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Silva Fennica 1926-1997
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Articles containing the keyword 'hybrid'

Category: Article

article id 5531, category Article
Anneli Viherä-Aarnio, Anna Saarsalmi. (1994). Growth and nutrition of willow clones. Silva Fennica vol. 28 no. 3 article id 5531. https://doi.org/10.14214/sf.a9171
Keywords: biomass; short rotation forestry; fuelwood; nutrients; clones; hybridization; Salix
Abstract | View details | Full text in PDF | Author Info

Growth and nutrition of 20 clones representing different species and interspecific hybrids of willows (Salix spp.) growing on an abandoned field were studied. There were highly significant differences between the clones as regards the survival, number of sprouts per stool, sprout mean height and diameter and stem biomass production per stool. The differences between the clones in the concentration of all nutrients in both the leaves and stems were highly significant. 

  • Viherä-Aarnio, E-mail: av@mm.unknown (email)
  • Saarsalmi, E-mail: as@mm.unknown
article id 4901, category Article
Veli Pohjonen. (1974). Istutustiheyden vaikutus eräiden lyhytkiertoviljelyn puulajien ensimmäisen vuoden satoon ja pituuskasvuun. Silva Fennica vol. 8 no. 2 article id 4901. https://doi.org/10.14214/sf.a14745
English title: Effect of spacing on the first-year yield and height increment of some species undergoing short rotation culture.
Original keywords: pituuskasvu; hybridihaapa; harmaaleppä; kiiltopaju; lyhytkiertoviljely; istutustiheys; tuotto; satotaso; vesipaju
English keywords: yield; height growth; Alnus incana; Populus tremula x Populus tremuloides; Populus x wettsteinii; Salix ’Aquatica Gigantea’; Salix phylicifolia; short rotation cultivation
Abstract | View details | Full text in PDF | Author Info

The effect of spacing on the first-year yield and height increment of Alnus incana (L.) Moench, Populus tremula L. x Populus tremuloides Michx. (Populus x wettsteinii), Salix ’Aquatica Gigantea’, and Salix phylicifolia L. was studied at the Arctic Circle Agricultural Experimental Station in Northern Finland. S. ’Aquatica Gigantea’ gave yields which were twice as high as those of the other species in the study. The highest yields were of the order of 60 tons per hectare (fresh yield including foliage). The annual height growth in S. ’Aquatica Gigantea’ was about 100 cm, in the others about 30–50 cm. S. ’Aquatica Gigantea’ had a maximal height growth when the distance between the seedlings was 25 cm.

The PDF includes a summary in English.

  • Pohjonen, E-mail: vp@mm.unknown (email)
article id 4871, category Article
Kari Löyttyniemi. (1972). Hybridihaavikoiden hyönteistuhoista. Silva Fennica vol. 6 no. 3 article id 4871. https://doi.org/10.14214/sf.a14678
English title: Insect damages in hybrid aspen stands.
Original keywords: hyönteistuhot; hybridihaapa
English keywords: hybrid aspen; insect damages; Populus tremula x Populus tremuloides; Saperda populnea; Saperda carcharias; Chionaspis salicis; Populus x wettsteinii
Abstract | View details | Full text in PDF | Author Info

Hybrid aspen (Populus tremula L. x Populus tremuloides Michx.) has been grown in Finland for about 20 years, and the area of the stands is currently about 400 ha. Growing is planned to be greatly expanded to grow raw material for match industry. The aim of this investigation was to study susceptibility of hybrid aspen to insect damages. Insect damages in hybrid aspen, growing in Southern Finland, were examined in 15 stands in 1972. Saperda species were observed to be the most numerous and harmful insect species. Saperda carcharias L. occurred in 26% and Saperda populnea L. in 36% off trees inspected. Mass occurrence of Chionaspis salicis L. was observed in some sample areas.

