Silvics and Silviculture of Coastal Western Redcedar

116 Pages·2009·3.036 MB·English

by  Karel Klinka and David Brisco

S P E C I A L R E P O R T S E R I E S
11
Silvics and Silviculture
of Coastal Western Redcedar
A LITERATURE REVIEW
2009
Ministry of Forests and Range Forest Science Program
S P E C I A L R E P O R T S E R I E S
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

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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 redc edar 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
4.8 Dendrochronology ................................................... 46
4.9 Redcedar Dieback on Eastern Vancouver Island .......................... 47
5 Silviculture and Management ............................................. 52
5.1 Management Strategies ................................................ 52
5.2 Growth and Yield ..................................................... 54
5.3 Site and Species Selection .............................................. 57
5.4 Cutting and Regeneration of Redcedar Stands ............................ 62
5.5 Stand Management .................................................... 69
6 Large-scale Redcedar-focussed Research Initiatives ......................... 78
6.1 Imajo Studies ......................................................... 78
6.2 Salal–Cedar–Hemlock Integrated Research Program (SCHIRP) ............. 80
6.3 HyP3 Studies ......................................................... 82
v
7 Recommendations for Future Research .................................... 85
Literature Cited ............................................................. 90
Appendix
1 Site index curves and tables for coastal western redcedar ...................... 86
2 Levels and symptoms of nutrient deficiency ................................. 89
Tables
1 Mortality of planted redcedar seedlings according to study sites,
growing seasons, and light classes .......................................... 18
2 Relative occurrence of redcedar in subzones of the Costal Douglas-fir,
Coastal Western Hemlock, and Mountain Hemlock zones .................... 27
3 Vegetation units of the most productive coastal Redcedar –
Salmonberry order and their occurrence ................................... 31
4 Site series in the subzones of the CDF and CWH zones where redcedar
is considered a significant or potential climax species ......................... 35
5 Means of selected growth characteristics of 17 studied redcedar stands
examined for site quality and by stem analysis ............................... 54
6 Site index of redcedar in CWHdm subzone and CWHvm subzone
in relation to actual soil moisture and nutrient regime ........................ 55
7 Comparison of site index estimates of Kayahara et al. and SIBEC for
redcedar for selected CWHdm and CWHvm site series ....................... 56
8 Generalized edatopic grid showing actual soil moisture regime and nutrient
regime of the upland sites, floodplain, and sites with fluctuating water table
that are suitable for growing redcedar as a reliable crop species ................ 60
9 Reliability ranking of TIPSY yield output, by species .......................... 69
10 Interpretations of foliar macronutrient concentrations for redcedar ............... 75
11 A summary of projects funded by the Imajo Cedar Management
Fund 1997/98 to 2006/07 ................................................. 78
12 R edcedar site index estimates from old-growth and second-growth
stands from the CWHvh2 subzone .......................................... 83
Figures
1 The range of redcedar in British Columbia .................................. 1
2 Second-growth, western hemlock in the Malcolm Knapp Research Forest ....... 2
3 An undisturbed forest on upland rocky sites in the CWHvh subzone
consisting of western hemlock, mountain hemlock, lodgepole pine, redcedar,
and yellow-cedar ........................................................ 2
4 As with Douglas -fir, large, sound, clear, old-growth redcedar trees have
been most sought after in harvesting the coastal forest ........................ 2
5 A dense, immature, naturally regenerated stand of redcedar in the
Malcolm Knapp Research Forest ........................................... 4
6 One of the managed, older-immature, experimental stands of redcedar
in Great Britain .......................................................... 4
7 A fragment of a log cut 80 years ago in the Malcolm Knapp
Research Forest showing negligible decay ................................... 7
8 Salvaged wood of yellow-cedar and redcedar from leftover logs after
past cutting, stored in Sechelt and awaiting further processing ................. 7
vi
9 Decay class III downed redcedar log in an old-growth stand,
estimated to be 120 years old .............................................. 7
10 An unfinished canoe from a redcedar log amidst advance regeneration,
abandoned for unknown reasons some years ago ............................ 8
11 Culturally modified trees in varying degrees of decompostion are
often found in the coastal rainforest ........................................ 8
12 One of several totem poles in Kitwanga village, west-central British Columbia ... 9
13 This scenic drive through an old-growth redcedar stand in the Coquitlam
