Norway Spruce In Sweden Research Articles

Irruptions of crossbills Loxia spp. in northern Europe – patterns and correlations with seed production by key and non‐key conifers

Irruptions by boreal seed‐eating and frugivorous birds are assumed to be driven by the production of seeds and fruits, crops of which are highly variable between years. Using data from Sweden, we tested whether irruptions of Common Crossbills Loxia curvirostra were correlated with low Norway Spruce Picea abies seed production in the same year as the irruption and/or high seed production in the year prior to an irruption. Similar tests were made for Parrot Crossbill Loxia pytyopsittacus irruptions in relation to Scots Pine Pinus sylvestris seed production. In northern Europe, these conifers represent the key food species of the two crossbill species, respectively. Despite differing times that seeds take to mature and asynchronous seed production between the two conifer species, including a 3‐year cycle for Norway Spruce, the two crossbill species often irrupted in the same year as one another. Analyses showed that irruptions into Britain and other parts of western Europe by both crossbill species were correlated with low seed production by Norway Spruce in Sweden. Low seed production by Scots Pine had a marginally non‐significant additive effect on both crossbill species. In a second set of analyses, the best‐fitting model was one in which low seed production by both conifers in a given year and high seed production in the previous year were each correlated with large numbers of irrupting Common and Parrot Crossbills. The models indicate that the incidental co‐occurrence of low seed production of Norway Spruce and Scots Pine in a given year, after a year of high seed production, may result in an irruption. The seed production of Norway Spruce and Scots Pine in Sweden was correlated with production by the same species in Finland, indicating widespread synchrony of cropping across northern Europe.

Innovation in forest tree genetics: A comparative economic analysis in the European context

In the context of global environmental change, European forests are expected to fulfil a broad range of functions, including the supply of raw materials to the bioeconomy, biodiversity preservation, and the provision of ecological services. Given fast progress in applied genetics, the selection and diffusion of genetically improved forest reproductive material (FRM) has a role to play towards the achievement of some of those goals. We therefore investigate European forest tree breeding conceived as an innovative activity on the basis of four case studies (eucalyptus in Portugal, maritime pine in France, and Norway spruce in Sweden and Finland), using a conceptual framework combining the innovation system approach and the economics of innovation. The genetic progress achieved for each of those species has been steady since the beginning of tree breeding activities. Despite that, we identify both systemic issues and market failures that hinder FRM genetic innovation and make the prospects of a forest tree breeding revolution unlikely. While the innovation systems in the studied countries are structurally sound, we identify several functional deficiencies. We also identify incentive problems limiting both supply and demand of genetically improved FRM. On the demand side, forest owners value improved FRM only moderately because of long lags between plantation and harvest, imperfect knowledge of the potential gains from adoption of genetically improved FRM, and risk aversion. On the supply side, returns to investments in genetic improvement are heavily constrained by the slowness of the breeding process, capacity constraints related to FRM production, limited demand-pull and regulatory uncertainty. Those incentive problems are partially overcome in situations where the industry is vertically integrated, from FRM production to wood processing, as observed in the case of eucalyptus in Portugal or Norway spruce in Sweden. In the other cases, public support for breeding programmes is paramount.

Management of spontaneously regenerated mixed stands of birch and Norway spruce in Sweden

Timber production and profitability were evaluated for spontaneously-regenerated mixtures on two formerly clearcut areas. The abandoned areas developed into birch-dominated ( Roth and Ehrh.) stands with successional ingrowth of Norway spruce ( (L.) H. Karst.). An experiment with randomized treatments within blocks was established, using three management strategies and one unthinned control, resulting in variation in optimal rotation age, merchantable volume and species composition. The management strategies were evaluated based on total production (volume) by using measured growth data 42 years after clearcutting and the modelled future stand development. The long-term effects of spontaneous regeneration and management strategies were evaluated based on land expectation value (LEV) and compared with a fifth management strategy using artificial regeneration and intense thinnings. 12 years after treatment, at a stand age of 42 years, the unthinned control had produced the highest total stem volume. At interest rates of 2% or higher, the unmanaged forest was an economically viable strategy, even compared to an intensive management strategy with a preferred merchantable timber species. Interest rates clearly impacted the profitability of the different management strategies. This study shows that when spontaneous regeneration is successful and dense, the first competition release can have a high impact on the development of future crop trees and on the species mixture.Betula pendulaBetula pubescensPicea abies

Exploiting jasmonate-induced responses for field protection of conifer seedlings against a major forest pest, Hylobius abietis

