Annals of Forest Science / Institut national de la recherche agronomique (1946 - 2019) . vol 72 n° 4Paru le : 01/06/2015 |
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Ajouter le résultat dans votre panierSeedlings of two Acacia species from contrasting habitats show different photoprotective and antioxidative responses to drought and heatwaves / Agnieszka Wujeska-Klause in Annals of Forest Science, vol 72 n° 4 (June 2015)
[article]
Titre : Seedlings of two Acacia species from contrasting habitats show different photoprotective and antioxidative responses to drought and heatwaves Type de document : Article/Communication Auteurs : Agnieszka Wujeska-Klause, Auteur ; Gerd Bossinger, Auteur ; Michael Tausz, Auteur Année de publication : 2015 Article en page(s) : pp 403 - 414 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Végétation
[Termes IGN] Acacia aneura
[Termes IGN] Acacia melanoxylon
[Termes IGN] analyse comparative
[Termes IGN] chaleur
[Termes IGN] photosynthèse
[Termes IGN] sécheresse
[Termes IGN] zone aride
[Termes IGN] zone humideRésumé : (auteur) Key message : Two Acacia species adapted to contrasting habitats showed different response of photoprotective and antioxidative defence systems to imposed drought and heatwave.
Context : Predicted increases in drought frequency and intense heatwaves are expected to lead to dieback of sensitive tree species. Stomatal closure restricts CO2 input into the leaf, resulting in imbalances between light energy-driven electron transport rate and electron consumption in the Calvin cycle. Reactive oxygen species formed under these circumstances have to be kept under control by photoprotective and antioxidative defence systems.
Aims : We hypothesised that these defence systems behave differently in tree species from contrasting habitats.
Methods : Acacia aneura (adapted to arid habitats) and Acacia melanoxylon (adapted to humid habitats) were exposed to two water treatments for 50 days including two short heatwave periods. Responses were assessed by gas exchange, chlorophyll fluorescence and concentrations of antioxidants (phyllodes, roots).
Results : Photosynthesis and quantum yield of photochemistry decreased significantly in both Acacia species, especially after water was withheld in combination with the second heatwave episode. In phyllodes, the concentration of antioxidants remained unchanged until exposure to severe drought and heatwave conditions (except for A. melanoxylon where changes in glutathione concentration were observed prior to exposure to severe stress), but after water was withheld and the second heatwave occurred, oxidised forms of glutathione increased. After exposure to the second heatwave, well-watered seedlings of A. melanoxylon but not A. aneura increased ascorbic acid concentration in phyllodes. Under well-watered conditions, Acacia species also showed increased concentration of antioxidants in roots following heatwaves.
Conclusions : Both Acacia species showed photodamage to photosystem II (PSII) after water was withheld and the second heatwave imposed, but with more gradual response in A. aneura. Total concentration of investigated antioxidants increased in response to the first (A. melanoxylon) and second (A. aneura) heatwaves rather than drought stress alone.Numéro de notice : A2015-425 Affiliation des auteurs : non IGN Thématique : FORET Nature : Article DOI : 10.1007/s13595-014-0438-5 Date de publication en ligne : 19/11/2014 En ligne : https://doi.org/10.1007/s13595-014-0438-5 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=77012
in Annals of Forest Science > vol 72 n° 4 (June 2015) . - pp 403 - 414[article]Comparing individual-tree approaches for predicting height growth of underplanted seedlings / John M. Lhotka in Annals of Forest Science, vol 72 n° 4 (June 2015)
[article]
Titre : Comparing individual-tree approaches for predicting height growth of underplanted seedlings Type de document : Article/Communication Auteurs : John M. Lhotka, Auteur ; Edward F. Loewenstein, Auteur Année de publication : 2015 Article en page(s) : pp 469 - 477 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Végétation
[Termes IGN] canopée
[Termes IGN] Géorgie (Etats-Unis)
[Termes IGN] hauteur des arbres
[Termes IGN] inventaire forestier étranger (données)
[Termes IGN] Liriodendron tulipifera
[Termes IGN] modèle de croissance végétale
[Termes IGN] plantation forestière
[Termes IGN] Quercus nigra
[Termes IGN] sous-bois
[Termes IGN] sylvicultureRésumé : (auteur) Key message : Individual-tree seeding height growth models developed using tree inventory data were comparable to those requiring the unique observation of point-based canopy structure data at each seedling.
