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Articles containing the keyword 'feeding'.

Category: Research article

article id 9946, category Research article
Frauke Fedderwitz, Niklas Björklund, Velemir Ninkovic, Göran Nordlander. (2018). Does the pine weevil (Hylobius abietis) prefer conifer seedlings over other main food sources? Silva Fennica vol. 52 no. 3 article id 9946. https://doi.org/10.14214/sf.9946
Highlights: Adult pine weevils feed on seedlings and mature conifers, but cause economic damage only on seedlings; Their feeding preferences for branches and roots over seedlings were tested in a laboratory experiment; The only clear preference was for Norway spruce roots; Results support new approaches of seedling protection attempting to redirect pine weevils from planted seedlings to other food sources.

Adult pine weevils (Hylobius abietis (L.)) feed on the tender bark of branches and roots of mature conifer trees and on the stem bark of conifer seedlings. Their feeding on mature trees does not cause any economic damage, but their feeding on planted seedlings is so devastating that the pine weevil is considered one of the most important forest pest insects in Europe. We asked whether the pine weevil prefers seedlings over other regularly utilized food sources. This question is of particular interest because new approaches to seedling protection are based on decreasing any preference for seedlings by using less palatable plants or by enhancing their defence (by genetic selection or by methyl jasmonate treatment). In a laboratory choice experiment we tested pine weevil feeding preferences for seedlings compared with branches and roots from mature trees (separately for Norway spruce and Scots pine). Pine weevils preferred roots, but not branches, of Norway spruce over seedlings of the same species. With Scots pine there were no clear preferences, but the weevils showed a tendency to prefer roots over seedlings. These results provide support for seedling protection approaches that attempt to redirect pine feeding from planted seedlings to other food sources.