  • Löyttyniemi, E-mail: kl@mm.unknown (email)
article id 4858, category Article
Tauno Kallio. (1972). Erään 10-vuotiaan hybridihaapametsikön lahovikaisuus. Silva Fennica vol. 6 no. 1 article id 4858. https://doi.org/10.14214/sf.a14661
English title: Decay in a ten-year old stand of hybrid aspen.
Original keywords: sienitaudit; laho; hybridihaapa; bakteerit
English keywords: hybrid aspen; decay; fungal diseases; bacteria; Populus tremula x Populus tremuloides
Abstract | View details | Full text in PDF | Author Info

A ten-year old stand of hybrid aspen (Populus tremula x Populus tremuloides), growing in Southern Finland on about 1.5 ha of Oxalis-Myrtillus type (OMT) soil and affected by crown blight, was examined in 1971. The study revealed that almost all trees, both those removed by thinning and the remaining growing stock, were decayed. A number of bacteria, Fungi imperfecti species and ascomycetous fungi were isolated from the discoloured heartwood of the affected trees. No fungus of the Bacidiomycetes was found in the discoloured wood material.

The PDF includes a summary in English.

  • Kallio, E-mail: tk@mm.unknown (email)
article id 4831, category Article
Lauri Mikkola. (1970). Kuusilajien risteytyvyydestä. Silva Fennica vol. 4 no. 4 article id 4831. https://doi.org/10.14214/sf.a14620
English title: On the crossability of Picea species.
Original keywords: mänty; metsänjalostus; itävyys; kuuset; risteytys; risteytyskokeet; keinollinen pölytys
English keywords: Pinus sylvestris; Picea abies; tree breeding; Picea; Abies; controlled pollination; interspecific sterility; hybrids; crossbreeding
Abstract | View details | Full text in PDF | Author Info

Seed development was microscopically studied after controlled pollinations. In all the interspecific crosses incompatibility occured. In the following crosses the growth of all the pollen tubes stopped before they had penetrated through the nuclear cap: Picea abies (L.) Karst. x mariana, abies x jezoensis (and the reciprocal), abies x omorika (and the reciprocal), mariana x asperata, mariana x jezoensis and Picea abies x Pinus sylvestris L.

Some of the eggs were fertilized in the crosses Picea abies x glauca (and the reciprocal) abies x asperata, abies x koyamai, abies x obovata, mariana x omorika and jezoensis x omorika. Embryo degeneration was observed in all these crosses. All the embryos died in the crosses abies x glauca (and the reciprocal) as well as jezoensis x omorika. Adequate amounts of full seed for germination test was obtained from the crosses abies x asperata, abies x koyamai and abies x obovata. In all these crosses there were seeds which were able to germinate and the hybrids are now one growth season old.

The PDF includes a summary in English.

  • Mikkola, E-mail: lm@mm.unknown (email)
article id 4753, category Article
Helge Johnsson. (1967). Different ways of genetic improvement of forest trees in Scandinavia. Silva Fennica vol. 1 no. 3 article id 4753. https://doi.org/10.14214/sf.a14537
Keywords: selection; provenance; tree breeding; breeding; seed orchads; hybridization
Abstract | View details | Full text in PDF | Author Info

Transfer of southern provenances of trees to the north leads to an increased growth until the limit of hardiness is exceeded, which may be utilized in practical forestry. Selection from certain local provenances are important both for the immediate supply of seed and on a somewhat longer view. A certain degree of improvement can be achieved by avoiding minus regions and concentrating seed collection on better areas. Also, seeds can be collected from the best stands only, and by accepting only seed from the best trees of such stands. The selection can be strengthened considerably by production of seed orchards. The seed production is based on a small number of trees of particular superiority that are reproduced vegetatively. The clones are planted in an orchard, which pollinate each other.

Hybridization of two different provenances might result in an increased capacity of production. Such hybridized seed can be produced in orchards established, for instance, as a combination of selection and hybridization orchards. As regards the major Scandinavian tree species there are only small prospects of advancement through species hybridization. The method available at present for efficient racial improvement of our forest trees is individual selection in connection with seed production in orchards. In special cases, however, other methods such as transfer of provenances, provenance hybridization, species hybridization, and polyploidization will result in considerable progress.

The PDF includes a summary in English.

  • Johnsson, E-mail: hj@mm.unknown (email)

Category: Article

article id 7216, category Article
L. Cockayne. (1929). Hybridism in the forests of New Zealand. Silva Fennica vol. 34 no. 3 article id 7216. https://doi.org/10.14214/aff.7216
Keywords: tree species; hybrid; polymorphism; hybridization
Abstract | View details | Full text in PDF | Author Info

The article gives examples of hybridization of forest tree and shrub species in the forests of New Zealand. According to the article, many of the 498 vascular plant species in the forest communities of the New Zealand region must be excluded from the standpoint of hybridism, because they belong either to genera of one species or are unable to cross owing to geographical or biological isolation. The hybrids are in most cases jordanons which cross, and may be more or less distantly related or closely related. The hybrids occur usually in polymorphic groups. Most of the hybrids in New Zealand are fertile. The hybrids can affect the forest communities in two ways; by effecting their composition or their structure. The article includes a list of hybrid groups.

