Regeneration of European boreal forests: Effectiveness of measures against seedling mortality caused by the pine weevil Hylobius abietis

Self Cite

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 ( L.) and Norway spruce ( (L.) Karst.), the non-host deciduous broadleaf hybrid aspen ( Ã HÃ¤met-Ahti) and four introduced conifers: Douglas fir ( (Mirb.) Franco), hybrid larch ( Ã Coaz), Sitka spruce ( (Bong.) CarriÃ©re) and lodgepole pine ( 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.Pinus sylvestrisPicea abiesPopuluswettsteiniiPseudotsuga menziesiiLarixmarschlinsiiPicea sitchensisPinus contorta

Section: Introductionmentioning

confidence: 99%

Damage by the pine weevil Hylobius abietis to seedlings of two native and five introduced tree species in Sweden

Wallertz¹,

Nordenhem²,

Nordlander³

2014

Self Cite

“…the initial growth gains are maintained in the long run and a more homogeneous stand is developed compared to stands established without the use of scarification (Nilsson and Allen 2003;Johansson et al 2013). Although scarification is mainly performed to promote seedling establishment and growth, it also protects the seedlings from being attacked by pine weevils (Hylobius abietis) (Petersson et al 2005;Nordlander et al 2011). Damage caused by pine weevils is a common problem when regenerating conifers in large parts of Europe (Day and Leather 1997).…”

Section: Introductionmentioning

confidence: 99%

Effects of pre-harvest fertilization and subsequent soil scarification on the growth of planted Pinus sylvestris seedlings and ground vegetation after clear-felling

Ring¹,

Högbom²

2013

Self Cite

Effects of pre-harvest fertilization and subsequent soil scarification on the growth of planted Pinus sylvestris seedlings and ground vegetation after clear-felling Johansson K., Ring E., Högbom L. (2013). Effects of pre-harvest fertilization and subsequent soil scarification on the growth of planted Pinus sylvestris seedlings and ground vegetation after clear-felling. Silva Fennica vol. 47 no. 4 article id 1016. 18 p. Highlights• Pre-harvest N fertilization had no significant effect on seedling growth and ground vegetation biomass.• Scarification improved seedling survival and growth and reduced the amount of ground vegetation.• Without scarification, pre-harvest fertilization increased the amount of damaged seedlings. AbstractFertilization and scarification are both performed to increase tree production at different stages of forest rotation periods. In this study, the effects of previous nitrogen fertilizations and scarification after clear felling on planted Pinus sylvestris L. seedlings and ground vegetation were investigated. Two fertilization experiments established around 1980 were harvested in 2006, after which the plots were scarified by disc trenching and re-planted. The plots had been repeatedly fertilized over a 20-year period before harvesting, with total N doses of 0, 450, 900 or 1800 kg N ha -1 . After five growing seasons, the growth, survival and nutrient contents of the seedlings were measured, and ground vegetation was collected to estimate its biomass and nutrient content. Pre-harvest fertilization alone had only minor effects on the results, but scarification increased both the survival and growth of the planted seedlings. However, without scarification, seedling mortality increased with increasing fertilization intensity. The ground vegetation biomass was higher in plots without scarification, but the total biomass of seedlings and ground vegetation was similar in all treatments. Scarification thus favored seedling growth at the expense of ground vegetation. Only a few effects on nutrient content were found, but there were no signs of nutrient imbalance in any of the treatments. At higher levels of fertilization, the K:N ratio in the seedlings decreased while the K content in the ground vegetation increased. Overall, scarification had a greater impact than pre-harvest fertilization on the planted seedlings and the ground vegetation.

“…However, since soak-sorting increased all the attributes of seedling size, including the mass of both the shoot and root system, the size increase observed can be interpreted as a beneficial change, especially that of large stem diameter which predicts high survival and good growth in tree seedlings (Rikala and Aphalo 1998;Aphalo and Rikala 2003;Grossnickle 2012). Large size (Nordlander et al 2011), and especially large stem diameter, also decreases mortality caused by pine weevils (Hylobius abietis (L.)) (Thorsén et al 2001) and other pests in Norway spruce seedlings after out-planting. As the differences in size were observed after both the first and second growing season between the treatments, it can be concluded that the effect of soak-sorting is not entirely short-term, but possibly influences growth or survival after out-planting.…”

Section: Seedling Morphology and Qualitymentioning

confidence: 99%

Seed soak-sorting prior to sowing affects the size and quality of 1.5-year-old containerized Picea abies seedlings

Himanen¹,

Nygren²

2015

Seed soak-sorting prior to sowing affects the size and quality of 1.5-year-old containerized Picea abies seedlings Himanen K., Nygren M. (2015). Seed soak-sorting prior to sowing affects the size and quality of 1.5-year-old containerized Picea abies seedlings. Silva Fennica vol. 49 no. 3 article id 1056. 14 p. Highlights• After soak-sorting all sunken seeds (bottom fraction) were full and viable, whereas floating seeds contained larvae-filled and immature seed.• Seedlings originating from the bottom fraction were greater in height and diameter than control seedlings or those originating from the floating seeds.• The proportion of saleable seedlings was four percentage points higher in the bottom fraction than in the other seedlings. AbstractWe studied the effect of soak-sorting Norway spruce (Picea abies (L.) H. Karst.) seeds on emergence, development and quality of container seedlings in two commercial seed lots. The seeds, separated by soaking into bottom and surface fractions, were sown in June, and the seedlings were grown during two growing seasons under typical Finnish nursery conditions. The first summer seedlings were grown in a greenhouse and outdoors for the second, full growing season. All sunken seeds were full and viable according to radiography, whereas the floating seeds contained 2% and 13% larvae-filled and 8% and 11% anatomically immature seeds, depending on the seed lot. Seedlings grown from the bottom fraction seed emerged 2.5-3.5 days earlier than seedlings of storage dry (i.e. control) seed. Height, diameter, and shoot and root dry mass of the seedlings were affected by soaking after both the first and second growing seasons. The largest seedlings originated from the bottom fraction. The proportion of saleable seedlings was four percentage points higher in the bottom fraction than in the other seedlings. The effects of soaking found in this study are more notable than as previously reported for Norway spruce seedlings. This suggests that soaking and soak-sorting may be most useful when the growing conditions are stressful, i.e. when seeds are sown in summer rather than 1-year-old seedling crops sown in spring under the climate conditions typical of Finland.