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Der vorliegende Beitrag beschreibt die theoriegeleitete Entwicklung und psychometrische Überprüfung eines Schülerfragebogens zur Erfassung von Unterrichtsqualität, der vorrangig als formatives Evaluationsinstrument in der schulischen Praxis eingesetzt werden soll. Grundlage des Schülerfragebogens stellt ein theoretisch begründetes Modell von Unterrichtsqualität dar, welches die drei Anforderungsbereiche Unterstützung des Wissenserwerbs, Motivierung und Klassenmanagement sowie die querliegende Dimension Individualisierung umfasst. Der Fragebogen wurde an einer Stichprobe von Schüler:innen an Berufsschulen eingesetzt. Am ersten Messzeitpunkt wurde eine vorläufige Version des Schülerfragebogens verwendet. Basierend auf den Ergebnissen wurde der Schülerfragebogen optimiert und an einem zweiten Messzeitpunkt überprüft. Konfirmatorische Faktorenanalysen belegen eine gute Passung zwischen empirischen Daten und theoretischem Modell. Die Skalen sind empirisch klar voneinander trennbar, mit der Ausnahme einer relativ hohen Faktorkorrelation auf Klassenebene. Auch die Reliabilitäten der Skalen erweisen sich mit einer Ausnahme als gut bis sehr gut. Die Ergebnisse sprechen dafür, dass Lehrkräfte mithilfe des Schülerfragebogens konkrete Ansatzpunkte für die Weiterentwicklung ihres Unterrichts ermitteln können. (DIPF/Orig.), This article describes the theory-driven development and psychometric evaluation of a student questionnaire for the assessment of teaching quality. The student questionnaire is supposed to be used in the context of formative evaluation within schools. It is based on a model of teaching quality that comprises the domains supporting knowledge acquisition, motivating, and classroom management as well as the lateral dimension individualization. The questionnaire was used on a sample of students in vocational schools. At the first measurement time point, a preliminary version of the student questionnaire was applied. Based on the results, the questionnaire was revised and tested at a second measurement time point. Confirmatory factor analyses yielded a good fit between empirical data and theoretical model. All scales are empirically distinguishable from each other with the exception of one relatively high factor correlation on the class level. Further, reliabilities of the scales are good to very good with one exception. The results suggest that teachers can use the student questionnaire for identifying leverage points for improving their teaching. (DIPF/Orig.)

Silvicultural interventions such as strip cuttings can change the resource availability of the edge trees. This may alter tree allometry, as light regime, water, and nutrient availability can change at the forest edge. Increased root growth may optimize resource uptake and/or enhance tree anchorage to withstand the altered wind regime. However, little is known about the patterns of the root-shoot allometric responses to strip cuttings. In three alpine stands differing in climate, site productivity, and stand characteristics, we selected 71 Norway spruce trees and took increment cores from stems, root collars, and main roots. This enabled us to study changes in the long-term root-stem allometry for 46 years and short-term allometric responses to intervention. The effects of cutting were compared between edge trees and trees from the stand interior in 10 years before and after the intervention. The long-term allocation to roots increased with stem diameter, with the strongest effects on the regularly managed stand with the tallest and largest trees. These results support the allometric biomass partitioning theory, which postulates resource allocation patterns between different plant organs to depend on plant size. Strip cutting on north-facing slopes boosted edge-tree growth in all plant compartments and enhanced allocation to roots. This change in allometry started 2 years after cutting but disappeared 7-8 years later. In the post-cutting period, the highest root-shoot increase was observed in the small trees independent of the site. This indicates the change in growing conditions to have the strongest effects in formerly suppressed trees. Thus, the effect of such acclimation on the wind firmness of subdominant spruce trees is a question with high importance for optimizing cutting layouts in lowering post-cutting vulnerability to disturbance. The results from this case study contribute to a better understanding of the structural acclimation of spruce trees from high-elevation forests to new forest edges. However, for a more mechanistic understanding of environmental drivers, further analyses of tree-ring stable isotopes are recommended.

During recent decades, stable oxygen isotopes derived from tree-ring cellulose (δ18OTRC) have been frequently utilised as the baseline for palaeoclimatic reconstructions. In this context, numerous studies take advantage of the high sensitivity of trees close to their ecological distribution limit (high elevation or high latitudes). However, this increases the chance that indirect climatic forces such as cold ground induced by permafrost can distort the climate-proxy relationship. In this study, a tree stand of sub-alpine larch trees (Larix decidua Mill.) located in an inner alpine dry valley (Val Bever), Switzerland, was analysed for its δ18OTRC variations during the last 180 years. A total of eight L. decidua trees were analysed on an individual base, half of which are located on verified sporadic permafrost lenses approximately 500 m below the expected lower limit of discontinuous permafrost. The derived isotope time series are strongly dependent on variations in summer temperature, precipitation and large-scale circulation patterns (geopotential height fields). The results demonstrate that trees growing outside of the permafrost distribution provide a significantly stronger and more consistent climate-proxy relationship over time than permafrost-affected tree stands. The climate sensitivity of permafrost-affected trees is analogical to the permafrost-free tree stands (positive and negative correlations with temperature and precipitation, respectively) but attenuated partly leading to a complete loss of significance. In particular, decadal summer temperature variations are well reflected in δ18OTRC from permafrost-free sites (r = 0.62, p &lt, 0.01), while permafrost-affected sites demonstrate a full lack of this dependency (r = 0.30, p &gt, 0.05). Since both tree stands are located just a few meters away from one another and are subject to the same climatic influences, discrepancies in the isotope time series can only be attributed to variations in the trees’ source water that constraints the climatic fingerprints on δ18OTRC. If the two individual time series are merged to one local mean chronology, the climatic sensitivity reflects an intermediate between the permafrost-free and –affected δ18OTRC time series. It can be deduced, that a significant loss of information on past climate variations arises by simply averaging both tree stands without prior knowledge of differing subsurface conditions.