iForest - Biogeosciences and Forestry


Performance assessment of two plotless sampling methods for density estimation applied to some Alpine forests of northeastern Italy

Monica Notarangelo (1)   , Marco Carrer (2), Emanuele Lingua (2), Nicola Puletti (1), Chiara Torresan (3)

iForest - Biogeosciences and Forestry, Volume 16, Issue 6, Pages 385-391 (2023)
doi: https://doi.org/10.3832/ifor4335-016
Published: Dec 19, 2023 - Copyright © 2023 SISEF

Research Articles

In this study, we tested two plotless sampling methods, the ordered distance method and point-centred quarter method, to estimate the tree density and basal area in some managed Alpine forests in northeastern Italy. We selected nine independent forest stands, classified according to the spatial distribution patterns of trees (cluster, random, regular). A plotless sampling survey was simulated within the selected stands and the tree density and basal area were estimated by applying both the ordered distance method and point-centred quarter method. We compared the estimates, in terms of accuracy and precision, between the two methods and against estimates obtained from a simulated survey based on a plot-based sampling method. The point-centred quarter method outperformed the ordered distance method in terms of both accuracy and precision, showing higher robustness towards the bias related to non-random spatial patterns. However, both the plotless methods we tested can provide unbiased accuracy of estimates which, in addition, do not differ from estimates of plot-based sampling. The satisfactory results are encouraging for further tests over other Italian Alpine as well as Apennine forests. If confirmed, the plotless sampling method, especially the point-centred quarter method, could represent an effective alternative whenever plot-based sampling is deemed redundant, or expensive.


Distance-based Density Estimator, Ordered Distance Method, Point-centred Quarter Method, Accuracy, Precision, Conditional Inference Trees, Forest Monitoring

Authors’ address

Monica Notarangelo 0000-0002-1968-8832
Nicola Puletti 0000-0002-2142-959X
Research centre for forestry and wood - Council for Agricultural Research and Economics - CREA, p.za Nicolini 6, I-38123 Trento (Italy)
Marco Carrer 0000-0003-1581-6259
Emanuele Lingua 0000-0001-9515-7657
Department of Land, Environment, Agriculture and Forestry - TESAF, University of Padua, v.le dell’Università 16, I-35020 Legnaro, PD (Italy)
Chiara Torresan 0000-0003-4529-4615
Institute of BioEconomy, National Research Council of Italy, v. Biasi 75, I-38098 San Michele all’Adige, TN (Italy)

Corresponding author

Monica Notarangelo


Notarangelo M, Carrer M, Lingua E, Puletti N, Torresan C (2023). Performance assessment of two plotless sampling methods for density estimation applied to some Alpine forests of northeastern Italy. iForest 16: 385-391. - doi: 10.3832/ifor4335-016

Academic Editor

Mirko Di Febbraro

Paper history

Received: Feb 23, 2023
Accepted: Oct 25, 2023

First online: Dec 19, 2023
Publication Date: Dec 31, 2023
Publication Time: 1.83 months

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