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Silva Fennica 1926-1997
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Acta Forestalia Fennica
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Articles by Hannu Rita

Category: Research article

article id 214, category Research article
Michelle de Chantal, Hannu Rita, Urban Bergsten, Mikaell Ottosson Löfvenius, Harald Grip. (2009). Frost heaving of Picea abies seedlings as influenced by soil preparation, planting technique, and location along gap-shelterwood gradients. Silva Fennica vol. 43 no. 1 article id 214. https://doi.org/10.14214/sf.214
The effects of soil preparation, planting technique and location along gap-shelterwood gradients (position and orientation) on frost heaving damage to seedlings were studied in Vindeln Experimental Forests, northern Sweden. The forest was harvested in a grid pattern in winter 2004–2005, forming gaps and shelterwood areas of 30 x 40 m each. Gap-shelterwood gradients were delimited in four orientations and subdivided into five positions: 7 m and 15 m into the gap and shelterwood, and at the gap edge. At each position, three replicates of three soil preparations were made: exposed E and B horizons and HuMinMix (milled vegetation and humus layers mixed with surface mineral soil). In early October 2005, one-year-old containerized Picea abies (L.) Karst. seedlings were planted using four techniques: normal and deep planting, and mobile and fixed experimental containers. After one winter, frost heaving damage was highest for seedlings on B horizon combined with the mobile container (51 ± 6%) and normal planting (43±6%). Normal- or deep-planted seedlings in HuMinMix had the least damage (5–6.6 ± 2.5%). Compared to normal planting, deep planting reduced frost heaving damage only on B horizon. When considering the orientation, seedlings in the experimental containers had more or similar frost heaving damage than normal- or deep-planted seedlings. Along the eastern gradient, seedlings incurred more frost heaving damage in the center of the gap than under the canopy.
  • Chantal, University of Helsinki, Dept of Forest Ecology & Dept of Forest Resource Management, Helsinki, Finland ORCID ID:E-mail: michelle.dechantal@helsinki.fi (email)
  • Rita, University of Helsinki, Dept of Forest Ecology & Dept of Forest Resource Management, Helsinki, Finland ORCID ID:E-mail:
  • Bergsten, Swedish University of Agricultural Sciences, Dept of Forest Ecology and Management, Umeå, Sweden ORCID ID:E-mail:
  • Löfvenius, Swedish University of Agricultural Sciences, Dept of Forest Ecology and Management, Umeå, Sweden ORCID ID:E-mail:
  • Grip, Swedish University of Agricultural Sciences, Dept of Forest Ecology and Management, Umeå, Sweden ORCID ID:E-mail:

Category: Article

article id 5549, category Article
Kari Leinonen, Hannu Rita. (1995). Interaction of prechilling, temperature, osmotic stress, and light in Picea abies seed germination. Silva Fennica vol. 29 no. 2 article id 5549. https://doi.org/10.14214/sf.a9200

A multi-factor experimental approach and proportional odds model were used to study interactions between five environmental factors significant to Norway spruce (Picea abies (L.) H. Karst.) seed germination: prechilling (at +4.5°C), suboptimal temperatures (+12 and +16°C), osmotically induced water stress (0.3 Mpa and 0 Mpa), prolonged white light, and short-period of far-red light. Temperature and osmotic stress interacted with one another in the germination of seeds; the effect off osmotic stress being stronger at +16°C than at +12°C. In natural conditions, this interaction may prevent germination early in the summer when soil dries and temperature increases. Prolonged white light prevented germination at low temperature and low osmotic potential. Inhibitory effect was less at higher temperatures and higher osmotic potential, as well as after prechilling. Short-period far-red light did not prevent germination of unchilled seeds in darkness. Prechilling tended to make seeds sensitive to short pulses of far-red light, an effect which depended on temperature: at +12°C the effect on germination was promotive, but at +16°C, inhibitory and partly reversible by white light. It seems that Norway spruce seeds may have adapted to germinate in canopy shade light rich in far-red. The seeds may also have evolved mechanisms to inhibit germination in prolonged light.

  • Leinonen, ORCID ID:E-mail:
  • Rita, ORCID ID:E-mail:

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