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  • 1
    Language: English
    In: Forest Ecology and Management, 15 November 2016, Vol.380, pp.261-273
    Description: Increasing frequency of extremely dry and hot summers in some regions emphasise the need for silvicultural approaches to increase the drought tolerance of existing forests in the short term, before long-term adaptation through species changes may be possible. The aim of this meta-analysis was to assess the potential of thinning for improving tree performance during and after drought. We used results from 23 experiments that employed different thinning intensities including an unthinned control and focused on the response variables: radial growth, carbon- and oxygen-isotopes in tree-rings and pre-dawn leaf-water potential. We found that thinning effects on the growth response to drought differed between broadleaves and conifers, although these findings are based on few studies only in broadleaved forests. Thinning helped to mitigate growth reductions during drought in broadleaves, most likely via increases of soil water availability. In contrast, in conifers, comparable drought-related growth reductions and increases of water-use efficiency were observed in all treatments but thinning improved the post-drought recovery and resilience of radial growth. Results of meta-regression analysis indicate that benefits of both moderate and heavy thinning for growth performance following drought (recovery and resilience) decrease with time since the last intervention. Further, growth resistance during drought became smaller with stand age while the rate of growth recovery following drought increased over time irrespective of treatment. Heavy but not moderate thinning helped to avoid an age-related decline in medium-term growth resilience to drought. For both closed and very open stands, growth performance during drought improved with increasing site aridity but for the same stands growth recovery and resilience following drought was reduced with increasing site aridity. This synthesis of experiments from a wide geographical range has demonstrated that thinning, in particular heavy thinning, is a suitable approach to improve the growth response of remaining trees to drought in both conifers and broadleaves but the underlying processes differ and need to be considered.
    Keywords: Stand Density ; Water Stress ; Radial Growth ; Stable Carbon and Oxygen Isotopes ; Water Potential ; Resilience ; Forestry ; Biology
    ISSN: 0378-1127
    E-ISSN: 1872-7042
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  • 2
    Language: English
    In: Forest Ecology and Management, Nov 15, 2013, Vol.308, p.188(10)
    Description: To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.foreco.2013.07.048 Byline: Julia A. Sohn, Timo Gebhardt, Christian Ammer, Jurgen Bauhus, Karl-Heinz Haberle, Rainer Matyssek, Thorsten E.E. Grams Abstract: acents We studied the effect of thinning on drought tolerance in Norway spruce at two sites. acents Changes in wood stable isotopes and growth during/after two droughts were analyzed. acents Effects of thinning on drought response differed with time span since thinning. acents Growth reduction during drought was lower in open stand but only if thinned recently. acents Thinning improved the growth recovery after drought at both short- and long-term. Article History: Received 4 June 2013; Revised 25 July 2013; Accepted 25 July 2013
    Keywords: Droughts -- Physiological Aspects
    ISSN: 0378-1127
    Source: Cengage Learning, Inc.
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  • 3
    In: Ecological Applications, October 2016, Vol.26(7), pp.2190-2205
    Description: Droughts and their negative effects on forest ecosystems are projected to increase under climate change for many regions. It has been suggested that intensive thinning could reduce drought impacts on established forests in the short‐term. Most previous studies on the effect of thinning on drought impacts, however, have been confined to single forest sites. It is therefore still unclear how general and persisting the benefits of thinning are. This study assesses the potential of thinning to increase drought tolerance of the wide spread Scots pine () in Central Europe. We hypothesized (1) that increasing thinning intensity benefits the maintenance of radial growth of crop trees during drought (resistance) and its recovery following drought, (2) that those benefits to growth decrease with time elapsed since the last thinning and with stand age, and (3) that they may depend on drought severity as well as water limitations in pre‐ and post‐drought periods. To test these hypotheses, we assessed the effects of thinning regime, stand age, and drought severity on radial growth of 129 Scots pine trees during and after drought events in four long‐term thinning experiments in Germany. We found that thinning improved the recovery of radial growth following drought and to a lesser extent the growth resistance during a drought event. Growth recovery following drought was highest after the first thinning intervention and in recently and heavily thinned stands. With time since the last thinning, however, this effect decreased and could even become negative when compared to unthinned stands. Further, thinning helped to avoid an age‐related decline in growth resistance (and recovery) following drought. The recovery following drought, but not the resistance during drought, was related to water limitations in the drought period. This is the first study that analyzed drought‐related radial growth in trees of one species across several stands of different age. The interaction between thinning intensity and time since the last thinning underline the importance to distinguish between short‐ and long‐term effects of thinning. According to our analysis, only thinning regimes, with relatively heavy and frequent thinning interventions would increase drought tolerance in pine stands.
