Artikkelit jotka sisältää sanan 'drained peatlands'

Metsäkeskusten kunnostusojitushankkeiden metsikkökuvioista muodostettiin satunnaisesti yhdistäen kolme 35–50 hehtaarin suunnittelualuetta, joiden avulla tarkasteltiin ns. kerralla kuntoon -menettelyn mukaisten (toteutetaan kunnostusojituksen lisäksi kaikki tarpeelliset metsänhoitotoimet yhdellä kerralla koko suoalueelle) ja toisaalta metsänhoitosuosituksia kuvioittain mukailevien metsänkäsittelyjen tuotos- ja talousvaikutuksia. Pääasiassa karuhkoja rämeitä edustavien alueiden puustojen kehitykset simuloitiin kunnostusojituksen ajankohdasta päätehakkuuseen saakka. Erityishuomiota kiinnitettiin alueisiin sisältyvien vähäpuustoisten kuvioiden ensiharvennusten voimakkuuteen sekä harvennusten ajoittumiseen suhteessa kunnostusojitukseen. Harvennusten myöhentäminen sekä vähäpuustoisilla että muilla ns. normaalipuustoisilla kuvioilla paransi koko suunnittelualueen pitkän aikavälin taloustulosta jonkin verran, mutta vähäpuustoisten kuvioiden käsittelyajankohdan vaikutus oli selvästi suurempi. Harvennuksia myöhentämällä myös ensiharvennusten ainespuukertymä kasvoi. Jos vähäpuustoiset kuviot kuitenkin harvennettiin kunnostusojitusvaiheessa ja samaan aikaan normaalipuustoisten kuvioiden kanssa, paras tulos saavutettiin suhteellisen voimakkailla harvennuksilla. Vähäpuustoisten kuvioiden jättäminen kokonaan harventamatta johti heikoimpaan aluetason taloustulokseen. Metsänkasvatuksen pidemmän aikavälin kannattavuutta voitaisiin käytännössä parantaa rajaamalla kunnostusojitusalueen vähäpuustoiset kuviot omiksi käsittelylohkoikseen ja siirtämällä niiden harvennukset toteutettaviksi vasta alueen seuraavalla hakkuukierrolla.

• Kojola, Soili Kojola, Metsäntutkimuslaitos, Etelä-Suomen alueyksikkö, PL 18, 01301 Vantaa, Puh./Tel. 029 532 2111, Fax: 029-532 2103, email: soili.kojola@metla.fi Sähköposti: ei.tietoa@nn.oo
• Penttilä, Sähköposti: ei.tietoa@nn.oo

The effects of potassium (K) fertilisation on the nutrient status and growth of Scots pine (Pinus sylvestris L.) stands on drained peatlands were studied on three field experiments in northern central Finland. The Scots pine stands were at a sapling or pole stage with a dominant height of 3–8 m when the experiments were set up. The stands differed from each other in their nutritional status, for example, the foliar K concentration varied considerably between the experiments. The experiments were fertilised with potassium chloride, rock phosphate (P 42kg ha-1) and urea (N 46kg ha-1) between 1979 and 1980. The potassium doses in terms of elemental K, were 50, 100, 200 and 400kg ha-1. The foliar samples were taken three times during the study period: 7–9 years, 14–15 years and 19–20 years after fertilisation. The stand measurements were done 19–22 years after the fertilisation. The rate and magnitude of stand response due to fertilisation depended essentially on the nutritional status of the trees. The strongest effect of PK-fertilisation was obtained on a nitrogen-rich peatland, where the stands suffered from severe phosphorus and potassium deficiencies (foliar P concentration < 1.2 mg g-1, K concentration < 3.5 mg g-1). During the study period, the annual stand volume growth on fertilised plots ranged from 3.9 to 5.4 m3 ha-1 a-1, and that of the unfertilised plots was 0.78 m3 ha-1 a-1. In other sites, where the lack of phosphorus and potassium was not so drastic, nor did the trees suffer from shortage of nitrogen, the effect of PK-treatment on tree growth was weak or almost non-existent. The foliar K concentrations rose with the amount of potassium chloride applied. The fertilisation effect of the dose of 100kg K ha-1 lasted 15–20 years, after which the foliar K concentration dropped close to the deficiency limit. The effect of the larger doses (200–400kg K ha-1) on the needle K concentration was more pronounced and still visible at the end of the study period. However, the stand growth responses gained with larger potassium applications were not essentially greater than those with the 100 kg ha-1 dose.

