| 1. |
- Blanck, Ylva-Li, et al.
(author)
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Plant species richness in a natural Argentinian matorral shrub-land correlates negatively with levels of plant phosphorus
- 2011
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In: Plant and Soil. - : Springer Science and Business Media LLC. - 0032-079X .- 1573-5036. ; 345:1-2, s. 11-21
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Journal article (peer-reviewed)abstract
- The aim of this study was to ascertain whether there is a relationship between plant species richness and plant-available N, P and water in an environment subject to little anthropogenic disturbance. To accomplish this we studied the vegetation in matorral shrub-lands in northern Patagonia, Argentina. Due to the variation in slope, precipitation and aspect between the sites water status was determined using the C-12/C-13 fraction, delta C-13, to investigate whether this was a confounding factor. The numbers of herb, shrub, liana and tree species were determined at 20 sites along an estimated precipitation gradient. Leaf P and N content and the delta C-13 of Berberis buxifolia were determined, as well as the soil P and N content at the different sites. A negative correlation was found between species richness and Berberis buxifolia foliar P concentration (52% of the species richness variation was accounted for), and a positive correlation was found between plant species richness and Berberis buxifolia foliar N: P ratios (54% of the species richness variation was accounted for). The relationship between species richness and foliar P was seen when all layers of vegetation were included (trees, lianas, shrubs and herbs). Foliar N showed no correlation with species richness, while soil extractable NH4 showed a weak positive correlation with the number of shrub layer species (lianas, shrubs and trees). The species richness of the shrub layer increased with decreasing values of delta C-13. Low soil P availability thus affects local species richness in the matorral shrub-lands of Patagonia in Argentina although the growth of vegetation in the area has been shown to be limited by N. We suggest that low P levels increase plant species richness because low soil P concentration is associated with a high P partitioning and high potential for niche separation.
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| 5. |
- Fransson, Ann-Mari, et al.
(author)
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Tillväxtökningar av biokol hos urbana träd på Herrhagsvägen
- 2014
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Reports (other academic/artistic)abstract
- Många stadsträd mår dåligt idag. Orsakerna är troligen många och många olika konstruktioner har testats för att förbättra förhållandena för träden. Denna rapport beskriver en studie där vi har undersökt om biokol kan öka tillväxten och vitaliteten hos körsbär (Prunus avium'Plena') längs en väg i Enskede, Stockholm.Vi har också testat om träden kunde växa med endast sten i växtbädden. De träd som vuxit i AMA B-jord som haft en inblandning av 50% biokol fick 35% större stamomkrets, ca 20% bredare krona och längre skottillväxt. Detta beror troligen på att biokol haren stor förmåga att fördröja uppehållelsetiden av näringsämnen i växtbäddenoch att hålla vättillgängligt vatten och biokol gör att jorden får en bättre struktur.Inga skillnader i vitalitet eller vattenupptagsförmågan under en solig dag kunde upptäckas vilket visar att den här tillväxtökningen troligen beror på näringstillgången eller på den förbättrade strukturen i jorden.De träd som växte i endast sten hade lika bra tillväxt som de i AMA B-‐växtjord. En annan slutsats man kan dra är att man inte behöver vara så noga med att få ner jord i en skelettjord eller någon annan växtbäddskonstruktion eftersom trädensrötter klarar att växa i endast sten.
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| 6. |
- Lankinen, Åsa, et al.
(author)
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Allocation to pollen competitive ability versus seed production in Viola tricoloras an effect of plant size, soil nutrients and presence of a root competitor
- 2012
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In: Oikos. - : John Wiley & Sons. - 0030-1299 .- 1600-0706. ; 122:5, s. 779-789
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Journal article (peer-reviewed)abstract
- In hermaphroditic plants, the effect of a social environment on sex allocation has not been studied to our knowledge, while in hermaphroditic animals such effects are known to be common. In recent years, studies on root competition beyond the effects of nutrients have shown that plants can respond to their conspecific root competitors (social environment), making it interesting to ask if these effects could also influence sex allocation in addition to more commonly studied factors, such as plant size or resources. In this study on hermaphroditic Viola tricolor, we investigated how plant size, soil nutrients and presence of a root competitor influenced allocation to pollen competitive ability versus seed production, i.e. male and female reproductive functions. We allowed plants to grow in pairs with partly intermingled or separate roots in the same amount of soil. In additional treatments with intermingled roots (as part of the same experiment) one of the two competitors was given combinations of nitrogen (N), phosphorous (P) and micro nutrients. We found that pollen performance but not seed production increased when plants were in contact in the soil. Additionally, pollen performance was negatively correlated to plant size across fertilisation treatments. For seed production, the opposite relation to plant size was seen, indicating that large, fertilized plants invest relatively more in the female function. In conclusion, in violets, sex allocation appears to be size-dependent and influenced by both the presence of a root competitor and by nutrients. These results suggest that social environment can influence sex allocation in plants as well as in animals, indicating that such effects are important to consider in sex allocation studies across taxa.
