SPECIES-SPECIFIC EQUATIONS: GREATER PRECISION IN COMMERCIAL VOLUME ESTIMATION IN MANAGED FORESTS IN THE AMAZON

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Published: Nov 17, 2020
Keywords:
commercial species, dendrometry, forest management, tropical forest, volumetric models.

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Misael Freitas dos Santos
Postgraduate Program in Forestry Sciences, State University of the Midwest of Parana, PR-153, Km 7, Irati, Parana State, Brazil, 84500-000
Afonso Figueiredo Filho
Postgraduate Program in Forestry Sciences, State University of the Midwest of Parana, PR-153, Km 7, Irati, Parana State, Brazil, 84500-000
João Ricardo Vasconcellos Gama
Postgraduate Program in Society, Nature and Development, Federal University of Western Para, Santarem, Para State, Brazil, 68035-110
Fabiane Aparecida de Souza Retslaff
Postgraduate Program in Forestry Sciences, State University of the Midwest of Parana, PR-153, Km 7, Irati, Parana State, Brazil, 84500-000
Daniele Lima da Costa
Postgraduate Program in Forestry Sciences, State University of the Midwest of Parana, PR-153, Km 7, Irati, Parana State, Brazil, 84500-000

Abstract

The objective of this study was to analyze the performance of species-specific equations (SSEs)  concerning  generic  ones  in  Annual  Production  Units  (GEAPUs)  and  in  a  Forest  Management  Area  (GEFMA)  in  the  Brazilian  Amazon.  A  total  of  29,119  trees  from  43  species  were  inventoried,  harvested,  and  volumetric  measurements  were  taken  in ten APUs, with 10% of this total being separated for validation and comparison of the selected equations. After selection and validation of the equations (GEFMA, GEAPUs and  SSEs)  they  were  compared  using  precision  statistics,  by  contrasting  estimated  and  observed volumes and by residual analysis. Precision statistics were clearly lower for the SSEs. Trend lines near the average observed volume were shown for the SSEs when the estimates were contrasted with the observations. The residuals generated by the SSEs  were  smaller  and  statistically  different  than  those  of  GEFMA  and  GEAPUs  for  the  majority of cases. The most important commercial species (M.  huberi) had its volume overestimated by 10.6, 9.3 and 3.0% when the GEFMA, the GEAPUs, and the SSEs were applied, respectively. Among the species that generally had very large trees, H. petraeumhad its volume underestimated by 15.7, 16.6 and 4.4% by the GEFMA, GEAPUs and SSEs, respectively. The greater precision of the SSEs is reflected in better forest management planning  decisions  with  respect  to  operational  and  economic  aspects.  These  results  show that besides being statistically valid, the SSEs are recommended for obtaining more precise estimates of commercial volume, especially since there is a great demand for reliable estimates for each individual species in forest management areas in the Amazon.

Article Details

Issue
Vol 26 No 3 (2020)
Section
Article
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