Current issue: 53(3)

Under compilation: 53(4)

Impact factor 1.683
5-year impact factor 1.950
Silva Fennica 1926-1997
1990-1997
1980-1989
1970-1979
1960-1969
Acta Forestalia Fennica
1953-1968
1933-1952
1913-1932

Articles containing the keyword 'flower'.

Category: Research article

article id 10150, category Research article
Petri Forsström, Jouni Peltoniemi, Miina Rautiainen. (2019). Seasonal dynamics of lingonberry and blueberry spectra. Silva Fennica vol. 53 no. 2 article id 10150. https://doi.org/10.14214/sf.10150
Highlights: Seasonal series of multiangular spectra for lingonberry (Vaccinium vitis-idaea L.) and blueberry (Vaccinium myrtillus L.); Decidous blueberry has strong seasonal pattern while temporal variations of evergreen lingonberry were linked to phenological stages of flowering and berrying; Detection of flowers and berries from shrub spectra was possible; Collected spectral data are openly available through SPECCHIO Spectral Information System.

Accurate mapping of the spatial distribution of understory species from spectral images requires ground reference data which represent the prevailing phenological stage at the time of image acquisition. We measured the spectral bidirectional reflectance factors (BRFs, 350–2500 nm) at varying view angles for lingonberry (Vaccinium vitis-idaea L.) and blueberry (Vaccinium myrtillus L.) throughout the growing season of 2017 using Finnish Geospatial Research Institute’s FIGIFIGO field goniometer. Additionally, we measured spectra of leaves and berries of both species, and flowers of lingonberry. Both lingonberry and blueberry showed seasonality in visible and near-infrared spectral regions which was linked to occurrences of leaf growth, flowering, berrying, and leaf senescence. The seasonality of spectra differed between species due to different phenologies (evergreen vs. deciduous). Vegetation indices, normalized difference vegetation index (NDVI), moisture stress index (MSI), plant senescence reflectance index (PSRI), and red-edge inflection point (REIP2), showed characteristic seasonal trends. NDVI and PSRI were sensitive to the presence of flowers and berries of lingonberry, while with blueberry the effects were less evident. Off-nadir observations supported differentiating the dwarf shrub species from each other but showed little improvement for detection of flowers and berries. Lingonberry and blueberry can be identified by their spectral signatures if ground reference data are available over the entire growing season. The spectral data measured in this study are reposited in the publicly open SPECCHIO Spectral Information System.

  • Forsström, Aalto University, School of Engineering, Department of Built Environment, FI-00076 Aalto, Finland ORCID ID: https://orcid.org/0000-0002-2357-2517 E-mail: petri.forsstrom@aalto.fi (email)
  • Peltoniemi, Finnish Geospatial Research Institute (FGI), Department of Geodesy and Geodynamics, Geodeetinrinne 2, FI-02430 Masala, Finland ORCID ID: https://orcid.org/0000-0002-4701-128X E-mail: jouni.peltoniemi@nls.fi
  • Rautiainen, Aalto University, School of Engineering, Department of Built Environment, FI-00076 Aalto, Finland; Aalto University, Department of Electronics and Nanoengineering, FI-00076 Aalto, Finland ORCID ID: https://orcid.org/0000-0002-6568-3258 E-mail: miina.a.rautiainen@aalto.fi
article id 7772, category Research article
Curt Almqvist. (2018). Improving floral initiation in potted Picea abies by supplemental light treatment. Silva Fennica vol. 52 no. 2 article id 7772. https://doi.org/10.14214/sf.7772
Highlights: Supplemental light treatment:
  • Increases the proportion of genotypes initiating reproductive buds.
  • Increases floral induction, especially of female floral buds.
  • Facilitates breeding programmes, and seed production of highly improved base material from new selections for vegetative production programmes, to be more efficient.

Light is an important environmental factor for all green plants. Its intensity, spectral composition and photoperiod can affect the regulatory pathways in plants that lead to floral initiation. In this report, results are presented from three experiments in which supplemental light with metal halide lamps (250 µmol m–2 s–1, 20 hours day–1, approx. 6 weeks) was tested as a complement to other flowering stimulation treatments (elevated temperature, treatment with gibberellin A4 and A 7 (GA4/7), restricted water supply) applied to potted Picea abies (L.) Karst. in the greenhouse. Flower stimulation in a greenhouse resulted in more floral initiation compared to flower stimulation outdoors. Supplemental light treatment increased floral initiation further, and to a larger extent in female than in male flowers. It also increased the proportion of trees and genotypes that induced reproductive buds. In a practical application of the supplemental light treatment to potted Picea abies breeding material, 90.6% of the clones produced either female or male flowers, or both. A subset of the same material kept outdoors, and thus subjected to natural light and temperatures, produced no flowers despite being treated with GA4/7 and receiving a restricted water supply. In conclusion, supplemental light treatment facilitates breeding programmes, and seed production of highly improved base material from new selections for vegetative production programmes, to be more efficient.

