| 1. |
- Aldea, Jorge
(författare)
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Influence of climate and thinning on Quercus pyrenaica Willd. coppices growth dynamics
- 2021
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Ingår i: European Journal of Forest Research. - : Springer Science and Business Media LLC. - 1612-4669 .- 1612-4677. ; 140, s. 187-197
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Tidskriftsartikel (refereegranskat)abstract
- Many oak stands (Quercusspp.) have been managed as coppices for firewood production for centuries in the Mediterranean area. After the abandonment of firewood production during the 1980s, current management practices attempt to convert coppices into coppices-with-standards through thinning and promoting forest regeneration via sexual reproduction. In this work, we used long-term data from repeated forest inventories and dendrometers in a thinning trial to assess the effects of thinning and climate on the intra- and inter-annual growth dynamics ofQuercus pyrenaicaWilld. coppices. Our results revealed that thinning favored the growth ofQ. pyrenaicatrees, especially when the stand density reduction was high (ca. 50% of the basal area extracted). Unthinned plots displayed more natural mortality i.e., self-thinning. Growth was enhanced with low vapor pressure deficit. Intense thinning treatments displayed higher intra-annual growth rates and interacted positively with rainfall to induce higher growth. We conclude that thinning, especially intensive thinning, may alleviate the negative effects of dry years and thus could provide a potential measure to adapt these stands to the different climatic scenarios with higher temperatures and less precipitation within the framework of sustainable forest management.
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| 2. |
- Bakys, Remigijus, et al.
(författare)
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Occurrence and pathogenicity of fungi in necrotic and non-symptomatic shoots of declining common ash (Fraxinus excelsior) in Sweden
- 2009
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Ingår i: European Journal of Forest Research. - : Springer Science and Business Media LLC. - 1612-4669 .- 1612-4677. ; 128, s. 51-60
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Tidskriftsartikel (refereegranskat)abstract
- Currently, massive dieback of Fraxinus excelsior is observed in countries of eastern, northern and central Europe, and the reasons for it are unclear. The aims of the present work were (a) to study fungal communities in declining F. excelsior crowns; (b) to clarify role of fungi in the decline. Shoots from symptomatic crowns were collected in four localities in central Sweden, and distributed into the following categories: (a) visually healthy; (b) initial necroses; (c) advanced necroses; (c) dead tops. The most frequently isolated fungi were Gibberella avenacea, Alternaria alternata, Epicoccum nigrum, Botryosphaeria stevensii, Valsa sp., Lewia sp., Aureobasidium pullulans and Phomopsis sp., and these taxa were consistently found in shoots of all four symptomatic categories. Forty-eight taxa of other fungi were isolated, and fungal diversity was not exhausted by the sampling effort. The same taxa of fungi were dominant in F. excelsior shoots of different symptomatic categories, and moderate to high similarity of fungal communities was observed in shoots despite the symptoms. Forty-four isolates from 24 fungal taxa were used for artificial inoculations of 277 1-year-old F. excelsior seedlings in bare root nursery. After 2 years, only four fungi caused symptomatic necroses of bark and cambium: A. alternata, E. nigrum, Chalara fraxinea and Phomopsis sp. The most pathogenic was C. fraxinea, inducing symptoms on 50% of inoculated trees, while three other fungi caused necroses on 3-17% of inoculated trees. Infection biology of C. fraxinea and environmental factors determining susceptibility of F. excelsior to decline deserve future investigations.
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| 3. |
- Barbeito, Ignacio, et al.
