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Articles containing the keyword 'evolution'.

Category: Commentary

article id 528, category Commentary
Annikki Mäkelä, Thomas J. Givnish, Frank Berninger, Thomas N. Buckley, Graham D. Farquhar, Pertti Hari. (2002). Challenges and opportunities of the optimality approach in plant ecology. Silva Fennica vol. 36 no. 3 article id 528. https://doi.org/10.14214/sf.528
A meeting was held in Hyytiälä, Finland 10–12 April 2000 to assess critically the current challenges and limitations of the optimality approach in plant ecophysiology and botany. This article summarises the general discussions and views of the participants on the use of optimisation models as tools in plant ecophysiological research. A general framework of the evolutionary optimisation problem is sketched with a review of applications, typically involved with balanced regulation between parallel processes. The usefulness and limitations of the approach are discussed in terms of published examples, with special reference to model testing. We conclude that, regardless of inevitable problems of model formulation, wider application of the optimality approach could provide a step forward in plant ecophysiology. A major role of evolutionary theory in this process is simply the formulation of testable hypotheses, the evaluation of which can lead to important advances in our ecophysiological understanding and predictive ability.
  • Mäkelä, University of Helsinki, Dept. of Forest Ecology, P.O. Box 27, FIN-00014 University of Helsinki, Finland ORCID ID:E-mail: annikki.makela@helsinki.fi (email)
  • Givnish, University of Wisconsin, Department of Botany, Madison, WI 53706 USA ORCID ID:E-mail:
  • Berninger, University of Helsinki, Dept. of Forest Ecology, P.O. Box 27, FIN-00014 University of Helsinki, Finland ORCID ID:E-mail:
  • Buckley, Cooperative Research Centre for Greenhouse Accounting and Environmental Biology Group, and Research School of Biological Sciences, Australian National University, ACT 2601, Australia ORCID ID:E-mail:
  • Farquhar, Cooperative Research Centre for Greenhouse Accounting and Environmental Biology Group, and Research School of Biological Sciences, Australian National University, ACT 2601, Australia ORCID ID:E-mail:
  • Hari, University of Helsinki, Dept. of Forest Ecology, P.O. Box 27, FIN-00014 University of Helsinki, Finland ORCID ID:E-mail:

Category: Research article

article id 1140, category Research article
Miguel Fabra Crespo, Olli Saastamoinen, Jukka Matero, Hannes Mäntyranta. (2014). Perceptions and realities: public opinion on forests and forestry in Finland, 1993–2012. Silva Fennica vol. 48 no. 5 article id 1140. https://doi.org/10.14214/sf.1140
Highlights: Analysis of the longest-running survey in the world on public perceptions of forestry; Comparison of perceptions with realities in forestry in Finland; The role of the forests and their management is well regarded by the Finns; More protection of the forests and better performance by the wood industry is demanded.
The perception of the Finns about forests and forestry has been tracked over a period of more than 15 years. The results of this survey constitute the longest sequence of data of this type at the national level anywhere in the world. The people’s perception of reality represents a factor that influences decisions about policy. For this reason, it deserves monitoring and analysis. Forests in Finland are highly meaningful to the people, who are generally well informed and link their opinions to the facts that they are able to observe. The variability of the responses over the years of the survey is not significant. Silviculture and forest management are perceived as good by most Finns. Finns are aware that more forest grows than is harvested, and they also know that some raw material is still imported. However, they demand that more forest be protected. Finns are aware that their forest industry is not performing well at the international level. They also demand an increased wood supply for building construction. Forest harvesting is viewed as a source of employment and welfare.
  • Fabra Crespo, School of Forest Sciences, University of Eastern Finland, P.O. Box 111, FI-80101 Joensuu, Finland ORCID ID:E-mail: mfabracrespo@yahoo.com (email)
  • Saastamoinen, School of Forest Sciences, University of Eastern Finland, P.O. Box 111, FI-80101 Joensuu, Finland ORCID ID:E-mail: olli.saastamoinen@uef.fi
  • Matero, School of Forest Sciences, University of Eastern Finland, P.O. Box 111, FI-80101 Joensuu, Finland ORCID ID:E-mail: materojukka@gmail.com
  • Mäntyranta, Finnish Forest Association, Salomonkatu 17 A, FI-00100 Helsinki, Finland ORCID ID:E-mail: hannes.mantyranta@smy.fi
article id 211, category Research article
Timo Pukkala. (2009). Population-based methods in the optimization of stand management. Silva Fennica vol. 43 no. 2 article id 211. https://doi.org/10.14214/sf.211
In Finland, the growth and yield models for tree stands are simulation programs that consist of several sub-models. These models are often non-smooth and non-differentiable. Direct search methods such as the Hooke-Jeeves algorithm (HJ) are suitable tools for optimizing stand management with this kind of complicated models. This study tested a new class of direct search methods, namely population-based methods, in the optimization of stand management. The tested methods were differential evolution, particle swarm optimization, evolution strategy, and the Nelder-Mead method. All these methods operate with a population of solution vectors, which are recombined and mutated to obtain new candidate solutions. The management schedule of 719 stands was optimized with all population-based methods and with the HJ method. The population-based methods were competitive with the HJ method, producing 0.57% to 1.74% higher mean objective function values than HJ. On the average, differential evolution was the best method, followed by particle swarm optimization, evolution strategy, and Nelder-Mead method. However, differences between the methods were small, and each method was the best in several stands. HJ was alone the best method in 7% of stands, and a population based method in 3% (Nelder-Mead) to 29% (differential evolution) of stands. All five methods found the same solution in 18% of stands.
  • Pukkala, University of Joensuu, Faculty of Forest Sciences, P.O. Box 111, FI-80101 Joensuu, Finland ORCID ID:E-mail: timo.pukkala@joensuu.fi (email)
article id 211, category Research article
Timo Pukkala. (2009). Population-based methods in the optimization of stand management. Silva Fennica vol. 43 no. 2 article id 211. https://doi.org/10.14214/sf.211
In Finland, the growth and yield models for tree stands are simulation programs that consist of several sub-models. These models are often non-smooth and non-differentiable. Direct search methods such as the Hooke-Jeeves algorithm (HJ) are suitable tools for optimizing stand management with this kind of complicated models. This study tested a new class of direct search methods, namely population-based methods, in the optimization of stand management. The tested methods were differential evolution, particle swarm optimization, evolution strategy, and the Nelder-Mead method. All these methods operate with a population of solution vectors, which are recombined and mutated to obtain new candidate solutions. The management schedule of 719 stands was optimized with all population-based methods and with the HJ method. The population-based methods were competitive with the HJ method, producing 0.57% to 1.74% higher mean objective function values than HJ. On the average, differential evolution was the best method, followed by particle swarm optimization, evolution strategy, and Nelder-Mead method. However, differences between the methods were small, and each method was the best in several stands. HJ was alone the best method in 7% of stands, and a population based method in 3% (Nelder-Mead) to 29% (differential evolution) of stands. All five methods found the same solution in 18% of stands.
  • Pukkala, University of Joensuu, Faculty of Forest Sciences, P.O. Box 111, FI-80101 Joensuu, Finland ORCID ID:E-mail: timo.pukkala@joensuu.fi (email)
article id 211, category Research article
Timo Pukkala. (2009). Population-based methods in the optimization of stand management. Silva Fennica vol. 43 no. 2 article id 211. https://doi.org/10.14214/sf.211
In Finland, the growth and yield models for tree stands are simulation programs that consist of several sub-models. These models are often non-smooth and non-differentiable. Direct search methods such as the Hooke-Jeeves algorithm (HJ) are suitable tools for optimizing stand management with this kind of complicated models. This study tested a new class of direct search methods, namely population-based methods, in the optimization of stand management. The tested methods were differential evolution, particle swarm optimization, evolution strategy, and the Nelder-Mead method. All these methods operate with a population of solution vectors, which are recombined and mutated to obtain new candidate solutions. The management schedule of 719 stands was optimized with all population-based methods and with the HJ method. The population-based methods were competitive with the HJ method, producing 0.57% to 1.74% higher mean objective function values than HJ. On the average, differential evolution was the best method, followed by particle swarm optimization, evolution strategy, and Nelder-Mead method. However, differences between the methods were small, and each method was the best in several stands. HJ was alone the best method in 7% of stands, and a population based method in 3% (Nelder-Mead) to 29% (differential evolution) of stands. All five methods found the same solution in 18% of stands.
  • Pukkala, University of Joensuu, Faculty of Forest Sciences, P.O. Box 111, FI-80101 Joensuu, Finland ORCID ID:E-mail: timo.pukkala@joensuu.fi (email)