  • Almqvist, Skogforsk (The Forestry Research Institute of Sweden), Uppsala Science Park, 751 83 Uppsala, Sweden ORCID ID: http://orcid.org/0000-0001-5739-4854 E-mail: curt.almqvist@skogforsk.se (email)
article id 5643, category Research article
Katarzyna A. Jadwiszczak, Stanisław Kłosowski, Iwona Zalewska, Agata Banaszek, Agnieszka Chrzanowska. (2017). Genetic diversity and sexual reproduction in relict populations of Betula nana. Silva Fennica vol. 51 no. 2 article id 5643. https://doi.org/10.14214/sf.5643
Highlights: Genetic diversity parameters and meiotic recombination frequencies in the relict populations were comparable to those from widespread localities; Contribution of seeds without ovule was very high; Fully developed seeds germinated better in central populations; Significant differences of groundwater parameters were observed between relict and central populations.

In the present study, the impact of geographical isolation and habitat conditions on genetic diversity and sexual reproduction was tested in four relict populations of dwarf birch Betula nana L. in Poland and Belarus. Amplified fragment length polymorphism (AFLP) method revealed that the endangered central European stands were not genetically extirpated compared with the widespread localities from Finland and Russia, which can result from infrequent outcrossing events in long-living clonal populations. However, genetic clustering methods indicated significant differentiation of the Polish populations because of their small sizes and long-term geographical isolation. Considerable numbers of empty seeds were observed in both relict and central locations, although fully developed seeds germinated better in widespread populations. Analysis of groundwater chemical parameters indicated that two relict populations were significantly different from the remaining samples with respect to pH, electrical conductivity and concentrations of phosphorus ions, which can also influence the efficiency of sexual reproduction. In the light of results obtained it seems that endangered B. nana localities are relatively stable.

