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Silva Fennica 1926-1997
Acta Forestalia Fennica

Articles containing the keyword 'conifers'

Category: Article

article id 5462, category Article
Wladyslaw Chalupka. (1991). Usefulness of hormonal stimulation in the production of genetically improved seeds. Silva Fennica vol. 25 no. 4 article id 5462.
Keywords: conifers; seed orchards; seed production; flowering regulation; growth regulation; gibberellins
Abstract | View details | Full text in PDF | Author Info

Application of growth regulators, primarily gibberellins, has become an efficient method of flowering regulation in many coniferous forest trees. In this paper some results are discussed with respect to various genetic processes in seed orchards. It is concluded that there are still several unsolved problems in the regulation of flowering in forest seed orchards. These problems are related to different genetic processes occurring in the seed orchards and they should be taken into account in endeavouring to produce genetically improved seeds. 

  • Chalupka, E-mail: wc@mm.unknown (email)
article id 5352, category Article
Lars Christersson, Heinrich A. von Fircks. (1988). Injuries to conifer seedlings caused by simulated summer frost and winter desiccation. Silva Fennica vol. 22 no. 3 article id 5352.
Keywords: Pinus sylvestris; Picea abies; Picea mariana; conifers; frost damage; Sweden; Pinus contorta; seedlings; cold tolerance; frost hardiness in growing phase; winter desiccation
Abstract | View details | Full text in PDF | Author Info

Visible frost damage to forest trees in Sweden seldom occurs in winter but is frequent in late spring, summer and early autumn. Frosts are frequent in all seasons in various parts of Sweden, even in the southernmost part (lat. 56°, N) and temperatures may be as low as -10°C even around mid-summer. Ice crystal formation within the tissues, which in most seedlings takes place at around -2°C, causes injury, not the sub-zero temperatures themselves.

The apical meristem, the elongated zone, and the needles of seedlings of Picea abies (L.) H. Karst. in a growing phase were damaged at about -3°C and those of Pinus sylvestris L. at about -6°C. Other species of the genus Pinus were tested and most were found to be damaged at about -6°C, with some variations. Picea species tested were damaged at about -3°C to -4°C.

A method has been designed to compare the response of different species to winter desiccation, which occurs under conditions of (1) low night temperature, (2) very high irradiation and increase in needle temperature during the photoperiod, (3) frozen soil, and (4) low wind speed. There were differences in response to winter desiccation between pine and spruce species. Seedlings of Pinus contorta tolerated these winter desiccation conditions much better than those of P. sylvestris or Picea abies. Picea mariana was the least tolerant of the species tested.

The PDF includes an abstract in Finnish.

  • Christersson, E-mail: lc@mm.unknown (email)
  • Fircks, E-mail: hf@mm.unknown
article id 5339, category Article
Peitsa Mikola. (1988). Ectendomycorrhiza of conifers. Silva Fennica vol. 22 no. 1 article id 5339.
Keywords: conifers; nurseries; ectendomycorrhiza; pseudomycorrhiza; Tricharina; Wilcoxina; Tricharina mikolae
Abstract | View details | Full text in PDF | Author Info

The fungal symbiont of ectendomycorrhizae is an ascomycete Wilcoxina (Tricharina) mikolae Yang & Korf. It forms ectendomycorrhizae with Pinus and Larix and ectomycorrhizae with Abies, Picea, Pseudotsuga and Tsuga. It is common in forest nurseries around the world. After transplanting the seedlings into natural forest soil, indegenous fungi rapidly replace Wilcoxina. Inoculation of nursery soil with Wilcoxina is recommended if soil has been sterilized or for other reasons mycorrhizal fungi are absent.

The PDF includes a summary in Finnish.