• Pietiläinen, Finnish Forest Research Institute, Muhos Research Station, Kirkkosaarentie 7, FIN-91500 Muhos, Finland Sähköposti: ei.tietoa@nn.oo
• Moilanen, Sähköposti: ei.tietoa@nn.oo
• Vesala, Sähköposti: ei.tietoa@nn.oo

TWINSPAN classifications of the same drained mire vegetation data using four different pseudospecies cut level scales were compared. The material consisted of 96 sample plots located on drained spruce and pine mires in eastern Finland. The pseudospecies cut level scales were the octave scale (0, 0.5, 1, 2, 4, 8, 16, 32 and 64%), a coarse scale (0, 5, 10, 20 and 50%), TWINSPAN default settings (0, 2, 5, 10 and 20%), and presence/absence. The classificatons were quite similar at the first division but they differed markedly from each other at the final third division showing that the choice of cut levels has an important effect on TWIN-SPAN results. The sample plots in one TWINSPAN cluster defined with set of cut levels were allocated to several clusters defined with other cut level settings. The presence/absence setting resulted in a classification which was the most different from the classification made using the default settings. The TWINSPAN classifications performed using the default and octave scale settings corresponded the best with the field classification of the plots and were ecologically the most interpretable. Keywords: Drained peatlands, mire classification, mire site type, multivariate analysis, vegetation

• Hotanen, The Finnish Forest Research Institute, Joensuu Research Station, P.O. Box 68, SF-80101 Joensuu, Finland Sähköposti: ei.tietoa@nn.oo

In the Finnish classification of drained peatlands in practical forestry, the post-drainage successional plant communities of recently drained areas have been traditionally classified according to their original mire site type (33 different types in forestry use), whereas the more stable communities of older drainage areas have been classified into so called "drained peat-land forest types" (4 types). This system is not firmly based on ecological factors or forestry requirements. The classification would be more logical and operational in forestry, if the successional plant communities of younger drainage areas already were classified into the drained peatland forest types. The paper describes seven such drained peatland forest types: herb-rich type, Vaccinium myrtillus type (I) and (II), Vaccinium vitis-idaea type (I) and (II), dwarf-shrub type and the Cladina type, which have their parallels in the series of upland forest types. The traditional V. myrtillus and V. vitis-idaea types have each been divided into two types; type (I) develops from genuine, forested mire types and type (II) from treeless and sparsely forested composite types. The proposed classification is supported by tree stand and peat property data presented in the paper. Keywords: Classification, drained peatlands, vegetation

• Laine, Department of Peatland Forestry, University of Helsinki, SF-00170 Helsinki, Finland Sähköposti: ei.tietoa@nn.oo

The short-term effects of wood ash, PK and NPK fertilizers on total N and P contents of various mosses at an old drainage area in eastern Finland are studied. Total N contents increased after NPK treatment and total P contents increased after treatments that contained phosphorus (NPK, PK, wood ash). N contents of some mosses also increased after treatments which did not contain any nitrogen (PK and wood ash). On these plots drainage and obviously the fertilizer treatment fastened the decomposition rate of the peat and at the same time the mobilization of the nutrients. On the control plots (no fertilization) the N contents of the mosses did not differ statistically between the years in either of the study sites. The P contents of some mosses decreased on the control plots of the spruce swamp. One reason for this was apparently the level of the ground water, which did not lower so much in the spruce swamp than in the pine mire, and so the mobilization of the nutrients remained smaller. The observed nutrient contents of the peat mosses were much smaller than those of the forest mosses and the nutrient contents were also smaller at pine mire than at spruce swamp. Keywords: bryophytes, fertilization, drained peatlands, nitrogen, phosphorus.

• Jäppinen, University of Joensuu. Department of Biology. P.O. Box 111, SF-80101 Joensuu, Finland Sähköposti: ei.tietoa@nn.oo

The short-terms effects of wood ash and NPK fertilizer on the population of Enchytraeidae worms in a drained spruce swamp and pine bog were studied. Both NPK fertilizer (300 kg/ha) and ash (3000 kg/ha) treatments reduced worm numbers at both sites, but the effects were slight compared to seasonal fluctuations. Temporal fluctuations in worm numbers were relatively smaller at the pine bog than at the spruce swamp. NPK fertilizer temporarily changed the relative vertical distribution while tha ash treatment did not. The effects upon worm biomass and respiration rate were similar as those for worm numbers . Key words: Enchytraeidae, NPK fertilization, ash fertilization, drained peatlands

• Hotanen, The Finnish Forest Research Institute, Joensuu Research Station, Yliopistonkatu 7, SF-80100 Joensuu, Finland Sähköposti: ei.tietoa@nn.oo