  • Fedderwitz, Department of Ecology, Swedish University of Agricultural Sciences, Box 7044, SE-750 07 Uppsala, Sweden ORCID ID:E-mail: frauke.fedderwitz@slu.se (email)
  • Björklund, Department of Ecology, Swedish University of Agricultural Sciences, Box 7044, SE-750 07 Uppsala, Sweden ORCID ID:E-mail: niklas.bjorklund@slu.se
  • Ninkovic, Department of Ecology, Swedish University of Agricultural Sciences, Box 7044, SE-750 07 Uppsala, Sweden ORCID ID:E-mail: velemir.ninkovic@slu.se
  • Nordlander, Department of Ecology, Swedish University of Agricultural Sciences, Box 7044, SE-750 07 Uppsala, Sweden ORCID ID:E-mail: goran.nordlander@slu.se
article id 1188, category Research article
Kristina Wallertz, Henrik Nordenhem, Göran Nordlander. (2014). Damage by the pine weevil Hylobius abietis to seedlings of two native and five introduced tree species in Sweden. Silva Fennica vol. 48 no. 4 article id 1188. https://doi.org/10.14214/sf.1188
Highlights: Both native and introduced confer species in Sweden can be highly susceptible to damage by the pine weevil; Douglas fir and Sitka spruce were generally the most damaged among six studied conifer species; The results highlight some of the risks in establishing exotic tree species for forest production.
There is increasing interest in using introduced species in Swedish forestry in response to climate change, but it is important to assess their resistance to native pests. Thus, we compared the extent of pine weevil feeding on two dominant native conifers, Scots pine (Pinus sylvestris L.) and Norway spruce (Picea abies (L.) Karst.), the non-host deciduous broadleaf hybrid aspen (Populus × wettsteinii Hämet-Ahti) and four introduced conifers: Douglas fir (Pseudotsuga menziesii (Mirb.) Franco), hybrid larch (Larix × marschlinsii Coaz), Sitka spruce (Picea sitchensis (Bong.) Carriére) and lodgepole pine (Pinus contorta Douglas ex Loudon). The extent of feeding damage on seedlings and its effect on their vitality were examined in a field study in south-central Sweden and a laboratory experiment, which gave largely consistent results. Generally, the species most heavily attacked by the pine weevil, in both experiments, were Douglas fir and Sitka spruce. In the field experiment pine weevils killed or severely damaged significantly higher proportions of Douglas fir and Sitka spruce seedlings (60%) than any other species except Norway spruce (49%). Among conifer seedlings the proportions of killed or severely damaged seedlings were lowest for Scots pine and hybrid larch (27%) and Lodgepole pine (36%). The results indicate that most conifer species planted on young clear-cuttings in Sweden need some kind of pine weevil protection, and the possibility that introducing new tree species might increase damage caused by pests must be considered. For instance, widespread use of hybrid aspen could reduce damage by pine weevils, but increase damage by other, untested pests or pathogens.
  • Wallertz, Unit for Field-based Forest Research, Swedish University of Agricultural Sciences (SLU), Asa Research Station, SE-36030 Lammhult, Sweden ORCID ID:E-mail: kristina.wallertz@slu.se (email)
  • Nordenhem, Department of Ecology, Swedish University of Agricultural Sciences (SLU), P.O. Box 7044, SE-75007 Uppsala, Sweden ORCID ID:E-mail: henrik.nordenhem@slu.se
  • Nordlander, Department of Ecology, Swedish University of Agricultural Sciences (SLU), P.O. Box 7044, SE-75007 Uppsala, Sweden ORCID ID:E-mail: goran.nordlander@slu.se
article id 302, category Research article
Gökay Nemli, Turgay Akbulut, Emir Zekoviç. (2007). Effects of some sanding factors on the surface roughness of particleboard. Silva Fennica vol. 41 no. 2 article id 302. https://doi.org/10.14214/sf.302
Effects of the grit sizes of the sand belt, feeding speed and the feed power of the heads of the sander on the surface roughness of the particleboard panels were investigated. Two surface roughness parameters, average roughness (Ra) and mean peak-to-valley height (Rz), obtained from board surfaces were used in the analysis. Sanding factors were found to have a significant effect on the surface roughness of the particleboard. Better results were obtained with 40 m/min of feeding speed, 40-60-80-120 of grit sizes, and 67 kW of the feed power of the heads of the sander.
  • Nemli, Karadeniz Technical University, Faculty of Forestry, Trabzon-Türkiye ORCID ID:E-mail: nemli@ktu.edu.tr (email)
  • Akbulut, Istanbul University, Faculty of Forestry, Istanbul-Türkiye ORCID ID:E-mail:
  • Zekoviç, Starwood Forest Product Company, Production Manager, Bursa-Türkiye ORCID ID:E-mail:

Category: Research note

article id 702, category Research note
Timo Kurkela, Heikki Nuorteva. (1998). Short-needle disease of Scots pine: an abnormal needle length distribution. Silva Fennica vol. 32 no. 1 article id 702. https://doi.org/10.14214/sf.702
Short-needle syndrome occurs commonly in southern Finland. The disease is characterized by abnormal length distribution of the needles in shoots. In most cases, affected shoots have needles of normal length as well as very short needles. The short needles are those injured during the needle elongation period; the tissues formed abnormal sclerenchymatic structures and wound periderm. One possible cause could be hemipterous insects feeding on growing needles. Salivary sheaths of such insects were often present in both deformed needle bases and undeformed mature tissues.
  • Kurkela, Finnish Forest Research Institute, P.O. Box 18, FIN-01301 Vantaa, Finland ORCID ID:E-mail: timo.kurkela@metla.fi (email)
  • Nuorteva, Finnish Forest Research Institute, P.O. Box 18, FIN-01301 Vantaa, Finland ORCID ID:E-mail:

Category: Article

article id 5506, category Article
Risto Heikkilä, Sauli Härkönen. (1993). Moose (Alces alces L.) browsing in young Scots pine stands in relation to the characteristics of their winter habitats. Silva Fennica vol. 27 no. 2 article id 5506. https://doi.org/10.14214/sf.a15667