Herbivore damage commonly initiates an increased synthesis of chemical defensive compounds in attacked plants. Such induced defences are a vital part of plant defence systems, but when herbivore pressure is high, as frequently occurs in man-made ecosystems such as agricultural and forest plantations, plants may suffer considerable damage before adequate induced defences build up. To prepare the plants for such conditions their induced defence may be artificially triggered by the exogenous application of different phytohormones involved in damage signalling. This method is already employed in agriculture but within forestry systems it has so far been restricted to promising laboratory results. The pine weevil, Hylobius abietis, causes damage by feeding on the bark of young conifer plants and it is one of the main threats to successful regeneration in the Palaearctic region. Here we present results from a large scale field experiment where we triggered the induced defences of conifer seedlings using exogenous application of the chemical elicitor methyl jasmonate. To enhance the generality of the results different species were planted under extremely different environmental conditions; Maritime pine and Monterrey pine in Spain, and Scots pine and Norway spruce in Sweden. Weevil damage, chemical defences, and seedling growth were studied during the two growing periods following planting. In general, treated plants showed increased quantitative defences, and were less attacked, less wounded, less girdled and showed lower mortality rates than their untreated counterparts. Effects were mostly dose dependent, although some interactive effects with tree species were observed. The treatment initially caused a growth reduction but it was later compensated by the benefit, in terms of growth, of being less damaged. The measures that are currently taken to protect forest plantations against this harmful pest all around Europe have enormous economic costs and cause important environmental hazards. Elicitation of inducible defences in seedlings in the nursery appears to be an attractive alternative to these measures. To our knowledge, this is the first field study that explores the applicability of chemical elicitors of induced defences as a way to protect forest plantations against biotic threats.

Compositional changes of forest-floor vegetation in young stands of Norway spruce as an effect of repeated fertilisation

Forestry practices that aim to increase biomass production may mitigate climate change through increased carbon sequestration and the potential of substituting fossil fuels with renewable biofuels. Fertilising young stands of Norway spruce in Sweden have shown to increase tree growth by more than 200%. Fertilisation, however, also has other effects on forest ecosystems. Here, we studied the response of the species composition of forest-floor vegetation to three different frequencies of fertilisation in young stands of Norway spruce. Fertiliser was applied every year, every second year or every third year. The total amount of N ranged from 425 kg ha −1 to 625 kg ha −1, in combination with P, K, Ca, Mg, S, Mn, Zi, B and Cu. The largest effects of the fertilisation were found among bryophytes and lichens, which lost substantial cover. Unexpectedly, Deschampsia flexuosa, commonly known to be favoured by fertilisation, was negatively affected. Species that increased in frequency were Oxalis acetosella, Brachythecium sp. and Plagiothecium sp. Decreased availability of light, as an indirect effect of fertilisation through increased tree canopy cover, was found to be the most important factor behind the change in species composition of vascular plants. The total cover of bryophytes, however, did not show any significant response to the changes in canopy cover, indicating that the effects seen in this group may be a result of more direct effects of the fertiliser. Few significant differences were found between the two most intensive fertilisation frequencies, although fertilisation every third year was often distinguished from both the control and the other fertilised treatments. Even though the effects at the stand level were substantial, the effects on biodiversity and function of ecosystems on a landscape or regional level need further investigation.

Decomposition of stump and root systems of Norway spruce in Sweden—A modelling approach

The demand for quantifying the biomass of stumps and roots and the carbon stored therein is related to aspects of biodiversity, site productivity, atmospheric carbon cycling issues, and the demand for bioenergy. This, in turn, creates a need to develop high-quality tools for estimating biomass and carbon-equivalents in the ground. The objective of this study was to develop decomposition functions for quantifying the remaining dry weight of the biomass of individual stumps and their associated roots in Norway spruce ( Picea abies (L.) Karst.). The negative exponential model was chosen for this purpose, combined with a chronosequence approach, involving 99 stumps and their roots from three sites in Sweden. The results showed a relative decay rate of 4.6% annually for stump and root systems. Based on this rate, the time required for the loss of 50% ( t 0.5) and 95% ( t 0.95) of the wood is 15 and 64 years, respectively. Although there are many variables that affect decomposition, residual studies indicated that the remaining biomass could be predicted fairly accurately on the basis of the independent variables stump diameter and time.

