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Articles by Irja Lehtonen

Category: Article

article id 4988, category Article
Irja Lehtonen. (1978). Ravinteiden kierto eräässä männikössä. Silva Fennica vol. 12 no. 1 article id 4988. https://doi.org/10.14214/sf.a14842
English title: Nutrient cycle in a Scots pine stand: IV The amount of phytomass and nutrients.

The distribution of the dry matter and nutrients in Scots pine (Pinus sylvestris L.) tree stock growing on a Vaccinium type site, ground vegetation, and humus were determined in the study. The greatest part of the dry matter in the tree was found in the stemwood. The living branches, roots, bark, needles and dead branches decreasing order of magnitude made up the rest of the biomass. The trees contained over 90%, the field layer vegetation 3% and the bottom layer vegetation 2% of the dry matter in the tree stand. The tree stock contained 86–95% of the total amount nutrients in the stand. The field layer vegetation contained less nutrients than the bottom layer vegetation. Nitrogen, however, was an exception, the amount being approximately the same in both vegetation layers. 

The PDF includes a summary in English.

  • Lehtonen, ORCID ID:E-mail:
article id 4975, category Article
Irja Lehtonen. (1977). Ravinteiden kierto eräässä männikössä. Silva Fennica vol. 11 no. 3 article id 4975. https://doi.org/10.14214/sf.a14826
English title: Nutrient cycle in a Scots pine stand. III Variation in nutrient content of soil, vegetation and precipitation.

The study is part of a project designed to elucidate the nutrient budget of a Scots pine (Pinus sylvestris L.) stand. Results of variation in the nutrient contents were compared with those obtained for the previous growing season.

The potassium and calcium contents varied the greatest in the humus layer. However, in the bottom and field layer vegetation and needles the variation in the nitrogen content was the greatest. The nutrient contents of the needles were affected by the physiological stage of development, needle age and the position in the crown of the tree. The nutrient content of the rainfall increased in the order: free rainfall, throughfall, and stem flow.

The PDF includes a summary in Finnish.

  • Lehtonen, ORCID ID:E-mail:
article id 4959, category Article
Irja Lehtonen, Pertti Hari, Seppo Kellomäki, Eero Väisänen. (1977). On control of daily structural matter production in population of Avenella flexuosa (L.) Parl. Silva Fennica vol. 11 no. 1 article id 4959. https://doi.org/10.14214/sf.a14810

In the boreal zone, the environmental control of growth rate, i.e. the rate of irreversible change in shoot dimensions, is assumed to be dominated by temperature. Promnitz (1975) emphasises that in boreal and temperate zones storage of photosynthetic products is an essential part of the growth process, and thus direct interaction between growth rate and radiation is not evident. The aim of the present study was to investigate the control of daily structural matter production in populations of Avenella flexuosa (L.) Drejer. Special attention was paid to the role of temperature and radiation in addition to the self-regulation of the plants themselves.

Temperature and self-regulation were found to explain over 90% of the daily variation of growth rate. Introduction of radiation into the analysis did not increase the explanatory power of the growth model based on temperature and self-regulation.

The PDF includes a summary in Finnish.

  • Lehtonen, ORCID ID:E-mail:
  • Hari, ORCID ID:E-mail:
  • Kellomäki, ORCID ID:E-mail:
  • Väisänen, ORCID ID:E-mail:
article id 4952, category Article
Irja Lehtonen, Seppo Kellomäki, Carl Johan Westman. (1976). Ravinteiden kierto eräässä männikössä. Silva Fennica vol. 10 no. 4 article id 4952. https://doi.org/10.14214/sf.a14798
English title: Nutrient cycle in a Scots pine stand. II. Amount and quality of precipitation in a Scots pine stand at the pole stage.

This study forms part of a project designed to elucidate the total nutrient budget of a Scots pine (Pinus sylvestris L.) stand in Central Finland during the 1974 growing period. Precipitation has been divided up into precipitation, throughfall and stemflow.

The acidity of the rainwater was found to increase in the order – Precipitation, throughfall and stemflow. The electrolyte content of the rain water from throughfall and stemflow was higher than that of precipitation. The nutrient contents of precipitation were rather low. Throughfall and stemflow were found to leach some nutrient from the trees. This was most clear in the case of potassium. The total amounts of nutrients reaching the ground in throughfall were found to be smaller than those in precipitation. On the other hand, the amounts of potassium, calcium and magnesium in stemflow were clearly greater than those in precipitation.

The PDF includes a summary in English.

  • Lehtonen, ORCID ID:E-mail:
  • Kellomäki, ORCID ID:E-mail:
  • Westman, ORCID ID:E-mail:

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