  • Mikola, E-mail: pm@mm.unknown (email)
article id 5140, category Article
Lars Westman. (1981). Monitoring of coniferous forest ecosystems in Sweden. Silva Fennica vol. 15 no. 4 article id 5140.
Keywords: soil respiration; conifers; tree growth; acidification; Sweden; air pollution; monitoring programme; acid compounds; heavy metals; bioindicators; phosphatase activity
Abstract | View details | Full text in PDF | Author Info

A monitoring program is planned for the terrestrial environment around industries in Sweden, which emit acid compounds and heavy metals. Directions for the County Government Boards are being prepared. The paper deals with the present pollution situation in Sweden, based on recent scientific results, the justifications for local monitoring, and the organizing of the monitoring including the parameters suggested.

Four examples from a case study at an oil power station illustrate reporting of the data and the difficulties in interpreting the results. The examples are the distribution of a lichen indicator, heavy metal content and phosphatase activity in the moor layer, soil respiration and tree growth.

  • Westman, E-mail: lw@mm.unknown (email)
article id 4910, category Article
Erkki Lähde, Katri Pahkala. (1974). Havupuiden siemenen kehitys ja itäminen kirjallisuuden valossa. Silva Fennica vol. 8 no. 4 article id 4910.
English title: Development and germination of the seeds of conifers according to literature.
Original keywords: kylvö; havupuut; itäminen; esi-idätysmenetelmä; kukkiminen; siementen kehitys; pölytys
English keywords: germination; flowering; conifers; pollination; seeds; sowing; seeding; development of seeds; pre-germination method
Abstract | View details | Full text in PDF | Author Info

The aim of the present study was to collect information presented in literature concerning the development and germination of the seeds of coniferous trees with special reference to those species which thrive in the conditions prevailing in Finland. Along with the increase in the importance of direct seeding as a silvicultural means in Northern Finland, there is a growing demand for methods by means of which the germination of seeds could be promoted. According to the results obtained from previous studies, such a method can be found, provided that a practically usable and reliable pre-germination method is developed.

The PDF includes a summary in English.

  • Lähde, E-mail: el@mm.unknown (email)
  • Pahkala, E-mail: kp@mm.unknown

Category: Article

article id 7517, category Article
Juha Nurmi. (1997). Heating values of mature trees. Silva Fennica vol. 0 no. 256 article id 7517.
Keywords: biomass; conifers; tree species; lignin; broadleaved trees; heating value; logging residue; carbohydrates
Abstract | View details | Full text in PDF | Author Info

The effective heating values of the above and below ground biomass components of mature Scots pine (Pinus sylvestris L.), Norway spruce (Picea abies (L.) H. Karst.), downy birch (Betula pubescens Ehrh), silver birch (B. pendula Roth), grey alder (Alnus incana (L.) Moench), black alder (A. glutinosa (L.) Gaertn.) and aspen (Populus tremula L.) were studied. Each sample tree was divided into wood, bark and foliage components. Bomb calorimetry was used to determine the calorimetric heating values.

The species is a significant factor in the heating value of individual tree components. The heating value of the wood proper is highest in conifers. Broadleaved species have a higher heating value of bark than conifers. The species factor diminishes when the weighted heating value of crown, whole stems or stump-root-system are considered. The crown material has a higher heating value per unit weight in comparison with fuelwood from small-sized stems or whole trees. The additional advantages of coniferous crown material are that it is non-industrial biomass resource and is readily available. The variability of both the chemical composition and the heating value is small in any given tree component of any species. However, lignin, carbohydrate and extractive content were found to vary from one part of the tree to another and to correlate with the heating value

  • Nurmi, E-mail: jn@mm.unknown (email)

Category: Research article

article id 1721, category Research article
Anna Hebda, Błażej Wójkiewicz, Witold Wachowiak. (2017). Genetic characteristics of Scots pine in Poland and reference populations based on nuclear and chloroplast microsatellite markers. Silva Fennica vol. 51 no. 2 article id 1721.
Keywords: Pinus sylvestris; phylogeography; conifers; genetic divergence; population structure; microsatellite markers; neutral variation
Highlights: Similar genetic variation was found between Polish Scots pine populations from a wide variety of habitats based on nSSR and cpSSR markers; Homogeneity was observed in the genetic structures of Polish and Finnish populations from the continuous pine range; Genetic differentiation in microsatellite markers was identified only when populations from the central pine distribution were compared to the marginal stands.
Abstract | Full text in HTML | Full text in PDF | Author Info

