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Articles containing the keyword 'age class'.

Category: Research article

article id 349, category Research article
Temel Sariyildiz, J. M. Anderson. (2006). Intra-specific variation in cell wall constituents of needle age classes of Pinus sylvestris in relation to soil fertility status in Southwest England. Silva Fennica vol. 40 no. 1 article id 349. https://doi.org/10.14214/sf.349
First, second and third year needles were collected from the same branches of young Scots pine trees growing on soils of two different status (high and low fertility sites) that varied in mineral nutrient concentrations and N mineralisation potential. All needle age classes were analysed for total carbon, acid detergent fibre (ADF), lignin, cellulose, phenylpropanoid derivatives (PPD) of lignin, sugar constituents of non-crystalline, hydrated cellulose and hemicellulose, and nutrient concentrations (N, P, K, Ca, Mg and Mn). Significant intra-specific variation in the litter quality variables in relation to soils of high and low fertility was found in the second and third year needles, whereas there were no differences in the other cell wall constituents and mineral elements of the first year needles. The second and third year needles from the low fertility soil contained higher concentrations of ADF, lignin, cellulose, sugar constituents of non-crystalline, hydrated cellulose and hemicellulose, and phenylpropanoid derivatives (PPD) of lignin, but lower concentrations of N, P and Mg than the same needles from the high fertility and fertilised soils. The results in the present study indicate that under different soil fertilities, needle age classes show significant variations in the cell wall constituents and mineral elements, and suggest that this can result in significant variation in litter quality and decomposition rates.
  • Sariyildiz, Kars Kafkas Üniversitesi, Artvin Orman Fakültesi, 08000 Artvin, Turkey ORCID ID:E-mail: t_sariyildiz@yahoo.com (email)
  • Anderson, Department of Biological Sciences, Hatherly Laboratories, University of Exeter, Exeter EX4 4PS, UK ORCID ID:E-mail:
article id 637, category Research article
Hirofumi Kuboyama, Hiroyasu Oka. (2000). Climate risks and age-related damage probabilities – effects on the economically optimal rotation length for forest stand management in Japan. Silva Fennica vol. 34 no. 2 article id 637. https://doi.org/10.14214/sf.637
We estimated the damage probability according to age class and major climatic disasters based on ‘Statistical Yearbook of National Forest Insurance’ from 1960 to 1996. The probability of snow damage is high for young stands, then gradually decreases with age. On the other hand, the risk of wind damage gradually increases with age. Decisions about rotation age should be based on the distribution of damage probability with stand age. Risk of damage has two contradictory effects on the optimal rotation period; one is that the rotation-shortening effect caused by risk of damage around harvest age; another is the rotation-extending effect due to decrease of rent by the risk of damage through the raising period. Change of optimal rotation depends on the relative magnitude of these effects. We examine this by calculating land expectation value (LEV) using a simulation model with the empirical damage probability, price and cost. Change of the optimal rotation period obtained from the national average damage probability is not significant. However, the optimal rotation is shorter in high wind risk areas and is longer in high snow risk areas. It is because the damage probability for a mature stand is high in the case of wind and low in the case of snow. In addition, the extent of decrease in LEV is smaller for wind than for snow. The results of simulation based on empirical data confirm that the optimal rotation period can become either shorter or longer through incorporating risk in decision making, depending on the damage probability distribution with stand age.
  • Kuboyama, Forestry and Forest Products Research Institute Tohoku Center, Nabeyashiki 72, Shimo-Kuriyagawa, Morioka, Iwate, 020-0123 Japan ORCID ID:E-mail: kuboyama@ffpri-thk.affrc.go.jp (email)
  • Oka, Forestry and Forest Products Research Institute Tohoku Center, Nabeyashiki 72, Shimo-Kuriyagawa, Morioka, Iwate, 020-0123 Japan ORCID ID:E-mail:

Category: Article

article id 7319, category Article
K. Linkola. (1935). Über die Dauer und Jahresklassenverhältnisse des Jugendstadiums bei einigen Wiesenstauden. Acta Forestalia Fennica vol. 42 no. 2 article id 7319. https://doi.org/10.14214/aff.7319
English title: Duration and age class distribution of some meadow grasses in the young age.

