Nutritional effects triggered by the extreme summer 2003 in the free air ozone fumigation experiment at the Kranzberger Forst

Since the year 2000 mature beech and spruce trees were treated in a field experiment with double ambient ozone concentrations. Elevated ozone had no influence on average single leaf biomass and there were also no ozone effects on leaf nutrient concentrations in climatic normal years. However, the extraordinary dry summer 2003 triggered significant differences between the fumigated and control trees. For beech in the year after the drought event the control trees surprisingly had significantly lower foliar levels of K and P than in former years, whereas the ozone exposed trees showed no significant nutritional effects. There are indications, that the trees exposed to double ambient ozone were already adapted to higher ozone values, whereas the control trees experienced extraordinary high ambient ozone concentrations in the dry and sunny summer 2003. For spruce in autumn 2003 and 2004 ozone treated trees had significantly higher foliar levels of K in current year needles than control trees, an effect which cannot be thoroughly interpreted yet on the basis of the dataset available. This article belongs to the special issue „Growth and defence of Norway spruce and European beech in pure and mixed stands“.     

Water sorption mechanisms of commercial wood adhesive films

As water moves inside the wood, the gluelines might act as barriers that are potentially leading to local moistening. Even low amounts of water may influence the mechanical performance of glued wood products. Dynamic vapor sorption analysis was performed to assess the sorption processes of six commercial wood adhesives. Vapor sorption isotherms were compared with vapor uptake dynamics. Phenol–resorcinol–formaldehyde showed high moisture uptake of 18 %, while vapor diffusion speed was low. Fish glue showed a water uptake of 45 % at otherwise moderate vapor uptake speed. Melamine–formaldehyde resin gained 22 % water, and polyvinyl acetate absorbed 10 %. The latter was also the fastest vapor absorbing adhesive. Polyurethane only absorbed 3.5 % of moisture at medium uptake speed. Mechanisms of water diffusion seem to be driven by (1) the available free volume in the polymer and (2) the interacting ionic groups of the polymer chain. While the free volume could be linked to the accumulated moisture, the ionic group interaction might determine the measured vapor diffusion dynamics.     

A flexible stem taper and volume prediction method based on mixed-effects B-spline regression

Modelling stem taper and volume is crucial in many forest management and planning systems. Taper models are used for diameter prediction at any location along the stem of a sample tree. Furthermore, taper models are flexible means to provide information on the stem volume and assortment structure of a forest stand or other management units. Usually, taper functions are mean functions of multiple linear or nonlinear regression models with diameter at breast height and tree height as predictor variables. In large-scale inventories, an upper diameter is often considered as an additional predictor variable to improve the reliability of taper and volume predictions. Most studies on stem taper focus on accurately modelling the mean function; the error structure of the regression model is neglected or treated as secondary. We present a semi-parametric linear mixed model where the population mean diameter at an arbitrary stem location is a smooth function of relative height. Observed tree-individual diameter deviations from the population mean are assumed to be realizations of a smooth Gaussian process with the covariance depending on the sampled diameter locations. In addition to the smooth random deviation from the population average, we consider independent zero mean residual errors in order to describe the deviations of the observed diameter measurements from the tree-individual smooth stem taper. The smooth model components are approximated by cubic spline functions with a B-spline basis and a small number of knots. The B-spline coefficients of the population mean function are treated as fixed effects, whereas coefficients of the smooth tree-individual deviation are modelled as random effects with zero mean and a symmetric positive definite covariance matrix. The taper of a tree is predicted using an arbitrary number of diameter and corresponding height measurements at arbitrary positions along the stem to calibrate the tree-individual random deviation from the population mean estimated by the fixed effects. This allows a flexible application of the method in practice. Volume predictions are calculated as the integral over cross-sectional areas estimated from the calibrated taper curve. Approximate estimators for the mean squared errors of volume estimates are provided. If the tree height is estimated or measured with error, we use the “law of total expectation and variance” to derive approximate diameter and volume predictions with associated confidence and prediction intervals. All methods presented in this study are implemented in the R-package TapeR.     

