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Manipulating tree crown structure to promote old-growth characteristics in second-growth redwood forest canopies / Stephen C. Sillett in Forest ecology and management, vol 417 (15 May 2018)
[article]
Titre : Manipulating tree crown structure to promote old-growth characteristics in second-growth redwood forest canopies Type de document : Article/Communication Auteurs : Stephen C. Sillett, Auteur ; Marie E. Antoine, Auteur ; Jim Campbell-Spickler, Auteur ; Allyson L. Carroll, Auteur ; Ethan J. Coonen, Auteur ; et al., Auteur Année de publication : 2018 Article en page(s) : pp 77 - 89 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Végétation
[Termes IGN] Californie (Etats-Unis)
[Termes IGN] canopée
[Termes IGN] croissance des arbres
[Termes IGN] élagage (sylviculture)
[Termes IGN] houppier
[Termes IGN] Sequoia sempervirensRésumé : (Auteur) In old-growth Sequoia sempervirens forests, reiterated trunks and limbs provide required habitat elements for specialized arboreal species, including an endangered seabird, Brachyramphus marmoratus. The oldest second-growth redwood forests—established after 19th century logging—lack species dependent on complex structure, presumably because redwoods maintain simple, model-conforming crowns for centuries unless damaged by wind or fire. We imposed a factorial experiment on 24 redwoods 59–75 m tall in six second-growth forests to determine if trunk reiteration and limb formation can be induced by removing treetops (topping) and branch tips (tipping) to disrupt apical control. We also increased light availability in the upper crown by pruning branches. After intensively mapping trunks and branches and imposing treatments, we re-mapped trees three years later to quantify growth increments. Topping stimulated trunk reiteration from the cut, and reiterated tops gained height more rapidly than controls. Tipping also stimulated trunk reiteration from branches, especially when combined with topping, resulting in formation of limbs (i.e., branches giving rise to reiterated trunks). Pruning had consistently negative effects on trunk and branch growth increments even after accounting for post-treatment variation in leaf area and light availability, suggesting that photosynthate was diverted to compartmentalization of wounds. Strategic injury of trees may have long-term conservation value in second-growth redwood forests if limbs can be initiated high enough in the crown to persist as trees approach maximum height. Topping and tipping treatments should be combined with silvicultural thinning of neighboring trees to increase light availability far more than can be achieved by pruning. Numéro de notice : A2018-469 Affiliation des auteurs : non IGN Thématique : FORET Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1016/j.foreco.2018.02.036 Date de publication en ligne : 08/03/2018 En ligne : https://doi.org/10.1016/j.foreco.2018.02.036 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=91150
in Forest ecology and management > vol 417 (15 May 2018) . - pp 77 - 89[article]Using radial basis functions in airborne gravimetry for local geoid improvement / Xiaopeng Li in Journal of geodesy, vol 92 n° 5 (May 2018)
[article]
Titre : Using radial basis functions in airborne gravimetry for local geoid improvement Type de document : Article/Communication Auteurs : Xiaopeng Li, Auteur Année de publication : 2018 Article en page(s) : pp 471 - 485 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie physique
[Termes IGN] fonction de base radiale
[Termes IGN] géoïde local
[Termes IGN] gravimétrie aérienne
[Termes IGN] Iowa (Etats-Unis)
[Termes IGN] levé gravimétrique
[Termes IGN] modèle de géopotentiel localRésumé : (Auteur) Radial basis functions (RBFs) have been used extensively in satellite geodetic applications. However, to the author’s knowledge, their role in processing and modeling airborne gravity data has not yet been fully advocated or extensively investigated in detail. Compared with satellite missions, the airborne data are more suitable for these kinds of localized basis functions especially considering the following facts: (1) Unlike the satellite missions that can provide global or near global data coverage, airborne gravity data are usually geographically limited. (2) It is also band limited in the frequency domain. (3) It is straightforward to formulate the RBF observation equations from an airborne gravimetric system. In this study, a set of band-limited RBF is developed to model and downward continue the airborne gravity data for local geoid improvement. First, EIGEN6c4 coefficients are used to simulate a harmonic field to test the performances of RBF on various sampling, noise, and flight height levels, in order to gain certain guidelines for processing the real data. Here, the RBF method not only successfully recovers the harmonic field but also presents filtering properties due to its particular design in the frequency domain. Next, the software