Occurrence, morphology and growth of understory saplings in Swedish forests

Growing demands for a multipurpose forestry leads to increased use of silvicultural systems that avoid clear-cutting. Regeneration in such systems is based on establishment and ingrowth of new seedlings under a more or less closed canopy. At long-term forestry planning reliable ingrowth models are needed to predict the future wood production. The objectives of this thesis were to review the field of ingrowth in established stands, to develop a model for prediction of ingrowth for the planning system Heureka and to deepen the insight in the ingrowth process by a case study. The ingrowth model consisted of four parts, describing: Probability for occurrence of saplings (1-39 mm diameter at breast height (DBH)) on plots with r = 5 m. Number of saplings on stocked plots (plots with saplings of target species). Probability for ingrowth of a sapling over 39 mm DBH during a 5-year period. Diameter of ingrown trees at the end of the 5-year period. The model was based on data from permanent plots at the National Forest Inventory. Separate functions were developed for seven species and species groups. Picea abies saplings had the widest distribution and occurred on 58 % of 12 469 representative plots in established forests. Betula spp. saplings occurred on 50 % of the plots, while the occurrence of saplings of other species was less than 20 %. Sapling density on stocked plots was highest for Betula spp, in average 10 per plot. Average ingrowth rate was 14.6 stems per ha and year, and P. abies made up more than half of this. The ingrowth varied according to the different functions with age, density and species composition of the stand and the moisture and fertility of the site. Growth and morphology of young conifers was examined in a species experiment on a clearcut and in shelterwoods of three different densities (41 – 124 stems per hectare). The largest intra-specific differences between clearcut and shelterwood were found for Pinus spp, while moderate differences were found for Picea spp. For Pinus spp, stem height and diameter decreased, while the stem slenderness increased with increasing shelterwood density. Moreover, the number of branches per whorl and the crown ratio decreased with increasing shelterwood density. The proportion of biomass in roots, stem, branches and needles was analysed as a function of estimated irradiance transmission for each individual. The proportion of stem decreased and the proportion of branches increased with increasing irradiance for Pinus spp. No significant trends were found for Picea spp

Spring water stress in Scots pine

Water use and net carbon assimilation during spring was examined on Scots pine trees exposed to different soil warming dynamics in the field. Sap flow, needle water potential and net carbon assimilation were measured on trees that were exposed to a wide range of soil temperature regimes caused by manipulating the snow cover on tree-scale soil plots. This made it possible to quantify the sensitivity of water uptake and recovery of gas exchange by Scots pine in the critical transition from winter dormancy to the growing season, which can be influenced by silvicultural practices. A part of the study was to find a tool for estimating the coupled effect of belowground and aboveground climate on transpiration, as well as to adapt this tool to the harsh climate of the boreal forest. Combining the results of field experiments on tree susceptibility to water stress with a physically based SVAT model as well as a model for estimating the recovery of photosynthesis helped to predict spatial and inter-annual variability of snow depths, soil warming, water uptake and net primary productivity during spring within different Scots pine stands across the landscape. This could provide a better basis for a more frostconscious forest management. The studies have confirmed the importance of low soil temperatures in combination with aboveground climate for root water uptake and net carbon assimilation during spring, when soil warming occurs after the start of the growing season. The studies have also confirmed that earlier, controlled laboratory studies on the inhibiting effects of low soil temperature on water relations and gas exchange for seedlings or saplings also hold true on mature trees in the field. The experimental data served well as the basis for model analyses of the interaction between belowground and aboveground conditions on water use and net photosynthesis. The results of the field studies and model analyses suggest that the effect of soil temperature on tree water uptake and net photosynthesis during spring, in conjunction with aboveground conditions, are factors that need to be considered in forest management in areas susceptible to soil frost and low soil temperatures

Development of an instrument for early detection of dementia in people with Down syndrome

The successful detection of early signs of dementia in people with Down syndrome could form a basis for useful early support and for drug treatment. This report describes the development and preliminary application of an interview and test instrument for the assessment of dementia among people with intellectual disability, as well as a framework for diagnosis that combines the findings of an interview and a test with the diagnostic criteria of ICD-10, DSM-IV and NINCDS-ADRDA. From among the number of tests and interview questions developed, those showing the most significant differences between participants in three groups of differing levels of intellectual disability and estimated dementia were kept. Reported are the assumptions for the items used, descriptions of the process and items used, and the associations of test items with predicting the presence of dementia. The authors conclude that a protocol combining testing and interview has promise and potential for detecting early signs of dementia in this population and could prove feasible for use in practice

Modelling procurement effects on cooperation

Cooperative arrangements, such as partnering, have received increased interest in recent years. Several studies show however that cooperative relationships are not easily achieved in construction. Implementation of cooperative relationships requires changes in several elements of the traditional procurement procedures. The purpose of this paper is therefore to propose and test a sequential model regarding clients’ cooperative procurement procedures. We especially ask: what elements in clients’ procurement procedures facilitate the establishment of cooperation and trust in their relationships with contractors? The model was tested through structural equation modelling. The empirical data required for the test were collected through a survey responded to by 87 Swedish professional construction clients. The empirical results show that cooperative procurement procedures are triggered by clients’ wish to involve contractors early in specification, which has a simultaneous effect on procedures regarding bid invitation and compensation. Furthermore, these simultaneous effects breed a certain kind of partner selection based on task-related attributes, which also has a direct positive effect on trust and above all on cooperation in client–contractor relationships. Besides these implications from the model, the improvement of measurements for future modelling is discussed.Construction; cooperation; procurement;

Myopic or constrained by balanced-budget-rules? The intertemporal spending behavior of Norwegian local governments

The paper analyzes the intertemporal spending behavior of Norwegian local governments with particular attention to liquidity constraints imposed by balanced-budget-rules (BBRs). The main findings are: (i) On average, local government spending behavior is neither perfectly forward looking nor fully myopic. (ii) Local governments with good fiscal conditions behave more forward looking than other local governments. (iii) A high degree of party fragmentations is associated with less forward looking behavior. The overall assessment is that the departure from rational forward looking behavior reflects both liquidity constraints imposed by BBRs and myopic behavior.Balanced-budget-rules; Intertemporal spending behavior; Consumption smoothing; Local government

Making the Distribution Subsystem Secure

This report presents how the Distribution Subsystem is made secure. A set of different security threats to a shared data programming system are identifed. The report presents the extensions nessesary to the DSS in order to cope with the identified security threats by maintaining reference security. A reference to a shared data structure cannot be forged or guessed; only by proper delegation can a thread acquire access to data originating at remote processes. Referential security is a requirement for secure distributed applications. By programmatically restricting access to distributed data to trusted nodes, a distributed application can be made secure. However, for this to be true, referential security must be supported on the level of the implementation

Sensitivity of coherent anti-Stokes Raman lineshape to time asymmetry of laser pulses

We show that coherent anti-Stokes Raman lineshapes do not follow known spectral profiles if the time asymmetry of realistic laser pulses is taken into account. Examples are given for nanosecond and picosecond laser pulses commonly employed in frequency-resolved coherent anti-Stokes Raman scattering. More remarkably, the analysis suggests an effect of line narrowing in comparison to the customary approach, based primarily on the Voigt lineshape.Comment: 8 pages, 3 short sections, 4 figure