Moose (Alces alces L.) browsing was studied in young Scots pine (Pinus sylvestris L.) stands mixed with deciduous trees in high-density winter ranges. The proportional use of twig biomass decreased as the availability increased. The total as well as proportional biomass consumption were higher on the moist than on the dry type of forest. The per tree consumption of pine was higher on the moist type, where the availability of pine was lower. Deciduous trees were more consumed on the moist type, where their availability was relatively high. The consumption of pine saplings increased as the availability of birch increased. Pine stem breakages were most numerous when birch occurred as overgrowth above pine and at high birch densities. The availability of other deciduous tree species did not correlate with browsing intensity of Scots pine. Moose browsing had seriously inhibited the development of Scots pines in 6% of the stands, over 60% of available biomass having been removed. Rowan and aspen were commonly over-browsed and their height growth was inhibited, which occurred rarely by birch. There was no difference in the proportion of young stands in forest areas with high and low moose density. A high proportion of peatland forests was found to indicate relatively good feeding habitats in the high-density areas.

The PDF includes an abstract in Finnish.

  • Heikkilä, ORCID ID:E-mail:
  • Härkönen, ORCID ID:E-mail:
article id 5476, category Article
Jukka Selander, Auli Immonen. (1992). Effect of fertilization and watering of Scots pine seedlings on the feeding preference of the pine weevil (Hylobius abietis L.). Silva Fennica vol. 26 no. 2 article id 5476. https://doi.org/10.14214/sf.a15637

Two-year-old containerized Scots pine (Pinus sylvestris L.) seedlings, raised under different fertilization and watering regimes, were subjected to feeding preference tests with pine weevils (Hylobius abietis L.) in a bioassay. In the tests carried out with pairs of seedlings, the weevil preferred water-stressed seedlings to well-watered ones. In the case of well-watered seedlings, the weevil caused significantly more damage to NPK-fertilized seedlings than those given pure PK fertilization, or no fertilization at all. It is apparent that PK fertilization reduces, and water stress increases seedling susceptibility to weevil damage. The results support findings from field trials that water stress (planting shock) predisposes seedlings to weevil damage. Weevil resistance is discussed with respect to fertilization and water stress as determinants of seedling quality.

The PDF includes an abstract in Finnish.

  • Selander, ORCID ID:E-mail:
  • Immonen, ORCID ID:E-mail:
article id 5434, category Article
Risto Heikkilä. (1990). Effect of plantation characteristics on moose browsing on Scots pine. Silva Fennica vol. 24 no. 4 article id 5434. https://doi.org/10.14214/sf.a15588

The effects of plantation characteristics on moose (Alces alces) browsing intensity was studied in 82 Scots pine (Pinus sylvestris L.) plantations in Southern Finland. Moose browsing occurred most commonly in plantations established on relatively fertile soil, and the degree of damage was at highest in plantations with openings. A high amount of brush, especially aspen, increased the risk of damage. Furthermore, damage was intensified in plantations situated on hills, slopes or at a long distance from main roads or settlements.

The PDF includes an abstract in Finnish.

  • Heikkilä, ORCID ID:E-mail:
article id 4778, category Article
Kari Löyttyniemi. (1968). Teeri (Lyrurus tetrix L.) männyn taimien tuholaisena taimitarhassa. Silva Fennica vol. 2 no. 4 article id 4778. https://doi.org/10.14214/sf.a14563
English title: Feeding of terminal shoots of Scots pine seedlings by the black grouse (Lyrurus tetrix) in nursery.
Original keywords: taimitarha; taimituhot; mänty; versot; teeri

In early spring 1968 it was noticed that the black grouses (Lyrurus tetris L.) was eating terminal shoots of Scots pine (Pinus sylvestris L.) seedlings in a tree nursery in Luumäki, Southern Finland. The terminal shoots were picked 1–4 cm from the top of the seedlings. In total some thousands of two-year-old seedlings were damaged. The depth of the snow was 10–15 cm deep and only the tops of the seedlings could be seen above the surface of the snow.

