96301 Rovaniemi, Finland
Sähköposti:
ei.tietoa@nn.oo
- Penttilä, Sähköposti: ei.tietoa@nn.oo
Ohutjuurten biomassa ja pituus ojitusalueen männikössä, koivu-mäntysekametsikössä ja kuusikossa.
English title: Fine root biomass and length in a pine, mixed birch-pine and spruce stand on a drained peatland.
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The biomass of Scots pine fine roots (diam. <10 mm) averaged ca. 5 000 kg/ha and total length ca. 12 000 km/ha on a tall-sedge pine mire. In a herb-rich sedge birch-pine mire, Scots pine fine root biomass was ca. 800 kg/ha and hairy birch fine root biomass 2 000-4 000 kg/ha. The total length of fine roots were correspondingly ca. 3 000 km/ha and 4 000-7 000 km/ha. Norway spruce fine root biomass was 7 000-8 000 kg/ha with a total length of ca. 11 000 km/ha on a Vaccinium myrtillus spruce mire. The root systems were superficial; over 90% of the root biomass was in the uppermost 20 cm peat layer. The biomass of 1-10 mm diameter fine roots was larger than that of the <1 mm roots on all sites. In the case of root length, the situation was just the opposite.
Keywords: Drainage, hairy birch, Norway spruce, root systems, Scots pine
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Finér,
Finnish Forest Research Institute, Joensuu Research Station, P.O. Box 68, SF-80100 Joensuu, Finland
Sähköposti:
ei.tietoa@nn.oo
Metsänparannuksella aikaansaadun tuloksen turvaaminen metsäojitusalueilla.
English title: Confirmation of the results of forest amelioration of drained peatland forests.
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Approximately half of the original area of Finnish peatlands, 10 Mha, have been drained for forestry. In addition slightly less than 1 Mha of paludified mineral soil have been drained. The drained area comprises approximately one quarter of the present total forest area in Finland and the current growth of tree stands on drained peatland forests is steeply increasing. Thus the increase in the annual growth increment due to forest amelioration is presently c. 8 Mm3 and increasing by several percent each year. While this trend is welcome a third of drained peatland area already needs urgent additional drainage and silviculture management if it is to continue.
Keywords: Drainage, peatlands, silviculture
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Antola,
Central Forestry Board Tapio, Maistraatinportti 4A, SF-00241 Helsinki, Finland
Sähköposti:
ei.tietoa@nn.oo
Suot Suomen metsätaloudessa.
English title: Peatlands in Finnish forestry.
Avainsanat:
forest drainage;
peatlands
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Up to the present 5 Mha of peatland, i.e. 50% of the total peatland area of Finland, have been drained for forestry. The annual growth of peatland forests has increased from 6 Mm3 in the 1920s up 15 Mm3 in the 1980s, which is 22% of the total annual growth of the country's forests. To maintain the drainage systems, about 40 000 km of ditches should be cleaned annually. Silvicultural management of tree stands on peatlands is another urgent task in the near future.
Keywords: Forest drainage, peatlands
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Mikola,
Department of Silviculture, University of Helsinki, Unionin-Icatu 40 B, SF-00170 Helsinki, Finland
Sähköposti:
ei.tietoa@nn.oo
Metsien uudistaminen vanhoilla ojitusalueilla.
English title: Forest regeneration in old forest drainage areas.
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There are 150 000 hectares of mature stands and about 270 000 hectares of low-yielding stands in forest drainage areas in Finland. Most of them are on transforming or transformed peatlands. Conditions of these areas for forest regeneration differ from those of virgin and newly ditched peat-lands. The paper presents a review of studies in forest regeneration in old drainage areas. Also the needs for further research is discussed.
Keywords: Drainage, regeneration, transformed mires
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Saarinen,
The Finnish Forest Research Institute, Parkano Research Station, SF-39700 Parkano, Finland
Sähköposti:
ei.tietoa@nn.oo
Korpirämeet ja karut korvet suomalaisissa suoluokitusjärjestelmissä.
English title: The place of spruce-pine mires and oligotrophic spruce mires in Finnish peatland site type classifications.