Jubileum publication of professor Aimo Kaarlo Cajander.

  • Cockayne, E-mail: lc@mm.unknown (email)
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. Silva Fennica vol. 0 no. 263 article id 7523. https://doi.org/10.14214/aff.7523
Keywords: Betula pendula; Betula pubescens; adaptation; seasonality; hybridization; male flowering; heat sum; timing of flowering; pollen catch; photoperiods; ecophysiological differences
Abstract | View details | Full text in PDF | Author Info

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, E-mail: al@mm.unknown (email)
article id 7657, category Article
Matti Rousi. (1990). Breeding forest trees for resistance to mammalian herbivores - a study based on European white birch. Silva Fennica vol. 0 no. 210 article id 7657. https://doi.org/10.14214/aff.7657
Keywords: Betula pendula; vole; breeding; resistance; clonal forestry; phenotypic plasticity; pests; mammals; Betula platyphylla; interspecific hybrids; climatic adaptibility; hare
Abstract | View details | Full text in PDF | Author Info

Resistance to browsing by mammals differs among birch species, and among origins and families of European white birch (Betula pendula Roth). The variation in resistance is large even among individual seedlings of the same family.

On the surface of the bark of European white birch seedlings there are resin droplets, and the number of droplets is strongly and positively correlated with resistance to browsing by hares. The resistance of European white birch apparently is not expensive metabolically because the rapid growth rate of seedlings was positively correlated with hare resistance, and no correlation was found between seedling size and vole resistance. In cafeteria experiments voles and hares were very discriminating in their feeding on birch seedlings. In field experiments, however, environmental heterogeneity partly masked differences in vole resistance among birch families. Fertilization of seedlings seems not to have a clear effect on resistance to hares. On the other hand, there were indications that greenhouse temperature had an effect on resistance to voles. Practical forestry applications of differences in resistance, e.g. use of species hybrids and clonal forestry, are discussed. The prospects for resistance breeding are good.

The PDF includes a summary in Finnish.

  • Rousi, E-mail: mr@mm.unknown (email)

Category: Research article

article id 9938, category Research article
Jyrki Hytönen, Egbert Beuker, Anneli Viherä-Aarnio. (2018). Clonal variation in basic density, moisture content and heating value of wood, bark and branches in hybrid aspen. Silva Fennica vol. 52 no. 2 article id 9938. https://doi.org/10.14214/sf.9938
Keywords: moisture content; wood; bark; hybrid aspen; basic density; branches; clonal variation; heating value; ash content
Highlights: Hybrid aspen clones differed in their moisture content, ash content, basic density and heating value; Stem wood had lower ash content, basic density and effective heating value than stem bark; There was significant vertical variation in wood and bark along the stem in moisture content and basic density.
Abstract | Full text in HTML | Full text in PDF | Author Info

Hybrid aspen (Populus tremula × P. tremuloides) is one of the fastest growing tree species in Finland. During the mid-1990s, a breeding programme was started with the aim of selecting clones that were superior in producing pulpwood. Hybrid aspen can also be grown as a short-rotation crop for bioenergy. To study clonal variation in wood and bark properties, seven clones were selected from a 12-year-old field trial located in southern Finland. From each clone, five trees were harvested and samples were taken from stem wood, stem bark and branches to determine basic density, effective heating value, moisture and ash content. Vertical within-tree variation in moisture content and basic density was also studied. The differences between clones were significant for almost all studied properties. For all studied properties there was a significant difference between wood and bark. Wood had lower ash content (0.5% vs. 3.9%), basic density (378 kg m–3 vs. 450 kg m–3) and effective heating value (18.26 MJ kg–1 vs. 19.24 MJ kg–1), but higher moisture content (55% vs. 49%) than bark. The values for branches were intermediate. These results suggest that the properties of hybrid aspen important for energy use could be improved by clonal selection. However, selecting clones based on fast growth only may be challenging since it may lead to a decrease in hybrid aspen wood density.

