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Optimal plot size or point sample factor for a fixed total cost using the Fairfield Smith relation of plot size to variance / Thomas B. Lynch in Forestry, an international journal of forest research, vol 90 n° 2 (March 2016)
[article]
Titre : Optimal plot size or point sample factor for a fixed total cost using the Fairfield Smith relation of plot size to variance Type de document : Article/Communication Auteurs : Thomas B. Lynch, Auteur Année de publication : 2016 Article en page(s) : pp 211 - 218 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Termes IGN] coût
[Termes IGN] placette d'échantillonnage
[Termes IGN] surface terrière
[Termes IGN] variance
[Vedettes matières IGN] Inventaire forestierRésumé : (auteur) Using the classical power function relationship between inverse plot size and sample variance, the method of Lagrangian multipliers was applied to minimize the variance of the sample mean among measurements on sample plots (e.g. volume or basal area per hectare) subject to a fixed total cost with varying plot size and sample size. This results in equations that can be used to determine optimal plot and sample size for a fixed total cost. The method does not require a prior estimate of variance. Optimal point sampling basal area factor can be substituted for plot size if variance and cost functions are available for point sampling. It was determined theoretically that no feasible optimum solution exists if the ratio of the relative change rate in variance to the relative change rate in cost per plot is less than negative one. This occurs because in that case the variance as a function of plot size is being reduced faster than the cost per plot is increasing in relative terms. An example application based on cost and variance functions from the literature found that the optimal surface was quite flat, so that an optimum existed but a rather wide range of plot and sample size combinations were close to optimum for a fixed total cost. In practical terms this means that a wide range of plot sizes would give nearly equal precision for a fixed total cost in this example. This may not be the case for all realistic parameterizations of the cost functions. Numéro de notice : A2016--135 Affiliation des auteurs : non IGN Thématique : FORET Nature : Article DOI : 10.1093/forestry/cpw038 En ligne : https://doi.org/10.1093/forestry/cpw038 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=85777
in Forestry, an international journal of forest research > vol 90 n° 2 (March 2016) . - pp 211 - 218[article]Terrestrial laser scanning in forest inventories / Xinlian Liang in GIM international [en ligne], vol 30 n° 2 (February 2016)
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Titre : Terrestrial laser scanning in forest inventories Type de document : Article/Communication Auteurs : Xinlian Liang, Auteur ; Juha Hyyppä, Auteur ; Harri Kaartinen, Auteur ; Norbert Pfeifer, Auteur Année de publication : 2016 Article en page(s) : pp 26 - 29 Langues : Anglais (eng) Descripteur : [Termes IGN] arbre (flore)
[Termes IGN] inventaire forestier (techniques et méthodes)
[Termes IGN] parangonnage
[Termes IGN] télémétrie laser terrestre
[Vedettes matières IGN] Inventaire forestierRésumé : (éditeur) Terrestrial laser scanning (TLS) is an effective technique for acquiring detailed tree attributes in forest plots. During the last two decades, tremendous effort by national mapping agencies, companies, universities and research organisations has been put into developing methods for tree attribute estimation casing TLS. There is, however, still a lack of proper understanding on TLS performance. Different data collection methods and processing standards have led to a large range in tree detection and measurement accuracy. This article explains the early results of an international benchmarking initiative for TLS methods in forest inventories. The study has identified important differences in methods that should lead to operational work guidelines. Numéro de notice : A2016-100 Affiliation des auteurs : non IGN Thématique : FORET/IMAGERIE Nature : Article DOI : sans Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=79920
in GIM international [en ligne] > vol 30 n° 2 (February 2016) . - pp 26 - 29[article]Use of models in large-area forest surveys: comparing model-assisted, model-based and hybrid estimation / Göran Stahl in Forest ecosystems, vol 3 (2016)
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Titre : Use of models in large-area forest surveys: comparing model-assisted, model-based and hybrid estimation Type de document : Article/Communication Auteurs : Göran Stahl, Auteur ; Svetlana Saarela, Auteur ; Sebastian Schnell, Auteur ; Sören Holm, Auteur ; et al., Auteur Année de publication : 2016 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Termes IGN] échantillonnage
[Termes IGN] estimation statistique
[Termes IGN] inférence statistique
[Termes IGN] inventaire forestier (techniques et méthodes)
[Vedettes matières IGN] Inventaire forestierRésumé : (auteur) This paper focuses on the use of models for increasing the precision of estimators in large-area forest surveys. It is motivated by the increasing availability of remotely sensed data, which facilitates the development of models predicting the variables of interest in forest surveys. We present, review and compare three different estimation frameworks where models play a core role: model-assisted, model-based, and hybrid estimation. The first two are well known, whereas the third has only recently been introduced in forest surveys. Hybrid inference mixes design-based and model-based inference, since it relies on a probability sample of auxiliary data and a model predicting the target variable from the auxiliary data..We review studies on large-area forest surveys based on model-assisted, model-based, and hybrid estimation, and discuss advantages and disadvantages of the approaches. We conclude that no general recommendations can be made about whether model-assisted, model-based, or hybrid estimation should be preferred. The choice depends on the objective of the survey and the possibilities to acquire appropriate field and remotely sensed data. We also conclude that modelling approaches can only be successfully applied for estimating target variables such as growing stock volume or biomass, which are adequately related to commonly available remotely sensed data, and thus purely field based surveys remain important for several important forest parameters. Numéro de notice : A2016--161 Affiliation des auteurs : non IGN Thématique : FORET Nature : Article DOI : 10.1186/s40663-016-006 En ligne : https://doi.org/10.1186/s40663-016-0064-9 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=87015