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In Finland three different mire classification systems can be distinguished: 1) those for ecological purposes based on detailed botanical surveys, 2) those for scientific forestry research purposes, and 3) more extensive systems for practical forestry purposes. All systems are based upon Cajan-der's site-type principle whereby habitats which are ecologically similar are considered to support a similar vegetation. The classification (site type names, analogy/correspondence, nutrient status level) of spruce-pine mires and oligotrophic spruce mires according to the above-mentioned systems is compared. Some criticism concerning especially the confusing naming of the same type is presented. The varying post-drainage suc-cession in these site type groups is also discussed. Finally an attempt to distinguish the more oligotrophic spruce-pine mires from the less oligotrophic ones is made.
Keywords: Drainage, mire classification, site type, succession, trophy
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Hotanen,
The Finnish Forest Research Institute, Joensuu Research Station, P.O. Box 68, SF-80101 Joensuu, Finland
Sähköposti:
ei.tietoa@nn.oo
Ojitusalueiden puunkorjuun ja metsänparannustöiden yhteensovittaminen.
English title: Combining of logging and forest improvement measures on forest drainage areas.
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The paper is partly based on a practical instruction procedure to combine harvesting and forest amelioration measures on forest drainage areas. It is simply a scheme of order and schedule presented in a table, the purpose of which is to serve as a guide for planning the order and timing of harvesting and forest amelioration practices. In efficient peatland forestry it is necessary to be aware of all the operations that will be required early in the planning phase which presupposes cooperation between different organizations. In the future, with the increase of additional drainage and ditch maintenance, the presented schedule (or similar working model) must be followed in order to avoid bad results in peatland forestry.
Keywords: Drainage, forest amelioration, harvesting, peatland
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Matilainen,
Forestry Board of Eastern Häme, Vesijärvenkatu 9D, P.O. Box 110, SF-15141 Lahti, Finland
Sähköposti:
ei.tietoa@nn.oo
Satakunnan suometsien kehitys vuosina 1977-1987.
English title: The development of peatland forests in Satakunta Forestry Board District between 1977 and 1987.
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The development of peatland forests over a 10-year-period (1977-1987) in Satakunta Forestry Board District, Western Finland, is presented, based on the results of the 7th and 8th National Forest Inventories. Over this period the amount of peatlands classified as forest land (MAI over bark over a 100 years rotation ≥ 1 m3ha-1) and the total volume and increment of peatland forests considerably increased, mainly as a result of drainage.
Keywords: Forest drainage, inventory, peatland forests
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Paavilainen,
Finnish Forest Research Institute, P.O. Box 18, SF-01301 Vantaa, Finland
Sähköposti:
ei.tietoa@nn.oo
Metsäojitettujen soiden kasvupaikkaluokituksen suunnanhakua.
English title: The need of improving the site classification of mires drained for forestry.
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A review of the historical development of mire site classification in Finland with special emphasis on the studies and theories of post-drainage succession is made. Some criticism of the prevailing classification system is presented and a work model for guiding further study of drained mire classification is proposed. Preliminary results of a new approach to classify the vegetation of old peatland forests using TWINSPAN classification and DCA ordination techniques are presented.
Keywords: Drainage, mire classification, site type, succession
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Reinikainen,
The Finnish Forest Research Institute, Department of Peatland Forestry, P.O. Box 18, SF-01301 Vantaa, Finland
Sähköposti:
ei.tietoa@nn.oo
Ojituksen ja lannoituksen vaikutus turpeen hiilen vapautumiseen ja ravinteiden mineralisoitumiseen.
English title: Effect of drainage and fertilization on carbon output and nutrient mineralization of peat.
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Carbon dioxide production increased to 2-3 fold from the peat of an oligotrophic sedge pine mire (VSR) after draining had lowered the water table to a depth c, 0.5 m. At two other sites, a mesotrophic sedge pine mire (RhSR) and a spruce swamp (MK), both the fall in the groundwater table and the increase in C02 production were smaller. At the VSR site, the fast-dissolving PK fertilizer and urea each caused a rapid increase while the slow-dissolving PK fertilizer a slow increase in soil respiration. The greatest, steady increase was achieved by treatment with wood ash. At RhSR and MK sites, the use of fertilizers generally led to a decline in soil respiration for 1-2 years, after which the initial level was normally regained. According to a simulation of the C02 production after drainage, the annual decomposition of peat was calculated to be c. 1 000 g (organic matter) m-2 in the VSR site. On the basis of this decomposition rate, the annual amount of nitrogen mineralizated was estimated to be c. 100 kg ha-1 and that of phosphorus c. 5 kg ha-1. Peat contains only a small amount of potassium, and the decomposition of old peat layers increases the amount of soluble potassium in peat very little.