  • Hytönen, Natural Resources Institute Finland (Luke), Natural resources, Teknologiakatu 7, FI-67100 Kokkola, Finland E-mail: jyrki.hytonen@luke.fi (email)
  • Beuker, Natural Resources Institute Finland (Luke), Production systems, Vipusenkuja 6, FI-57200 Savonlinna, Finland E-mail: egbert.beuker@luke.fi
  • Viherä-Aarnio, Natural Resources Institute Finland (Luke), Production systems, Latokartanonkaari 9, FI-00790 Helsinki, Finland E-mail: anneli.vihera-aarnio@luke.fi
article id 1442, category Research article
Silva Šēnhofa, Mārtiņš Zeps, Roberts Matisons, Jānis Smilga, Dagnija Lazdiņa, Āris Jansons. (2015). Effect of climatic factors on tree-ring width of Populus hybrids in Latvia. Silva Fennica vol. 50 no. 1 article id 1442. https://doi.org/10.14214/sf.1442
Keywords: dendroclimatology; hybrid aspen; hybrid poplar; fast-growing hybrids; weather conditions
Highlights: Hybrid poplar and hybrid aspen were sensitive to temperature in summer and dormant periods, but none of the tested factors were strictly limiting; Hybrid poplar was sensitive to a higher number of climatic factors than hybrid aspen; Temperature showed a negative correlation with tree-ring width.
Abstract | Full text in HTML | Full text in PDF | Author Info

Fast-growing hybrids of Populus L. have an increasing importance as a source of renewable energy and as industrial wood. Nevertheless, the long-term sensitivity of Populus hybrids to weather conditions and hence to possible climatic hazards in Northern Europe have been insufficiently studied, likely due to the limited age of the trees (short rotation). In this study, the climatic sensitivity of ca. 65-year-old hybrid poplars (Populus balsamifera L. × P. laurifolia Ledeb.), growing at two sites in the western part of Latvia, and ca. 55-year-old hybrid aspens (Populus tremuloides Michx. × P. tremula L.), growing in the eastern part of Latvia, have been studied using classical dendrochronological techniques. The high-frequency variation of tree-ring width (TRW) of hybrid poplar from both sites was similar, but it differed from hybrid aspen due to the diverse parental species and geographic location of the stands. Nevertheless, some common tendencies in TRW were observed for both hybrids. Climatic factors influencing TRW were generally similar for both hybrids, but their composition differed. The strength of climate-TRW relationships was similar, but the hybrid poplar was affected by a higher number of climatic factors. Hybrid poplar was sensitive to factors related to water deficit in late summer in the previous and current years. Hybrid aspen was sensitive to conditions in the year of formation of tree-ring. Both hybrids also displayed a reaction to temperature during the dormant period. The observed climate-growth relationships suggest that increasing temperatures might burden the radial growth of the studied hybrids of Populus.

  • Šēnhofa, LSFRI “Silava”, Rigas str. 111, Salaspils, Latvia, LV2169 E-mail: silva.senhofa@gmail.com
  • Zeps, LSFRI “Silava”, Rigas str. 111, Salaspils, Latvia, LV2169 E-mail: martins.zeps@silava.lv
  • Matisons, LSFRI “Silava”, Rigas str. 111, Salaspils, Latvia, LV2169 E-mail: robism@inbox.lv (email)
  • Smilga, LSFRI “Silava”, Rigas str. 111, Salaspils, Latvia, LV2169 E-mail: janis.smilga@silava.lv
  • Lazdiņa, LSFRI “Silava”, Rigas str. 111, Salaspils, Latvia, LV2169 E-mail: dagnija.lazdina@silava.lv
  • Jansons, LSFRI “Silava”, Rigas str. 111, Salaspils, Latvia, LV2169 E-mail: aris.jansons@silava.lv
article id 1283, category Research article
Ivana Bjedov, Dragica Obratov–Petković, Danijela Mišić, Branislav Šiler, Jelena M Aleksic. (2015). Genetic patterns in range-edge populations of Vaccinium species from the central Balkans: implications on conservation prospects and sustainable usage. Silva Fennica vol. 49 no. 4 article id 1283. https://doi.org/10.14214/sf.1283
Keywords: marginal populations; genetic structure; Vaccinium sp.; the Balkans; RAPD markers; genetic profiles; interspecific hybridization
Highlights: We studied fragmentary distributed range-edge populations of Vaccinium myrtillus, Vaccinium uliginosum and Vaccinium vitis-idaea from the Balkans using RAPDs; Low genetic diversities and high genetic differentiation were found in all species; The prevalence of clonal individuals was not observed; Past interspecific hybridization among V. vitis-idaea and the other two species was detected; Guidelines for conservation and sustainable usage were provided.
Abstract | Full text in HTML | Full text in PDF | Author Info