was tested for the GSVS14 (Geoid Slope Validation Survey 2014) area in Iowa as well as for the area around Puerto Rico and the US Virgin Islands by use of the real airborne gravity data from the Gravity for the Redefinition of the American Vertical Datum (GRAV-D) project. By fully utilizing the three-dimensional correlation information among the flight tracks, the RBF can also be used as a data cleaning tool for airborne gravity data adjustment and cleaning. This property is further extended to surface gravity data cleaning, where conventional approaches have various limitations. All the related numerical results clearly show the importance and contribution of the use of the RBF for high- resolution local gravity field modeling. Numéro de notice : A2018-147 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-017-1074-2 Date de publication en ligne : 24/10/2017 En ligne : https://doi.org/10.1007/s00190-017-1074-2 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=89758
in Journal of geodesy > vol 92 n° 5 (May 2018) . - pp 471 - 485[article]Mapping forest characteristics at fine resolution across large landscapes of the southeastern united states using NAIP imagery and FIA field plot data / John Hogland in ISPRS International journal of geo-information, vol 7 n° 4 (April 2018)
[article]
Titre : Mapping forest characteristics at fine resolution across large landscapes of the southeastern united states using NAIP imagery and FIA field plot data Type de document : Article/Communication Auteurs : John Hogland, Auteur ; Nathaniel Anderson, Auteur ; Joseph St. Peter, Auteur ; Jason Drake, Auteur ; Paul Medley, Auteur Année de publication : 2018 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Termes IGN] composition floristique
[Termes IGN] densité du bois
[Termes IGN] Etats-Unis
[Termes IGN] image aérienne
[Termes IGN] inventaire forestier (techniques et méthodes)
[Termes IGN] inventaire forestier étranger (données)
[Termes IGN] Pinus (genre)
[Termes IGN] surface terrière
[Termes IGN] télédétection aérienne
[Vedettes matières IGN] Inventaire forestierRésumé : (Auteur) Accurate information is important for effective management of natural resources. In the field of forestry, field measurements of forest characteristics such as species composition, basal area, and stand density are used to inform and evaluate management activities. Quantifying these metrics accurately across large landscapes in a meaningful way is extremely important to facilitate informed decision-making. In this study, we present a remote sensing based methodology to estimate species composition, basal area and stand tree density for pine and hardwood tree species at the spatial resolution of a Forest Inventory Analysis (FIA) program plot (78 m by 70 m). Our methodology uses textural metrics derived at this spatial scale to relate plot summaries of forest characteristics to remotely sensed National Agricultural Imagery Program (NAIP) aerial imagery across broad extents. Our findings quantify strong relationships between NAIP imagery and FIA field data. On average, models of basal area and trees per acre accounted for 43% of the variation in the FIA data, while models identifying species composition had less than 15.2% error in predicted class probabilities. Moreover, these relationships can be used to spatially characterize the condition of forests at fine spatial resolutions across broad extents. Numéro de notice : A2018-109 Affiliation des auteurs : non IGN Thématique : FORET/IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.3390/ijgi7040140 En ligne : https://doi.org/10.3390/ijgi7040140 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=89538
in ISPRS International journal of geo-information > vol 7 n° 4 (April 2018)[article]Evaluation of 10-year temporal and spatial variability in structure and growth across contrasting commercial thinning treatments in spruce-fir forests of northern Maine, USA / Christian Kuehne in Annals of Forest Science, vol 75 n° 1 (March 2018)
[article]
Titre : Evaluation of 10-year temporal and spatial variability in structure and growth across contrasting commercial thinning treatments in spruce-fir forests of northern Maine, USA Type de document : Article/Communication Auteurs : Christian Kuehne, Auteur ; Aaron R. Weiskittel, Auteur ; Arne Pommerening, Auteur ; Robert G. Wagner, Auteur Année de publication : 2018 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Termes IGN] Abies balsamea
[Termes IGN] arbre aléatoire
[Termes IGN] éclaircie (sylviculture)
[Termes IGN] Maine (Etats-Unis)
[Termes IGN] Picea rubens
[Termes IGN] Pinus strobus
[Termes IGN] station forestière
[Termes IGN] thuja (genre)
[Vedettes matières IGN] SylvicultureRésumé : (Auteur) Key message: Detailed measures of growth pattern and structural heterogeneity applied in this study helped to quantify the immediate effects of various thinning regimes on forest structure and the resulting alterations in tree size as well as observed longer term stand dynamics.