Predicting species-specific basal areas in urban forests using airborne laser scanning and existing stand register data

The aim of this work was to examine how well species-specific stand attributes can be predicted using a combination of airborne laser scanning (ALS) and existing stand register data in urban forests. In this context, the ability of three data combinations: ALS data and stand register data, ALS data and digital aerial images and all of these combined, was tested in the prediction of species-specific basal areas. We divided tree species into seven and three different tree species strata and applied two prediction methods: (1) regression method, in which the predicted total basal area was divided into tree species based on tree species proportions from stand register data, and (2) the nearest neighbour (NN) method, in which tree species proportions were used as predictor variables for species-specific basal areas. Prediction models were built based on training data of 205 field plots, and the accuracy of the models was tested based on validation data of 52 forests stands. Our results showed that species-specific predictions of seven tree species were more accurate when tree species proportions from stand register data were used in the prediction. Both the regression and the NN method provided reasonable accuracy. This study showed that tree species information from existing stand register data could be used as an alternative for aerial images in ALS-based forests inventories. The use of ALS data together with stand register data and small field data could also be economically beneficial in an inventory of urban forests.     

Fledermäuse und Bilche in Nistkästen —Eine Erhebung in Bayern

About 150,000 nest boxes were examined in the years 1985 and 1986 in 160 forest districts. Additionally the record books about nestbox contents were checked in 35 districts (200,000 hectares) for the last 2–3 decades. The distribution of bats and dormice was mapped out according to the available data. The absolute number and the percentage of nestboxes occupied by bats increased in the two decades passed. The dormice, especially the Edible Dormouse (Glis glis) increased too, mainly in the western parts of Bavaria. Some hints are given for more detailed investigations about key factors of distribution and development of bats and dormice.     

Nebenwirkungen von Toxaphen auf Maüse

Side-effects of Toxaphene of Mice. Albino-mice (swiss) and wild-captured voles and mice were given a high dose of 50 mg toxaphene (M 5055) per kg body weight daily for a period of some weeks or months. Three weasels and one ermine were fed on 300 of these sublethally poisoned mice without showing any negative effect. The following parameters of mice unpoisoned and poisoned with a sublethal dose of toxaphen were examined: mortality, number of litters, resorption rate of embryoes, growth, haematological values, activity of enzymes, amino acids and proteins in serum and urine. In the group of poisoned mice a slight increase of neutrophile blood cells (Tab. 2), a higher level of enzyme activities (SP, GPT, GT; Tab. 3) in serum and a typical change in uric proteins were observed. (Abb. 1).In the field 6 liters of toxaphen (M5055) were sprayed over a forest plantination of 1,5 ha for mouse control. The following development of mice, especially of the Common Vole (Microtus agrestis) was investigated with the capture, mark and recapture (CMR) method. Toxaphene had an influence on the parasitic complex of the vole for a long time. The number of fleas, mites, ticks, blood protozoa, grahemella and haemobartonella of the voles was reduced for more than 6 months in the treated area. This may be one reason for the fast recovery, good growth and increasing number of the voles observed after control with the insecticide toxaphene.

---

---

Die Arbeiten wurden durch Mittel der Gesellschaft für Strahlen- und Umweltforschung (GSF), München-Neuherberg, unterstützt     