(författare)
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Contrasting patterns of tree species mixture effects on wood delta C-13 along an environmental gradient
- 2020
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Ingår i: European Journal of Forest Research. - : Springer Science and Business Media LLC. - 1612-4669 .- 1612-4677. ; 139, s. 229-245
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Tidskriftsartikel (refereegranskat)abstract
- Establishing mixed-species stands is frequently proposed as a strategy to adapt forests to the increasing risk of water scarcity, yet contrasted results have been reported regarding mixing effects on tree drought exposure. To investigate the drivers behind the spatial and temporal variation in water-related mixing effects, we analysed the delta C-13 variation in 22-year tree ring chronologies for beech and pine trees sampled from 17 pure and mixed pine-beech stands across a large gradient of environmental conditions throughout Europe. In the pure stands, average delta C-13 values were lower for beech (-27.9 parts per thousand to -22.2 parts per thousand) than for pine (-26.0 parts per thousand to -21.1 parts per thousand), irrespective of site conditions. Decreasing SPEI values (calculated over June to September) were associated with an increase in delta C-13 for both species, but their effect was influenced by stand basal area for pine and site water availability for beech. Mixing did not change the temporal constancy of delta C-13 nor the tree reaction to a drought event, for any of the species. While the mixing effect (Delta delta C-13 = delta C-13 pure stands - delta C-13 mixed stands) was on average positive for beech and non-significant for pine across the whole gradient, this effect strongly differed between sites. For both species, mixing was not significant at extremely dry sites and positive at dry sites; on moderately wet sites, mixing was positive for beech and negative for pine; at sites with permanent water supply, no general patterns emerge for any of the species. The pattern of mixing effect along the gradient of water availability was not linear but showed threshold points, highlighting the need to investigate such relation for other combinations of tree species.
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| 4. |
- Belyazid, Salim, et al.
(författare)
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Water limitation can negate the effect of higher temperatures on forest carbon sequestration
- 2019
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Ingår i: European Journal of Forest Research. - : Springer Science and Business Media LLC. - 1612-4669 .- 1612-4677. ; 138:2, s. 287-297
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Tidskriftsartikel (refereegranskat)abstract
- Climate change will bring about a consistent increase in temperatures. Annual precipitation rates are also expected to increase in boreal countries, but the seasonal distribution will be uneven, and several areas in the boreal zone will experience wetter winters and drier summers. This study uses the dynamic forest ecosystem model ForSAFE to estimate the combined effect of changes in temperature and precipitation on forest carbon stocks in Sweden. The model is used to simulate carbon stock changes in 544 productive forest sites from the Swedish National Forest Inventory. Forest carbon stocks under two alternative climate scenarios are compared to stocks under a hypothetical scenario of no climate change (baseline). Results show that lower water availability in the future can cause a significant reduction in tree carbon compared to a baseline scenario, particularly expressed in the southern and eastern parts of Sweden. In contrast, the north-western parts will experience an increase in tree carbon stocks. Results show also that summer precipitation is a better predictor of tree carbon reduction than annual precipitation. Finally, the change in soil carbon stock is less conspicuous than in tree carbon stock, showing no significant change in the north and a relatively small but consistent decline in the south. The study indicates that the prospect of higher water deficit caused by climate change cannot be ignored in future forest management planning.
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| 5. |
- Bengtsson, Jan
(författare)
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Forest multifunctionality is not resilient to intensive forestry
- 2021
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Ingår i: European Journal of Forest Research. - : Springer Science and Business Media LLC. - 1612-4669 .- 1612-4677. ; 140, s. 537-549
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Tidskriftsartikel (refereegranskat)abstract
- There is ample evidence that intensive management of ecosystems causes declines in biodiversity as well as in multiple ecosystem services, i.e., in multifunctionality. However, less is known about the permanence and reversibility of these responses. To gain insight into whether multifunctionality can be sustained under intensive management, we developed a framework building on the concept of resilience: a system's ability to avoid displacement and to return or transform to a desired state. We applied it to test the ability of forest multifunctionality to persist during and recover from intensive management for timber production in a boreal forest. Using forest growth simulations and multiobjective optimization, we created alternative future paths where the forest was managed for maximal timber production, for forest multifunctionality, or first maximal timber production and then multifunctionality. We show that forest multifunctionality is substantially diminished under intensive forestry and recovers the slower, the longer intensive forestry has been continued. Intensive forestry thus not only reduces forest multifunctionality but hinders its recovery should management goals change, i.e., weakens its resilience. The results suggest a need to adjust ecosystem management according to long-term sustainability goals already today.
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| 6. |
- Bergkvist, John, et al.
(författare)
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Maintenance and enhancement of forest ecosystem services: a non-industrial private forest owner perspective
- 2023
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Ingår i: European Journal of Forest Research. - 1612-4669 .- 1612-4677.