The data has been collected from an old natural meadow in Sortavala, Karelia (on that time it was part of Finland). The vegetation on that meadow was very homogenous. All plants of the selected species (Trollius europaeus; Ranunculus auricomus; R. acer; Potentilla erecta; Alchemilla vulgaris; Geum rivale; Prunella vulgaris; Chrysanthemum leucanthemum; Polygonum viviparum) were collected from the sample plots with their roots. The seedlings were then ordered into age classes, and the shortest possible time before inflorescence was determined. To find out the germination time sowing trials were conducted.

The seedlings are very abundant in the youngest age classes and then the amount of plant individuals sinks quickly. The reasons for dying are e.g. insufficient amount of nutrients available and the lack of winter hardiness.   

The PDF contains a summary in Finnish.  

  • Linkola, ORCID ID:E-mail:
article id 7010, category Article
O. J. Lakari. (1915). Studien über die Samenjahre und Altersklassenverhältnisse der Kiefernwälder auf dem nordfinnischen Heideboden. Acta Forestalia Fennica vol. 5 no. 1 article id 7010. https://doi.org/10.14214/aff.7010
English title: Studies on seed years and age-class distribution of pine forests on heathlands of northern Finland.

The data has been collected from northern Finland between about 64th and 68th north latitudes, excluding the polar tree line areas. The sample plots have been selected to represents greatest variation of the habitats in altitude, rainfall and other site factors. The selected trees were cut, their age, height, and diameter at various heights examined and possible signs of forest fires noticed. The age of the trees was examined also with microscope. The age class distribution of the sample plots was studied. The determination of historical seed years was based on age class distribution of the sample plots.  

Grouping of the trees into different age classes was too weak a method to make any conclusions about the periodicity or even less about the frequency of the seed years.  There were also noticeable differences in determining the age of the trees between macroscopic and microscopic age examination. There are also differences in the amount of seedlings between different forest types.

The growth of pines in northern Finland is very slow particularly in the young ages but the growth increases after they reach 1,3 meters, which may take up to 30 years. The development of the forest has been similar through last centuries
  • Lakari, ORCID ID:E-mail:
article id 7594, category Article
Yrjö Kangas. (1977). Die Messung der Bestandesbonität: 3. Teil. Acta Forestalia Fennica no. 160 article id 7594. https://doi.org/10.14214/aff.7594
English title: Measurement of stand classification based on height over age: Part 3.

The data used to control the developed methods are presented in chapter two. The third chapter presents the statistical analysis conducted. The factor analysis shows that tree stand characteristics must be divided into three factors to able the information needed for site indexing to distinguish different site classes. The phases of model development are presented and the results of calculations with control data are shown.   

The results indicate that for calculations of nature-normal forests the suitable amount of tree stand characters for creating the site indexing function, is three.  These are: number of trees (N), basal area of the stand (G) and mean height (H).

The PDF contains a summary in Finnish. 

  • Kangas, ORCID ID:E-mail:
article id 7586, category Article
Yrjö Kangas. (1976). Die Messung der Bestandesbonität: 1-2 Teil: Theoretische Grundlagen. Acta Forestalia Fennica no. 152 article id 7586. https://doi.org/10.14214/aff.7586
English title: Measurement of stand classification based on height over age: Part 1-2: Theoretical basis.

The article is the first part of a wider project aiming to study the measurement practices of stand’s height-over-age based classifications and to develop new methods for actually measuring the side index.  

The first part of the article presents the concepts of site indexing and discusses it with a mathematical model. The second part of the article examines the structure of site indexing system regarding the reliability of the method. Third part presents the factors affecting the method development and the fourth part discusses the possible site index classes and their characteristics.   

The PDF contains a summary in Finnish. 

  • Kangas, ORCID ID:E-mail:

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