The PDF includes a summary in English.

  • Löyttyniemi, ORCID ID:E-mail:
article id 4775, category Article
Erkki Pulliainen, Kalevi Loisa, Tauno Pohjalainen. (1968). Hirven talvisesta ravinnosta Itä-Lapissa. Silva Fennica vol. 2 no. 4 article id 4775. https://doi.org/10.14214/sf.a14560
English title: Winter food of the moose (Alces alces) in eastern Lapland.

The winter food of moose (Alces alces L.) was examined in 1967-68 in the Saariselkä fell area in the communes of Inari and Sodankylä, in the northern parts of the communes of Salla and Savukoski, and in the central part of the commune of Salla in eastern Lapland in Finland.

In northern parts of Salla and Savukoski 25 moose were followed during 3.-13.4.1968. This area is typical wintering terrain of moose in north-east Lapland. According to the estimate, 45% food taken by the moose was Scots pine shoots and needles, 28% birch, 17% juniper sprigs and needles, 9% willow, and 1.5% bear moss. According to observations of the researchers in 26.1.-16.5.1968, moose seemed to avoid birch, even if it was available in the area, and eat Scots pine shoots and needles and juniper.

Moose seemed to prefer willow in as a winter feed in the southern part of the area studied, where it accounts according to the present and earlier studies 50-90% of the winter food. In the northern wintering areas of moose, where willow is not as common, willow seemed to account for less than 10% of the winter food. There Scots pine is the most important winter food for moose.

The PDF includes a summary in English.

  • Pulliainen, ORCID ID:E-mail:
  • Loisa, ORCID ID:E-mail:
  • Pohjalainen, ORCID ID:E-mail:
article id 4775, category Article
Erkki Pulliainen, Kalevi Loisa, Tauno Pohjalainen. (1968). Hirven talvisesta ravinnosta Itä-Lapissa. Silva Fennica vol. 2 no. 4 article id 4775. https://doi.org/10.14214/sf.a14560
English title: Winter food of the moose (Alces alces) in eastern Lapland.

The winter food of moose (Alces alces L.) was examined in 1967-68 in the Saariselkä fell area in the communes of Inari and Sodankylä, in the northern parts of the communes of Salla and Savukoski, and in the central part of the commune of Salla in eastern Lapland in Finland.

In northern parts of Salla and Savukoski 25 moose were followed during 3.-13.4.1968. This area is typical wintering terrain of moose in north-east Lapland. According to the estimate, 45% food taken by the moose was Scots pine shoots and needles, 28% birch, 17% juniper sprigs and needles, 9% willow, and 1.5% bear moss. According to observations of the researchers in 26.1.-16.5.1968, moose seemed to avoid birch, even if it was available in the area, and eat Scots pine shoots and needles and juniper.

Moose seemed to prefer willow in as a winter feed in the southern part of the area studied, where it accounts according to the present and earlier studies 50-90% of the winter food. In the northern wintering areas of moose, where willow is not as common, willow seemed to account for less than 10% of the winter food. There Scots pine is the most important winter food for moose.

The PDF includes a summary in English.

  • Pulliainen, ORCID ID:E-mail:
  • Loisa, ORCID ID:E-mail:
  • Pohjalainen, ORCID ID:E-mail:
article id 7677, category Article
Risto Heikkilä, Timo Mikkonen. (1992). Effects of density of young Scots pine (Pinus sylvestris) stand on moose (Alces alces) browsing. Acta Forestalia Fennica no. 231 article id 7677. https://doi.org/10.14214/aff.7677

The study was carried out at Padasjoki, Southern Finland, where moose (Alces alces L.) density on the winter range had been over 1.5 individuals/km2. Moose browsing intensity, expressed in terms of number of twigs eaten and biomass used, increased with stand density (biomass). Total biomass consumption (dry weight) per sample plot and per sapling. The number of bites increased, but the percentage biomass removed did not differ when stand density increased. A relatively large bite size was observed on the plots of low stand density. The quantity of food, which on average was of relatively low quality, was obviously important due to the benefit gained through reducing the search time.

