Photosynthetic responses of Scots pine to elevated CO(2) and nitrogen supply: results of a branch-in-bag experiment

Naturally seeded Scots pine (Pinus sylvestris L.) trees, age 25-30 years, were subjected to two soil-nitrogen-supply regimes and to elevated atmospheric CO(2) concentrations by the branch-in-bag method from April 15 to September 15 for two or three years. Gas exchange in detached shoots was measured in a diffuse radiation field. Seven parameters associated with photosynthetic performance and two describing stomatal conductance were determined to assess the effects of treatments on photosynthetic components. An elevated concentration of CO(2) did not lead to a significant downward regulation in maximum carboxylation rate (V(cmax)) or maximum electron transport rate (J(max)), but it significantly decreased light-saturated stomatal conductance (g(sat)) and increased minimum stomatal conductance (g(min)). Light-saturated rates of CO(2) assimilation were higher (24-31%) in shoots grown and measured at elevated CO(2) concentration than in shoots grown and measured at ambient CO(2) concentration, regardless of treatment time or nitrogen-supply regime. High soil-nitrogen supply significantly increased photosynthetic capacity, corresponding to significant increases in V(cmax) and J(max). However, the combined elevated CO(2) + high nitrogen-supply treatment did not enhance the photosynthetic response above that observed in the elevated CO(2) treatment alone.     

Heterobasidion abietinum on Abies species in western Turkey

Forty‐five basidiocarp specimens of Heterobasidion were collected from native Abies species in three locations in western Turkey: A. nordmanniana ssp. bornmülleriana in Bolu province, A. nordmanniana ssp. equi‐trojani in Balikesir province and A. cilicica in Antalya province. Pure cultures were isolated from the basidiocarps and identified to the species level with the aid of mating tests. All the specimens proved to belong to the species Heterobasidion abietinum. This root rot fungus is common in the forests investigated and appears to be relatively virulent on Abies in Turkey. This is the first report of H. abietinum outside Europe.     

Public health effects of accidents in self-employed forestry work

Little is known about the extent of work-related accidents occurring during the performance of forestry work by the non-industrial private forest owner or their assistant (hereafter called self-employed NIPF). The absence of an effective accident registration system largely excludes this group from accurate representation in official statistics. In this study, data from 1996 to 2001 were collected from hospital injury records managed by the Umeå Accident Analysis Group at the University Hospital in Umeå. During that period, it was found that 485 persons in the Umeå region were given medical attention due to injuries possibly acquired during self-employed forestry work. Questionnaires about the accidents were sent to each of the 485 injured persons and 80% were returned. Responses revealed that 225 of the respondents were injured during self-employed forestry work. Out of these, 81% performed fewer than 31 days of forestry work annually. Due to the injury, 29% had been on sick leave for some period of time and 42% had persistent symptoms. On average, each injury led to 13 days of sick leave and 24 hours of institutional care. Firewood production was shown to be a key factor behind the large number of accidents for self-employed NIPF. Further studies on the lack of knowledge about how the work should be done and conscious risk taking should be considered as an important link to the development of effective accident prevention strategies.     

Über lästige Vögel und Säuger als Kulturfolger an Müllkippen und Mö glichkeiten zu ihrer biologischen Bekämpfung

Zusammenfassung Müllkippen begünstigen lästige Kulturfolger, vor allem Krähen(Corvus c. corone, C. frugilegius) und die Wanderratte(Rattus norvegicus). Dabei ist die Lage und Umgebung für das Auftreten der Krähen von großer Bedeutung. Sie bevorzugen offene Landschaften.Wichtigste Feinde der Wanderratte an solchen Plätzen sind das Hermelin(Mustela erminea) und der Iltis(Putorius putorius). Sie verdienen Schutz und Förderung. Es werden einige Möglichkeiten zur biologischen Bekämpfung der Ratten und Krähen aufgezeigt.Summary Observations were made on 19 rubbish tips in the surrounding of Munich which revealed the fact that these areas are favourable for some injurious birds and mammals, i. e., such as crows(Corvus c. corone, C. frugilegius) and rats(Rattus norvegicus). The geographical distribution and the composition of the environment are very important aspects for the existance of the crows in mass number, because these birds prefer open lands and avoid larger forests.General survey indicated that the most important natural enemies of the rats are the white stoat(Mustela erminea) and the polecat(Putorius putorius). These rabacious mammals were observed to enter through the underground rat-tunnels and were able to drive them out.The mustelids should be protected and encouraged to live in rubbish tips. Some suggestions to apply the biological control approch against crows and rats were discussed.     

Leichthölzer und Tonnenstämme in Schwarzwassergebieten und Dornbuschwäldern des tropischen Südamerika

European Journal of Forest Research -     

Derivation of stem taper from the pipe theory in a carbon balance framework

A dynamic tree growth model is described. The model derives the development of stem taper and vertical distribution of branch basal area from the pipe model, assuming that reuse of active pipes is regulated by foliage dynamics in a vertically explicit crown with a foliage distribution of constant shape. Based on empirical findings, the pipe model was modified slightly to allow the foliage/sapwood ratio to vary as a function of distance from the treetop. Growth was derived from carbon balance in a stand of different size trees that may shade each other. The model was applied to old and middle-aged trees growing in dense and sparse stands of Scots pine for which stand-level measurements are available as a chronosequence, but individual trees have been measured only once. Measured trees were compared with corresponding simulated trees for stem taper and vertical distribution of branch basal area. The results indicated that the pipe model assumptions, combined with a model of tree growth, are capable of producing realistic predictions of the vertical distribution of stem and branch diameter in trees of different sizes in the stand. A comparison of the results with a simple form of the uniform stress theory showed good agreement between the two models. However, a significant difference was found between the measured relative contribution of heartwood to total stem diameter and the predicted share of disused pipes in the stem. A possible explanation for this discrepancy is that the transition from sapwood to heartwood is gradual rather than abrupt as assumed in the model. A modification of the pipe model to incorporate a gradual transition is outlined.     

Entwicklung einiger Nistkastenbewohner in ostbayerischen Waldgebieten Teil II: Säuger

From 1950 until 1987 up to 3,350 nest-boxes were checked each year in woodland of Eastern Bavaria. Among the mammals bats (Myotis daubentoni and other species), dormice (Muscardinus avellanarius, Glis glis andEliomys quercinus) and mice (Apodemus spp.) were observed. The distribution of the dominant species is mapped (Figs. 1, 3) and the annual percentage of occupied boxes by different groups and species is shown in diagrams (Figs. 2, 4, 5). The quote of nest-boxes inhabited by small mammals increased since 1980. Several factors influencing the occurrence of mammals in nest-boxes such as adaption, competition, population density and climatic conditions are discussed.

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Mit 6 Abbildungen