Current issue: 54(2)
The article presents the background of increment calculations and periodic measurements of forests, as well the historical development of increment calculations in North-America, Middle-Europe, Scandinavia and Finland. The measurements and calculations are presented for individual trees, for a forest stand and for the total resource of a normal forest stand.
The practice of increment calculations has still some problems regarding the measurements of standing and harvested trees. The article discusses some ways to overcome the problems.
The article describes the method of improving the leveling line of the volume of sample trees so that the volume figures themselves indicate the best leveling. The original method of leveling line originates from Kopezky. Here the method is illustrated with a data from Finnish pine forest.
The PDF contains a summary in Finnish.
A mirror dendrometer consists of a hollow metal tube and three mirrors that are installed in the tube in a certain way. The tool is used to determine the diameter of a tree trunk above the reach. The article presents the formulas that can be used to correct the measuring mistakes that are caused by the wrong position of the dendrometer.
To determine the form class of a stand with the diameter measurements from a certain height the Jonson’s diameter relations tables can be used. The calculation of the form class for a stand is presented.
The PDF contains a summary in Finnish.
Volume formulas have been developed already for long time but there are still some questions to be solved. The volume of a stem can be calculated based on measurements of diameter on various heights or based on mathematic formula. The article presents the formula development for that. The study is based on measurements of 24 pine stands.
The results of the new formula can be seen satisfactory with the relatively small data of this study. Coincidentally the formally best mean solution of the here compared volume calculation formulas was the one based on Denzin’s formula. There the deviation from total mean is almost zero.
The article features a critical observation on used methods for calculating the errors and a trial to improve it. The article describes the calculation method used in Sweden, county of Värmland and another method used by Ilvessalo and developed by Cajanus. The shortcomings of these models are discussed. An improved calculation is presented.
The structure and functional responses of roots in planted seedlings when acclimatizing at the planting site are reviewed. A wide range of methods for classifying roots has been employed, and the terminology used is not uniform. Roots can be classified by their morphology, origin, and function. The temporal and spatial variation of soil temperature, moisture, structure, and concentration of nutrients are among the most important properties to which root systems acclimatize. In order to reliably describe the function of the root system, several parameters usually have to be measured. Studies on the root-soil interface have indicated that roots are not necessarily in continuous contact with soil. The control mechanism of root growth is inadequately known and theoretically formulated. Generally, only the mass needed for water and nutrient uptake has been allocated to the roots. However, the amount of photosynthates allocated to the roots is high. Acclimatization of seedlings out at the planting site is a complicated process which is influenced by the growing conditions at both the nursery and at the site. The function, distribution and structure of roots are controlled by the environment in a way similar to the shoot, but the control mechanism is imperfectly known.
The PDF includes an abstract in English.
With developing possibilities to analyse data automatically there is a need to develop the mathematical and statistical practices for calculations. The article presents the basis about the growth of trees and the existing models of growth, the basics on growth functions, and the construction of a regression model to analysis the growth. The theoretical model development has been tested with three existing data sets.
The analysis of growth should be considered with dynamic models. The model need to take into account various aspects and growth factors. The model should have practical implications.
The PDF contains a summary in German.