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Recherches sur l'application aux taillis-sous-futaie des Méthodes Mathématiques-Statistiques d'Inventaire / Jean Pardé in Annales de l'école nationale des eaux et forêts et de la station de recherches et expériences, vol 15 n° 2 (1957)  

Public [article]  inAnnales de l'école nationale des eaux et forêts et de la station de recherches et expériences > vol 15 n° 2 (1957) . - pp 455 - 557 Titre : Recherches sur l'application aux taillis-sous-futaie des Méthodes Mathématiques-Statistiques d'Inventaire Type de document : Article/Communication Auteurs : Jean Pardé, Auteur Année de publication : 1957 Article en page(s) : pp 455 - 557 Langues : Français (fre) Descripteur : [Termes IGN] données statistiques [Termes IGN] échantillonnage (statistique) [Termes IGN] estimation statistique [Termes IGN] inventaire forestier (techniques et méthodes) [Termes IGN] statistique mathématique [Termes IGN] taillis sous futaie [Vedettes matières IGN] Inventaire forestier Résumé : (auteur) After an analysis of foreign works on the application to forest management of forest survey by statistical methods of sampling, the author describes the stands which he studied himself. The domanial forest of Izeure, a rich composite forest about to be converted, lies in the valley of the Saône, 25 km South-East of Dijon. The characteristic species of the reserve is oak (Quercus robar andQ. pedunculata) forming 77 % of the total volume together with some beech (12 %) and various species (11 %).The average volume per hectare is 177 cubic meter (stem and branch wood). The survey of 170,47 ha of the forest was done on the one hand stem by stem, along traditional methods, and compartment by compartment, on the other hand by mathematical-statistical methods of sampling. Systematically laid circular plots of io ares in area were used at the density of one every for 50 ares of forest. The main following results were obtained: I° Survey of forest stands by sampling and use of mathematical-statistical methods can be applied in France in the framework of managements, and in particular to the case of cannice with standards forests such as are found in the plain of the Saône. 2 ° Systematic samplings in forest surveys give results that are at least as good as random probings and the computation of the standard error of the mean usualy reserved to the latter type of surveys can eotially be applied to them. 3° Circular sampling plots are very convenient. In this study 10 ares plots revealed therselve dequate. 4° The methods described can be readily utilized by the ordinary personnel of the Forest Service. The conduct of inventory operations— preparatory office work, actual field application, calculations — has been established. 5° For the management of a forest, it appears sufficient to obtain, at the 5 % level of significance, an error on the mean smaller than± 10 % for total volumes. 6° Sampling 1/10th of the area inventoried — one 10 ares plot per hectare of stand — costs twice less than complete sampling in the case studied here. It is adequate for area larger than 75 hectares. 7° Sampling 1/20th of the area inventoried — one 10 ares plot per two hectares of stand — is at least one third cheaper than complete sampling. It is applicable to areas larger than 170 hectares. 8° This type of inventory also gives accurate enough results —standard error of the man of ± 15 % for exemple, — for secondary data used un the estimation of the possibility (separation of stems between mature and immature in particular). 9° A methode is shown for finding by a preliminary test survey the number of sampling points to be laid over a given forest in order to obtain a given level of precision. 10° After a division of the forest into elementary units, the author studied the eventual use of variance analysis permitting a reduction of the true error on the survey. This method may certainly be useful in dealing with a heterogeneous forest; but in this particular case, it appeared that the variations between stands, although noticeable, did not motivate an analysis of the variance. The subdivision of a forest into blocks, if it is to be justified, should essentially be based on the study of the ecological sites.(Traduction L. ROUSSEAU.) Numéro de notice : A1957-003 Affiliation des auteurs : non IGN Thématique : FORET/MATHEMATIQUE Nature : Article DOI : sans En ligne : http://hdl.handle.net/2042/33574 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=97761 [article]

Exemplaires(2)

Code-barres	Cote	Support	Localisation	Section	Disponibilité
IFN-001-000950	PAR	Tiré à part	Nogent-sur-Vernisson	1er étage - PFC	Disponible
IFN-001-000951	PAR	Tiré à part	Nogent-sur-Vernisson	1er étage - PFC	Disponible