Assessment of the impacts of climate change and weather extremes on boreal forests in northern Europe, focusing on Norway spruce

CR Climate Research Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsSpecials CR 31:75-84 (2006) - doi:10.3354/cr031075 Assessment of the impacts of climate change and weather extremes on boreal forests in northern Europe, focusing on Norway spruce Peter Schlyter1,*, Ingrid Stjernquist1, Lars Bärring2, Anna Maria Jönsson3, Carin Nilsson2 1Department of Physical Geography and Quaternary Geology, Stockholm University, 106 91 Stockholm, Sweden 2Geobiosphere Science Centre, Department of Physical Geography and Ecosystems Analysis, Lund University, Sölvegatan 12, 223 62 Lund, Sweden 3Department of Ecology, Plant Ecology and Systematics, Lund University, Ecology Building, 223 62 Lund, Sweden *Email: peter.schlyter@natgeo.su.se ABSTRACT: The boreal and boreo-nemoral forests in Europe, which occur in northern and northeastern Europe, are dominated by 2 coniferous species, Norway spruce Picea abies (L.) Karst. being economically the most important one. Forestry is of major economic importance in this region. Forestry planning and climate change scenarios are based on similar (long-term) timescales, i.e. between 70 and 120 yr. Within the EU project ‘Modelling the Impact of Climate Extremes’ (MICE), we have used ‘present day’ runs (1961–1990) and future scenarios (2070–2100, emission scenarios A2 and B2 from the Special Report on Emissions Scenarios [SRES]) of the HadRM3 regional climate model to study and model direct and indirect effects of changing climate on Norway spruce in Sweden and northern Europe. According to our results, extreme climate events like spring temperature backlashes and summer drought will increase in frequency and duration. In combination with a raised mean temperature, climate extremes will negatively precondition trees (i.e. increase their susceptibility) to secondary damage through pests and pathogens. Decreased forest vitality also makes stands more susceptible to windthrow. Storm damage is discussed based on a 100 yr storm damage record for Sweden. Marginally increased frequencies and windspeeds of storms may cause disproportionate increases in windthrow. Increased economic hazards can be expected from a combination of the increased volumes of wind-thrown timber, and a greater likelihood of additional generations of spruce bark beetle Ips typographus (further encouraged by the increase in fallen timber), as a result of a changing climate with warmer summers. KEY WORDS: Drought · Frost · Windstorm damage · Insect damage · Modelling · Forestry Full text in pdf format PreviousNextExport citation RSS - Facebook - Tweet - linkedIn Cited by Published in CR Vol. 31, No. 1. Online publication date: June 26, 2006 Print ISSN: 0936-577X; Online ISSN: 1616-1572 Copyright © 2006 Inter-Research.

Simulated carbon sink response of shortgrass steppe, tallgrass prairie and forest ecosystems to rising [CO2], temperature and nitrogen input

The response of plant ecosystems to environmental change will determine whether the terrestrial biosphere will remain a substantial carbon sink or become a source during the next century. We use two ecosystem models, the Generic Decomposition And Yield model (G'DAY) and the daily time step version of the Century model (DAYCENT), to simulate net ecosystem productivity (NEP) for three contrasting ecosystems (shortgrass steppe in Colorado, tallgrass prairie in Kansas, and Norway spruce in Sweden) with varying degrees of water, temperature, and nutrient limitation, to determine responses to gradual increases in atmospheric CO2 concentration ([CO2]), temperature, and nitrogen input over 100 years. Using G'DAY, under rising [CO2], there is evidence of C sink “saturation,” defined here as positive NEP reaching an upper limit and then declining toward zero, at all three sites (due largely to increased N immobilization in soil organic matter) but a positive C sink is sustained throughout the 100 years. DAYCENT also predicts a sustained C sink at all three sites under rising [CO2], with evidence of C sink saturation for the Colorado grassland and the C sink levels off after 80 years for the Kansas grassland. Warming reduces soil C and the C sink in both grassland ecosystems but increases the C sink in the forest. Warming increases decomposition and soil N mineralization, which stimulates net primary productivity (NPP) at all sites except when inducing water limitation. At the forest site some of the enhanced N release is allocated to a woody biomass pool with a low N:C ratio so that warming enhances NEP without increased N input at the forest site, but not at the grassland sites. Responses to combinations of treatments are generally additive for DAYCENT but more interactive for G'DAY, especially under combined rising [CO2] and warming at the strongly water‐ and N‐limited shortgrass steppe. Increasing N input alleviates C sink saturation and enhances NEP, NPP, and soil C at all sites. At the water‐limited grassland sites the effect of rising [CO2] on growth is greatest during the drier seasons. Key sensitivities in the simulations of NEP are identified and include NPP sensitivity to gradual increase in [CO2], N immobilization as a long‐term feedback, and the presence or not of plant biomass pools with low N:C ratio.

