Category :
Article
article id 7626,
category
Article
Aarne Nyyssönen,
Risto Ojansuu.
(1982).
Metsikön puutavaralajirakenteen, arvon ja arvokasvun arviointi.
Acta Forestalia Fennica
no.
179
article id 7626.
https://doi.org/10.14214/aff.7626
English title:
Assessment of timber assortments, value and value increment of stands in Finland.
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The paper is the final report of a study on the estimation of value increment and inherent variables of Scots pine (Pinus sylvestris L.) and Norway spruce (Picea abies (L.) H. Karst.) stands. The main aim was to obtain improved criteria for decision-making concerning the priority of stands for regeneration.
The construction of various estimation models and their reliability are discussed in detail. The study, together with some previous papers, has resulted in a system which on the basis of a number of easily assessed stand variables gives for the stands concerned the volume of stems, percentages of timber assortments, stumpage value, volume increment and value increment.
The following examples are given with regard to the practical application of the results, in addition to the determination of the relative maturity of stands: 1) The study of various trends in stand development; the comparison between the volume and value variables. 2) The estimation of timber assortments needed for a cutting budget, trees marked for felling etc. 3) The calculation of the value of forests.
The PDF includes a summary in English.
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Nyyssönen,
E-mail:
an@mm.unknown
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Ojansuu,
E-mail:
ro@mm.unknown
article id 7624,
category
Article
English title:
Dynamics of early development of tree stand.
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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.
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Hari,
E-mail:
ph@mm.unknown
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Kellomäki,
E-mail:
sk@mm.unknown
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Mäkelä,
E-mail:
am@mm.unknown
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Ilonen,
E-mail:
pi@mm.unknown
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Kanninen,
E-mail:
mk@mm.unknown
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Korpilahti,
E-mail:
ek@mm.unknown
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Nygren,
E-mail:
mn@mm.unknown
Category :
Research article
article id 1564,
category
Research article
Stanislav Vacek,
Zdeněk Vacek,
Lukáš Bílek,
Jaroslav Simon,
Jiří Remeš,
Iva Hůnová,
Jan Král,
Tereza Putalová,
Miroslav Mikeska.
(2016).
Structure, regeneration and growth of Scots pine (Pinus sylvestris L.) stands with respect to changing climate and environmental pollution.
Silva Fennica
vol.
50
no.
4
article id 1564.
https://doi.org/10.14214/sf.1564
Highlights:
Pine forest stands showed positive development of stand structural characteristics related to their diversity, number of regeneration individuals and growth characteristics; Tree-ring width was positively correlated with precipitation, while it was negatively correlated with temperature in growing seasons; Mean NOx concentrations showed positive effect on radial growth of pine; Serious defoliation was caused by SO2 concentrations and N deposition in combination with extreme climate events.
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Changes in the structure and development of managed Scots pine (Pinus sylvestris L.) stands with respect to changing environmental conditions were set for the period 1979–2015. The study was conducted in conditions of natural pinewoods and pine-oak sites on five permanent research plots (0.25 ha) in Eastern Bohemia, Czech Republic (CR). Studied forest stands showed positive development of stand structural characteristics related to their diversity, number of regeneration individuals and growth characteristics. The standing volume of regularly distributed tree layer in 2015 was in the range of 320–434 m3 ha–1, which indicates an increase by 5.9–20.0% over 10 years. Correlation between pine radial increment and the amount of precipitation was generally the strongest one. Positive statistically significant correlation between diameter increment and temperature was demonstrated only for the average March temperature of the current year. Within the CR, study site can be characterised as a medium polluted area both for sulphur and nitrogen, despite this SO2 concentrations and N deposition in combination with extreme climate events caused severe defoliation in pine stands. Conversely, radial growth was positively significantly correlated with mean NOx concentrations. Drought mainly in combination with even medium environmental pollution can further worsen the health status of pine stands in lowland areas of Central Europe. Thus, formulation of silvicultural techniques able to mitigate the impact of these stress factors is needed.
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Vacek,
Czech University of Life Sciences Prague, Faculty of Forestry and Wood Sciences, Kamýcká 129, 165 21 Prague, Czech Republic
E-mail:
vacekstanislav@fld.czu.cz
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Vacek,
Czech University of Life Sciences Prague, Faculty of Forestry and Wood Sciences, Kamýcká 129, 165 21 Prague, Czech Republic
E-mail:
vacekz@fld.czu.cz
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Bílek,
Czech University of Life Sciences Prague, Faculty of Forestry and Wood Sciences, Kamýcká 129, 165 21 Prague, Czech Republic
E-mail:
bilek@fld.czu.cz
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Simon,
Mendel University in Brno, Faculty of Forestry and Wood Technology, Zemědělská 3, 613 00 Brno, Czech Republic
E-mail:
jaroslav.simon@mendelu.cz
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Remeš,
Czech University of Life Sciences Prague, Faculty of Forestry and Wood Sciences, Kamýcká 129, 165 21 Prague, Czech Republic
E-mail:
remesj@email.cz
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Hůnová,
Czech Hydrometeorological Institute, Na Šabatce 17 143 06 Prague, Czech Republic
E-mail:
hunova@chmi.cz
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Král,
Czech University of Life Sciences Prague, Faculty of Forestry and Wood Sciences, Kamýcká 129, 165 21 Prague, Czech Republic
E-mail:
kraljan@fld.czu.cz
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Putalová,
Czech University of Life Sciences Prague, Faculty of Forestry and Wood Sciences, Kamýcká 129, 165 21 Prague, Czech Republic
E-mail:
putalova@fld.czu.cz
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Mikeska,
University of Hradec Králové, Faculty of Science, Rokitanského 62, 500 03 Hradec Králové, Czech Republic
E-mail:
Mikeska.Miroslav@uhul.cz
article id 395,
category
Research article
Lauri Mehtätalo.