  • Jadwiszczak, Institute of Biology, University of Białystok, Ciołkowskiego 1J, 15-245 Białystok, Poland ORCID ID: http://orcid.org/0000-0002-9345-8891 E-mail: jadwiszczak2010@gmail.com (email)
  • Kłosowski, Department of Environment Protection and Modelling, The Jan Kochanowski University, Świętokrzyska 15, 25-406 Kielce, Poland ORCID ID:E-mail: stanislaw.klosowski@ujk.kielce.pl
  • Zalewska, Faculty of Pharmacy, Medical University of Białystok, Mickiewicza 2a, 15-222 Białystok, Poland ORCID ID:E-mail: iwonazalewska1988@gmail.com
  • Banaszek, Institute of Biology, University of Białystok, Ciołkowskiego 1J, 15-245 Białystok, Poland ORCID ID:E-mail: banaszek@uwb.edu.pl
  • Chrzanowska, Institute of Biology, University of Białystok, Ciołkowskiego 1J, 15-245 Białystok, Poland ORCID ID:E-mail: maga.chrzanowska@gmail.com
article id 131, category Research article
Timo Pukkala, Tatu Hokkanen, Teijo Nikkanen. (2010). Prediction models for the annual seed crop of Norway spruce and Scots pine in Finland. Silva Fennica vol. 44 no. 4 article id 131. https://doi.org/10.14214/sf.131
Many studies indicate that the flowering abundance of boreal trees strongly correlates with the weather conditions of the previous summer. This study developed prediction models for the seed crops of Norway spruce and Scots pine using weather variables one and two years prior to flowering year as predictors. Weather data, systematically recorded at many weather stations, were obtained from the Finnish Meteorological Institute. Seed crop monitoring data came from 22 spruce stands and 44 pine stands. In every stand, seed crop has been monitored for many years, the longest continuous period being 45 years. Monthly mean temperatures, monthly rainfalls, and periodical temperature sums were used as predictors in the seed crop models. Generally, both tree species flowered abundantly one year after a warm summer and two years after a cool summer. While the models only explained about 45% of the variation in the annual seed crop, they accurately predicted good and bad seed years: when the models predicted good seed crops the likelihood to have at least a medium seed crop was very high and when the models predicted small seed crops, the likelihood to obtain medium or good seed crop was very low. Therefore, the models reliably predict if a particular year will be a good seed year or a poor seed year. These predictions can be used in forestry practice for proper timing of natural regeneration activities, and when activities in seed orchards are planned.
  • Pukkala, University of Eastern Finland, School of Forest Sciences, P.O. Box 111, FI-80101 Joensuu, Finland ORCID ID:E-mail: timo.pukkala@uef.fi (email)
  • Hokkanen, Finnish Forest Research Institute, P.O. Box 18, FI-01301 Vantaa, Finland ORCID ID:E-mail:
  • Nikkanen, Finnish Forest Research Institute, Finlandiantie 18, FI-58450 Punkaharju, Finland ORCID ID:E-mail:
article id 482, category Research article
Yaye Kène Gassama-Dia, Djibril Sané, Mansor N'Doye. (2003). Reproductive biology of Faidherbia albida (Del.) A. Chev. Silva Fennica vol. 37 no. 4 article id 482. https://doi.org/10.14214/sf.482
Phenology, flowering and fructification were studied in 5 natural populations of Faidherbia albida in a semi-arid zone in Senegal. In this species, the inflorescence acts as the reproductive unit; the basal flowers, opening first, have a low rate of fertilisation; the maximum rate of fertilisation (65%) was obtained in the apical flowers. Stigmatic receptivity, tested by esterasic reaction, was maximal immediately after anthesis. Stigmata of F. albida can bear simultaneously 2 or 3 polyads. Controlled pollination revealed that allogamy is the dominant reproductive system (ISI = 0.2) in natural populations of F. albida. Intra-specific variability in selfing (ISI ranging from 0 to 0.54) was also observed. Despite of the complete reproductive mechanism during flowering, only a small number of ripe pods (1.25%) is produced, and an average of 70% of the ovules per carpel are fertilized.
  • Gassama-Dia, Université Cheikh Anta Diop de Dakar, Faculté des Sciences et Techniques, Département de biologie végétale, Dakar, Sénégal ORCID ID:E-mail: ykdia@ucad.sn (email)
  • Sané, Université Cheikh Anta Diop de Dakar, Faculté des Sciences et Techniques, Département de biologie végétale, Dakar, Sénégal ORCID ID:E-mail:
  • N'Doye, Université Cheikh Anta Diop de Dakar, Faculté des Sciences et Techniques, Département de biologie végétale, Dakar, Sénégal ORCID ID:E-mail:
article id 602, category Research article
Teijo Nikkanen. (2001). Reproductive phenology in a Norway spruce seed orchard. Silva Fennica vol. 35 no. 1 article id 602. https://doi.org/10.14214/sf.602
Reproductive phenology was studied in a Norway spruce seed orchard, located in southern Finland (62°13’N, 25°24’E), consisting of 67 clones from northern Finland (64°–67°N). Timing of flowering was determined on the basis of data recorded by a pollen catch meter during 1984–1995, and visual observations made on grafts in 1989, 1992, 1993 and 1995. The genetic and environmental factors affecting female and male phenology, and reproductive synchronisation were studied. The between-year variation in the timing of flowering was more than three weeks. However, when it was defined on the basis of the effective temperature sum, the variation was smaller. No phenological reproductive isolation was found between the seed orchard and surrounding natural forests. The duration of the receptive period of the seed orchard varied from 5 to 8 days, and anthesis determined on the basis of airborne pollen from 5 to 10 days. The receptive period started about one day earlier than anthesis, except in one abnormally warm flowering period when female and male flowering started simultaneously. In general, the flowering periods of the different clones overlapped. The clonal differences in the phenology of receptivity were in most cases statistically significant, but in pollen shedding they were not. The broad-sense heritability estimates were higher for female than for male phenology. Environmental factors, conversely, had a stronger effect on male phenology. A wide graft spacing and a graft position that favoured solar radiation on the lower parts of the crown promoted early pollen shedding and, subsequently, better reproductive synchronisation between female and male flowering.
  • Nikkanen, Finnish Forest Research Institute, Punkaharju Research Station, FIN-58451 Punkaharju, Finland ORCID ID:E-mail: teijo.nikkanen@metla.fi (email)
article id 647, category Research article
Tapio Linkosalo. (1999). Regularities and patterns in the spring phenology of some boreal trees. Silva Fennica vol. 33 no. 4 article id 647. https://doi.org/10.14214/sf.647
Phenological time series of flowering and bud burst of Populus tremula (L.) and Betula sp., and the flowering of Pinus sylvestris (L.), Alnus glutinosa (L.) and Alnus incana (L.) were constructed from data collected in Finland during the period 1896–1955. The resulting combined time series were examined with two aims in mind: first, to determine the phenological regularities between different species and, second, to detect patterns of spring advancement over a geographically large area. The results indicate that the geographical pattern of spring advancement is rather uniform from year to year, and between different species. Furthermore, the mechanisms regulating the timing of phenological events in different species seem to function in a similar way, suggesting an unanimous optimal response to climatic conditions.
  • Linkosalo, University of Helsinki, Department of Forest Ecology, Unioninkatu 40 B, P.O. Box 24, FIN-00014 University of Helsinki, Finland ORCID ID:E-mail: tapio.linkosalo@helsinki.fi (email)

