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Developing predictive models of wind damage in Austrian forests / Ferenc Pasztor in Annals of Forest Science, vol 72 n° 3 (May 2015)  

Public [article]  inAnnals of Forest Science > vol 72 n° 3 (May 2015) . - pp 289 - 301 Titre : Developing predictive models of wind damage in Austrian forests Type de document : Article/Communication Auteurs : Ferenc Pasztor, Auteur ; Christoph Matulla, Auteur ; Maja Zuvela-Aloise, Auteur ; et al., Auteur Année de publication : 2015 Article en page(s) : pp 289 - 301 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Végétation [Termes IGN] Autriche [Termes IGN] discrétisation [Termes IGN] dommage matériel [Termes IGN] forêt [Termes IGN] modèle linéaire [Termes IGN] Picea abies [Termes IGN] station forestière [Termes IGN] tempête [Termes IGN] vent Résumé : (auteur) Context : Among natural disturbances, wind storms cause the greatest damage to forests in Austria. Aim : The aim of this study is to quantify the effects of site, stand and meteorological attributes on the wind disturbance regime at the operational scale of forest stands. Methods : We used binomial generalized linear mixed models (GLMMs) to quantify the probability of damage events and linear mixed models (LMMs) to explain the damage intensity at the forest stand level in four management units with a total forest area of approximately 28,800 ha. Results : Timber stock volume, stand age, elevation, previous disturbances, wind gust speed and frozen state of soil contributed in explaining probability of wind damage. While the model of disturbance probability correctly classified 90 % of all cases in the data set (specificity 95 %, sensitivity 26 %), the model for damage intensity explained only low percentages of the variation in the observed damage data (full model R 2 = 0.38, fixed effects-only model R 2 = 0.09; cross-validation in the four forest management units yielded similar R 2 values). Conclusion : The developed models indicated that decreasing the proportion of Norway spruce (Picea abies [L.] Karst), limiting stand age and reducing the timber stock in course of tending treatments in stands exposed to wind disturbance can mitigate the risk and the expected damage intensity. High gust speeds and salvage cuts after earlier damage increase the probability of further wind disturbance events. Numéro de notice : A2015-452 Affiliation des auteurs : non IGN Thématique : FORET Nature : Article DOI : 10.1007/s13595-014-0386-0 Date de publication en ligne : 11/06/2014 En ligne : https://doi.org/10.1007/s13595-014-0386-0 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=77108 [article]

Response of Swiss forests to management and climate change in the last 60 years / Meinrad Küchler in Annals of Forest Science, vol 72 n° 3 (May 2015)  

Public [article]  inAnnals of Forest Science > vol 72 n° 3 (May 2015) . - pp 311 - 320 Titre : Response of Swiss forests to management and climate change in the last 60 years Type de document : Article/Communication Auteurs : Meinrad Küchler, Auteur ; Helen Küchler, Auteur ; Angéline Bedolla, Auteur ; et al., Auteur Année de publication : 2015 Article en page(s) : pp 311 - 320 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Végétation [Termes IGN] analyse diachronique [Termes IGN] arbuste [Termes IGN] changement climatique [Termes IGN] espèce végétale [Termes IGN] forêt [Termes IGN] herbe [Termes IGN] inventaire forestier étranger (données) [Termes IGN] plantation forestière [Termes IGN] recensement [Termes IGN] Suisse [Termes IGN] sylviculture [Termes IGN] température Résumé : (auteur) Context : Forest vegetation is forecasted to shift upslope several hundred metres by 2100 due to climate warming. However, only a small number of detailed assessments in selected regions have confirmed a climate response on the part of forest vegetation. Aims : This study aimed to analyse the relative contributions of temperature and other factors to range shifts in forest vegetation by comparing old and revisited relevés in Swiss forests. Methods : In order to investigate such range shifts, we revisited 451 relevé plots in forests in all parts of Switzerland. Collected data comprise two independent samples, one dating from the 1950s (age 60 sample) on 126 plots and the other dating from the 1990s (age 15 sample) on 325 plots. We defined an indicator value for elevation to estimate the upslope and downslope range shifts of forest species. The influence of different site factors on range shifts was assessed by variance partitioning using Landolt’s (2010) averaged species indicator values. Vegetation changes were analysed by balancing both increasing and decreasing frequencies of plant species. Results : Our findings show significant differences between the two survey periods, where the averaged species indicator for elevation varied greatly in both the age-60 and the age-15 samples. In addition, a significant upslope shift in the herbaceous forest layer (herbs and tree regeneration) of about 10 m per decade since the mid-twentieth century is evident. Downslope shifts were detected in the shrub/tree layer at lower elevations, which may be explained by factors other than climate warming. Conclusions : To date, the impact of global warming on tree species composition in Swiss forests has been weaker in comparison to the effects arising from forest management and land use change. Understorey vegetation, however, shows a strong signal of upslope shift that may be explained most adequately by a combination of climate change and other factors. Numéro de notice : 2015-453 Affiliation des auteurs : non IGN Thématique : FORET Nature : Article DOI : 10.1007/s13595-014-0409-x Date de publication en ligne : 29/07/2014 En ligne : https://doi.org/10.1007/s13595-014-0409-x Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=77109 [article]

