SPECIAL REPORT SERIES Silvics and Silviculture of Coastal Western Redcedar A LITERATURE REVIEW 2 0 0 9 Ministry of Forests and Range Forest Science Program SPECIAL REPORT SERIES Silvics and Silviculture of Coastal Western Redcedar A LiteratURE REVIEW Karel Klinka and David Brisco Ministry of Forests Ministry of Forests and Range Forest Science Program The use of trade, firm, or corporation names in this publication 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 report are presented as information only. Funding assistance does not imply endorsement of any statements or information contained herein by the Government of British Columbia. Library and Archives Canada Cataloguing in Publication Main entry under title: Silvics and silviculture of coastal western redcedar : a literature review / Karel Klinka and David Brisco. (Special report series, issn 0843-6452 ; 11) Includes bibliographical references. isbn 978-0-7726-6110-4 1. Western Redcedar - British Columbia. 2. Forests and forestry - British Columbia. 3. Forest management - British Columbia. I. British Columbia. Ministry of Forests and Range. II. Title. III. Series: Special report (British Columbia. Ministry of Forests and Range) ; 11. sd397.w46k55 2009 634.9'756509711 c2009-900862-9 Citation: Klinka, K. and D. Brisco. 2009. Silvics and silviculture of coastal western redcedar: a literature review. B.C. Min. For. Range, For. Sci. Prog., Victoria, B.C. Spec. Rep. Ser. 11. www.for.gov.bc.ca/hfd/pubs/Docs/Srs/Srs11.htm Prepared by Karel Klinka Forest Sciences Department University of British Columbia 3041 – 2424 Main Mall Vancouver, BC v6t 1z4 David Brisco Ecotope Consulting Services 269 Gordonhorn Crescent Kamloops, BC v2e 1g5 © 2009 Province of British Columbia When using information from this or any Forest Science Program report, please cite fully and correctly. Copies of this report may be obtained, depending upon supply, from: Crown Publications, Queen’s Printer PO Box 9452 Stn Prov Govt 563 Superior Street, 2nd Flr Victoria, BC V8W 9V7 1 800 663-6105 www.crownpub.bc.ca For more information on Forest Science Program publications, visit: www.for.gov.bc.ca/scripts/hfd/pubs/hfdcatalog/index.asp EXECUTIVE SUMMARY This report has been produced at the given in consideration of possible changing request of B.C. Forest Service staff interest- climatic conditions, as well as details regard- ed in the future of western redcedar on the ing the first study on redcedar dieback on coast of British Columbia, and provides a eastern Vancouver Island. summary of current knowledge regarding The silviculture section includes this species. In response to their concerns, management-related topics such as growth we have brought together all pertinent and yield, regeneration strategies, and information related to the establishment intensive silviculture options. When the and growth of redcedar scattered in various decision to establish redcedar has been publications and journals, supplemented made, we propose several principles to with visuals to express the statements and guide management strategies. This subsec- support the inferences made in this report. tion is followed by growth and yield infor- The first three sections introduce our mation indicating potential productivity approach to the report and summarize of redcedar. Considering the impact of well-known information about the red- climate change, we updated the list of cedar resource and the uses of redcedar coastal site series by including only those products. The fourth, silvics section sites that are thought to provide for a reli- describes morphological and reproduction able growth as a timber crop. Suitable characteristics, tolerance, damaging agents, methods of cutting to promote the regen- growth development patterns, and genetics. eration of redcedar, including site prepara- In this section, we include summaries of tion, potential for natural regeneration, several studies investigating redcedar stem and aspects of planting are described. The form and root characteristics. Survival and stand management subsection discusses growth of redcedar in relation to light spacing options, pruning, and thinning, availability has a direct connection to its and introduces the stand density manage- growth development patterns. ment diagram. The fertilization subsection The ecology section describes climatic is based primarily upon the results amplitude of redcedar, its occurrence within achieved in the Salal–Cedar–Hemlock biogeoclimatic units, edaphic amplitude, and Integration Research Program (SCHIRP). associated tree species. A review of vegeta- Three prominent and ongoing redcedar tion and site classification of