    Keywords: Basal Area Increment ; Drought ; Pinus Sylvestris L. ; Radial Growth ; Recovery ; Resistance ; Scots Pine ; Stand Density ; Water Stress
    ISSN: 1051-0761
    E-ISSN: 1939-5582
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  • 4
    Language: English
    In: Forest Ecology and Management, 01 May 2018, Vol.415-416, pp.148-159
    Description: Future increases in temperature and changes in precipitation patterns may negatively affect the growth performance of economically important tree species such as Norway spruce, which in the past have often been established and managed in monocultures. Structural diversity has been advocated as a silvicultural approach to increase resistance and resilience of forests to climate change extremes. Whether it promotes growth stability during and following drought years has not yet been analyzed. We investigated stem growth reactions to the extreme drought of 2003 in 23 uneven-structured, mixed Norway spruce and Silver fir stands in southwestern Germany. Using linear mixed-effects models we analyzed the resistance and resilience of basal area increment in relation to species identity, drought intensity, tree size, competition, density and diversity. Structural diversity, measured as variation in tree diameter at breast height, had no influence on increment stability during the extreme summer drought of 2003. Likewise, the effect of species diversity was weak and inconclusive. However, a higher presence of Silver fir in the mixture appeared to reduce increment stability in 2003 for both fir and spruce. Reducing competition through thinning counteracted this effect and promoted increment stability. Our findings indicate that the species identity of competitors in mixtures is a better predictor of stem growth reactions to drought than diversity. They support the conclusion that diversity does not generally increase stability to drought stress. Silver fir consistently showed a substantially higher increment resistance and resilience than spruce. Its resistance increased with diminishing drought intensity, yet spruce reacted uniformly, manifesting a low resistance across the whole drought intensity gradient. Spruce did not regain pre-drought growth levels within the first three years after drought, whereas fir did. We conclude that fir may be able to act as a silvicultural alternative to spruce under changing climatic conditions, given appropriate sites and thinning regimes. Considering the expected increase in drought intensity and frequency in the 21 century, understanding species interactions at the local scale emerges as an essential prerequisite for developing resilient forest stands.
    Keywords: Basal Area Increment ; Drought Stress ; Plant–Plant Interactions ; Silver Fir ; Norway Spruce ; Structural Diversity ; Forestry ; Biology
    ISSN: 0378-1127
    E-ISSN: 1872-7042
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  • 5
    Language: English
    In: Forest Ecology and Management, 15 November 2013, Vol.308, pp.188-197
    Description: We hypothesize that reductions in stand density through thinning improve the recovery of radial stem growth in Norway spruce trees ( ) from severe drought. However, thinning may not lead to higher relative radial growth during drought. Annual stem growth and stable carbon and oxygen isotopes in early- and latewood were assessed in trees from heavily thinned (HT), moderately thinned (MT) and un-thinned control stands at two sites in southern Germany. Physiological performance of trees as inferred from stable isotope analysis was used to interpret annual stem growth in response to the drought events in 1976 and 2003. Only in recently thinned stands, trees maintained growth probably through higher soil water availability during the drought year when compared to controls. In contrast, thinning improved the growth recovery in the years following the drought irrespective of the time span between thinning and drought. We conclude that thinning improves drought recovery response in the short and long term and should be considered as an effective management strategy to increase drought tolerance of Norway spruce stands.
