Browsing by Subject "maanmuokkaus"

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  • Kubin, Eero; Kemppainen, Lauri (The Society of Forestry in Finland - The Finnish Forest Research Institute, 1994)
    The effect of scarification, ploughing and cross-directional plouhing on temperature conditions in the soil and adjacent air layer have been studied during 11 consecutive growth periods by using an unprepared clear-cut area as a control site. The maximum and minimum temperatures were measured daily in the summer months, and other temperature observations were made at four-hour intervals by means of a Grant measuring instrument. The development of the seedling stand was also followed in order to determine its shading effect on the soil surface. Soil preparation decreased the daily temperature amplitude of the air at the height of 10 cm. The maximum temperatures on sunny days were lower in the tilts of the ploughed and in the humps of the cross-directional ploughed sites compared with the unprepared area. Correspondingly, the night temperatures were higher and so the soil preparation considerably reduced the risk of night frost. In the soil at the depth of 5 cm, soil preparation increased daytime temperatures and reduced night temperatures compared with unprepared area. The maximum increase in monthly mean temperatures was almost 5 °C, and the daily variation in the surface parts of the tilts and humps increased so that excessively high temperatures for the optimal growth of the root system were measured from time to time. The temperature also rose at the depths of 50 and 100 cm. Soil preparation also increased the cumulative temperature sum. The highest sums accumulated during the summer months were recorded at the depth of 5 cm in the humps of cross-directional ploughed area (1127 dd.) and in the tilts of the ploughed area (1106 dd.), while the corresponding figure in the unprepared soil was 718 dd. At the height of 10 cm the highest temperature sum was 1020 dd. in the hump, the corresponding figure in the unprepared area being 925 dd. The incidence of high temperature amplitudes and percentage of high temperatures at the depth of 5 cm decreased most rapidly in the humps of cross-directional ploughed area and in the ploughing tilts towards the end of the measurement period. The decrease was attributed principally to the compressing of tilts, the ground vegetation succession and the growth of seedlings. The mean summer temperature in the unprepared area was lower than in the prepared area and the difference did not diminish during the period studied. The increase in temperature brought about by soil preparation thus lasts at least more than 10 years.
  • Kubin, Eero (Suomen metsätieteellinen seura, 1990)
  • Aaltonen, V. T. (Suomen metsätieteellinen seura, 1938)
  • Mannerkoski, Hannu; Möttönen, Veikko (Suomen metsätieteellinen seura, 1990)
  • Jalkanen, Risto; Jalkanen, Esko; Jalkanen, Jyrki; Jalkanen, Marja (Suomen metsätieteellinen seura, 1984)
  • Räsänen, A. A. (Suomen metsätieteellinen seura, 1939)
  • Hautamäki, Tauno (Suomen metsätieteellinen seura, 1953)
  • Kaila, Simo; Päivänen, Juhani (Suomen metsätieteellinen seura, 1981)
  • Sianoja, Maija (Helsingin yliopisto, 2014)
    Tukkimiehentäi (Hylobius abietis) on merkittävä metsänuudistamisvaiheen tuhohyönteinen Pohjois- Euroopassa. Se aiheuttaa syönnillään tuhoa etenkin istutetuille havupuun taimille. Näin ollen Suomen istutusta suosiva metsätalous on erityisen herkkä tukkimiehentäituhoille. Tukkimiehentäituhojen torjuntaan on perinteisesti käytetty kemiallisia kasvinsuojeluaineita, joilla taimet on käsitelty ennen istutusta. Torjunta-aineilla on saatu helposti ja edullisesti vähennettyä taimien tukkimiehentäituhoja. Torjunta-aineisiin liittyvien ympäristö- ja terveysriskien takia niiden käyttö on kuitenkin kyseenalaistettu tai jopa kielletty monissa maissa viime aikoina. Vaihtoehtoisten torjuntatapojen kehitys ja tutkimus on noussut yhä tarpeellisemmaksi. Maanmuokkauksen tukkimiehentäituhoja pienentävä vaikutus on todistettu useaan otteeseen aikaisemmissa tutkimuksissa. Tässä tutkimuksessa tavoitteena oli selvittää, voisiko maanmuokkaus olla sellainen metsänhoitotoimenpide, joka laadukkaasti tehtynä suojaisi taimia tukkimiehentäituhoilta niin, että torjunta-aineilla tehtävää suojausta ei tarvittaisi lainkaan. Laadukkaan maanmuokkauksen ja torjunta-ainekäsittelyn vaikutuksia tukkimiehentäituhoihin tutkittiin keväällä 2012 perustetulla maastokokeella. Koe koostui 11:sta uudistusalasta. Uudistusaloille istutettiin torjunta-aineella käsiteltyjä ja käsittelemättömiä yksivuotiaita kuusen paakkutaimia laikkumättäisiin. Torjunta-ainekäsittely tehtiin 0,75 % Karate Zeon tukkimiehentäin torjunta-aineliuoksella, jossa oli tehoaineena lambda-syhalotriini. Taimia seurattiin yhden kasvukauden ajan siten, että istutuksen jälkeisenä syksynä taimien kasvu, kunto ja tukkimiehentäin syönti kartoitettiin. Lisäksi mitattiin taimien maatakertuma, etäisyys hakkuutähteisiin ja etäisyys humusreunaan. Näin voitiin tutkia maanmuokkauksen ja torjunta-ainekäsittelyn lisäksi myös muiden mahdollisten ympäristötekijöiden vaikutuksia tukkimiehentäituhoihin. Ensimmäisen kasvukauden jälkeen kaikista taimista laskettu tukkimiehentäin kokonaissyönti oli 12 % ja tukkimiehentäin syönnin seurauksena vakavasti syötyjä taimia oli 3 % (kuolleita tai vakavasti heikentyneitä taimia). Sekä kokonaissyönnissä että vakavassa syönnissä käsittelemättömiä taimia oli syöty enemmän kuin käsiteltyjä taimia. Vakavasti syötyjä oli käsittelemättömistä taimista 5 % ja käsitellyistä taimista 1 %. Kun taimen etäisyys humusreunaan kasvoi syönnin todennäköisyys laski. Myös taimen runkoon tarttunut maa, maatakertuma, pienensi tukkimiehentäin syönnin todennäköisyyttä. Tutkimuksen perusteella tyydyttävä uudistamistulos voidaan saada aikaan Keski-Suomen ilmasto-oloissa ilman torjunta-aineiden käyttöä, kun taimet istutetaan laadukkaisiin kivennäismaapintaisiin mättäisiin tarpeeksi etäälle humusreunasta.