Vaccinium myrtillus L., Vaccinium uliginosum L. and Vaccinium vitis-idaea L. are perennial, cold-adapted clonal shrubs distributed throughout Europe, northern Asia and North America. Due to their usage in food (berries) and pharmaceutical industry (berries and leaves), their natural populations are exposed to anthropogenic and other impacts that affect their genetic make-up. We analyzed 14 fragmentary distributed and small-sized peripheral populations of these species from the Balkans, which represents the southeastern-European marginal area of their wide European distributions, using RAPD molecular markers. The contemporary genetic patterns in all three species within the Balkans were generally similar, and in comparison to previous reports on populations of these species found in northward Europe, where they have a more continuous distribution, the levels of genetic diversity were more or less halved, genetic differentiation was several times higher, gene flow exceptionally low, and the expected prevalence of clonal individuals was lacking. The population dynamics of all three species within the Balkans was complex and distinct, and was characterized by a past admixture of individuals from discrete populations of the same species and interspecific hybridisation not only between V. myrtillus and V. vitis-idaea but also between V. uliginosum and V. vitis-idaea, the latter not being reported to date. Conservation measures suitable for preservation of presumably genetically distinct portions of the Balkans’ gene pools of studied species have been suggested, while the utility of interspecific hybrids in breeding programs and/ or in food/pharmaceutical industry is yet to be assessed. 