Context: Forest management, stand structure, and tree growth are highly inter-correlated. Prior analyses, however, have resulted in mixed outcomes with limited success in revealing ecological mechanisms.
Aims: The study aimed at evaluating the relationship between forest structure and stand dynamics by applying several sophisticated measures of growth pattern and structural heterogeneity.
Methods : Data from a controlled and fully stem-mapped commercial thinning experiment with seven contrasting treatments including a non-thinned control at six locations across the Acadian Forest of Maine, USA, was used. Stand-level attributes examined included tree size and growth heterogeneity, spatial tree distribution, and growth dominance.
Results: Thinning generally reduced stand structural heterogeneity compared to the non-thinned control. In addition, the spatial arrangement of trees changed from fully random (non-thinned control) to a more clustered (removal of dominant and co-dominant individuals) or regular distribution (removal of intermediate and suppressed individuals). Overall, stand growth exhibited increasing (non-thinned control, removal of intermediate and suppressed individuals) or decreasing growth dominance of large trees (removal of co-dominant competitors). Forwarder trails increased basal area growth of individual trees up to a distance from the trail of approximately 5 m.
Conclusion: Findings of this study validate an earlier insight according to which interactions between management practices, forest structure, and tree growth form a permanent feedback loop.
KeywordsNuméro de notice : A2018-315 Affiliation des auteurs : non IGN Thématique : BIODIVERSITE/FORET Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s13595-018-0697-7 Date de publication en ligne : 26/02/2018 En ligne : https://doi.org/10.1007/s13595-018-0697-7 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=90439
in Annals of Forest Science > vol 75 n° 1 (March 2018)[article]Harmonic regression of Landsat time series for modeling attributes from national forest inventory data / Barry T. Wilson in ISPRS Journal of photogrammetry and remote sensing, vol 137 (March 2018)
[article]
Titre : Harmonic regression of Landsat time series for modeling attributes from national forest inventory data Type de document : Article/Communication Auteurs : Barry T. Wilson, Auteur ; Joseph F. Knight, Auteur ; Ronald E. McRoberts, Auteur Année de publication : 2018 Article en page(s) : pp 29 - 46 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image optique
[Termes IGN] attribut
[Termes IGN] classification par forêts d'arbres décisionnels
[Termes IGN] image Landsat
[Termes IGN] inventaire forestier étranger (données)
[Termes IGN] Minnesota (Etats-Unis)
[Termes IGN] plus proche voisin, algorithme du
[Termes IGN] régression harmonique
[Termes IGN] série temporelleRésumé : (Auteur) Imagery from the Landsat Program has been used frequently as a source of auxiliary data for modeling land cover, as well as a variety of attributes associated with tree cover. With ready access to all scenes in the archive since 2008 due to the USGS Landsat Data Policy, new approaches to deriving such auxiliary data from dense Landsat time series are required. Several methods have previously been developed for use with finer temporal resolution imagery (e.g. AVHRR and MODIS), including image compositing and harmonic regression using Fourier series. The manuscript presents a study, using Minnesota, USA during the years 2009–2013 as the study area and timeframe. The study examined the relative predictive power of land cover models, in particular those related to tree cover, using predictor variables based solely on composite imagery versus those using estimated harmonic regression coefficients. The study used two common non-parametric modeling approaches (i.e. k-nearest neighbors and random forests) for fitting classification and regression models of multiple attributes measured on USFS Forest Inventory and Analysis plots using all available Landsat imagery for the study area and timeframe. The estimated Fourier coefficients developed by harmonic regression of tasseled cap transformation time series data were shown to be correlated with land cover, including tree cover. Regression models using estimated Fourier coefficients as predictor variables showed a two- to threefold increase in explained variance for a small set of continuous response variables, relative to comparable models using monthly image composites. Similarly, the overall accuracies of classification models using the estimated Fourier coefficients were approximately 10–20 percentage points higher than the models using the image composites, with corresponding individual class accuracies between six and 45 percentage points higher. Numéro de notice : A2018-077 Affiliation des auteurs : non IGN Thématique : FORET/IMAGERIE/MATHEMATIQUE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1016/j.isprsjprs.2018.01.006 En ligne : https://doi.org/10.1016/j.isprsjprs.2018.01.006 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=89439
in ISPRS Journal of photogrammetry and remote sensing > vol 137 (March 2018) . - pp 29 - 46[article]Réservation
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