Category: Article

article id 5542, category Article
Leena Ryynänen, Anneli Viherä-Aarnio. (1995). Growth, crown structure and seed production of birch seedlings, grafts and micropropagated plants. Silva Fennica vol. 29 no. 1 article id 5542. https://doi.org/10.14214/sf.a9193

Growth, crown structure, flowering and seed production of silver birch (Betula pendula Roth) seedlings, grafts and micropropagated plants was compared during four years in a polythene greenhouse experiment. The growth of the seedlings was clearly the most vigorous and that of the grafts the weakest, the micropropagated plants being intermediate. The seedlings had the highest and the grafts the lowest number of branches before cutting the tops of the plants, but the differences between the material types were no more significant after cutting the tops. The grafts had significantly shorter and thinner branches than the seedlings and the micropropagated plants, whereas the differences in branch length and branch thickness between the latter two groups were not significant. The grafts started flowering at the age of two years, one year earlier than the other two types of material. At the age of four years the micropropagated plants had abundant seed production, about 75% of that of the seedlings and about two times higher than that of the grafts. Thus, the micropropagated plants can be used instead of grafts when establishing polythene greenhouse seed orchards of birch.

  • Ryynänen, ORCID ID:E-mail:
  • Viherä-Aarnio, ORCID ID:E-mail:
article id 5530, category Article
Anna Saarsalmi, Erkki Lipas, Jouni Mikola, Teijo Nikkanen, Eira-Maija Savonen. (1994). Effect of fertilization on flowering and seed crop in Scots pine seed orchards. Silva Fennica vol. 28 no. 3 article id 5530. https://doi.org/10.14214/sf.a9170

The aim of the study was to obtain information needed in preparing more precise fertilization recommendations for seed orchards. The fertilization requirement was estimated on basis of soil and needle analyses, and by investigating the effects of different fertilization treatments on male and female flowering, size of seed crop and seed quality.

The study was carried out in two Scots pine (Pinus sylvestris L.) seed orchards in Southern Finland, one established on forest soil in 1971 and 1972, and the other on a peat field in 1974. 10 clones and 39 grafts from each clone were selected randomly from both orchards in autumn 1985. The treatments consisted of N, P and K in various combinations, micronutrients, wood ash and grass control. The orchards were fertilized in spring 1986.

There were statistically significant differences between the clones in both orchards as regards amount of flowers, size of the seed crop and seed quality. The annual variation in flowering and the size of the seed crop was also large. In general, the seeds from cones collected in October matured well and their germination percentage was high. The effects of fertilization on flowering, the size of seed crop and seed quality were small. It would appear that the size of the crop can be affected to a much greater extent by favouring clones with a high seed-producing capacity than through fertilization. Fertilization is unnecessary if the nutrient status of the soil is satisfactory.

  • Saarsalmi, ORCID ID:E-mail:
  • Lipas, ORCID ID:E-mail:
  • Mikola, ORCID ID:E-mail:
  • Nikkanen, ORCID ID:E-mail:
  • Savonen, ORCID ID:E-mail:
article id 5464, category Article
Donald I. Dickmann. (1991). Role of physiology in forest tree improvement. Silva Fennica vol. 25 no. 4 article id 5464. https://doi.org/10.14214/sf.a15622

The paper introduces different ways plant physiology research can avail the process of tree improvement. The breeding of tree cultivars that efficiently produce a particular wood product or amenity will be an important aspect of forest management. What physiologist can provide to breeders and genetic engineers is the opportunity to move their work from empirical level towards a more theoretical level, and help to make breeding more predictable and more precise in its objectives. The areas of research discussed in the paper are biotechnology, flowering, selection criteria, adaptability and application of ideotypes.

  • Dickmann, ORCID ID:E-mail:
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. https://doi.org/10.14214/sf.a15620

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, ORCID ID:E-mail:
article id 5311, category Article
Timo Pukkala. (1987). Kuusen ja männyn siemensadon ennustemalli. Silva Fennica vol. 21 no. 2 article id 5311. https://doi.org/10.14214/sf.a15468
English title: Model for predicting the seed crop of Picea abies and Pinus sylvestris.