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| 7. |
- Levinsson, Anna, et al.
(author)
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Influence of nursery production system on water status in transplanted trees
- 2014
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In: Scientia Horticulturae. - : Elsevier. - 0304-4238 .- 1879-1018. ; 178, s. 124-131
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Journal article (peer-reviewed)abstract
- The objective of this study was to investigate the influence of the nursery production system on post-transplant water uptake and stress in urban trees during the establishment phase. Field-grown trees of sweet cherry (Prunus avium L) and red oak (Quercus rubra L) were either transplanted as bare-rooted or balled & burlapped, or subjected to fine-root-stimulating measures (in so called pre-establishing systems) as root-pruning, air-potting or fabric-container-cultivation in the nurseries one year prior to transplanting. All trees were planted at two sites: one occasionally dry site in the city of Malmö and one with adequate water supply at all times, at an experimental rural site at Alnarp campus, both in Sweden. Shoot water potential was determined every third week at midday and pre-dawn the following morning during the three first years after transplanting. Leaf surface area was measured annually. The red oak trees from the pre-establishing systems showed higher water potentials at every measuring occasion compared to that of bare-rooted red oak trees at the rural site during the first year. The air-potted sweet cherry trees at the rural site had higher midday water potential than the bare-rooted trees at every measuring occasion during the first year. Leaf surface area was larger for air-potted red oaks than bare-rooted red oaks during the first post-transplant year (p < 0.001, both sites). The differences between the production systems did not persist during the following two years. Leaf surface area was restored to pre-transplant size in all trees at the rural site after three years but still reduced at the urban site. These results suggest that the pre-establishing systems do have an impact on water status when soil water availability is sufficient, but less significance in typically urban areas, with limited soil water during the initial post-transplant phase. The results indicate that red oak and sweet cherry trees planted in an urban context, with occasionally low soil water amounts, are not favored by cultivation in pre-establishing systems prior to transplant, and that low water availability cannot be compensated for by high amounts of fine roots. Good establishment management is required also for trees submitted to pre-establishing measures.
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| 8. |
- Pedersen, Jorgen, et al.
(author)
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Performance of Anisantha (Bromus) tectorum and Rumex acetosella in sandy calcareous soil
- 2011
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In: Flora: Morphology, Distribution, Functional Ecology of Plants. - : Elsevier BV. - 0367-2530. ; 206:3, s. 276-281
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Journal article (peer-reviewed)abstract
- Many plants are adapted to an eroded landscape with a large proportion of virgin soil. Open and disturbed soils are today almost only restricted to agricultural fields with high loads of fertilizers. We conducted a pot experiment in order to investigate growth and nutritional constraints of one calcicole species, Anisantha (syn. Bromus) tectorum, and one calcifuge species, Rumex acetosella, in decalcified topsoil and recently exposed calcareous subsoil from a field experiment in sandy grassland. In the pot experiment we implemented one treatment where we limed topsoil with CaCO3 to the same amount as in subsoil. The subsoil had approximately 10% CaCO3 and both species grew less in this soil compared to the topsoil, which had less than 1% CaCO3. Germination rate of A. tectorum was higher in subsoil than in topsoil or limed topsoil. P fertilization of the limed topsoil counteracted the negative liming effect for A. tectorum, but only partly so for R. acetosella. P fertilization of subsoil increased the shoot biomass of A. tectorum, but not of R. acetosella. P concentration in plants was not reduced when growing on subsoil or limed topsoil compared to topsoil. The results show that lime addition may reduce the P availability also to calcicole species such as A. tectorum and we found indications for that Ca toxicity may be a causing factor for the calcifuge behavior of R. acetosella. The significance of the results for conservation management practices in sandy grasslands is discussed. (C) 2010 Elsevier GmbH. All rights reserved.
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| 9. |
- Östberg, Johan, et al.