The nutritive value of the browse, expressed in terms of chemical compounds indicating low food digestibility, was lower in the dense than in the sparse Scots pine stand. However, the amount of crude protein and arginine were relatively high in the dense stand. We concluded that shading affected the nutritional status of saplings on high density plots.

Although the biomass removed by moose per sapling was high for low density plots, the remaining biomass was larger than that on the high-density plots owing to the relatively large twig biomass of saplings. The number of saplings per hectare without main stem breakage increased significantly as stand density increased.

The PDF includes a summary in Finnish.

  • Heikkilä, ORCID ID:E-mail:
  • Mikkonen, ORCID ID:E-mail:
article id 7670, category Article
Risto Heikkilä. (1991). Moose browsing in a Scots pine plantation mixed with deciduous tree species. Acta Forestalia Fennica no. 224 article id 7670. https://doi.org/10.14214/aff.7670

The utilization of available food resources by the moose (Alces alces L.) was studied in a Scots pine (Pinus sylvestris L.) plantation containing an admixture of deciduous species. Rowan (Sorbus aucuparia L.) and aspen (Populus tremula L.) were highly utilized compared to pine and both silver birch (Betula pendula Roth) and downy birch (B. pubescens Ehrh.). However, they were not capable of withstanding continuous browsing by moose owing to their diminished biomass. In total, the browsing intensity (number of browsed twigs/tree) on pine and birch was about double of that on rowan and aspen.

The number of browsed twigs per tree increased as the amount of available main branches increased. The number of bites per available branch, as well as the maximum diameter of the bites, decreased as the density of the plantation increased. Silver birch was more used by moose than pubescent birch as well as planted silver birch compared with naturally regenerated trees.

Main stem breakage was especially common in winter 1988, the average height of the pine and birch trees being over two meters. The tops of broken stems were commonly utilized as food. The increase in moose density and the relatively deep snow cover evidently promoted the incidence of serious damage. The number of undamaged trees/ha was greater in dense than in sparse parts of the stand.

The PDF includes a summary in Finnish.

  • Heikkilä, ORCID ID:E-mail:
article id 7659, category Article
Ari Lääperi. (1990). Hoidettujen talvilaitumien vaikutus hirvituhoihin mäntytaimikoissa. Acta Forestalia Fennica no. 212 article id 7659. https://doi.org/10.14214/aff.7659
English title: Effect of winter feeding on moose damage to young Scots pine stands.

The establishment of moose (Alces alces L.) winter feeding sites, their utilization and their effect on damage to young Scots pine (Pinus sylvestris L.) plantations was studied in Ruokolahti-Imatra area in Eastern Finland in 1987–89. During the period, the density in the area was about 3–5 moose/ 1,000 ha.

Six feeding sites were established by fertilization, offering mineral lics and the tops of aspen and Scot pine and by salting the tops of pine. The moose preferred the feeding site to control areas during both summer and winter. In winter browsing was very heavy, especially in those areas located in or close to traditional wintering areas. In winter no moose were seen in the summer habitats.

The extent of, and fluctuations in moose damage were studied in 47 Scots pine plantations in the immediate surroundings of the feeding sites (29 plantations), control areas (18 plantations) and also 68 randomly selected pine plantations. Before the experiment began in 1987 four plantations had been seriously damaged. During the study period only one plantation was seriously damaged. However, it could not be conclusively proved that damage to the pine plantations had been reduced as a result of the feeding sites. The results of the study can be put into practice elsewhere to create better living conditions for moose in their winter habitats. However, the food offered at the feeding site should be in the right proportion to the number of animals wintering in the area, so that the risk of damage to nearby plantations would be kept as small as possible.

The PDF includes a summary in Finnish.

  • Lääperi, ORCID ID:E-mail:

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