Category: Review article

article id 694, category Review article
Gösta Eriksson. (1998). Evolutionary forces influencing variation among populations of Pinus sylvestris. Silva Fennica vol. 32 no. 2 article id 694. https://doi.org/10.14214/sf.694
The evolutionary forces influencing genetic differentiation among populations are identified. Natural selection, random genetic drift, and mutations promote differentiation while phenotypic plasticity and gene flow delay or prevent differentiation. Evolution is a dynamic force which leads to instability and absence of any perfection in the adaptive process. Natural selection acts mainly on phenotypes and only indirectly on the components of important breeding traits. In the northern part of the distribution of Scots pine there is a large among- and within-population variation in survival. The high among-population variation occurs in spite of an assumed high gene flow. Biomass is a product of many components and it also shows a high population variation. Many markers are neutral and such markers will not reveal adaptive variation.
  • Eriksson, Swedish University of Agricultural Sciences, Department of Forest Genetics, Uppsala, Sweden ORCID ID:E-mail: gosta.eriksson@sgen.slu.se (email)

Category: Article

article id 7067, category Article
Aimo Kaarlo Cajander. (1921). Einige Reflexionen über die Entstehung der Arten inbesondere innerhalb der Gruppe der Holzwächse. Acta Forestalia Fennica vol. 21 no. 3 article id 7067. https://doi.org/10.14214/aff.7067
English title: Reflections on the evolution of the species, especially on arborescent plants.

The most abundant tree species occur in different variants in different geographical regions. They differ in their genetic, biological and partly also in morphological characters, however making clear difference between these subspecies is not possible. The different subspecies have developed according the respective areas' climatic and soil conditions, developing adaptive characters. These subspecies play a great role in practical forest management, since they differ in for forestry important characters, such as cold tolerance or stem form. 

The subspecies hybridize with each other in areas where their distribution areas overlap. In these areas the subspecies cannot be always clearly defined.   

  • Cajander, ORCID ID:E-mail:
article id 7067, category Article
Aimo Kaarlo Cajander. (1921). Einige Reflexionen über die Entstehung der Arten inbesondere innerhalb der Gruppe der Holzwächse. Acta Forestalia Fennica vol. 21 no. 3 article id 7067. https://doi.org/10.14214/aff.7067
English title: Reflections on the evolution of the species, especially on arborescent plants.

The most abundant tree species occur in different variants in different geographical regions. They differ in their genetic, biological and partly also in morphological characters, however making clear difference between these subspecies is not possible. The different subspecies have developed according the respective areas' climatic and soil conditions, developing adaptive characters. These subspecies play a great role in practical forest management, since they differ in for forestry important characters, such as cold tolerance or stem form. 

The subspecies hybridize with each other in areas where their distribution areas overlap. In these areas the subspecies cannot be always clearly defined.   

  • Cajander, ORCID ID:E-mail:

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