Keywords: Carbon balance, drainage, fertilization, nutrient mineralization, peat decomposition
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Silvola,
Department of Biology, University of Joensuu, P.O. Box 111, SF-80101 Joensuu, Finland
Sähköposti:
ei.tietoa@nn.oo
Ojitustilanne Etelä- ja Keski-Suomen sekä Pohjanmaa-Kainuun alueella.
English title: A survey of peat-land drainage activity in southern and central Finland.
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The results of a survey of 254 random sample plots, each 1 km2 in area and covering 1 543 km of mire transect line are reported. 74% of the peat-land encountered were drained with open ditch networks for forestry purposes. Of those 19% were classified as recently drained, 66% as transitional, 10% as transformed peat-moor peatlands, and 5% as being under the influence of nearby drainage. Drainage activity had been most often carried out on spruce mires, pine bogs, combination types, and rich fens and to a lesser extent on poor fens/bog hollows. The nutrient status and peat thickness had been taken into account only to a limited extent although ombrotrophic peatlands had been drained to a lesser extent than rich peatlands. There was an increasing tendency to extend drainage activities to thick, ombrotrophic mire types. 17% of peatland under the influence of drainage (750 000 ha) are unsuitable for forestry purposes. Considered within each unsuitable mire type more than 50% of their area is drained.
Keywords: Drainage, Finland, mire types, peatland
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Eurola,
Department of Botany, University of Oulu, Linnanmaa, SF-90570 Oulu, Finland
Sähköposti:
ei.tietoa@nn.oo
- Aapala, Sähköposti: ei.tietoa@nn.oo
- Kokko, Sähköposti: ei.tietoa@nn.oo
Lapin kolmion lettoisista soista.
English title: The rich fens of the Lapland triangle region.
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The Lapland triangle region, located between the lower courses of the rivers Tornion-joki and Kemijoki in NW-Finland covers an area of 3500 km2. The region is renowed for its concentration of rich fen mire site types, including Campylium stellatum — Limprichtia intermedia — rich fens, eutrophic flark fens, eutrophic birch fens, eutrophic pine mires and eutrophic spruce mires. Peatlands cover about 60 % of the total land area of the region. By the end of the 1970's some 90 % of the area of rich fens had been drained and utilized for cultivation and forestry purposes and several plant species had become endangered. Although some 20 sites have been listed for conservation, enforcement so far has been very limited.
Keywords: fens, peatland drainage, endangered species, conservation.
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Ylimartimo,
Department of Silviculture, University of Helsinki, Unioninkatu 40 B, SF-00I70, Finland
Sähköposti:
ei.tietoa@nn.oo
Quebecin soista ja metsäojitustoiminnasta.
English title: Peatlands and forest drainage in Quebec, Canada.
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The interest in peatland forestry in Quebec is increasing as the peatlands of the St-Lawrence valley are considered to have a good drainage response capacity A relatively important forest drainage project is being carried out on a practical scale. However, the lack of a practically oriented peatland classification system is an important drawback. This paper is an attempt to produce a preliminary classification system intended for practical peatland forestry.
Keywords: Quebec, forest drainage, site type classification.
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Schneider,
University of Helsinki, Department of Peatland Forestry, Unioninkatu 40 B, SF-00170 Helsinki, Finland
Sähköposti:
ei.tietoa@nn.oo
Puuntuotannon ja puunhankinnan kehittämismahdollisuudet Etelä-Lapin ojitetuilla soilla.
English title: The development opportunities of silviculture and wood procurement on drained peatland forests in southern Lapland, Finland.
English keywords:
Drainage;
ditching;
site type;
harvesting;
thinning;
tree species;
carrying capacity;
forest management
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