SIBEC Site Index Estimates in Support of Forest Management in British Columbia - Technical Report 004

Sep 21, 2026

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In response to a request by the Chief Forester of British Columbia, this report evaluates the accuracy (unbiasedness) of Site Index by Biogeoclimatic Ecosystem Classification (SIBEC) site series estimates for use in supporting allowable annual cut (AAC) determinations. Using data from the Old Growth Site Index project, the first approximation SIBEC estimates show less bias than inventory-based site index estimates for old-growth stands. The study concludes first and second approximation SIBEC estimates are suitable for AAC and related timber decisions such as silvicultural investments. Productivity estimates in the second approximation rely on minimum sample size and known precision, with ongoing sampling needed to calibrate the model and improve application for resource management.

LanguageEnglish

CategoryResearch & Report

FormatPDF

Pages24

Reading Time1 h 0 min

AccessFree to download

Abstract

Acknowledgements

Introduction

The SIBEC Project

Data Sources

Methods

Results

Unbiasedness of the SIBEC estimates

Precision of the SIBEC estimates

Discussion

Conclusions

Tables

Figures

Appendices

Literature Cited

2003 # SIBEC Site Index Estimates in Support of Forest Management inBritish Columbia SIBEC Site Index Estimates in # Support of Forest Management inBritish Columbia Shirley Mah and Gordon Nigh NOTE:The Technical Report Series supersedes the Working Paper Series.Working Paper 64,published 2002,was the last of that series. | The use of trade,frm,or corporation names in thispublication is for the information and
convenience of the reader.Such use does not constitute an official endorsement or approval
by the Government of British Columbia of any product or service to the exclusion of any
others that may also be suitable.Contents of this reportare presented for discussion purposes
only.Funding assistance does not imply endorsement of any statements or information con-
tained herein by the Government of British Columbia. | | --- | National Library of CanadaCatalogingin Publication Data Mah,Shirley SIBEC sie indexestimates in support of forest management in British Columbia (Technical report;004) Includes bibliographical references:p.ISBN O-7726-4910-3 1.Site index(Forestry)-British Columbia.2.Forests and forestry-BritishColumbia-Mensuration.3.Trees-British Columbia-Growth.4.Forest productivity ·BritishColumbia.1.Nigh Gordon D.(Gordon Donald),1956·.II.Title.IV.Series:Technical report(British Columbia.Forest Science Program);004 C2003-960033-5 634-9'285 SD396.M432003 Citation: Mah,S.andG.D.Nigh.2003.SIBEC site index estimates in support o forest managementin British Columbia.Res.Br.B.C.Min.For.Victoria,B.C.Tech.Rep.004.www.for.gov.bc.ca/hfd/pubs/Docs/Tr/Troo4.htm Copiesof this report may be obtained,depending on supply from:Crown Publications521 Fort StreetVictoria,BCv8w IE7Phone:(250)386-4636email:crown@pinc.comwww.crownpub.bc.ca For more information on Forest Science Program publications,visit our web site atwww.for.gov.bc.ca/hfd/pub/index.htm 2003 Province of British Columbia When using information from this or any Forest Scicnce Program report,please cite fully and correctly. ABSTRACT In response to a request by the Chief Forester of British Columbia,weevaluated the accuracy(unbiasedness)of the Site Index by BiogeoclimaticEcosystem Classification site series(SIBEC)estimates for use in supportingallowable annual cut(AAc)determinations.Using data from the Old GrowthSite Index project,we found that the first approximation SIBECestimatesare less biased than the site index estimates used in the forest inventory forold-growth stands.We therefore concluded that the first and second approxi-mation sIBEC estimates are suitable for supporting AACdeterminations andother timber management decisions(such as silvicultural investments).Es-timates of site productivity in the second approximation SIBEC estimates arebased on a minimum sample size and have a known level of precision.SIBECestimates of productivity are generally higher than inventory estimates ofproductivity for old-growth stands.Ongoing SIBEC sampling is required tocalibrate the SIBEC model.This wil further improve the qualityof the esti-mates for application in resource management. ACKNOWLEDGEMENTS We thank John Barker,Jim Thrower,lan Cameron,Eleanor McWilliams,Guillaume Therien,David Carson,Darrell Errico,Peter Ott,Vera Sit,JannaJessee,Albert Nussbaum,Chris Fletcher,Pat Martin,and Rob Drummond forvaluable review comments.We also thank Del Meidinger,Ray Coupé,DennisLloyd,and Allen Banner for their helpful review of an earlier draft. Digitized by the Internet Archivein 2014 https://archive.org/details/sibecsiteindexes00mahs Abstract………………………………………………………………………………………………………………………………………………iii Acknowledgements…………………………………………………………………………………………………………………………iii Introduction…………………………………………………………………………………………………………………………1 The SIBEC Project…………………………………………………………………………………………………………………1 Data Sources …………………………………………………………………………………………………………………………2

FAQs

What problem does the report address for British Columbia’s forest management?

The report evaluates whether SIBEC site index estimates are reliable enough to support allowable annual cut (AAC) determinations, and whether evidence can show improved accuracy across stand types and ages.

How does the report assess the accuracy of SIBEC estimates?

It evaluates accuracy using unbiasedness, comparing SIBEC site index estimates with forest inventory site index estimates for old-growth stands using data from the Old Growth Site Index project.

What conclusions are made about using SIBEC estimates for AAC and related decisions?

The report concludes that first and second approximation SIBEC estimates are suitable for supporting AAC determinations and other timber management decisions, while ongoing SIBEC sampling is needed to calibrate the model and improve estimate quality.

Sep 21, 2026

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