Occurrence and management of oak in southern Swedish forests

This article describes the current proportions of forest types with oak (Quercus robur and Q. petraea) in southern Sweden, provides an overview of oak distribution over time and reviews literature about oak regeneration relevant for the region. Further we discuss silvicultural possibilities to maintain and promote oak in Scandinavia. In Götaland pure oak forest covers 1% of the forest area and mixed forest types with > 10% oak proportion cover approximately 10% of the area. Common types of mixture are spruce-oak and pine-oak forest. Both mixtures are frequent in mature forest, especially pine-oak. Additionally, about one third of spruce-oak mixtures can be found in medium-aged forest. Intensive management would be necessary to promote single oak trees in old pine stands or spruce plantations, but the proportion of oak in coniferous forest provides some potential to maintain additional oak trees. The distribution of acorns by Jays, enhanced measures against browsing, and the release of single oak trees from competing tree species could help to maintain more oak trees for nature conservation. However, regarding management of oak for timber production, conventional methods are recommended. Planting after clear cutting of coniferous forest, or short shelter periods after mast years in oak stands, are established methods to regenerate pure oak stands. Another possibility to develop mature oak forest are mixed oak-spruce plantations, as traditionally practised in a small region in southern Sweden. The different approaches of oak management in Sweden were presented in April 2012 on the annual meeting of the section silviculture of DVFFA (German Union of Forest Research Organizations) in Wermsdorf near Leipzig to give an overview and access to recent forest research in Sweden

Jointness through fishing days input in a multi-species Fishery

Some multi-species fisheries are characterised by production jointness in the sense that several species are caught through a joint production process (literally in the same haul of the net). Other multi-species fisheries (so called purse seine fisheries) are specialized in the sense that species are targeted individually and by-catch is negligible, but over the fishing season the same boat chooses to target several species with varying intensity which also results in a sort of jointness. Both types of fisheries are typically modelled using standard multi-input multi-output profit function forms (e.g. translog, normalized quadratic). In this paper we argue that jointness in the latter, essentially separable fishery is caused by allocation of fishing days input among harvested species. We developed a structural model of a multi-species fishery where the allocation of fishing days input causes production jointness. We estimate the model for the Norwegian purse seine fishery and find that it is characterised by non-jointness, while estimations for this fishery using the standard multi-input multi-output profit function imply jointness.production jointness, multi-species fisheries, structural modeling

A model analysis on nitrate leaching under different soil and climate conditions and use of catch crops

The use of crops and catch crops with deep rooting can strongly improve the possibility of retaining nitrate-N that will otherwise be leached to the deeper soil layers and end up in the surrounding environment. But will it always be an advantage for the farmer to grow a catch crop? This will depend on factors such as soil mineral nitrogen level, soil water holding capacity, winter precipitation, rooting depth and N demand of the scceeding crop. These factors interact, and it can be very difficult for farmers or advisors to use this information to decide whether growing a catch crop will be beneficial. To analyse the effect of catch crops under different Danish soil and precipitation conditions, we used the soil, plant and atmosphere model Daisy

Dynamic critical behaviors of three-dimensional XY models related to superconductors/superfluids

The dynamic critical exponent z is determined from numerical simulations for the three-dimensional XY model subject to two types of dynamics, i.e. relaxational dynamics and resistively shunted junction (RSJ) dynamics, as well as for two different treatments of the boundary, i.e., periodic boundary condition (PBC) and fluctuating twist boundary condition (FTBC). In case of relaxational dynamics, finite size scaling at the critical temperature gives $z\approx 2$ for PBC and 1.5 for FTBC, while for RSJ dynamics $z\approx 1.5$ is obtained in both cases. The results are discussed in the context of superfluid/superconductors and vortex dynamics, and are compared with what have been found for other related models.Comment: 7 pages, 5 figures with europhys.sty, to appear in Europhys. Let

Dynamic critical exponent of two-, three-, and four-dimensional XY models with relaxational and resistively shunted junction dynamics

The dynamic critical exponent $z$ is determined numerically for the $d$-dimensional XY model ($d=2, 3$, and 4) subject to relaxational dynamics and resistively shunted junction dynamics. We investigate both the equilibrium fluctuation and the relaxation behavior from nonequilibrium towards equilibrium, using the finite-size scaling method. The resulting values of $z$ are shown to depend on the boundary conditions used, the periodic boundary condition, and fluctuating twist boundary condition (FTBC), which implies that the different treatments of the boundary in some cases give rise to different critical dynamics. It is also found that the equilibrium scaling and the approach to equilibrium scaling for the the same boundary condition do not always give the same value of $z$. The FTBC in conjunction with the finite-size scaling of the linear resistance for both type of dynamics yields values of $z$ consistent with expectations for superfluids and superconductors: $z = 2$, 3/2, and 2 for $d=2$, 3, and 4, respectively.Comment: 21 pages, 16 figures, final versio

By George! Exploring explorers - encountering Bam Goober at nutcur

In the current post-colonial discourse on the revising of imperial history, George Bowering\u27s novel Burning Water provides an interesting case study, as it presents itself as a historical fictional rewriting of George Vancouver\u27s journey of exploration. While bearing clear evidence of extensive research it simultaneously deliberately distances itself from its historical sources, primarily through its imaginary rendering of the dialogue amongst the Europeans and the Indians. With regards to the actual course of events during the expedition as described in the journals of the naval officers, the plot in Burning Water diverges little from the primary material except for the ending. Where the novel does deviate from the historical records is in its selection of certain events as a backdrop for the novel\u27s story, the inclusion of the twentieth century narrator\u27s own movements and narrative considerations in the writing process, the suspension of a linear narrated time and most significantly of all the author\u27s invention of dialogue between his historical characters. This dialogue lends life to the records providing a narrative without which, in Bowering\u27s words, \u27George Vancouver is just another dead sailor\u27 (p. 9)