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Tidskriftsartikel (refereegranskat)abstract
- The transition to a fossil-free society in Sweden is expected to cause an increased demand for forest-derived products which may intensify existing conflicts between forest ecosystem services. This study investigated the preferences among non-industrial private forest owners for maintaining multiple forest ecosystem services and their preferences for future forest development. The findings were related to their prioritizations for and knowledge of forest management. The study results were generated through the means of a survey which revealed a consistent high valuation among all respondents of ecosystem services relating to water quality, timber quality, recreation, and biodiversity. A majority of the respondents desired increasing proportions of mixed species and broadleaved stands within the future forest landscape. Certified forest owners who were members of a forest owner association (CMs) prioritized achieving high economic income through roundwood production with strong preferences for the ecosystem services high stand growth and high timber quality. For CMs, carbon substitution was the preferred means of mitigating climate change. Forest owners lacking both certification and membership in a forest owner association ranked the ecosystem services recreation and biodiversity significantly higher, and also preferred retaining more old forest within the landscape. The survey results revealed a higher management activity among CMs, resulting in a more frequent establishment of mixed and broadleaved stands. Forest owners with medium to large scale properties were well-represented within the CM category. The results indicated that while the CMs have stronger preferences for roundwood production compared to owners of small properties, they are also more likely to have taken adaptive measures favoring risk management and biodiversity.
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| 7. |
- Bergvall, Ulrika A., et al.
(författare)
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Anti-browsing effects of birch bark extract on fallow deer
- 2013
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Ingår i: European Journal of Forest Research. - : Springer Science and Business Media LLC. - 1612-4669 .- 1612-4677. ; 132:5-6, s. 717-725
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Tidskriftsartikel (refereegranskat)abstract
- A major problem within forest industry is unwanted browsing on seedlings from mammalian herbivores. The aim of this study was to evaluate the effects of birch bark extracts as repellents towards fallow deer. Birch bark was extracted in a conventional way with ethanol as solvent at ambient temperature and with a new method, liquid CO2 extraction. An analysis of the ethanol-extracted birch bark showed that it contained large amounts of terpenoids, of which the most abundant was betulin. In seven different treatment trials, we used 15 individually handled fallow deer. To investigate the binary taste preferences, birch bark extract was added to food and presented in two bowls in typical two-choice tests. We found that the amount of a food type consumed during a trial and the number of shifts between food bowls were dependent on the amount of the birch extract the food contained. Concentrations of above 1 % by dry weight of birch extract acted as a repellent. In addition, such concentrations produced shorter feeding bouts by a greater willingness to change bowls. Therefore, our conclusion is that birch bark extract acts as a repellent towards fallow deer and is therefore likely to act as a repellent against other deer species. In addition, we show that birch bark extract produced by the new and more environmentally sustainable method employing liquid CO2 mixed with ethanol has the same repellent effect as the traditional ethanol extraction.
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| 8. |
- Binkley, Dan
(författare)
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The effects of soil fertility and scale on competition in ponderosa pine
- 2016
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Ingår i: European Journal of Forest Research. - : Springer Science and Business Media LLC. - 1612-4669 .- 1612-4677. ; 135, s. 153-160
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Tidskriftsartikel (refereegranskat)abstract
- The intensity of competition between neighboring trees depends on local stand structure, and the influence of stand structure may vary across gradients in soil resource supplies. We used model selection techniques to look for variation in the nature and intensity of interactions between trees along a gradient of soil nitrogen supply in a 9-ha stand of old-growth ponderosa pine (Pinus ponderosa) in Colorado, USA. We used spatially explicit competition indexes to describe the interactions between trees and developed individual tree growth models to look at how soil nitrogen (N) supply affects competition. The growth of focal trees showed an asymmetric influence of neighbors up to 14-m distance. The predictive ability of our growth models more than doubled (to an r(2) = 0.69) as the size of the neighborhood used to calculate the competition indexes increased from a 2-m to a 14-m radius. The supply of soil nitrogen modified competition, with increasing N enhancing competition from neighbors. Neighborhood structure and soil resource supplies jointly influenced the growth of individual trees, but at different scales. Tree interactions are both spatially and temporally complex and may be studied most usefully with explicit evaluation of gradients in resource availability.