redcedar eco- research initiatives are summarized in the systems is presented in a tabular format. The last chapter of this document: Imajo studies subsequent discussion describes the ecologi- funded through the University of British cal role of redcedar, which includes the pos- Columbia Forest Program, the SCHIRP sible modification of soil properties, increase Program funded co-operatively through of community diversity, self-pruning of the Ministry of Forests and Range and overstorey crop tree species, and suppression Western Forest Products, and the HyP3 of under storey vegetation. We also attempt Project funded through the Ministry of to elucidate the origin and perpetuation of Forests and Range Forest Science Program. old-growth redcedar stands, and conclude For this first initiative we provide only a list that in the CWH zone the species may have of recent studies supported by the Imajo a polyclimax role. General succession trends fund. However, the other two research pro- after disturbance of old-growth redcedar grams merit additional attention and dis- stands by clearcutting and windthrow are cussion because they convey applicable described, and the origin of many of these information about salal- dominated and stands in southern coastal British Columbia is low-productivity sites found throughout attributed to fire disturbance. Site selection the northern portion of the redcedar range recommendations for coastal redcedar are of coastal British Columbia. iii PREFACE The intent of this report is to present the other topics. We have aimed to present the most current and available information available knowledge in a manner compre- concerning establishment and growth of hensible to those determined to restore redcedar in the coastal region of British redcedar to the role it deserves in the Columbia. The report represents a synthe- coastal forests of British Columbia. We sis of selected information from several hope that those users will find this report major sources, such as Minore (1983, a practical and useful tool, facilitating 1990), Smith, N.J. (1988), Wiggins (1999), their promotion of redcedar as a key and Klinka et al. (2000), and from several component of our future forests. recent research studies carried out at the It should be noted that any mention of Forest Sciences Department, University of particular manufacturers or brands are British Columbia. The report is not a com- solely intended for simplicity for the reader. prehensive review because we have No products described within this docu- focused on the information pertinent to ment are explicitly endorsed by the regeneration and growth of redcedar, and authors to the exclusion of other suitable have limited the information related to products. NOTES ON TAXONOMY AND NOMENCLATURE Thuja is a small genus limited to six species common name of western redcedar (just worldwide, with only two species native to two words, abbreviated to redcedar in the North America: eastern white cedar text) is preferred to western red cedar, and (T. occidentalis) and western redcedar the full scientific citation is Thuja plicata (T. plicata). Following Little (1979), the (Donn ex D.Don in Lamb.). ACKNOWLEDGEMenTS The authors thank Louise de Montigny, are noted and appreciated. Thanks are Hal Reveley, and Alan Banner of the also due to Katrine Evans of the Dean’s B.C. Ministry of Forests and Range for office, Faculty of Forestry, University of their interest and support of this project. British Columbia, for preparing the list of Additional credit must go to Christine Imajo-supported studies, and to all Forest Chourmouzis, who significantly improved Service personal who reviewed earlier early drafts of this report with her thor- drafts of this report. Unless otherwise ough editing, suggestions, and comments. noted, all photographic images were pro- The contributions and suggestions from vided by Karel Klinka. Gordon Weetman and Jaroslav Dobry iv CONTENTS Executive Summary. iii Preface. iv Notes on Taxonomy and Nomenclature. iv Acknowledgements. iv 1 Introduction. 1 2 A Prized Resource. 6 2.1 Wood Properties. 6 2.2 Wood Products. 6 2.3 First Nations Usage . 8 2.4 Spiritual and Aesthetic Aspects. 9 3 Silvics. 11 3.1 Morphological Characteristics. 11 3.2 Reproduction . 15 3.3 Tolerances. 16 3.4 Survival and Growth of Redcedar Seedlings under Varying Light Conditions . 17 3.5 Damaging Agents. 19 3.6 Growth Development Patterns. 23 3.7 Genetics. 24 4 Ecology. 27 4.1 Climatic Amplitude. 27 4.2 Occurrence in Biogeoclimatic Units. 27 4.3 Edaphic Amplitude. 28 4.4 Associated Tree Species . 30 4.5 Vegetation and Site Classification. 31 4.6 Ecological Role. 34 4.7 Succession. 39