Context : Quantitative approaches describing the relationship between canopy structure and seedling growth can inform silvicultural decision making regarding the development of tree reproduction beneath a dominant forest canopy.
Aims : Individual-tree seedling growth models with canopy structure predictors derived from tree inventory data have not been well-explored. This study compared a model framework fit using point-based measures of canopy structure observed at the seedling level to one fit using area-wide canopy structure variables derived from standard inventory plot data.
Methods : Species-specific models predicting 5-year height growth were fit for cherrybark oak (Quercus pagoda Raf.), water oak (Quercus nigra L.), and yellow-poplar (Liriodendron tulipifera L.) underplanted within a canopy structure gradient created by silvicultural manipulation of a closed-canopy forest in Georgia, USA.
Results : Though the species varied in shade tolerance and growth rates, the general relationship between the predictor variables and height growth was similar among species and model type. Models highlight the importance of including predictor variables that describe seedling size along with openness and vertical structure of the forest canopy.
Conclusion : While the two model frameworks had comparable fit statistics, the one with predictors derived from tree inventory data may have enhanced utility as it can be directly integrated into existing individual-tree forest growth simulators.Numéro de notice : A2015-424 Affiliation des auteurs : non IGN Thématique : FORET Nature : Article DOI : 10.1007/s13595-014-0453-6 Date de publication en ligne : 16/01/2015 En ligne : https://doi.org/10.1007/s13595-014-0453-6 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=77014
in Annals of Forest Science > vol 72 n° 4 (June 2015) . - pp 469 - 477[article]Stand volume models based on stable metrics as from multiple ALS acquisitions in Eucalyptus plantations / Eric Bastos Görgens in Annals of Forest Science, vol 72 n° 4 (June 2015)
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Titre : Stand volume models based on stable metrics as from multiple ALS acquisitions in Eucalyptus plantations Type de document : Article/Communication Auteurs : Eric Bastos Görgens, Auteur ; Petteri Packalen, Auteur ; André Gracioso Peres da Silva, Auteur ; et al., Auteur Année de publication : 2015 Article en page(s) : pp 489 - 498 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Lasergrammétrie
[Termes IGN] cubage de peuplement
[Termes IGN] données lidar
[Termes IGN] données localisées 3D
[Termes IGN] données multisources
[Termes IGN] Eucalyptus (genre)
[Termes IGN] semis de points
[Termes IGN] spatial metricsRésumé : (auteur) Key message : The selection of stable metrics can generate reliable models between different data sets. The height metrics provide the greatest stability, specifically the higher percentiles and the mode. Height metrics transfer more predictive power than density metrics.
Context : In forestry, there is an increasing development of aerial laser scanning (ALS). The flight missions that permit to record ALS point clouds are not yet standardized. Therefore, there is a need to identify the metrics that permit to infer robust forest stand estimates from the different point cloud acquisitions.
Aims : The aim of this study is to identify stable metrics derived from different ALS data sets to be used as independent variable in stand volume models.
Methods : Three different ALS data sets were taken from the same Eucalyptus plantation on the same day, each differing from the others in terms of flight altitude, laser power, and pulse frequency rate. Two sets of best predictive models were obtained for each data set based on two approaches: a basic approach using noncollinear metrics and an exhaustive search, and a second approach that added a pairwise Kolmogorov-Smirnov test to select stable metrics.
Results : Height metrics proved more stable, especially higher percentiles (>50 %) and the mode. Models developed with stable metrics had similar performance compared to the basic approach.
Conclusion : Percentiles higher than 50 % and the mode proved stable for that 6-year-old Eucalyptus plantation with a very homogeneous vertical structure. Further research widening the scope in terms of age and heterogeneity of vertical profiles is needed.Numéro de notice : A2015-426 Affiliation des auteurs : non IGN Thématique : FORET/IMAGERIE Nature : Article DOI : 10.1007/s13595-015-0457-x Date de publication en ligne : 28/01/2015 En ligne : https://doi.org/10.1007/s13595-015-0457-x Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=77015
in Annals of Forest Science > vol 72 n° 4 (June 2015) . - pp 489 - 498[article]