Damage characteristics of three boring pests in Artemisia ordosica

The population density and distribution of the three major boring pests, Holcocerus artemisiae, Sphenoptera sp. and Adosopius sp. were studied in their host plant Artemisia ordosica. Results show that the larvae of H. artemisiae mainly bore the rhizome of A. ordosica, but also the larvae of Sphenoptera sp. and Adosopius sp. bore the rhizome of A. tordosica. The adults of Sphenoptera sp. and Adosopius sp. feed on the leaves of A. ordosica as a nutritional supplement. The distribution of the larvae of three pests in their host plant is completely different. H. artemisiae and Sphenoptera sp. are distributed in the whole A. ordosica plant. The newly hatched larvae first feed on the phloem and xylem of stem and then burrow to the roots before the winter of the same year. However, Adosopius sp. is distributed mainly in the roots. The newly hatched larvae move from the phloem to the xylem, and gradually damage the lower part of the trunk. The larvae of the three pests sometimes coexist in a single A. ordosica plant. However, the probability of the coexistence of the three pests is very small. The highest probability of coexistence of two pests was observed in Sphenoptera sp. and H. artemisiae, while the probability of coexistence of Sphenoptera sp. and Adosopius sp. as well as H. artemisiae and Adosopius sp. was smaller. The reasons for coexistence or its avoidance are not only related to the amount of food provided nor the volume of larval living space in a single A. ordosica plant, but also related to the development characteristics of different kinds of larvae and interspecific competition.     

Sekrete und Delta-16-Steroide als Lockmittel für die Rötelmaus (Clethrionomys glareolus)

Zusammenfassung Lebendfallen, die Nestmaterial oder Ausscheidungen von Rötelmäusen enthielten, wurden im Freiland von Artgenossen signifikant häufiger besucht als nicht-kontaminierte Fallen. Die Untersuchungen wurden im Spätsommer und Herbst in den Jahren 1986 und 1987 in Forstkulturen durchgeführt. In den Monaten August bis Oktober wurden Fallen, die kontaminierte Einstreu von Artgenossen enthielten, bevorzugt, in den Monaten November und Dezember Fallen mit Nestgeruch.Von den beiden Verbindungen 16-(5-alpha)-androsten-3-on (Androsten-on) und 16-(5-alpha)-androsten-3-alpha-ol (Androsten-ol) wurde die letztere signifikant von der Rötelmaus bevorzugt.

---

Secretions and Delta-16-steroids as attractants for Bank Voles (Clethrionomys glareolus)

Bank Voles (Clethrionomys glareolus) preferred significantly live traps containing bedding or nesting material contaminated by conspecifics in comparision to clean traps (=control). The tests were conducted in forest cultivations in late summer and autumn of 1986 and 1987. In both years at the begin in August the traps contaminated with urin of conspecifics were most attractive. Females were significantly more frequently caught in traps contaminated by conspecific males and vice versa males visited preferably traps with bedding material of females. Later during October and November traps with nest odour were preferred by both sexes.It was assumed that derivatives of hormones could act as pheromones. Both compounds 16-(5-alpha)-androsten-3-one and 16-(5-alpha)-androsten-3-alpha-ol were tested in field plots. The latter was significantly preferred by Bank Voles but not by other species.

---

---

Mit 7 Abbildungen und einer Tabelle     

Hymenoscyphus albidus is not associated with an anamorphic stage and displays slower growth than Hymenoscyphus pseudoalbidus on agar media

Examination of isolates of Hymenoscyphus albidus from France revealed that this fungus does not form an anamorphic stage in culture. The lack of an asexual stage in this fungus is a conspicuous morphological difference to the ash dieback pathogen Hymenoscyphus pseudoalbidus, which is associated with its Chalara fraxinea anamorphic state. In growth studies on malt extract agar (MEA) and MEA amended with ash leaflets (ash leaf malt extract agar, AMEA) at 20°C, isolates of H. albidus grew slower than those of H. pseudoalbidus. On AMEA, the growth of cultures of both species was greatly enhanced.     

Greytown,Plantations and Drought: A Note

A 25-year old Populus canescens stand was selected for sampling to estimate the one-side leaf surface area per unit ground area. A portable area meter was used to determine leaf surface areas of a sample of branches of the first order. Different unweighted and weighted regression equations were compared to estimate leaf surface area. The estimated tree leaf areas were regressed on D.B.H., with unit weight being assigned to the single observation.