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| 9. |
- Brunet, Jörg
(författare)
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Climate change impacts on stand structure and competitive interactions in a southern Swedish spruce-beech forest
- 2010
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Ingår i: European Journal of Forest Research. - : Springer Science and Business Media LLC. - 1612-4669 .- 1612-4677. ; 129, s. 261-276
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Tidskriftsartikel (refereegranskat)abstract
- It is believed that European beech (Fagus sylvatica L.) will increase its competitive ability at its northern range margin in Scandinavia due to climate change. In mixed old-growth forests of beech and Norway spruce (Picea abies (L.) Karst.) at Siggaboda nature reserve (southern Sweden), stand structure characteristics were sequentially recorded in the years 2004, 2005 and 2007 as well as growth in stem diameter using tree-coring analyses. Using these measurements, we studied the effects on stand dynamics of an extreme storm event (2005 "Gudrun" hurricane), drought and heat (mid-summer 2006, spring 2007) and subsequent bark beetle attacks on spruce (growing season 2007), overlaid with warming tendencies. The storm, which caused disastrous damage in many stands nearby, had comparatively little impact on the structure of the spruce-beech stand. All together, only 32 trees (19 spruces, 10 beeches, 3 other species) per hectare were thrown or broken mainly in the leeward direction (NE) or impacted by secondary damage by uprooted neighbour trees; this represents 7% of the total tree number and 11% of the growing stock. Diameter and height structure did not change significantly. However, the 2006 drought and the 2007 attack of biotic agents changed the stand structure and composition strongly due to the death of about 19% of the dominating older spruce trees that accounted for 35% of total stand volume. This resulted in a considerable increase in beech's contribution to stem number (4% increase) and wood volume of the living stand (7% increase). A comparison of diameter growth of beech and spruce during the periods 1894-1949 and 1950-2005 showed a distinct decrease in growth superiority of spruce during the last 50 years. These results support the idea of a northward migration of European beech as a nemoral tree species in Sweden, due to a higher tolerance to the abiotic and biotic threats accompanying climate change and an increased competitive ability compared to boreal tree species Norway spruce.
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| 10. |
- Chen, Zhi‑Qiang, et al.
(författare)
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Early selection for resistance to Heterobasidion parviporum in Norway spruce is not likely to adversely affect growth and wood quality traits in late-age performance
- 2018
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Ingår i: European Journal of Forest Research. - : Springer Science and Business Media LLC. - 1612-4669 .- 1612-4677. ; 137:4, s. 517-525
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Tidskriftsartikel (refereegranskat)abstract
- Infections with Heterobasidion parviporum devalue the Norway spruce timber as the decayed wood does not meet the necessary quality requirements for sawing. To evaluate the incorporation of disease resistance in the Norway spruce breeding strategy, an inoculation experiment with H. parviporum on 2-year-old progenies of 466 open-pollinated families was conducted under greenhouse (nursery) conditions. Lesion length in the phloem (LL), fungal growth in sapwood (FG) and growth (D) were measured on an average of 10 seedlings for each family. The genetic variation and genetic correlations between both LL, FG and growth in the nursery trial and wood quality traits measured previously from 21-year old trees in two progeny trials, including solid-wood quality traits (wood density, and modulus of elasticity) and fiber properties traits (radial fiber width, tangential fiber width, fiber wall thickness, fiber coarseness, microfibril angle and fiber length). For both LL and FG, large coefficients of phenotypic variation (> 26%) and genetic variation (> 46%) were detected. Heritabilities of LL and FG were 0.33 and 0.42, respectively. We found no significant correlations between wood quality traits and growth in the field progeny trials with neither LL nor FG in the nursery trial. Our data suggest that the genetic gains may reach 41 and 52% from mass selection by LL and FG, respectively. Early selection for resistance to H. parviporum based on assessments of fungal spread in the sapwood in nursery material, FG, will not adversely affect growth and wood quality traits in late-age performance.
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