Yield, wood properties, and timber harvest at establishment of seed-tree and shelterwood regeneration systems

Variation in wood properties, timber harvest and yield, on the establishment of seed-tree and shelter-tree stands as compared with clear-felling of Pinus sylvestris, was studied at two sites. Seed trees and shelter trees were selected on the basis of seed productivity, health and vitality criteria. Pines not needed to establish seed or shelter tree stand are referred to as %different pines". The annual radial increment of seed trees was superior to that of indifferent pines but basic density from pith to bark was lower. Shelter trees were intermediate. Differences in wood properties and dimensions between seed trees, shelter trees and indifferent pines reflect the selection criteria used. Differences in value were related to the timber section of the tree, the amounts of pulpwood being more or less constant. At the two sites the change from conventional clearfelling to shelter-tree stands reduced the timber harvest by 100 m-3 s.u.b. ha-1. The increased percentage of pulpwood, the decreased percentage of U/S logs and a decrease in mean diameter lead to a substantial reduction in value m-3s.u.b. Basal area increment was reduced by 10% in a shelter-tree stand and by less than 25% in a seed-tree stand

Provenance variation in early growth and development in Picea mariana (Mill) B.S.P.

Provenance variation in Picea mariana (Mill) B.S.P. (Black spruce) seedlings was studied to provide recommendations for introducing the species into Scandinavia. Provenances were analysed in a series of tests covering root and shoot development and mineral nutrient (N. P and K) content. The studies were carried out as greenhouse tests, as nursery trials, as cold tolerance tests in growth chambers and by destructive sampling. The performance of Black spruce was compared with that of Norway spruce. Black spruce seed sources exhibited large clinal variation for most of the properties evaluated. Compared with northwestern seed sources, southeastern sources were taller, exhibited later bud flushing and bud set, showed a lower degree of lignification and a lower dry matter content in autumn, had a higher incidence of winter-damaged seedlings and a higher shoot: root ratio. Within the eastern region, east of 100"W. provenance variation was characterized using cluster analysis. Provenances orginating around latitudes 47-51"N and west of longitudes 65"W were tallest, whereas southeastern provenances produced most dry matter. Norway spruce exhibited a developmental phenology and biomass properties similar to Black spruce orginating at latitudes between 50 and 60% However, Norway spruce had thicker roots and stems and was more susceptible to spring frosts following bud flushing

Individual tree biomass equations or biomass expansion factors for assessment of carbon stock changes in living biomass - A comparative study

AbstractSignatory countries to the United Nations Framework Convention on Climate Change (UNFCCC) and its supplementary Kyoto Protocol (KP) are obliged to report greenhouse gas emissions and removals. Changes in the carbon stock of living biomass should be reported using either the default or stock change methods of the Intergovernmental Panel on Climate Change (IPCC) under the Land Use, Land-Use Change and Forestry sector. Traditionally, volume estimates are used as a forestry measures. Changes in living biomass may be assessed by first estimating the change in the volume of stem wood and then converting this volume to whole tree biomass using biomass expansion factors (BEFs). However, this conversion is often non-trivial because the proportion of stem wood increases with tree size at the expense of branches, foliage, stump and roots. Therefore, BEFs typically vary over time and their use may result in biased estimates. The objective of this study was to evaluate differences between biomass estimates obtained using biomass equations and BEFs with particular focus on uncertainty analysis. Assuming that the development of tree fractions in different ways can be handled by individual biomass equations, BEFs for standing stock were shown to overestimate the biomass sink capacity (Sweden). Although estimates for BEFs derived for changes in stock were found to be unbiased, the estimated BEFs varied substantially over time (0.85–1.22ton CO2/m3). However, to some extent this variation may be due to random sampling errors rather than actual changes. The highest accuracy was obtained for estimates based on biomass equations for different tree fractions, applied to data from the Swedish National Forest Inventory using a permanent sample design (estimated change in stock 1990–2005: 420million tons CO2, with a standard error amounting to 26.7million tons CO2) Many countries have adopted such a design combined with the stock change method for reporting carbon stock changes under the UNFCCC/KP

