Improving precision of field inventory estimation of aboveground biomass through an alternative view on plot biomass  

作　　者：Christoph Kleinn Steen Magnussen Nils Nölke Paul Magdon Juan GabrielÁlvarez-González Lutz Fehrmann César Pérez-Cruzado 

机构地区：[1]Forest Inventory and Remote Sensing,Georg-August-Universität Göttingen,37077 Göttingen,Germany. [2]Canadian Forest Service,Natural Resources Canada,Victoria,BC V8Z 1M5,Canada. [3]Department of Agroforestry Engineering,University of Santiago de Compostela,E-27002 Lugo,Spain

出　　处：《Forest Ecosystems》2020年第4期760-769,共10页森林生态系统（英文版）

摘　　要：We contrast a new continuous approach(CA)for estimating plot-level above-ground biomass(AGB)in forest inventories with the current approach of estimating AGB exclusively from the tree-level AGB predicted for each tree in a plot,henceforth called DA(discrete approach).With the CA,the AGB in a forest is modelled as a continuous surface and the AGB estimate for a fixed-area plot is computed as the integral of the AGB surface taken over the plot area.Hence with the CA,the portion of the biomass of in-plot trees that extends across the plot perimeter is ignored while the biomass from trees outside of the plot reaching inside the plot is added.We use a sampling simulation with data from a fully mapped two hectare area to illustrate that important differences in plot-level AGB estimates can emerge.Ideally CA-based estimates of mean AGB should be less variable than those derived from the DA.If realized,this difference translates to a higher precision from field sampling,or a lower required sample size.In our case study with a target precision of 5%(i.e.relative standard error of the estimated mean AGB),the CA required a 27.1%lower sample size for small plots of 100 m2 and a 10.4%lower sample size for larger plots of 1700 m2.We examined sampling induced errors only and did not yet consider model errors.We discuss practical issues in implementing the CA in field inventories and the potential in applications that model biomass with remote sensing data.The CA is a variation on a plot design for above-ground forest biomass;as such it can be applied in combination with any forest inventory sampling design.

关 键 词：Branch biomass Foliage biomass Stem biomass Biomass surface plots Sampling surfaces Standard error of estimation 

分 类 号：S757.2[农业科学—森林经理学]