  • Bjedov, University of Belgrade, Faculty of Forestry, Kneza Višeslava 1, 11000 Belgrade, Serbia E-mail: ivana.bjedov@sfb.bg.ac.rs
  • Obratov–Petković, University of Belgrade, Faculty of Forestry, Kneza Višeslava 1, 11000 Belgrade, Serbia E-mail: dragica.obratov-petkovic@sfb.bg.ac.rs
  • Mišić, University of Belgrade, Institute for Biological Research “Siniša Stanković”, Boulevard Despota Stefana 142, 11000 Belgrade, Serbia E-mail: dmisic@ibiss.bg.ac.rs
  • Šiler, University of Belgrade, Institute for Biological Research “Siniša Stanković”, Boulevard Despota Stefana 142, 11000 Belgrade, Serbia E-mail: branislav.siler@ibiss.bg.ac.rs
  • Aleksic, University of Belgrade, Institute of Molecular Genetics and Genetic Engineering, Vojvode Stepe 444a, P.O. Box 23, 11010 Belgrade, Serbia E-mail: aleksic_jelena@yahoo.com.au (email)
article id 1135, category Research article
Matts Lindbladh, Per-Ola Hedwall, Ida Wallin, Annika M. Felton, Henrik Böhlenius, Adam Felton. (2014). Short-rotation bioenergy stands as an alternative to spruce plantations: implications for bird biodiversity. Silva Fennica vol. 48 no. 5 article id 1135. https://doi.org/10.14214/sf.1135
Keywords: Norway spruce; Picea abies; hybrid aspen; Sweden; Populus × wettsteinii; production forests
Highlights: There is a gap in knowledge regarding the biodiversity implications of replacing production forests with bioenergy stands; We compared the avian biodiversity of early rotation hybrid aspen stands and spruce plantations, the latter being the dominant production forest type in southern Sweden; Our results indicate that young hybrid aspen stands can support relatively diverse and distinctive bird communities.
Abstract | Full text in HTML | Full text in PDF | Author Info
Global efforts to decrease dependence on fossil fuels have increased interest in bioenergy production. One source of bioenergy is fast growing deciduous tree species, such as hybrid aspen (Populus × wettsteinii Hämet-Ahti). The majority of research on hybrid aspen which assesses biodiversity implications, has however primarily focused on agricultural lands as the reference condition. This has resulted in a substantial gap in our knowledge regarding the biodiversity implications of replacing production forest types with hybrid aspen, a form of reforestation taking place in northern Europe. In this study we address this knowledge gap by comparing the avian biodiversity of young hybrid aspen and spruce (Picea abies L.) plantations of similar age, the latter being the most prevalent forestry alternative in in southern Sweden. We found that hybrid aspen stands had higher bird species richness and abundance as well as a distinct community composition compared to the spruce stands. We suggest that the most likely driver was the greater structural and tree species complexity in the aspen stands, provided for by the fenced exclusion of ungulates from the regenerating hybrid aspen stands. Our results indicate that at least during early stages of regeneration, and in comparison to the dominating production forest type in the region, hybrid aspen stands can support relatively high levels of bird diversity, and a bird species composition more closely associated with broadleaf habitat types requiring restoration in this region.
  • Lindbladh, Southern Swedish Forest Research Centre, SLU – Swedish University of Agricultural Sciences, P.O. Box 49, SE-230 53 Alnarp, Sweden E-mail: matts.lindbladh@slu.se (email)
  • Hedwall, Southern Swedish Forest Research Centre, SLU – Swedish University of Agricultural Sciences, P.O. Box 49, SE-230 53 Alnarp, Sweden E-mail: per-ola.hedwall@slu.se
  • Wallin, Southern Swedish Forest Research Centre, SLU – Swedish University of Agricultural Sciences, P.O. Box 49, SE-230 53 Alnarp, Sweden E-mail: ida.wallin@slu.se
  • Felton, Southern Swedish Forest Research Centre, SLU – Swedish University of Agricultural Sciences, P.O. Box 49, SE-230 53 Alnarp, Sweden E-mail: annika.felton@slu.se
  • Böhlenius, Southern Swedish Forest Research Centre, SLU – Swedish University of Agricultural Sciences, P.O. Box 49, SE-230 53 Alnarp, Sweden E-mail: henrik.bohlenius@slu.se
  • Felton, Southern Swedish Forest Research Centre, SLU – Swedish University of Agricultural Sciences, P.O. Box 49, SE-230 53 Alnarp, Sweden E-mail: adam.felton@slu.se
article id 1043, category Research article
Jorge Martín-García, Luc Barbaro, Julio Javier Diez, Hervé Jactel. (2013). Contribution of poplar plantations to bird conservation in riparian landscapes. Silva Fennica vol. 47 no. 4 article id 1043. https://doi.org/10.14214/sf.1043
Keywords: management; Populus x euramericana; clone I-214; hybrid; native
Highlights: Poplar plantations should not be used as surrogate habitat for native riparian forests with the aim of preserving bird species diversity; Native riparian forests should be preserved or restored as far as possible; Bird communities occurring in poplar plantations can still accommodate rich communities of forest bird species, providing that suitable management is applied at local and landscape levels.
Abstract | Full text in HTML | Full text in PDF | Author Info
