4,921 research outputs found
Root spatial distribution and biomass partitioning in Quercus robur L. seedlings: the effects of mounding site preparation in oak plantations
No full textIn a reforestation field experiment undertaken in southern Sweden and planted with pedunculate oak, three site preparation treatments (herbicide application (H), mounding site preparation (MSP) and combined herbicide and mounding treatment (H + MSP)) were compared to an undisturbed control (C). We analysed root spatial and biomass distribution in 48 harvested seedlings. Compared to the control, both MSP and H treatments resulted in a significantly higher root system biomass (means C: 16.4 g, H: 45.7 g, MSP: 41.4 g, MSP + H: 102.2 g). The proportion of lateral root biomass increased from 38% (C) to 62% (MSP + H), while the two remaining treatments (H, MSP) attained percentages of 48% and 51%, respectively. The treatments did not alter seedlings' allometry and root:shoot ratio significantly. However, biomass distribution of different root system parts varied among treatments, so that lateral root biomass increased relative to leaf biomass from C to MSP + H variant. Site preparation treatments (MSP, MSP + H) increased the horizontal extension of root biomass, compared to C and H variants. We conclude that mounding site preparation is an efficient method for the reforestation of pedunculate oak stands. Due to the comparative positive effects on root system development, MSP presents an alternative to herbicide treatment, particularly at sites where the use of chemicals is restricted
Space sequestration below ground in old-growth spruce-beech forests—signs for facilitation?
No full textScientists are currently debating the effects of mixing tree species for the complementary resource acquisition in forest ecosystems. In four unmanaged old-growth spruce-beech forests in strict nature reserves in southern Sweden and northern Germany we assessed forest structure and fine rooting profiles and traits (<= 2 mm) by fine root sampling and the analysis of fine root morphology and biomass. These studies were conducted in selected tree groups with four different interspecific competition perspectives: (1) spruce as a central tree, (2) spruce as competitor, (3) beech as a central tree, and (4) beech as competitor. Mean values of life fine root attributes like biomass (FRB), length (FRL), and root area index (RAI) were significantly lower for spruce than for beech in mixed stands. Vertical profiles of fine root attributes adjusted to one unit of basal area (BA) exhibited partial root system stratification when central beech is growing with spruce competitors. In this constellation, beech was able to raise its specific root length (SRL) and therefore soil exploration efficiency in the subsoil, while increasing root biomass partitioning into deeper soil layers. According to relative values of fine root attributes (rFRA), asymmetric below-ground competition was observed favoring beech over spruce, in particular when central beech trees are admixed with spruce competitors. We conclude that beech fine rooting is facilitated in the presence of spruce by lowering competitive pressure compared to intraspecific competition whereas the competitive pressure for spruce is increased by beech admixture. Our findings underline the need of spatially differentiated approaches to assess interspecific competition below ground. Single-tree approaches and simulations of below-ground competition are required to focus rather on microsites populated by tree specimens as the basic spatial study area
Critical limits of soil water availability (CL-SWA) for forest trees - an approach based on plant water status
No full textDue to climate change, heat waves and drought are expected to increase in frequency and intensity in Central Europe. Thus, assessments of critical constraints of water supply in forest trees are! needed to develop adequate forest adaptation measure;. We present a novel 'critical limit' approach to soil water availability (SWA) for the major central European forest tree species based on the physiological plant water status. In regards to the conductivity of trees' xylem, three thresholds of pre-dawn water potential (psi(wp)) were chosen, referring to (i) slight conductivity loss (10%), (ii) critical conductivity loss (50%) and (iii) complete conductivity loss (>90%). In times of drought, pre-dawn water potential relates to the soil water potential at the lowest soil depth in which plant's root system is able to deplete water resources; the 'effective rooting depth' (ERD). The critical limit of soil water availability (CL-SWA) represents the proportion of plant-available water within the variable effective rooting depth (ERD) that meets both the critical soil water potential at the lower limit of the ERD and the critical plant water status. The CL-SWA-approach can be implemented in water budget models like BROOK90.German Federal Ministry of Education and Science (BMBF
Mounding site preparation for forest restoration: Survival and short term growth response in Quercus robur L. seedlings
No full textMounding site preparation for forest restoration: survival and short term growth response in Quercus robur L. seedlings control of natural vegetation during afforestation and reforestation is necessary to avoid economical losses through growth reduction and mortality in seedlings. The present field experiment, carried out on a ground-water influenced site with planted oak, included three site preparation treatments and undisturbed control (Q. The treatments were: repeated herbicide application (H), mounding site preparation (MSP), and mounding site preparation in combination with repeated herbicide application (MSP + H). The mounds were 25 m long, 2 m wide and 20 cm high inverted mounds on humus, and this method is sometimes also called bedding. Seedlings were monitored for 3 years and at the end of the experiment 90% of oak seedlings survived in the various site preparation methods compared with 58% in the undisturbed control. The best growth was obtained when mounding site preparation was combined with repeated herbicide treatment, producing five times greater seedling biomass compared with the control. Mounding site preparation resulted in equal growth of seedlings compared with repeated herbicide application. Interference from vegetation had a strong negative effect on seedling growth while mounding site preparation itself resulted in a positive seedling growth response. We conclude that mounding site preparation is an efficient tool for forest managers in establishing oak stands and is a good alternative to herbicide treatment on certain sites. On the other hand, a relatively large disturbance area and deep soil disturbances may impair recreational values and destroy archaeological remains. (c) 2006 Elsevier B.V. All rights reserved