The seed crop of Norway spruce (Picea abies (L.) H. Karst.) and Scots pine (Pinus sylvestris L.) is predicted with the help of mean monthly temperatures during May–August one and two years before the flowering year. The prediction models were made separately for Lapland and for the rest of Finland. The models are based on 10-year periods of seed crop measurements and climatic data. The total number of time series was 59.

In Lapland, Norway spruce flowered abundantly and produced an abundant seed crop after warm July–August and two years after cool July–August. In other parts of Finland, warm June and July produced a good flowering year, especially if these months were cool two years before the flowering year.

In Lapland, Scots pine flowered abundantly if the whole previous growing season was warm. Elsewhere in Finland, a cool June preceded prolific flowering in the coming year if the rest of the growing season was considerably warmer than the average.

The prediction models explained 37–49 % of the variation in the size of the seed crop. The occurrence of good and poor seed years was usually predicted correctly. Using the presented models, the prediction of the seed crop is obtainable 1.5 year for Norway spruce and 2.5 year for Scots pine before the year of seed fall.

The PDF includes an abstract in English.

  • Pukkala, ORCID ID:E-mail:
article id 5129, category Article
Olavi Luukkanen. (1981). Effects of gibberellins GA4 and GA7 on flowering in Scots pine grafts. Silva Fennica vol. 15 no. 4 article id 5129. https://doi.org/10.14214/sf.a15186

Ethanolic sprays of GA4 or GA7 on 9-year old Scots pine (Pinus sylvestris L.) grafts, repeated four times during the shoot elongation period, resulted in a statistically significant increase in female flowering one year after the treatment. Of the two compounds, GA4 seemed to be somewhat more efficient, yielding 47 female strobili/100 shoots vs. 36 and 6 strobili/100 shoots in GA7 and control treatments respectively. The mixture of GA4 and GA7 compounds was also applied and seemed to have an effect intermediary to those of the pure compounds. However, due to the limited amounts of material, none of the differences between the gibberellins could be statistically confirmed. Male flowering frequencies were also too low to allow any firm conclusions, but the numerical results suggested that the purified gibberellins may promote male and female flowering in different ways.

The PDF includes a summary in Finnish.

  • Luukkanen, ORCID ID:E-mail:
article id 5129, category Article
Olavi Luukkanen. (1981). Effects of gibberellins GA4 and GA7 on flowering in Scots pine grafts. Silva Fennica vol. 15 no. 4 article id 5129. https://doi.org/10.14214/sf.a15186

Ethanolic sprays of GA4 or GA7 on 9-year old Scots pine (Pinus sylvestris L.) grafts, repeated four times during the shoot elongation period, resulted in a statistically significant increase in female flowering one year after the treatment. Of the two compounds, GA4 seemed to be somewhat more efficient, yielding 47 female strobili/100 shoots vs. 36 and 6 strobili/100 shoots in GA7 and control treatments respectively. The mixture of GA4 and GA7 compounds was also applied and seemed to have an effect intermediary to those of the pure compounds. However, due to the limited amounts of material, none of the differences between the gibberellins could be statistically confirmed. Male flowering frequencies were also too low to allow any firm conclusions, but the numerical results suggested that the purified gibberellins may promote male and female flowering in different ways.

The PDF includes a summary in Finnish.

  • Luukkanen, ORCID ID:E-mail:
article id 5129, category Article
Olavi Luukkanen. (1981). Effects of gibberellins GA4 and GA7 on flowering in Scots pine grafts. Silva Fennica vol. 15 no. 4 article id 5129. https://doi.org/10.14214/sf.a15186

Ethanolic sprays of GA4 or GA7 on 9-year old Scots pine (Pinus sylvestris L.) grafts, repeated four times during the shoot elongation period, resulted in a statistically significant increase in female flowering one year after the treatment. Of the two compounds, GA4 seemed to be somewhat more efficient, yielding 47 female strobili/100 shoots vs. 36 and 6 strobili/100 shoots in GA7 and control treatments respectively. The mixture of GA4 and GA7 compounds was also applied and seemed to have an effect intermediary to those of the pure compounds. However, due to the limited amounts of material, none of the differences between the gibberellins could be statistically confirmed. Male flowering frequencies were also too low to allow any firm conclusions, but the numerical results suggested that the purified gibberellins may promote male and female flowering in different ways.

The PDF includes a summary in Finnish.