In Mediterranean areas, riparian zones are particularly important for maintaining biodiversity. Nevertheless, the native vegetation in these zones has been modified or lost at an alarming rate during the last decades. The main objective of this study was to investigate the influence of poplar plantations on bird diversity in riparian zones, in order to estimate the ecological implications of a substantial expansion of poplar plantations. Breeding birds were sampled by the point-count method in twenty-four poplar plantations of I-214 clone, according to a factorial design combining stand age and understory management. Furthermore, the three native riparian forests remaining in the study area were also surveyed. Explanatory variables included (1) dendrometric, (2) understory and (3) landscape variables within six different radii of circular buffers. The species richness and abundance index were higher in riparian forests than in poplar plantations. Landscape variables (percentage of poplar plantations in the surrounding landscape) strongly influenced bird diversity in poplar plantations. Furthermore, at the local scale, understory cover was also a key factor in shaping bird assemblages. This suggests that poplar plantations should not be used as surrogates for native forests. Nevertheless, poplar plantations can still accommodate rich communities of forest bird species, providing that suitable management is applied at local and landscape levels.
  • Martín-García, Sustainable Forest Management Research Institute, University of Valladolid – INIA, Avenida Madrid, 57, 34004 Palencia, Spain E-mail: jorgemg@pvs.uva.es (email)
  • Barbaro, NRA, UMR 1202 BIOGECO, 69 Route d’Arcachon, F-33612 Cestas cedex, France E-mail: luc@pierroton.inra.fr
  • Diez, Sustainable Forest Management Research Institute, University of Valladolid – INIA, Avenida Madrid, 57, 34004 Palencia, Spain E-mail: jdcasero@pvs.uva.es
  • Jactel, NRA, UMR 1202 BIOGECO, 69 Route d’Arcachon, F-33612 Cestas cedex, France; Université de Bordeaux, UMR 1202, Bordeaux, F-33000 France E-mail: herve.jactel@pierroton.inra.fr
article id 63, category Research article
Leena Koivuranta, Tarja Latva-Karjanmaa, Pertti Pulkkinen. (2012). The effect of temperature on seed quality and quantity in crosses between European (Populus tremula) and hybrid aspens (P. tremula x P. tremuloides). Silva Fennica vol. 46 no. 1 article id 63. https://doi.org/10.14214/sf.63
Keywords: climate change; gene flow; germination; hybrid vigour
Abstract | View details | Full text in PDF | Author Info
Hybrid aspen (Populus tremula L. Populus tremuloides Michx.) plantations are expanding in Fennoscandia and the Baltic countries; however, the possible effects of plantations on the native European aspen (P. tremula) and the level of gene flow between European and hybrid aspen have not been investigated. We studied seed quantity and quality in intraspecific and interspecific crosses of the European and hybrid aspens over a two year period. In order to study whether elevated temperatures due to climate change would benefit the species differently, we performed the crosses in different temperatures. In both years, interspecific crosses produced more seeds with higher quality than intraspecific crosses. This result was most distinct in crosses between female hybrid aspen and male European aspen. In higher temperatures, relative germination difference between hybrid aspen seeds and seeds from P. tremula P. tremula crosses seems to increase. These results suggest that hybrid aspen may have a significant genetic impact on the European aspen, and this effect may be strengthened by climate warming.
  • Koivuranta, Finnish Forest Research Institute, Haapastensyrjä, Finland E-mail: lk@nn.fi
  • Latva-Karjanmaa, Finnish Forest Research Institute, Haapastensyrjä, Finland E-mail: tlk@nn.fi
  • Pulkkinen, Finnish Forest Research Institute, Haapastensyrjä, Finland E-mail: pertti.pulkkinen@metla.fi (email)
article id 342, category Research article
Jaana Luoranen, Juha Lappi, Gang Zhang, Heikki Smolander. (2006). Field performance of hybrid aspen clones planted in summer. Silva Fennica vol. 40 no. 2 article id 342. https://doi.org/10.14214/sf.342
Keywords: survival; Populus; growth; hybrid aspen; micropropagation; planting date; root cutting; root egress; survivalgrowth
Abstract | View details | Full text in PDF | Author Info
We investigated the possibility to plant clonal hybrid aspen (Populus tremula x tremuloides) during the summer of propagation when the plants are 20–25 cm tall and only a few months old. In four experiments carried out in years 1998–2001, survival of summer-planted hybrid aspens was at least as high as that of hybrid aspen planted in autumn and spring. In all experiments, compared to planting in September or the following May, height growth was greater with planting in July and early August. Root egress of hybrid aspens planted in July and August was also greater than that of aspens planted in autumn or the following spring. Summer planting was thus possible both with plants produced by micropropagation and with those produced from root cuttings.