in Forest ecosystems > vol 3 (2016)[article]Estimation of forest biomass using multivariate relevance vector regression / Alireza Sharifi in Photogrammetric Engineering & Remote Sensing, PERS, vol 82 n° 1 (January 2016)
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Titre : Estimation of forest biomass using multivariate relevance vector regression Type de document : Article/Communication Auteurs : Alireza Sharifi, Auteur ; Jalal Amini, Auteur ; Ryutaro Tateishi, Auteur Année de publication : 2016 Article en page(s) : pp 41 - 49 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Termes IGN] biomasse aérienne
[Termes IGN] biomasse forestière
[Termes IGN] estimation statistique
[Termes IGN] forêt
[Termes IGN] image ALOS-PALSAR
[Termes IGN] Iran
[Termes IGN] Perceptron multicouche
[Termes IGN] régression multiple
[Termes IGN] séparateur à vaste marge
[Vedettes matières IGN] Inventaire forestierRésumé : (auteur) The objective of this study is to develop a method based on multivariate relevance vector regression (MVRVR) as a kernelbased Bayesian model for the estimation of above-ground biomass (AGB) in the Hyrcanian forests of Iran. Field AGB data from the Hyrcanian forests and multi-temporal PALSAR backscatter values are used for training and testing the methods. The results of the MVRVR method are then compared with other methods: multivariate linear regression (MLR), multilayer perceptron neural network (MLPNN), and support vector regression (SVR). The MLR model showed lower values of R2 than the three other approaches. Although the SVR model was found to be more accurate than MLPNN, it had the lowest saturation point of 224.75 Mg/ha. The use of MVRVR model significantly improves the estimation of AGB (R2 = 0.90; RMSE = 32.05 Mg/ha), and the model showed a superior performance in estimating AGB with the highest saturation point (297.81 Mg/ha). Numéro de notice : A2016-053 Affiliation des auteurs : non IGN Thématique : FORET Nature : Article DOI : 10.14358/PERS.83.1.41 En ligne : https://doi.org/10.14358/PERS.83.1.41 Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=79654
in Photogrammetric Engineering & Remote Sensing, PERS > vol 82 n° 1 (January 2016) . - pp 41 - 49[article]Forest inventory, assessment, and monitoring, and long-term forest observational studies, with special reference to India / V.P. Tewari in Forest science and technology, vol 12 n° 1 ([01/01/2016])
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Titre : Forest inventory, assessment, and monitoring, and long-term forest observational studies, with special reference to India Type de document : Article/Communication Auteurs : V.P. Tewari, Auteur Année de publication : 2016 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Termes IGN] Inde
[Termes IGN] inventaire forestier étranger (données)
[Termes IGN] surveillance forestière
[Vedettes matières IGN] Inventaire forestierRésumé : (auteur) National forest assessments are attracting increasing attention owing to their role in providing information related to manifold forest functions. Large-area information is in high demand, both for the forest in its role as ecosystem and in its role as resource and service provider. Of particular current interest are forest assessment systems at national level by countries that wish to engage in the REDD+ initiative. Large-area forest monitoring has never had a prominent place on the curricula of forestry faculties in India or many other tropical countries. As a consequence, in many tropical countries, there is only very limited technical capacity for large-area forest monitoring. The discipline of “forest inventory” has developed a versatile toolbox of techniques and methods useful for national level assessments, and remote sensing technology has, over the last few decades, added some exciting options to this toolbox. This article analyzes the process of national forest monitoring and identifies key areas where national capacity may be developed. A brief description of forest assessment in India, long-term observational studies, and synergy with the national forestry inventory is also presented. Numéro de notice : A2016--159 Affiliation des auteurs : non IGN Thématique : FORET Nature : Article DOI : 10.1080/21580103.201 En ligne : http://dx.doi.org/10.1080/21580103.2015.1018962 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=87010
in Forest science and technology > vol 12 n° 1 [01/01/2016][article]La forêt en chiffres et en cartes / Institut national de l'information géographique et forestière (2012 -) (2016)PermalinkLes indicateurs de gestion durable des forêts françaises métropolitaines, édition 2015, Tome 2. Notice méthodologique : Caractéristiques techniques des données, méthode de calcul et pistes d'amélioration / Ministère de l’Agriculture, de l’Agroalimentaire et de la Forêt (France) (2016)PermalinkNational Forest Inventories : assessment of wood availability and use, ch. Progress towards harmonised assessment of availability and use of wood resources in Europe / Claude Vidal (2016)PermalinkNational Forest Inventories : assessment of wood availability and use, ch. Report France : Forest resource assessment in France / Jean-Christophe Hervé (2016)PermalinkRésultats d'inventaire forestier : méthodologie pour bien comprendre les résultats publiés 2011- 2015 / Institut national de l'information géographique et forestière (2012 -) (2016)PermalinkLa valorisation des données écologiques de l’inventaire forestier de l’IGN / Marie-Françoise Slak (2016)PermalinkLinear models for airborne-laser-scanning-based operational forest inventory with small field sample size and highly correlated LiDAR data / Virpi Junttila in IEEE Transactions on geoscience and remote sensing, vol 53 n° 10 (October 2015)PermalinkTropical forest canopy cover estimation using satellite imagery and airborne lidar reference data / Lauri Korhonen in Silva fennica, vol 49 n° 5 ([01/10/2015])PermalinkAn overview of existing and promising technologies for national forest monitoring / Matieu Henry in Annals of Forest Science, vol 72 n° 6 (September 2015)PermalinkHow much do we know about the endangered Atlantic Forest? Reviewing nearly 70 years of information on tree community surveys / Renato A.F. de Lima in Biodiversity & Conservation, vol 24 n° 9 (September 2015)Permalink