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Thinking outside the square: Evidence that plot shape and layout in forest inventories can bias estimates of stand metrics / Thomas S. H. Paul in Methods in ecology and evolution, vol 10 n° 3 (March 2019)  

Public [article]  inMethods in ecology and evolution > vol 10 n° 3 (March 2019) . - pp 381 - 388 Titre : Thinking outside the square: Evidence that plot shape and layout in forest inventories can bias estimates of stand metrics Type de document : Article/Communication Auteurs : Thomas S. H. Paul, Auteur ; Mark O. Kimberley, Auteur ; Peter N. Beets, Auteur Année de publication : 2019 Article en page(s) : pp 381 - 388 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Termes IGN] cercle (géométrie) [Termes IGN] diamètre à hauteur de poitrine [Termes IGN] erreur systématique [Termes IGN] inventaire forestier (techniques et méthodes) [Termes IGN] inventaire forestier étranger (données) [Termes IGN] Nouvelle-Zélande [Termes IGN] placette d'échantillonnage [Vedettes matières IGN] Inventaire forestier Résumé : (auteur) Plot‐based data collection is an important component of quantitative ecological research and is widely used. Some of the most extensive plot‐networks can be found in country‐wide forest inventories, which provide critical information about the state of forest ecosystems. While sampling designs for forest inventories have been well studied, plot design and installation has received less attention. The New Zealand National Forest Inventory of natural forest uses a nested plot design with a 0.126 ha circular plot superimposed concentrically on a 0.04 ha square plot. Stems ≥ 60 cm diameter at breast height (DBH) are measured in the circular plot while stems ≥ 2.5 DBH are measured in the square plot. Stem density of ≥60 cm DBH stems measured in the circular plots were compared with those from square plots. Stem densities estimated from square plot measurements were 23.7% higher than those estimated from circular plot measurements in the 2002–2007 inventory, and 18.4% higher in the 2009–2014 inventory. The main cause of this discrepancy appears to be due to the placement of plot boundaries during establishment of square plots. This effect may have resulted from a subconscious tendency of field teams to include large trees inside plots when laying out these boundaries. It is concluded that estimates from the circular plots are unlikely to be biased while those from the square plots are positively biased. This study highlights the critical importance of plot design and plot placement in forest inventories to ensure that estimates of stand attributes are unbiased. Especially on undulating or uneven terrain, methods of determining whether trees are inside or outside plot boundaries of circular plots are likely to be more accurate than those typically used for square or rectangular plots. Numéro de notice : A2019-372 Affiliation des auteurs : non IGN Thématique : FORET Nature : Article DOI : 10.1111/2041-210X.13113 Date de publication en ligne : 29/10/2018 En ligne : https://doi.org/10.1111/2041-210X.13113 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=93409 [article]