(2005).
Height-diameter models for Scots pine and birch in Finland.
Silva Fennica
vol.
39
no.
1
article id 395.
https://doi.org/10.14214/sf.395
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Height-Diameter (H-D) models for two shade-intolerant tree species were estimated from longitudinal data. The longitudinal character of the data was taken into account by estimating the models as random effects models using two nested levels: stand and measurement occasion level. The results show that the parameters of the H-D equation develop over time but the development rate varies between stands. Therefore the development of the parameters is not linked to the stand age but to the median diameter of the basal-area weighted diameter distribution (DGM). Models were estimated with different predictor combinations in order to produce appropriate models for different situations. The estimated models can be localized for a new stand using measured heights and diameters, presumably from different points in time, and the H-D curves can be projected into the future.
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Mehtätalo,
Finnish Forest Research Institute, Joensuu Research Centre, P.O. Box 68, FI-80101 Joensuu, Finland
E-mail:
lauri.mehtatalo@metla.fi
article id 579,
category
Research article
Matti Maltamo,
Kalle Eerikäinen.
(2001).
The Most Similar Neighbour reference in the yield prediction of Pinus kesiya stands in Zambia.
Silva Fennica
vol.
35
no.
4
article id 579.
https://doi.org/10.14214/sf.579
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The aim of the study was to develop a yield prediction model using the non-parametric Most Similar Neighbour (MSN) reference method. The model is constructed on stand level but it contains information also on tree level. A 10-year projection period was used for the analysis of stand growth. First, the canonical correlation matrix was calculated for the whole study material using stand volumes at the beginning and at the end of the growth period as independent variables and stand characteristics as dependent variable. Secondly, similar neighbour estimates were searched from the data categories reclassified according to thinnings. Due to this, it was possible to search for growth and yield series which is as accurate as possible both at the beginning and at the end of the growth period. The reliability of the MSN volume predictions was compared to the volumes predicted with the simultaneous yield model. The MSN approach was observed to be more reliable volume predictor than the traditional stand level yield prediction model both in thinned and unthinned stands.
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Maltamo,
Faculty of Forestry, University of Joensuu, P.O. Box 111, FIN-80101 Joensuu, Finland
E-mail:
matti.maltamo@forest.joensuu.fi
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Eerikäinen,
Faculty of Forestry, University of Joensuu, P.O. Box 111, FIN-80101 Joensuu, Finland
E-mail:
ke@nn.fi
article id 668,
category
Research article
Hannu Hökkä,
Timo Penttilä.
(1999).
Modelling the dynamics of wood productivity on drained peatland sites in Finland.
Silva Fennica
vol.
33
no.
1
article id 668.
https://doi.org/10.14214/sf.668
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The dynamics of wood productivity on drained peatland sites was analyzed from the covariance structure generated by stand yield data of repeatedly measured permanent sample plots in 81 Scots pine (Pinus sylvestris L.) or Norway spruce (Picea abies Karst. (L.)) stands with admixtures of birch (Betula pubescens Ehrh.). The site production potential, considered a latent variable, was assumed to follow an autoregressive process over time elapsed since drainage. As a measure of the latent variable, a relative growth rate (RGR) index was determined for all stands at the time of drainage and at four successive measurement time points following drainage (on average 16, 23, 30, and 41 years). The index was calculated as the site index of an upland conifer stand with the ratio of periodic volume growth and standing volume and adjusted by changes in stand stocking and thinning. The observed covariance structure was described by fitting a structural equation model to the data of RGR indices. When only the post-drainage measurement times were included, a quasi-simplex model with equal error variances and equal structural parameters at different measurement times fit the data well indicating a permanent covariance structure among the different measurements. Including the measurement at the time of drainage resulted in a non-permanent structure. The stand parameters at the time of drainage were poorly correlated with post-drainage growth. A considerable increase in the wood productivity of the sites was observed, being greatest during twenty years after drainage and continuing up to 40 years since drainage. This was concluded to be due to changes in site properties rather than stand structure although the effects of the single factors could not be analytically separated from one another. Our modelling approach appeared to improve long-term site productivity estimates based merely on botanical site indices.
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Hökkä,
Finnish Forest Research Institute, Rovaniemi Research Station, PO Box 16, 96301 Rovaniemi, Finland
E-mail:
hannu.hokka@metla.fi
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Penttilä,
Finnish Forest Research Institute, Rovaniemi Research Station, PO Box 16, 96301 Rovaniemi, Finland
E-mail:
tp@nn.fi