Polymorphisms at a set of eighteen nuclear (nSSR) and chloroplast (cpSSR) microsatellite loci were investigated in sixteen populations of Scots pine (Pinus sylvestris L.) derived from the provenance trial experiment and representative of the species distribution range and climatic zones in Poland. The patterns of genetic variation were compared to the reference samples from the species distribution in Europe and Asia. A similar level of genetic variation and no evidence of population structure was found among the Polish stands. They showed genetic similarity and homogenous patterns of allelic frequency spectra compared to the Northern European populations. Those populations were genetically divergent compared to the marginal populations from Turkey, Spain and Scotland. The population structure patterns reflect the phylogeography of the species and the divergence of populations that most likely do not share recent history. As the analysed provenance trial populations from Poland are diverged in phenotypic traits but are genetically similar, they could be used to test for selection at genomic regions that influence variation in quantitative traits.

  • Hebda, University of Agriculture in Krakow, Faculty of Forestry, Institute of Forest Ecology and Silviculture, Department of Genetics and Forest Tree Breeding, 29 Listopada 46, 31-425 Kraków, Poland ORCID E-mail: (email)
  • Wójkiewicz, Institute of Dendrology, Polish Academy of Sciences, Parkowa 5, 62-035 Kórnik, Poland E-mail:
  • Wachowiak, Institute of Dendrology, Polish Academy of Sciences, Parkowa 5, 62-035 Kórnik, Poland; Institute of Environmental Biology, Faculty of Biology, Adam Mickiewicz University, Umultowska 89, 61-614 Poznań, Poland E-mail:
article id 138, category Research article
Santiago Martín-Alcón, José Ramón González-Olabarría, Lluís Coll. (2010). Wind and snow damage in the Pyrenees pine forests: effect of stand attributes and location. Silva Fennica vol. 44 no. 3 article id 138.
Keywords: models; stand structure; conifers; Pyrenees; snow damages; stability; wind damages
Abstract | View details | Full text in PDF | Author Info
Wind and snow-induced damage have been analyzed at stand level for three pine forests in the Central-Eastern Pyrenees (Pinus nigra Arn. salzmanii, Pinus sylvestris L. and Pinus uncinata Ram.). Stand-level models have been then developed for the most affected two species, Pinus sylvestris L. and Pinus uncinata Ram., to describe damage severity. The models were based on data from national forest inventory plots. They included variables related to the spatial location and structure of the stands, being validated using a sub-set of the database (25% of the plots randomly selected). Mountain pine forests (Pinus uncinata Ram.) were the most heavily affected by wind and snow disturbances. For both mountain and Scots pine species, topographic exposure and the severity of the local storm regime had an important effect on the degree of damage. Stand’s resistance to wind and snow was found to be dependent on the combined effect of basal area and mean slenderness of the dominant trees. For a given slenderness ratio, damage increased strongly in lower-density stands, particularly in stands with basal areas below 15 m2/ha. Stand structure was particularly important to define the resistance of Scots pine stands, which presented a higher vulnerability to wind and snow under higher degree of even-agedness. The models presented in this study provide empirically-based information that can be used to implement silvicultural practices to minimize the risk of those forests to suffer wind and snow-related damages.
  • Martín-Alcón, Forest Technology Center of Catalonia, Solsona, Lleida, Spain E-mail: (email)
  • González-Olabarría, Forest Technology Center of Catalonia, Solsona, Lleida, Spain E-mail:
  • Coll, Forest Technology Center of Catalonia, Solsona, Lleida, Spain E-mail:
article id 532, category Research article
Pedro J. Aphalo, Anna W. Schoettle, Tarja Lehto. (2002). Leaf life span and the mobility of “non-mobile” mineral nutrients – the case of boron in conifers. Silva Fennica vol. 36 no. 3 article id 532.
Keywords: needle age; conifers; model; boron; leaf life span; nutrient mobility; toxicity
Abstract | View details | Full text in PDF | Author Info
Nutrient conservation is considered important for the adaptation of plants to infertile environments. The importance of leaf life spans in controlling mean residence time of nutrients in plants has usually been analyzed in relation to nutrients that can be retranslocated within the plant. Longer leaf life spans increase the mean residence time of all mineral nutrients, but for non-mobile nutrients long leaf life spans concurrently cause concentrations in tissues to increase with leaf age, and consequently may reduce non-mobile nutrient use efficiency. Here we analyze how the role of leaf life span is related to the mobility of nutrients within the plant. We use optimality concepts to derive testable hypotheses, and preliminarily test them for boron (B), a nutrient for which mobility varies among plant species. We review published and unpublished data and use a simple model to assess the quantitative importance of B retranslocation for the B budget of mature conifer forests and as a mechanism for avoiding toxicity.
  • Aphalo, Faculty of Forestry, University of Joensuu, P.O. Box 111, FIN-80101 Joensuu, Finland; Current address Department of Biological and Environmental Science, University of Jyväskylä, P.O. Box 35, FIN-40351 Jyväskylä, Finland. E-mail: (email)
  • Schoettle, Rocky Mountain Research Station, 240 West Prospect Road, Fort Collins, CO 80526, USA E-mail:
  • Lehto, Faculty of Forestry, University of Joensuu, P.O. Box 111, FIN-80101 Joensuu, Finland E-mail:

