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Silva Fennica 1926-1997
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Acta Forestalia Fennica
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Silva Fennica 1926-1997 vol. 21 no. 3 | 1987

Category: Article

article id 5320, category Article
Veikko Hintikka. (1987). Peltopillikkeen itämisekologia ja esiintyminen metsäsukkession pioneerilajina. Silva Fennica vol. 21 no. 3 article id 5320. https://doi.org/10.14214/sf.a15477
English title: Germination ecology of Galeopsis bifida (Lamiaceae) as a pioneer species in forest succesion.

The occurrence of Caleopsis bifida on clear-cut and burned forest soil and its disappearance in 4–6 years after disturbance is attributed to its germination ecology. Initially the seeds are dormant 96–100% and remain dormant in nylon gaze bags in different types of forest humus layers at least 10 years. Dormancy is released in laboratory (1) by treatment of 100 ppm aqueous solution of GA3, (2) by heating the dormant seeds to 40–55°C for 1–5 h, and (3) by 1% KNO3 solution. It is concluded that conditions in clear-cut and burned areas favour germination of seeds in regard to temperature and content of nitrates in contrast to humus of closed vegetation where the seeds remain dormant.

The PDF includes an abstract in Finnish.

  • Hintikka, ORCID ID:E-mail:
article id 5319, category Article
Heikki Hänninen. (1987). Lämpötilan vaikutus puiden dormanssin purkautumiseen. Silva Fennica vol. 21 no. 3 article id 5319. https://doi.org/10.14214/sf.a15476
English title: Effects of temperature on dormancy release in woody plants.

Logical structure of three simulation models and one conceptual model concerning effects of temperature on dormancy release in woody plants was examined. The three basic types of simulation models differed in their underlying assumptions. Contrasting implications of the models were inferred by deduction. With the aid of these implications, the model types can be tested using experiments with continuous and interrupted chilling. Similarly, implications of the conceptual model of rest phases were inferred, by which the model can be tested using experiments with continuous chilling and forcing in multiple temperatures. The possibilities to synthetize the conceptual model with any of the three simulation model types, as well as the biological interpretation of the model variables, were discussed.

The PDF includes an abstract in Finnish.

  • Hänninen, ORCID ID:E-mail:
article id 5318, category Article
Tapio Lindholm, Harri Vasander. (1987). Kasvillisuuden ja puuston kehitys tuoreella kankaalla kulotuksen jälkeen. Silva Fennica vol. 21 no. 3 article id 5318. https://doi.org/10.14214/sf.a15475
English title: Vegetation and stand development of mesic forest after prescribed burning.

This study deals with the succession of vegetation and tree stand in 16 mesic Myrtillus site type Scots pine (Pinus sylvestris L.) plantations after prescribed burning in Evo, Southern Finland. The oldest tree stands studied were about 30-year-old. The growth of trees followed the height index of Myrtillus type. The vegetation was first mesic, dominated by grasses and herbs, turning more xeric after four years. This change was accelerated by treatment with herbicides. After the closure of tree stand, vegetation became more characteristic of forest vegetation, but pioneer species and composition disappeared slowly. The basic characters of vegetation succession could be clearly described by DCA ordination and TWINSPAN classification. The study confirmed that Myrtillus type has succession phases which are typical for each age phases as Cajander’s forest site type theory has proposed. However, differences in primary and secondary site factors have their own effects on the vegetation of the succession phases.

The PDF includes an abstract in Finnish.

  • Lindholm, ORCID ID:E-mail:
  • Vasander, ORCID ID:E-mail:
article id 5317, category Article
Ilari Lumme, Markku Yli-Halla. (1987). Eräiden fosfori- ja kaliumlannoitteiden liukoisuudesta saraturpeessa. Silva Fennica vol. 21 no. 3 article id 5317. https://doi.org/10.14214/sf.a15474
English title: Behaviour of certain phosphorus and potassium compounds in a sedge peat soil.

The solubilityof various phosphorus and potassium compounds in a sedge peat soil was studied in an incubation experiment aimed at screening potential fertilizers for the cultivation of fast-growing willows. (KPO3)n proved not to be a source of the slow-released K regarded as most desirable for this kind of cultivation as it was hydrolysed completely in the soil during incubation. Phosphorus from easily soluble or hydrolysable compounds (superphosphate, KH2PO4, (KPO3)n) was bound in the soil largely by Al and Fe and elevated the level of readily soluble P considerably, whereas rock phosphates were found to be practically unchanged after incubation and did not contribute to the readily soluble P in the soil. Apatites proved to be quite insoluble and are therefore assumed to be unsuitable as P fertilizers for fast-growing willows, which have a high nutrient demand.

The PDF includes an abstract in Finnish.

  • Lumme, ORCID ID:E-mail:
  • Yli-Halla, ORCID ID:E-mail:
article id 5316, category Article
Timo Pukkala, Timo Kuuluvainen. (1987). Latvuston rakenteen vaikutus metsikön päivittäiseen suoran säteilyn pidätykseen ja fotosynteesiin. Silva Fennica vol. 21 no. 3 article id 5316. https://doi.org/10.14214/sf.a15473
English title: Effect of canopy structure on the diurnal interception of direct solar radiation and photosynthesis in a tree stand.

The utilization of direct radiation was studied in five model stands of Poisson-type tree distribution and cone-shaped crowns. The radiation extinction depended on the self-shading of the crown and the shading caused by other trees. The results indicate that at low sun elevation a stand populated by very narrow-crowned trees is most effective in light interception and photosynthesis. At high sun elevation a broad-crowned canopy is best illuminated and most favourable for photosynthesis. A stand with a two-storey canopy is effective in all latitudes when the crowns are moderately narrow. In two-storey canopies the foliage of the lower storey can be better illuminated than in the lower parts of the upper storey, because of the smaller self-shading in the small crowns of the lower storey. A canopy where the crown volume is concentrated on few big crowns is less effective than a canopy consisting of many small crowns.

The PDF includes an abstract in Finnish.

  • Pukkala, ORCID ID:E-mail:
  • Kuuluvainen, ORCID ID:E-mail:

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