  • Luoranen, Finnish Forest Research Institute, Suonenjoki Research Unit, Juntintie 154, FI-77600 Suonenjoki, Finland E-mail: jaana.luoranen@metla.fi (email)
  • Lappi, Finnish Forest Research Institute, Suonenjoki Research Unit, Juntintie 154, FI-77600 Suonenjoki, Finland E-mail: lj@nn.fi
  • Zhang, College of Horticulture, Agricultural University of Hebei, Baoding, Hebei, China E-mail: gz@nn.cn
  • Smolander, Finnish Forest Research Institute, Suonenjoki Research Unit, Juntintie 154, FI-77600 Suonenjoki, Finland E-mail: hs@nn.fi
article id 490, category Research article
Veiko Uri, Hardi Tullus, Krista Lõhmus. (2003). Nutrient allocation, accumulation and above-ground biomass in grey alder and hybrid alder plantations. Silva Fennica vol. 37 no. 3 article id 490. https://doi.org/10.14214/sf.490
Keywords: biomass; Alnus incana; Alnus incana x Alnus glutinosa; grey alder; hybrid alder; nutrient allocation; nutrient accumulation
Abstract | View details | Full text in PDF | Author Info
The aim of the present work was to investigate the nutrient (N,P,K) allocation and accumulation in grey alder (Alnus incana (L.) Moench) and hybrid alder (Alnus incana (L.) Moench x Alnus glutinosa (L.) Gaertn.) plantations growing on former agricultural land and to estimate the above-ground biomass production during 4 years after establishment. In August of the 4th year, when leaf mass was at its maximum, the amount of nitrogen accumulated in above-ground biomass of grey alder stand was 142.0 kg ha–1, the amount of phosphorus 16.3 kg ha–1 and the amount of potassium 49.5 kg ha–1. The amount of nitrogen accumulated in a hybrid alder stand totalled 76.8 kg ha–1, that of phosphorus 6.2 kg ha–1 and that of potassium 28.2 kg ha–1. The smaller amounts of N,P and K bound in the hybrid alder plantation are related to the smaller biomass of the stand. Still, the amounts of N,P and K consumed for the production of one ton of biomass were similar in the case of up to 4-year-old grey alder and hybrid alder stands. In the 4th year, the amount of nutrients consumed in one ton of biomass produced were: 16.0 kg N, 1.6 kg P and 5.4 kg K for grey alder and 14.6 kg N, 1.1 kg P and 5.2 kg K for hybrid alder. In the 4th year the total above-ground biomass (dry mass) of grey alder (15750 plants ha–1) amounted to 12.3 t ha–1, current annual increment being 6.7 t ha–1. In hybrid alder stands (6700 plants ha–1), the respective figures were 6.1 t ha–1 and 4.5 t ha–1. Comparison of the production capacity on the basis of mean stem mass in the 4th year revealed that the stem mass of grey alder exceeded that of hybrid alder (0.64 kg and 0.58 kg, respectively). Grey alder outpaced hybrid alder in height growth; in the 4th year after establishment, the mean height of the grey alder stand was 4.6 ± 0.9 m and that of the hybrid alder plantation 3.5 ± 0.9 m.
  • Uri, Institute of Silviculture, Estonian Agricultural University, Kreutzwaldi 5, 51014 Tartu, Estonia E-mail: vuri@eau.ee (email)
  • Tullus, Institute of Silviculture, Estonian Agricultural University, Kreutzwaldi 5, 51014 Tartu, Estonia E-mail: ht@nn.ee
  • Lõhmus, Institute of Geography, University of Tartu, Vanemuise 46, 51014 Tartu, Estonia E-mail: kl@nn.ee
article id 600, category Research article
Qibin Yu, P. M. A. Tigerstedt, Matti Haapanen. (2001). Growth and phenology of hybrid aspen clones (Populus tremula L. x Populus tremuloides Michx.). Silva Fennica vol. 35 no. 1 article id 600. https://doi.org/10.14214/sf.600
Keywords: phenology; growth rate; hybrid aspen; growth pattern
Abstract | View details | Full text in PDF | Author Info
Height, basal diameter, diameter at breast height, bud burst, and leaf development were recorded in a 5-year-old hybrid aspen clonal trial. The field trial consisted of four aspen hybrid clones (Populus tremula x Populus tremuloides) and one local P. tremula seedling source. Phenological traits were observed in the 3rd year. Growth patterns were recorded during the 3rd and 4th years. Phenological traits were explored in relation to hybrid vigor expressed as growth traits. Differences were observed for phenological and growth traits among hybrid clones and P. tremula. The growth period varied from 143–158 days for the four hybrid clones, and was 112 days for P. tremula. The correlation between growth period and yield was highly significant. The annual growth rate of height for the hybrids was 4.2 cm per 7 days (2.4 for P. tremula) in the 3rd year and 6.4 cm per 7 days (2.9 for P. tremula) in the 4th year. After 5 years, mean estimated stem volume of the hybrids was 3.9 times that of P. tremula. Significant clone by year interaction was observed for height, diameter, and volume growth. The hybrid vigor seems to be mainly attributable to a longer growth period.
  • Yu, Department of Plant Biology, P.O. Box 27, FIN-00014 University of Helsinki, Finland E-mail: qibin.yu@helsinki.fi (email)
  • Tigerstedt, Department of Plant Biology, P.O. Box 27, FIN-00014 University of Helsinki, Finland E-mail: pmat@nn.fi
  • Haapanen, Finnish Forest Research Institute, P.O. Box 18, FIN-01301 Vantaa, Finland E-mail: mh@nn.fi

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