Investigations of solutions of Einstein's field equations close to lambda-Taub-NUT

We present investigations of a class of solutions of Einstein's field equations close to the family of lambda-Taub-NUT spacetimes. The studies are done using a numerical code introduced by the author elsewhere. One of the main technical complication is due to the S3-topology of the Cauchy surfaces. Complementing these numerical results with heuristic arguments, we are able to yield some first insights into the strong cosmic censorship issue and the conjectures by Belinskii, Khalatnikov, and Lifschitz in this class of spacetimes. In particular, the current investigations suggest that strong cosmic censorship holds in this class. We further identify open issues in our current approach and point to future research projects.Comment: 24 pages, 12 figures, uses psfrag and hyperref; replaced with published version, only minor corrections of typos and reference

Perceptions of pastoralist problems: A participatory study on animal management, disease spectrum and animal health priorities of small ruminant pastoralists in Georgia

Small ruminants support the livelihoods of millions of poor pastoralist and sedentary households around the world. While pastoralists are generally not amongst the poorest in terms of assets, they are frequently marginalised in terms of their access to political power, health and education. This study was undertaken among pastoralist households keeping small ruminants in four regions of the country of Georgia. Small ruminants are an important cultural, social and economic asset in Georgia and are mainly managed in a transhumant pastoralist system. Georgia suffered its first, and so far only outbreak of peste des petits ruminants (PPR) in 2016. This qualitative interview study was designed to acquire contextual understanding of local small ruminant husbandry and the livelihood situations of the participating pastoralists, and to detect historical, unreported PPR outbreaks. Focus group discussions comprising participatory epidemiology tools and other forms of interviews were used to explore small ruminant management, disease spectrum and management, and animal health priorities.The participants had experienced a wide variety of animal health constraints, with intestinal worms, braxy, piroplasmosis, pasture-related problems, predators and lameness emerging as priorities. No historic, unreported PPR outbreak was detected in this study, and PPR was not a priority for participants. Instead, the day-to-day reality of animal health for the pastoralists was characterised by co-infections of mainly endemic pathogens, and problems related to other challenges such as access to land, feed and genetic resources. The rationale behind the participants' prioritisation of animal health problems was supported by the need to pay extra attention to animals in order to avoid risk factors, keep animals healthy and minimise the negative impact of diseases or management problems; the various epidemiological and clinical parameters of the prioritised diseases; the economic impact of the specific problems and the zoonotic potential of diseases and predation. Even within regions, and within seemingly socially and culturally homogenous groups, there were important local differences in the problems faced by pastoralists that affect their livestock management. This study underlines the importance of a contextualised understanding of the local disease panorama and complexities in the livelihood situations of rural people when designing actions to improve animal health in general or, more specifically, passive surveillance as well as prevention or control measures. Finally, it is concluded that to achieve such an understanding, there is a need for participatory, scoping-style studies that specifically acknowledge diversity and power relations

Regularity of Cauchy horizons in S2xS1 Gowdy spacetimes

We study general S2xS1 Gowdy models with a regular past Cauchy horizon and prove that a second (future) Cauchy horizon exists, provided that a particular conserved quantity $J$ is not zero. We derive an explicit expression for the metric form on the future Cauchy horizon in terms of the initial data on the past horizon and conclude the universal relation A\p A\f=(8\pi J)^2 where A\p and A\f are the areas of past and future Cauchy horizon respectively.Comment: 17 pages, 1 figur

Emotions in context: examining pervasive affective sensing systems, applications, and analyses

Pervasive sensing has opened up new opportunities for measuring our feelings and understanding our behavior by monitoring our affective states while mobile. This review paper surveys pervasive affect sensing by examining and considering three major elements of affective pervasive systems, namely; “sensing”, “analysis”, and “application”. Sensing investigates the different sensing modalities that are used in existing real-time affective applications, Analysis explores different approaches to emotion recognition and visualization based on different types of collected data, and Application investigates different leading areas of affective applications. For each of the three aspects, the paper includes an extensive survey of the literature and finally outlines some of challenges and future research opportunities of affective sensing in the context of pervasive computing