  • Luukkanen, ORCID ID:E-mail:
article id 5070, category Article
Olavi Luukkanen, Stig Johansson. (1980). Flower induction by exogenous plant hormones in Scots pine and Norway spruce grafts. Silva Fennica vol. 14 no. 1 article id 5070. https://doi.org/10.14214/sf.a15011

The aim of the present study was to establish whether hormone treatments would promote flowering in Scots pine (Pinus sylvestris L.) and Norway spruce (Picea abies (L.) H. Karst.) grafts under Finnish conditions. Also, an attempt was made to test the efficiency of hormones as well as the variation in response among different clones. Six Scots pine and six Norway spruce clones were selected in each seed orchard based on their flowering intensity, and treated with growth hormones (GA, NAA) of different dosages by spraying. Flowering was observed one year after the treatments.

None of the treated or untreated spruce grafts flowered. However, poor flowering in the natural stands indicated that the environmental conditions during the previous years did not favour flowering. On the other hand, a distinct increase in flowering in Scots pine was observed as a result of spraying with hormone solutions. Treatments with gibberellin had a distinct promoting effect both on male and female flowering in the Scots pine grafts, although the responses varied between the different hormones or clones. The relative effect was generally stronger in male flowering.

The PDF includes a summary in Finnish.

  • Luukkanen, ORCID ID:E-mail:
  • Johansson, ORCID ID:E-mail:
article id 5067, category Article
Veikko Koski. (1980). On the variation of flowering and seed crop in mature stands of Pinus sylvestris L. Silva Fennica vol. 14 no. 1 article id 5067. https://doi.org/10.14214/sf.a15008

The paper discusses the variation of flowering and seed crop of Scots pine (Pinus sylvestris L.) stands based on literature published in Finland. According to the studies, the list of good seed years given by different authors do not completely match, and no essentially new about the periodicity of the seed crop or the causes of variation has been found. The difficulty in classification of the seed crops in different years in different stands and locations can be handled through the concept of capacity. It is suggested in the paper that to be able to compare the occurrence of good flowering and seed years of different stands and localities, a case exceeding 50% of the capacity is described as abundant, and a case exceeding 75% as very heavy.

The PDF includes a summary in Finnish.

  • Koski, ORCID ID:E-mail:
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. https://doi.org/10.14214/sf.a14754
English title: Development and germination of the seeds of conifers according to literature.

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, ORCID ID:E-mail:
  • Pahkala, ORCID ID:E-mail:
article id 4868, category Article
Mikko Tormilainen. (1972). Havaintoja Oitin siemenviljelyksen mäntykloonien kukinnasta ja käpysadosta. Silva Fennica vol. 6 no. 2 article id 4868. https://doi.org/10.14214/sf.a14671
English title: Studies of flowering and cone crop in a seed orchard of Scots pine.

Male and female flowering, cone crop, and some vegetative characteristics were studied in grafts 10 to 16 years of age in a clonal seed orchard of Scots pine (Pinus sylvestris L.). Genetic variation was found between clones in flowering as well as in cone production. Clone evaluation resulted in similar classifications of clones in different years. A regression analysis showed that crown size clearly increased but previous height growth slightly decreased flowering and cone production. The percentage of pollinated female strobili did not differ between clones.

The PDF includes a summary in English.

  • Tormilainen, ORCID ID:E-mail:
article id 4854, category Article
G. M. Kozubov. (1971). Elektronimikroskooppisia tutkimuksia männyn ja kuusen kukka-aiheiden kehityksestä. Silva Fennica vol. 5 no. 4 article id 4854. https://doi.org/10.14214/sf.a14656
English title: Electron microscopic studies in the development of strobile primordia of Scots pine and Norway spruce.

This article is an abstract from a lecture given in Helsinki on 2.12.1970. Physiological differences in different parts of developing primordia of micro- and macrostrobiles are manifested in the ultrastructure of the cell tissues. In electron microscopy, the study off metabolic activities can be combined with the anatomical examination of the flower primordia.

The generative cells of Scots pine (Pinus sylvestris L.) and Norway spruce (Picea abies (L.) H. Karst.) develop under the strong metabolic activity of surrounding layers of cells. Simultaneously the activity and development of the organelles in generative cells becomes hindered, and these inhibitions will exist until the fertilization. It can be concluded that the higher the gradient of sexualization of the cells in different parts of flower primordia, the weaker the metabolic activity in these cells.

The PDF includes a summary in English.