(author)
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Förebyggande av rotinträngningar i VA-ledningar - utveckling av beslutsstöd
- 2010
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Reports (other academic/artistic)abstract
- In 2007 data regarding sewage pipes and CCTV-inspections of the sewage pipe interior, a total of 1 113 sewage pipes with 3 417 root intrusions, was collected from the three cities; Malmö, Skövde and Katrineholm. In 2008 additional data was collected consisting of an inventory of 4 590 trees in Malmö Skövde and Katrineholm, and CCTV inspections in another city, Växjö. Another 74 778 trees were inventoried and 23 312 trees registered from the participating cities’ databases. These trees were geographically distributed throughout the cities. Overall this constitutes a database of 102 680 trees. By using the collected data, analysis showed that PVC-pipes have less root intrusions penetrating through the joints than pipes made of other materials. However, PVC-pipes have more root intrusions per meter pipe. This is probably due to roots entering the pipes through service connections and at the transition between PVC and other materials. The reason why PVC has less root intrusions that have penetrated through the joints compared to concrete pipes can also be affected by the joint frequency which is significantly lower in the PVC pipes. By this comparison it is not concluded that PVC is better or worse to resist root intrusions than concrete. We can see indications that a large share of the root intrusions might be avoided if fewer damages were present on the pipes and if the connections were made in a more root-resistant manner. These indications demonstrate that root intrusions even in the future will be a serious operational problem, despite the use of pipes with high sealing ability of the joints or the jointless pipes. The survey also showed that renovated pipes have problems with root intrusions a relatively short time after the renovation from root intrusions. Root intrusions into renovated pipes may have occurred at the manholes or at the service connections. To overcome the problem with root intrusions future research must be directed to enhance the sealing capacity along the whole pipeline, rather than on individual sealings. The investigation has shown that the minimum distance of three meters that was previously recommended in order to reduce the risk of root intrusion is insufficient. We can see a high number of trees at a distance between 3 to 7 meters from the root intrusions, and we suggest that the distance be increased to 7 meters. This will create challenges for the landscapers, but it is of great importance if to reduce the number root intrusions in the future. The species that have been regarded as more or less likely to give rise to root intrusions has previously been listed. This project provides a new such list. In this list both willow, poplar/aspen, roses and thuja occurs. It is thereby clear that even shrubs can cause root intrusions. The species that occur with a higher frequency close to root intrusions are also interestingly not only willow, poplar/aspen. In addition it seems that the species that are frequent surrounding root intrusions are not the same in the cities investigated. In light of these results, previous recommendations must be taken with some caution
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| 12. |
- Östberg, Johan, et al.
(author)
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Risk of root intrusion by tree and shrub species into sewer pipes in Swedish urban areas
- 2012
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In: Urban Forestry & Urban Greening. - : Elsevier. - 1618-8667 .- 1610-8167. ; 11:1, s. 65-71
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Journal article (peer-reviewed)abstract
- Blockages in sewer pipes caused by roots are very common and several tree and shrub species are reported to be particularly likely to cause root intrusion. This study examined the relative ability of roots of different species to intrude into urban sewer pipes.Data on root-intruded pipes and the woody plants surrounding these pipes were collected from two Swedish cities, Malmö and Skövde. Plant material, location data and closed-circuit television (CCTV) inspections on root-intruded pipes with a total length of 33.7 km, containing 2180 different points of root intrusion, were examined. An inventory of 4107 woody plants was compiled.The results showed that broad-leaved trees dominated as a cause of root intrusion, but that conifers and a number of shrubs, e.g. the genera Ligustrum, Spiraea and Syringa, were also likely to have caused root intrusion. Malus floribunda Van Houtte was found to have the highest mean share of root intrusions per estimated number of pipe joints when all joints and all root intrusions within a 10 m radius from trees were calculated (0.694, maximum number of intrusions per joint 1.0), while Populus canadensis ‘Robusta’ Moench had the second highest, with 0.456 intrusions per estimated joint. However, other Malus and Populus species and cultivars had a much lower mean share of root intrusions.Most species seemed capable of causing root intrusion, and not only species of the genera Populus and Salix that were previously seen as the species most likely to cause damage to stormwater and sewer systems. There were differences in the frequency of joint intrusion by roots of different species, but the reasons for these differences were not identified and further research in the area is needed.
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| 15. |
- Östberg, Johan, et al.
(author)
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Standardiserad trädinventering och insamling av data för träd i urban miljö
- 2012
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Reports (other academic/artistic)abstract
- Trädinventeringar och insamling av data om träd blir allt vanligare inom olika verksamheter som berör stadens utemiljö. Det är viktigt att dessa arbeten utförs med hög noggrannhet och kvalitet. Om de metoder och inventeringsparameter som tillämpas är jämförbara kan olika aktörer bättre dra nytta av varandras erfarenheter, och upphandlingsarbetet underlättas. Område Landskapsutveckling vid SLU i Alnarp startade därför den 1 januari 2010 arbetet med att ta fram riktlinjer för insamling av träddata. Denna standard är slutprodukten av detta projekt. Som ett komplement till standarden finns en rapport som beskriver hur författarna har tänkt gällande valet och definitionerna av de olika parametrarna, tillsammans med exempel på användningsområden för trädinformationen. Förhoppningen är att denna rapport ska besvara de eventuella frågor som kan dyka upp vid arbetet med denna standard.
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| 16. |
- Östberg, Johan, et al.
(author)
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Sådan registrerer man bytræer
- 2012
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In: Grønt miljø. - 0108-4755. ; 4, s. 32-33
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Journal article (pop. science, debate, etc.)
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