  • Pesonen, Karoliina (Helsingin yliopisto, 2019)
    In Finland, approximately 20 percent of forest regeneration is done by sowing and the most commonly used method is mechanical direct seeding. Scots pine seeds are mostly used in sowings. It has been shown in previous studies that covering the seeds with a thin layer of soil makes the seed bed conditions better. Mechanical sowing equipment that makes it possible to cover the seeds in a controlled way has not been available earlier but technology has improved. ViperMetal-Ajutech Oy has developed a sowing bucket for forestry use which can scarify, sow seeds and cover the seeds with soil. The aim of this study was to investigate whether the covering of the Scots pine seeds by using the sowing bucket improve seedling emergence. Moreover, does mechanical covering of the seeds affect labour productivity. The experiments were set up on three previously cut regeneration sites in South Ostrobothnia and Central Finland in spring 2018. Each site had three blocks. Within the blocks, half of the patches were sown and covered and the other half was left as control and was sown without covering. The number of seedlings in the patches was counted at the end of the first growing season. The effect of covering was tested with generalized linear modelling. For productivity analysis, a video camera was installed inside the cabin of the excavator and the working times for both sowing methods were analysed by using the recordings. Covering the seeds increased the number of seedlings significantly. On average, there were almost double the number of seedlings in the covered patches. However, there was variation between the regeneration sites. Soil properties had an effect on the number of seedlings. In addition, the results indicated that covering significantly reduced the number of empty patches. Productivity analysis showed that it took about two seconds more time to cover the seeds in one patch. There was no considerable variation between the sites or the blocks. The analysis showed that covering decreased productivity per hectare and increased costs.
  • Kyrö, Johannes (Helsingfors universitet, 2016)
    The idea of preparatory cutting is to improve possibilities for natural regeneration. Seed tree cutting is done usually about ten years after preparatory cutting. Preparatory cuttings as a forestry practice method has been known already for a long, but it is not yet commonly used in Finnish forestry. Preparatory cuttings is a recommended method in Finnish forestry guidelines even it is not well studied. The aim of study is to find out effects of different factors for the establishment of pine seedlings in natural regeneration. The main aim is to find out effects of stem density to the number and the height of seedlings. In old forestry literature site preparation does not include to forestry practices when preparatory cutting is a main method. In this study site preparation is examined, because it is known to increase the amount of seedlings when seed tree method is used. Site preparation can be done also under quite dense seed tree cover without essentially damaging trees staying on stand (e.g. Norokorpi 1983). Effects of ground and field layer vegetation are also examined. Data was recorded on study sites of Natural resources institute of Finland. Study sites locate in Northern Finland and eastern part of middle Finland. Experimental plots were thinned to densities of 50, 150 and 250 stems per hectare in 2004 –2008 and each site had also non-thinned control plots. To study effects of site preparation each study site had also plots that were thinned to densities 50 and 150 stems per hectare and prepared. Data is measured during seven years. To statistically test the effects of stem densities and site preparation on the number and height of seedlings four linear mixed effect models were constructed. More seedlings were recorded on stands thinned to density 50 stems per hectare than on non-thinned stands. However, the amount of seedlings in all stem densities was inadequate for successful regeneration. Density of 50 stems per hectare was best for height growth of seedlings. Site preparation increased significantly the amount of seedlings, but it didn’t have statistically significant effect on the height of seedlings. According to the results of the present study preparatory cutting without site preparation does not increase the amount of seedlings to the level required. Statistical models showed that vegetation had often a negative impact to number of seedlings. Logging waste had also a negative impact to the number of seedlings. Spot of germination had statistically significant effect to height of seedlings, but not to number of seedlings. The border zone between the exposed mineral soil and humus was the most favourable spot for the height growth of seedlings.