  • Kozubov, ORCID ID:E-mail:
article id 7523, category Article
Alpo Luomajoki. (1999). Differences in the climatic adaptation of silver birch (Betula pendula) and downy birch (B. pubescens) in Finland based on male flowering phenology. Acta Forestalia Fennica no. 263 article id 7523. https://doi.org/10.14214/aff.7523

Male flowering was studied at the canopy level in 10 silver birch (Betula pendula Roth) stands from 8 localities and 14 downy birch (B. pubescens Ehrh.) stands from 10 localities in Finland in 1963–73. Distribution of cumulative pollen catches was compared to the normal Gaussian distribution. The basis for timing of flowering was the 50% point of the anthesis-fitted normal distribution. To eliminate effects of background pollen, only the central, normally distributed part of the cumulative distribution was used. Development was measured and tested in calendar days, in degree days (> 5°C) and in period units. The count of the parameters began in March 19.

Male flowering in silver birch occurred from late April to late June depending on latitude, and flowering in downy birch took place from early May to early July. The heat sums needed for male flowering varied in downy birch stands latitudinally but there was practically no latitudinal variation in silver birch flowering. The amount of male flowering in stands of the both species were found to have a large annual variation but without any clear periodicity.

The between years pollen catch variation in stands of either birch species did not show any significant latitudinal correlation in contrast to Norway spruce stands. The period unit heat sum gave the most accurate forecast of the timing of flowering for 60% of the silver birch stands and for 78.6% of the downy birch stands. Silver birch seems to have a local inclination for a more fixed flowering date compared to downy birch, which could mean a considerable photoperiodic influence on flowering time of silver birch. The species had different geographical correlations.

Frequent hybridization of the birch species occurs more often in Northern Finland than in more southerly latitudes. The different timing in the flowering causes increasing scatter in flowering times in the north, especially in the case of downy birch. Thus, the change of simultaneous flowering of the species increases northwards due to a more variable climate and higher altitudinal variation. Compared with conifers, the reproduction cycles of the two birch species were found to be well protected from damage by frost.

  • Luomajoki, ORCID ID:E-mail:
article id 7523, category Article
Alpo Luomajoki. (1999). Differences in the climatic adaptation of silver birch (Betula pendula) and downy birch (B. pubescens) in Finland based on male flowering phenology. Acta Forestalia Fennica no. 263 article id 7523. https://doi.org/10.14214/aff.7523

Male flowering was studied at the canopy level in 10 silver birch (Betula pendula Roth) stands from 8 localities and 14 downy birch (B. pubescens Ehrh.) stands from 10 localities in Finland in 1963–73. Distribution of cumulative pollen catches was compared to the normal Gaussian distribution. The basis for timing of flowering was the 50% point of the anthesis-fitted normal distribution. To eliminate effects of background pollen, only the central, normally distributed part of the cumulative distribution was used. Development was measured and tested in calendar days, in degree days (> 5°C) and in period units. The count of the parameters began in March 19.

Male flowering in silver birch occurred from late April to late June depending on latitude, and flowering in downy birch took place from early May to early July. The heat sums needed for male flowering varied in downy birch stands latitudinally but there was practically no latitudinal variation in silver birch flowering. The amount of male flowering in stands of the both species were found to have a large annual variation but without any clear periodicity.

The between years pollen catch variation in stands of either birch species did not show any significant latitudinal correlation in contrast to Norway spruce stands. The period unit heat sum gave the most accurate forecast of the timing of flowering for 60% of the silver birch stands and for 78.6% of the downy birch stands. Silver birch seems to have a local inclination for a more fixed flowering date compared to downy birch, which could mean a considerable photoperiodic influence on flowering time of silver birch. The species had different geographical correlations.

Frequent hybridization of the birch species occurs more often in Northern Finland than in more southerly latitudes. The different timing in the flowering causes increasing scatter in flowering times in the north, especially in the case of downy birch. Thus, the change of simultaneous flowering of the species increases northwards due to a more variable climate and higher altitudinal variation. Compared with conifers, the reproduction cycles of the two birch species were found to be well protected from damage by frost.

  • Luomajoki, ORCID ID:E-mail:
article id 7504, category Article
Alpo Luomajoki. (1993). Kuusen sopeutuminen Suomen ilmastoon hedekukkimisaikojen perusteella arvioituna. Acta Forestalia Fennica no. 242 article id 7504. https://doi.org/10.14214/aff.7504
English title: Climatic adaptation of Norway spruce (Picea abies (L.) Karsten) in Finland based on male flowering phenology.

Anthesis was studied at the canopy level in 10 Norway spruce (Picea abies (L.) H. Karst.) stands from 9 localities in Finland was studied in 1963-74. Distribution of pollen catches were compared with the normal Gaussian distribution. The basis for the timing studies was the 50% point of the anthesis-fitted normal distribution. Development was characterized in calendar days, in degree days (>5°C) and in period units. The count of each unit began on March 19 (included). Male flowering in Norway spruce stands was found to have more annual variation in quantity than in Scots pine (Pinus sylvestris L.) stands studied earlier.