    Keywords: Stable Carbon and Oxygen Isotopes ; Radial Growth ; Water Stress ; Tree Rings ; Resistance ; Recovery ; Forestry ; Biology
    ISSN: 0378-1127
    E-ISSN: 1872-7042
    Source: ScienceDirect Journals (Elsevier)
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  • 6
    Language: English
    In: The Journal of Allergy and Clinical Immunology, February 2018, Vol.141(2), pp.AB141-AB141
    Description: Methods We assessed specific IgG4 to milk proteins (alpha-lactalbumin, beta-lactoglobulin, and caseins) in sera from 71 children with EoE. Younger boys had lower levels of IgG4 to all three milk proteins as compared to older boys.
    Keywords: Medicine
    ISSN: 0091-6749
    E-ISSN: 1097-6825
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  • 7
    Language: English
    In: Cancer Research, 04/15/2010, Vol.70(8 Supplement), pp.3871-3871
    ISSN: 0008-5472
    E-ISSN: 1538-7445
    Source: CrossRef
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  • 8
  • 9
    Language: English
    In: PLoS ONE, 01 January 2016, Vol.11(12), p.e0168215
    Description: Therapeutic options to cure advanced, recurrent, and unresectable thymomas are limited. The most important factor for long-term survival of thymoma patients is complete resection (R0) of the tumor. We therefore evaluated the response to and the induction of resectability of primarily or locally recurrent unresectable thymomas and thymic carcinomas by octreotide Long-Acting Release (LAR) plus prednisone therapy in patients with positive octreotide scans. In this open label, single-arm phase II study, 17 patients with thymomas considered unresectable or locally recurrent thymoma (n = 15) and thymic carcinoma (n = 2) at Masaoka stage III were enrolled. Octreotide LAR (30 mg once every 2 weeks) was administered in combination with prednisone (0.6 mg/kg per day) for a maximum of 24 weeks (study design according to Fleming´s one sample multiple testing procedure for phase II clinical trials). Tumor size was evaluated by volumetric CT measurements, and a decrease in tumor volume of at least 20% at week 12 compared to baseline was considered as a response. We found that octreotide LAR plus prednisone elicited response in 15 of 17 patients (88%). Median reduction of tumor volume after 12 weeks of treatment was 51% (range 20%-86%). Subsequently, complete surgical resection was achieved in five (29%) and four patients (23%) after 12 and 24 weeks, respectively. Octreotide LAR plus prednisone treatment was discontinued in two patients before week 12 due to unsatisfactory therapeutic effects or adverse events. The most frequent adverse events were gastrointestinal (71%), infectious (65%), and hematological (41%) complications. In conclusion, octreotide LAR plus prednisone is efficacious in patients with primary or recurrent unresectable thymoma with respect to tumor regression. Octreotide LAR plus prednisone was well tolerated and adverse events were in line with the known safety profile of both agents.
    Keywords: Sciences (General)
    E-ISSN: 1932-6203
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  • 10
    Language: English
    In: European Journal of Forest Research, 2010, Vol.129(6), pp.1109-1118
    Description: To investigate whether drought tolerance of individual trees can be increased through the provision of more growing space, trees from a thinning experiment were analysed for reductions in radial growth during drought years and their subsequent recovery. Tree-ring widths were quantified on increment cores as well as stem discs of 32 trees from stands of a thinning trial established in 1974 in 27-year-old spruce stands in the Alpine Foreland of Southwest Germany. Three different thinning regimes of the trial were selected for this study: unthinned control (8 trees), moderate (13 trees) and heavy thinning (11 trees) intensities. All trees sampled were of a co-dominant to dominant canopy status. The standardisation of growth data was carried out using the software program ARSTAN (University of Arizona). For the year 1976—a widespread and severe drought year in Germany—we found year ring widths were not reduced compared to those of the pre-drought years for all treatments. However, we observed the formation of false year rings and resin ducts for this year in all trees investigated. The drought events in 1992 and 2003 led to severe growth depressions in the year of the drought event in all trees, regardless of previous thinning regimes. However, the resilience—the recovery of basal area growth in subsequent years—was significantly more rapid in trees from heavily thinned stands, even if the drought event occurred more than 10 years after the last thinning intervention. This indicates a shorter stress period for trees with more growing space, which may reduce the susceptibility to secondary pathogens or pest species such as bark beetles.
    Keywords: Norway spruce ; Drought response ; Thinning regime ; Dendrochronology
    ISSN: 1612-4669
    E-ISSN: 1612-4677
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