Potential production of Norway spruce in Sweden

In this paper, the potential stem wood production for Norway spruce was estimated for different regions in Sweden. This was done by using basic physiological relationships of intercepted radiation versus biomass production and knowledge of how a water deficit reduces the potential production, derived from results of field experiments on nutrient optimisation. To scale these relationships up to regional and national levels, data of incident radiation and humidity during the growing season for all of Sweden were used. The figures for potential and attainable production indicate that the temperate to boreal climate allows considerably higher production than the current production, if availability of water and nutrients is non-limiting. In northern Sweden, the attainable production is ca. 300% higher than the current production and in southern Sweden, the yield can be increased by ca. 100%. In absolute numbers, as a mean for a whole rotation period, it is possible to achieve an annual stem-wood dry mass production of 7–9 Mg ha −1 in southern and central and ca. 5–6 Mg in northern Sweden. This increased production would mean that rotation periods can be shorter than they are now by 20–30 years in southern Sweden and by ca. 50–60 years in northern Sweden.

Long-term N addition effects on the C mineralization and DOC production in mor humus under spruce

This study was based on laboratory incubations of mor humus from two N fertilized stands of Norway spruce in Sweden (Skogaby and Stråsan), which had received repeated N additions (100 kg N ha −1 yr −1 as (NH 4) 2SO 4 at Skogaby and 35, 73 and 108 kg ha −1 yr −1 as NH 4NO 3 at Stråsan) during 8 and 24–29 years, respectively. The aim was to investigate long-term N effects on the mineralization of C and production of DOC. Mor humus (Oe and Oa) was incubated in columns at 20 °C for 49 days. Columns were leached once a week with artificial throughfall solution, which was analyzed for DOC, total N, NH 4 +-N and NO 3 −-N. Prior to each leaching event, CO 2 evolution from the columns was determined. C-to-N ratios in the N-treated Oe layers at Stråsan (21–24) and Skogaby (24) were significantly lower than those of the controls (Stråsan, 32; Skogaby, 28). The cumulative amount of CO 2-C showed a significant treatment effect in the Oe layer at Skogaby, i.e. 18 and 29 mg C g −1 C in the N treatment and control, respectively. At Stråsan, the cumulative CO 2-C was significantly lower in the N3 treatment compared to the control in both layers (33 compared to 74 mg C g −1 C in the Oe layer and 16 compared to 35 mg C g −1 C in the Oa layer). Neither the DOC nor the DON production showed any significant treatment effects at the two sites. However, DOC was lower in the fertilized Oe layer at Skogaby throughout the incubation. The leaching of DON was highest in the Oe layers at both sites, and DON increased with time at Skogaby while there was a decreasing trend at Stråsan. The DOC-to-DON ratio tended to be lower in the fertilized Oe layers at both sites. The NH 4 + leaching at Skogaby decreased in the N-treated Oe and Oa layers. At Stråsan, NH 4 + from the Oe layer increased in N2 and control. The NO 3 − leaching was low and constant in both Skogaby layers. At Stråsan, NO 3 − increased in the Oe layer of N1. Cumulative CO 2 was positively correlated to C-to-N ratio (r 2=0.71, p<0.01) and to cumulative DOC (r 2=0.63, p<0.05) in the Oe layer at Stråsan. Our conclusion was that long-term N additions caused decreased C-to-N ratios and decreased CO 2 evolution rates. The correlation between CO 2 and C-to-N ratio in the Oe layers at Stråsan may be due to a changed quality of the fertilized forest floor material and presence of more N efficient microorganisms.

Effects of soil acidification and liming on ground flora establishment after clear-felling of Norway spruce in Sweden