Anthesis in spruce in Northern Finland occurred at a later date than in the south. The heat sums needed for anthesis varied latitudinally less in spruce than in pine. The variation of pollen catches in spruce increased towards north-west as in the case of Scots pine. In the unprocessed data, calendar days were found to be the most accurate forecast of anthesis in Norway spruce. Locally, the period unit could be a more accurate parameter for the stand average. However, on a calendar day basis, when annual deviations between expected and measured heat sums were converted to days, period units were narrowly superior to days.

The geographical correlations respected to timing of flowering, calculated against distances measured along simulated post-glacial micgation routes, were stronger than purely latitudinal correlations. Effects of the reinvasion of Norway spruce into Finland are thus still visible in spruce populations just as they were in Scots pine populations.

The proportion of the average annual heat sum needed for spruce anthesis grew rapidly north of a latitude of ca. 63° and the heat sum needed for anthesis decreased only slightly towards the timberline. In light of flowering phenology, it seems probable that north-western third of Finnish Norway spruce populations are incompletely adapted to the prevailing cold climate. A moderate warming of the climate would therefore be beneficial for Norway spruce. This accords roughly with the adaptive situation in Scots pine

The PDF includes a summary in Finnish.

  • Luomajoki, ORCID ID:E-mail:
article id 7683, category Article
Alpo Luomajoki. (1993). Climatic adaptation of Scots pine (Pinus sylvestris L.) in Finland based on male flowering phenology. Acta Forestalia Fennica no. 237 article id 7683. https://doi.org/10.14214/aff.7683

Timing of anthesis in 21 Scots pine (Pinus sylvestris L.) stands from 14 localities in Finland was studied at the canopy level in 1963-74. Distribution of pollen catches were compared with the normal Gaussian distribution. The basis for the timing studies was the 50 per cent point of the anthesis-fitted normal distribution. Development was characterized in calendar days, in degree days (>5°C) and in period units. The count of each unit began on March 19 (included).

Period unit was found to be the most accurate delineation of development. Locally, calendar days were sometimes a more accurate parameter. Anthesis in Northern Finland occurred at a later date than in the south as was expected, but at lower heat sum. The variation in the timing of anthesis and the variation of pollen catches increased northwards. The geographical correlations calculated against distances measured along simulated post-glacial migration routes were stronger than purely latitudinal correlations. Effects of the reinvasion of Scots pine into Finland are thus still visible in pine populations.

The proportion of the average annual heat sum needed for anthesis grew rapidly above a latitude of 63° even though the heat sum needed for anthesis decreased towards the timberline. In light of flowering phenology, it seemed probable that the northern populations in Scots pine in Finland have still not completely adapted to the prevailing cold climate at these latitudes. A moderate warming of the climate would therefore be beneficial for Scots pine.

The PDF includes a summary in Finnish.

  • Luomajoki, ORCID ID:E-mail:
article id 7616, category Article
Min-Sup Chung. (1981). Flowering characteristics of Pinus sylvestris L. with special emphasis on the reproductive adaptation to local temperature factor. Acta Forestalia Fennica no. 169 article id 7616. https://doi.org/10.14214/aff.7616

Flowering time and characteristics of cones and seed development of Scots pine (Pinus sylvestris L.) plus tree clones originating from various parts of Finland and planted (grafts) in Southern Finland (61° 48’ N, 29° 19’ E) were studied during 1976-1978.

The flowering time (in terms of period unit (p.u.) sums for flowering) of the Scots pine plus tree clones showed characteristics specific to each population and the characteristics appear mainly adapted to the local temperature factor within Finland. Generally, the development of floral organs, cones and seed in the spring and summer seasons also showed a temperature dependence in that the reproductive organs are developed rapidly and/or favourably under higher temperature conditions within its optimum range.

In this respect, establishment of northern Scots pine seed orchards in Central or Southern Finland or an optimum flowering, and a favourable seed development with an optimum physiological reproductive isolation from surrounding Scots pine populations can be justified. Problem arising from the north-south transfer of seed orchards and the significance of trees’ growth rhythm are discussed in connection with tree improvement.

The PDF includes a summary in Finnish.

  • Chung, ORCID ID:E-mail:

Register
Click this link to register for Silva Fennica submission and tracking system.
Log in
If you are a registered user, log in to save your selected articles for later access.
Contents alert
Sign up to receive alerts of new content
Your selected articles

Committee on Publication Ethics A Trusted Community-Governed Archive