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Articles by Pirkko Ilonen

Category : Article

article id 5079, category Article
Seppo Kellomäki, Pertti Hari, Pirkko Ilonen, Markku Kanninen. (1980). Eco-physiological studies on young Scots pine stands. II. Silva Fennica vol. 14 no. 3 article id 5079. https://doi.org/10.14214/sf.a15020
Keywords: Pinus sylvestris; photosynthesis; Scots pine; stand density; needle biomass; crown class; needle distribution
Abstract | View details | Full text in PDF | Author Info

The technique of double normalizing, i.e. normalizing the relative needle biomass and the length of the living crown system, is applied to the modelling of the distribution of needle biomass in the canopy of young Scots pine (Pinus sylvestris L.) stands. The study based on the parameters of β-function shows that at the individual-tree level, the variance in needle distribution was not closely associated with any tree characteristics. A shift in the point of maximum needle biomass upwards unsuppressed trees was, however, evident. This was associated with an increase in the height of the trees. At the stand level, the stand mean height and stand density had an equal and a rather high potential for explaining the variance in the needle distribution. The normalized crowns are utilized in models for determining light extinction in the crown. A special technique for determining the amount of photosynthates available for growth in a particular tree is presented.

The PDF includes a summary in Finnish.

  • Kellomäki, E-mail: sk@mm.unknown (email)
  • Hari, E-mail: ph@mm.unknown
  • Ilonen, E-mail: pi@mm.unknown
  • Kanninen, E-mail: mk@mm.unknown
article id 5049, category Article
Pirkko Ilonen, Pertti Hari, Markku Kanninen, Seppo Kellomäki. (1979). On distribution of growth in crown system of young Scots pine stands. Silva Fennica vol. 13 no. 4 article id 5049. https://doi.org/10.14214/sf.a14906
Keywords: Pinus sylvestris; light; Scots pine; needle; branching; terminal growth
Abstract | View details | Full text in PDF | Author Info

Branching and terminal growth of lateral shoots and needle growth of Scots pine (Pinus sylvestris L.) is investigated as a function of the whorl’s position and age and prevailing light climate. Number of buds per whorl was linearly and positively related to the whorl’s position and prevailing light climate. The growing whorl’s number counting from the apex was associated with declining bud number. The terminal growth of lateral shoots increased exponentially within the values 0.6–1.0 of the whorls position. Under these values the terminal growth was negligible. The growing whorl’s number indicated curvlinear decrease in shoot growth respectively, and only negligible growth occurred when the whorl’s age exceeded 10 years. The shoot growth was linearly related to the prevailing light climate but differences between dominating and dominated trees were apparent. The distribution of needle growth in the crown system was similar to that of shoot growth.

The PDF includes a summary in Finnish.

  • Ilonen, E-mail: pi@mm.unknown (email)
  • Hari, E-mail: ph@mm.unknown
  • Kanninen, E-mail: mk@mm.unknown
  • Kellomäki, E-mail: sk@mm.unknown

Category : Article

article id 7624, category Article
Pertti Hari, Seppo Kellomäki, Annikki Mäkelä, Pirkko Ilonen, Markku Kanninen, Eeva Korpilahti, Markku Nygren. (1982). Metsikön varhaiskehityksen dynamiikka. Acta Forestalia Fennica no. 177 article id 7624. https://doi.org/10.14214/aff.7624
English title: Dynamics of early development of tree stand.
Original keywords: tiheys; mänty; metsikön rakenne; metsikön kehitys; valo-olosuhteet; yhteyttäminen
English keywords: Pinus sylvestris; stand structure; photosynthesis; Scots pine; density; stand development; light conditions
Abstract | View details | Full text in PDF | Author Info

The report concludes a series of studies on the early development of young Scots pine (Pinus sylvestris L.) stands. The basis assumption made in the study series was that the within-stand light regime is the main driving force for total tree growth and its allocation of photosynthates for crown, stem and root growth. An individual tree growing in a stand under a varying light regime which is controlled by the stand structure, is the basic unit used in the study. The photosynthesis of an individual tree is determined by the light regime. The stand is formed from individual trees.

The model is applied in simulation of the growth and development of tree stands. Several computer runs representing various densities, height distributions and tree species mixtures were carried out. Potential application areas, properties of the model and future needs of investigations are discussed.

The PDF includes a summary in English.

  • Hari, E-mail: ph@mm.unknown (email)
  • Kellomäki, E-mail: sk@mm.unknown
  • Mäkelä, E-mail: am@mm.unknown
  • Ilonen, E-mail: pi@mm.unknown
  • Kanninen, E-mail: mk@mm.unknown
  • Korpilahti, E-mail: ek@mm.unknown
  • Nygren, E-mail: mn@mm.unknown

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