We used 2 long-term field experiments with Norway spruce Picea abies (L.) Karst. to investigate the influence of lime, acid sulphur compounds, or nitrogen (1 site) on the rate of recruitment of new vascular species after clear-fellings. On the study sites, Farabol in southern Sweden and Fäxboda in south–central Sweden, the chemical treatments had been applied before clear-felling and whole-tree harvesting. An additional, post-harvest experiment was conducted at Farabol in which lime, hardened wood-ash, or logging residues were applied. A germination experiment including seven species was carried out in a greenhouse using sifted humus from Fäxboda that was sampled 2 years before clear-felling. The clear-fellings resulted in establishment of many ephemeral species. The number of newly established species was greater than the number of disappeared species. There was an overall positive correlation with pH in the humus layer and the number of newly established species. The treatment effects differed between the sites, probably reflecting differences in total dose and initial soil conditions. Farabol is characterised by more acid soils and greater atmospheric deposition of S and N than Fäxboda. At Farabol, liming (in total 6000 kg limestone ha −1 distributed over 12 years) resulted in about 20 new species established after clear-felling, four times more species than in untreated, sulphur-treated, or nitrogen-fertilised plots. At Fäxboda, where lime (2000 kg dolomite ha −1), sulphuric acid, and elementary S had been applied 16 years before clear-felling, the number of newly established species was about 15, and no effect of the treatments was revealed. The post-harvest treatments at Farabol showed that wood-ash and logging residues had similar effects as lime on the establishment of new species. The pot experiment showed that liming or acidification can affect the germination of seeds. Compared with untreated soil, a greater proportion of seeds of Primula veris ( P. veris) and Senecio sylvaticus ( S. sylvaticus) germinated in limed soil and the germination of P. veris was lower in acid- or sulphur-treated soils. The germination of Vaccinium myrtillus ( V. myrtillus) seeds was negatively affected by liming. No effects of the treatments were discovered on the germination of Deschampsia flexuosa, Calamagrostis arundinacea, Galeopsis bifida ( G. bifida), or Poa nemoralis. The soil water in the pot experiment had higher pH, higher concentrations of Ca and Mg, and higher NO 3 −/NH 4 + ratios in limed soil compared with other treatments. Nomenclature of plants follows Lid (1985).

Individual tree basal area growth models for young stands of Norway spruce in Sweden

Models for predicting the basal area growth of individual trees of Norway spruce ( Picea abies (L.) Karst.) in young stands in Sweden were developed. The models were based on data obtained from 146 operationally planted stands with Norway spruce, mainly established during the 1950s. The main feature of the study was to compare different approaches to include site effects in the models (site index or primary site factors). Models were developed both with and without site index, competition index and tree age included in the functions. There were no apparent differences in fit statistics between models using site index according to site properties, and models using an independent variable based on average yearly temperature during the growing season. Models based on a distance-dependent competition index and tree age explained about 79% of the variance in basal area increment, while models without distance-dependent competition index and tree age explained 74%. Inclusion of tree age in the models accounted for about 3% of the explained variation and the competition index for about 2% of the explained variation in basal area growth.

Endophytic fungi in branches of Norway spruce with particular reference to Tryblidiopsis pinastri

A variety of endophytic fungi were isolated from the branches of Norway spruce (Picea abies). We found that as internodes age, the composition of endophytic species gradually changes, both qualitatively and quantitatively. One of the dominating species, Tryblidiopsis pinastri, was most common in young internodes. In contrast, three other common species, Phialocephala scopiformis, Geniculosporium serpens, and Tapesia livido-fusca, were most frequently isolated from old internodes. Mollisia spp. were also common components of the endophytic flora of the Norway spruce in Sweden. Keywords: Picea abies, Tryblidiopsis pinastri, Phialocephala scopiformis, Geniculosporium spp., Tapesia spp., Mollisia spp.

Quality of timber products from Norway spruce

Strength and stiffness together with some properties characterizing the stand and the growth of trees were studied. Specimens (45 × 70 × 2900 mm3) were cut from different radial and longitudinal positions, from fast-grown trees from two stands in southern Sweden. These trees had relatively large annual rings (4–6 mm) and were not representative of Norway spruce in Sweden but are an example of the intensivelymanaged stands which will probably constitute a substantial part of the raw material supply in the future. The results indicate that the mean values for strength and stiffness were lowest for the core studs and increased further away from the pith. This radial variation in strength and stiffness appears to be associated with the variation in ring width. Density alone, on the other hand, does not explain the radial variation but should be used together with either ring width or knot area ratio to explain the stiffness and strength respectively. The increase in the strength and stiffness of the core studs from the butt logs to the top logs was significant. Density alone was found to be the best variable to explain the longitudinal variation between the butt logs and the top logs. The heartwood formation in the butt log juvenile core appeared not to have a positive effect on strength and stiffness. The occurrence of compression wood, the magnitude of grain angle and the margin knot area ratio had only a minor effect on strength and stiffness.

Predicting the risk of frost occurrence after budburst of Norway spruce in Sweden.

Predicting the risk of frost occurrence after budburst of Norway spruce in Sweden.