Category: Review article

article id 1416, category Review article
Ulf Sikström, Hannu Hökkä. (2015). Interactions between soil water conditions and forest stands in boreal forests with implications for ditch network maintenance. Silva Fennica vol. 50 no. 1 article id 1416.
Keywords: peatland; forest drainage; conifers; tree growth; drainage intensity; ditch deterioration; forest water use; ground-water table; profitability
Highlights: Ditch network maintenance (DNM) may influence soil water conditions less than initial ditching due to reduced hydraulic conductivity of the peat; Stand stocking and management substantially influence soil-water conditions; DNM can lower the GWL and increase tree growth; DNM growth responses of 0.5–1.8 m3 ha–1 yr–1 during 15–20-years in Scots pine peatland stands reported; Greatest need for DNM in the early phase of a stand rotation; Need for better understanding of the link between soil water and tree growth.
Abstract | Full text in HTML | Full text in PDF | Author Info

At sites with either peat or mineral soils in large areas of boreal forests, high soil-water contents hamper tree growth and drainage can significantly increase growth. Hence, areas covering about 15 × 106 ha of northern peatlands and wet mineral soils have been drained for forestry purposes. Usually ditches gradually deteriorate, thus reducing their functionality as drains, and ditch-network maintenance (DNM) might be needed to maintain stand growth rates enabled by the original ditching. This article reviews current knowledge on establishing the need for DNM in boreal forest stands, subsequent growth responses, and the financial outcome of the activity. The issues covered in the review are: (i) ditching, changes in ditches over time and the need for DNM; (ii) interactions between soil water and both stand properties and stand management; (iii) ground-water level (GWL) and tree growth responses to DNM; and (iv) financial viability of DNM. Conclusions about the current understanding of issues related to DNM are drawn and implications for DNM in practice are summarized. Finally, gaps in knowledge are identified and research needs are suggested.

  • Sikström, The Forestry Research Institute of Sweden (Skogforsk), Uppsala Science Park, SE-751 83 Uppsala, Sweden E-mail: (email)
  • Hökkä, Natural Resources Institute Finland (Luke), Management and Production of Renewable Resources, P.O. Box 16, FI-96301 Rovaniemi, Finland E-mail:

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