Short Rotation Coppice (SRC) Plantations Provide Additional Habitats for Vascular Plant Species in Agricultural Mosaic Landscapes
No full textIncreasing loss of biodiversity in agricultural landscapes is often debated in the bioenergy context, especially with respect to non-traditional crops that can be grown for energy production in the future. As promising renewable energy source and additional landscape element, the potential role of short rotation coppice (SRC) plantations to biodiversity is of great interest. We studied plant species richness in eight landscapes (225 km(2)) containing willow and poplar SRC plantations (1,600 m(2)) in Sweden and Germany, and the related SRC alpha-diversity to species richness in the landscapes (gamma-diversity). Using matrix variables, spatial analyses of SRC plantations and landscapes were performed to explain the contribution of SRC alpha-diversity to gamma-diversity. In accordance with the mosaic concept, multiple regression analyses revealed number of habitat types as a significant predictor for species richness: the higher the habitat type number, the higher the gamma-diversity and the lower the proportion of SRC plantation alpha-diversity to gamma-diversity. SRC plantation alpha-diversity was 6.9 % (+/- 1.7 % SD) of species richness on the landscape scale. The contribution of SRC plantations increased with decreasing gamma-diversity. SRC plantations were dominated more by species adapted to frequent disturbances and anthropo-zoogenic impacts than surrounding landscapes. We conclude that by providing habitats for plants with different requirements, SRC alpha-diversity has a significant share on gamma-diversity in rural areas and can promote diversity in landscapes with low habitat heterogeneity and low species pools. However, plant diversity enrichment is mainly due to additional species typically present in disturbed and anthropogenic environments
Stand age characteristics and soil properties affect species composition of vascular plants in short rotation coppice plantations
No full textVolume: 7Start Page: 51End Page: 7
The north-eastern distribution range of European beech a review
No full textToday, European beech (Fagus sylvatica L.) seems to be a markedly successful tree species in the north-east of its distribution range. The distribution area may be larger than originally assumed; past forest management is probably the main cause of the contraction in the postglacial European beech range. Numerous attempts consistently have failed to locate a distinct distribution edge for European beech. Therefore, we de. ne northern and eastern Poland and the southern regions of the Baltic States as margins of European beech distribution. Ecophysiological approaches have identified the drought constraints for European beech in terms of (1) the critical limit for xylem cavitation and loss of hydraulic conductivity, reached at a shoot water potential of -1.9 MPa, and (2) a reduction in gross primary production and total ecosystem respiration when relative extractable soil water reaches 40 and 20 per cent, respectively. However, it is difficult to correlate European beech distribution margins with single macro-climatic factors. Moreover, the adaptation of European beech populations and provenances to drought and frost varies. The phenotypic plasticity and evolutionary adaptability of European beech appear to be underestimated. These characteristics may counteract a further contraction of the European beech range arising from climate change in the future
Does climate drive the defoliation of European beech (Fagus sylvatica L.)?
No full texthttp://dx.doi.org/10.13039/501100000780 European Commissio
Potenziale und Risiken eingeführter Baumarten. Baumartenportraits mit naturschutzfachlicher Bewertung
No full textEine nachhaltige, multifunktionale Forstwirtschaft hat den Anspruch, Wälder so zu pflegen und zu nutzen, dass deren Produktivität, Verjüngungsfähigkeit, Vitalität und biologische Vielfalt erhalten bleiben. In der Vergangenheit hat sich gezeigt, dass weder im Kielwasser der Rohholzerzeugung noch in jenem des Naturschutzes alle Waldfunktionen angemessen erfüllt werden. Die Integration eingeführter Baumarten in einen Waldbau auf ökologischen Grundlagen erfordert daher Kompromisse, die sich auf der Basis wissenschaftlicher Erkenntnisse in der Regel auch finden lassen. Konkret bedeutet dies, dass der Anbau nicht invasiver eingeführter Baumarten in gewissem Umfang vom Naturschutz ebenso akzeptiert wird, wie seitens der Forstwirtschaft naturschutzfachliche Interessen berücksichtigt werden, indem bei ihrem Anbau auf eine räumliche Ordnung geachtet wird und bestehende Vorkommen invasiver Baumarten zurückgedrängt werden. Ziel dieser Ausarbeitung ist es vor diesem Hintergrund, die Potenziale und Risiken von 15 eingeführten Baumarten auf der Grundlage wissenschaftlicher Literatur und langjähriger Forschungsarbeiten auf Versuchsflächen der verschiedenen Forschungseinrichtungen und Anbauflächen der Forstbetriebe aufzuzeigen, um die zwischen Naturschutz und Forstwirtschaft aufgekommene Diskussion zu versachlichen
Biological Monitoring of Pollution in Forests and of Pollution caused by Wood Utilisation
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