Species-specific, pan-European diameter increment models based on data of 2.3 million trees

ResearchBackground: Over the last decades, many forest simulators have been developed for the forests of individual European countries. The underlying growth models are usually based on national datasets of varying size, obtained from National Forest Inventories or from long-term research plots. Many of these models include country- and location-specific predictors, such as site quality indices that may aggregate climate, soil properties and topography effects. Consequently, it is not sensible to compare such models among countries, and it is often impossible to apply models outside the region or country they were developed for. However, there is a clear need for more generically applicable but still locally accurate and climate sensitive simulators at the European scale, which requires the development of models that are applicable across the European continent. The purpose of this study is to develop tree diameter increment models that are applicable at the European scale, but still locally accurate. We compiled and used a dataset of diameter increment observations of over 2.3 million trees from 10 National Forest Inventories in Europe and a set of 99 potential explanatory variables covering forest structure, weather, climate, soil and nutrient deposition. Results: Diameter increment models are presented for 20 species/species groups. Selection of explanatory variables was done using a combination of forward and backward selection methods. The explained variance ranged from 10% to 53% depending on the species. Variables related to forest structure (basal area of the stand and relative size of the tree) contributed most to the explained variance, but environmental variables were important to account for spatial patterns. The type of environmental variables included differed greatly among species. Conclusions: The presented diameter increment models are the first of their kind that are applicable at the European scale. This is an important step towards the development of a new generation of forest development simulators that can be applied at the European scale, but that are sensitive to variations in growing conditions and applicable to a wider range of management systems than before. This allows European scale but detailed analyses concerning topics like CO2 sequestration, wood mobilisation, long term impact of management, etcinfo:eu-repo/semantics/publishedVersio

Physician-assisted death in psychiatric practice in the Netherlands

textabstractBACKGROUND: In 1994 the Dutch Supreme Court ruled that in exceptional instances, physician-assisted suicide might be justifiable for patients with unbearable mental suffering but no physical illness. We studied physician-assisted suicide and euthanasia in psychiatric practice in the Netherlands. METHODS: In 1996, we sent questionnaires to 673 Dutch psychiatrists - about half of all such specialists in the country - and received 552 responses from the 667 who met the study criteria (response rate, 83 percent). We estimated the annual frequencies of requests for physician-assisted suicide by psychiatrists and actual instances of assistance. RESULTS: Of the respondents, 205 (37 percent) had at least once received an explicit, persistent request for physician-assisted suicide and 12 had complied. We estimate there are 320 requests a year in psychiatric practice and 2 to 5 assisted suicides. Excluding those who had ever assisted, 345 of the respondents (64 percent) thought physician-assisted suicide because of a mental disorder could be acceptable, including 241 who said they could conceive of instances in which they themselves would be willing to assist. The most frequent reasons for refusing were the belief that the patient had a treatable mental disorder, opposition to assisted suicide in principle, and doubt that the suffering was unbearable or hopeless. Most, but not all, patients who had been assisted by their psychiatrists in suicide had both a mental disorder and a serious physical illness, often in a terminal phase. Thirty percent of the respondents had been consulted at least once by a physician in another specialty about a patient's request for assisted death. The annual number of such consultations was estimated at 310, about 3 percent of the estimated 9700 requests for euthanasia or physician-assisted suicide in medical practice. CONCLUSIONS: Explicit requests for physician-assisted suicide are not uncommon in psychiatric practice in the Netherlands, but these requests are rarely granted. Psychiatric consultation for medical patients who request physician-assisted death is relatively rare