An improved species distribution model for Scots pine and downy oak under future climate change in the NW Italian Alps / Giorgio Vacchiano in Annals of Forest Science, vol 72 n° 3 (May 2015)  

Public [article]  inAnnals of Forest Science > vol 72 n° 3 (May 2015) . - pp 321 - 334 Titre : An improved species distribution model for Scots pine and downy oak under future climate change in the NW Italian Alps Type de document : Article/Communication Auteurs : Giorgio Vacchiano, Auteur ; Renzo Motta, Auteur Année de publication : 2015 Article en page(s) : pp 321 - 334 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Végétation [Termes IGN] Aoste (val d') [Termes IGN] distribution spatiale [Termes IGN] inventaire forestier étranger (données) [Termes IGN] Normalized Difference Vegetation Index [Termes IGN] Pinus sylvestris [Termes IGN] Quercus pubescens [Termes IGN] sécheresse Résumé : (auteur) Context : Scots pine is currently declining in most inner alpine sectors of southern Europe. The relative contribution of climate, land use change, and disturbances on the decline is poorly understood. What will be the future distribution of the species? Is vegetation shifting toward oak-dominated forests? What is the role of extreme drought years? Aims : The aims of the study were to determine drivers of current distribution of Scots pine and downy oak in Aosta valley (SW Alps), to extrapolate species distribution models to year 2080 (Special Report on Emissions Scenarios (SRES) A1B), and to assess the correlation between pine vitality after the extreme droughts of 2003 and 2006, and modeled longterm vegetation changes. Methods : Ensemble distribution models were created using climate, topography, soil, competition, natural disturbances, and land use. Species presence was derived from a regional forest inventory. Pine response to drought of 2003–2006 was assessed by Normalized Difference Vegetation Index (NDVI) differencing and correlated to modeled cover change between 2080 and present. Results : Scots pine and downy oak were more likely to occur under higher climatic aridity. Scots pine was also associated to higher wildfire frequency, land use intensity, and lack of competition. In a warming scenario, pine experienced an elevational displacement. This was partially counteracted if no land abandonment was hypothesized. Downy oak cover increased in all scenarios. Short- and long-term drought responses of pine were unrelated. Conclusion : Warming will induce an upward displacement of pine, but this can be partially mitigated by maintaining a more intense land use. The drought-induced decline in pine vitality after extreme years did not overlap to the modeled species response under climate warming; responses to short-term drought must be more thoroughly understood in order to predict community shifts. Numéro de notice : A2015-454 Affiliation des auteurs : non IGN Thématique : FORET Nature : Article DOI : 10.1007/s13595-014-0439-4 Date de publication en ligne : 19/12/2014 En ligne : https://doi.org/10.1007/s13595-014-0439-4 Format de la ressource électronique : URL Article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=77111 [article]

Do competition-density rule and self-thinning rule agree? / Sonja Vospernik in Annals of Forest Science, vol 72 n° 3 (May 2015)  

Public [article]  inAnnals of Forest Science > vol 72 n° 3 (May 2015) Titre : Do competition-density rule and self-thinning rule agree? Type de document : Article/Communication Auteurs : Sonja Vospernik, Auteur ; Hubert Sterba, Auteur Année de publication : 2015 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Termes IGN] Abies (genre) [Termes IGN] auto-éclaircie [Termes IGN] Autriche [Termes IGN] croissance des arbres [Termes IGN] densité de la végétation [Termes IGN] inventaire forestier étranger (données) [Termes IGN] Larix decidua [Termes IGN] Normalized Difference Vegetation Index [Termes IGN] Picea abies [Termes IGN] Pinus nigra [Termes IGN] Pinus pinea [Termes IGN] Pinus sylvestris [Vedettes matières IGN] Foresterie Résumé : (auteur) Context : The competition-density principle, which can mathematically be described by the competition-density rule, is an important principle in plant ecology. The border line relationship is the self-thinning rule. Despite the importance of both rules for forest management, they have been fit for few species. Aims : The aim of this study is to compare competition-density rule and self-thinning rule in particular with respect to potential density for 15 species from the Austrian National Forest Inventory (ANFI). Methods : The self-thinning line was estimated using quantile regression. The competition-density rule was fit as four- and as three-parameter model, where the fourth parameter was substituted (a) with a specific slope from the self-thinning line estimated from the ANFI and (b) Reineke’s slope (−1.605). Results : Potential density was highest for Austrian pine and Norway spruce, followed by silver fir and Scots pine; it was considerably lower for European larch, stone pine and broadleaf species. Species-specific slopes of the self-thinning line ranged between −1.5 and −2.0 and were significantly different from Reineke’s slope for Norway spruce, European larch and European beech. Conclusions : Using robust estimation techniques, both competition-density rule and self-thinning line can also be fit for minor species, providing an important guide for practical forest management. Numéro de notice : A2015-456 Affiliation des auteurs : non IGN Thématique : FORET Nature : Article DOI : 10.1007/s13595-014-0433-x Date de publication en ligne : 30/10/2014 En ligne : https://doi.org/10.1007/s13595-014-0433-x Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=77120 [article]