watershed resembles the experience from a visit to MacMillan Park on
Vancouver Island or Stanley Park in Vancouver .............................. 9
14 Redcedar makes an attractive ornamental tree especially when grown
alone or in small groups .................................................. 10
15 A redcedar hedge in Vancouver ............................................ 10
16 Forked or candelabra crowns in an old-growth redcedar stand,
often characteristic of old growth .......................................... 11
17 Interestingly, not all trees in a stand will develop these forked crowns ........... 11
18 One of the distinguishing features of redcedar can be extensive fluting
at the base, as seen on a burned snag and a sound log ........................ 12
19 Long, coarse, and persistent branches at the lower stem in a low-density stand ... 13
20 An excessively high number of long, coarse, and persistent upper and
middle crown branches in a low-density stand ................................ 13
21 The dense root system of an old redcedar established on a rock outcrop ......... 13
22 The very dense and profuse system of an old redcedar tree established in a
shallow soil over bedrock ................................................. 13
23 Root density of fine, medium, and coarse roots in the forest floor and two
mineral soil layers in hemlock, hemlock–redcedar, and redcedar stands ......... 14
24 In redcedar, a developing branch is often taller than a terminal ................ 15
25 Redcedar veglings rising from branches on a downed tree and fallen branches ... 16
26 Scattergram and regression line of total biomass and specific leaf area of
harvested redcedar seedlings on percent of above-canopy light three
growing seasons after planting ............................................. 18
27 A healthy and vigorous redcedar seedling 2 years after planting, protected by
Vexar tubing ............................................................ 22
28 Relationship between total needle monoterpenes and percent browsing by
clone in western redcedar grown at Fairservice Main, south Vancouver Island ... 22
29 Distinctly developed fluting in a redcedar tree that had established on a
downed, above-ground log ................................................ 23
30 Examples of dense, immature, naturally regenerated, pure redcedar stands
established after clearcutting and burning ................................... 24
31 Generalized edaphic amplitude of redcedar in the CWH zone in relation
to actual soil moisture and nutrient regimes ................................. 28
32 Skunk cabbage – redcedar communities typically occupy margins of
coastal lakes and depressions, forming a transition from non-forested
wetland to upland communities ........................................... 29
33 A very dry, rock outcrop site on Bowen Island ............................... 29
34 A chlorotic redcedar plantation on an N-deficient, salal-dominated,
old-growth cutover on northern Vancouver Island ........................... 29
vii
35 A markedly stratified structure is typical for mixed-species stands of
Douglas-fir and redcedar ................................................. 30
36 A stratified structure is typical for mixed-species stands of hardwoods
and redcedar ............................................................ 30
37 A low-density, old-growth stand of Sitka spruce, redcedar, western hemlock,
and Pacific silver fir on a lower, steep, seepage slope in the central
coastal mainland ........................................................ 32
38 A high-density, naturally regenerated, second-growth stand of western
hemlock and redcedar on a zonal site in the CWHvm subzone. ................ 32
39 An unmanaged mixed-species stand of redcedar and Pacific silver fir on a
moist, nutrient-rich site in the CWHvm subzone. ............................ 33
40 The bark of old redcedar trees is calcium-rich, often supporting corticolous
fern and bryophyte communities .......................................... 34
41 Redcedar stands on rocky sites can lessen erosion of shallow soils during
heavy rains ............................................................. 37
42 Redcedar stands, along with red alder, frequently occupy stream-edge sites
and help stabilize streambanks ............................................ 37
43 A fully stocked, uniform forest with a preponderance of old redcedar on a
second-order drainage in the Seymour watershed ............................ 40
44 One of the many old redcedar stands in the Capilano watershed
maintaining high density and uniform appearance ........................... 40
45 Natural regeneration of redcedar amidst bryophytes on a well-decayed
downed log near Tofino, Vancouver Island .................................. 41
46 Abundant advance regeneration of western hemlock in the shrub layer
under the canopy of redcedar in the Seymour watershed ..................... 41
47 A dense, naturally regenerated stand of redcedar with some western hemlock
and lodgepole pine on a burnt, cutover area in the CWHvh subzone ............ 42
48 Salmonberry – Red alder communities effectively prevent ingress of shade-
tolerant conifers; winter aspect and summer aspect of the same stand .......... 42
49 Scattered saplings of redcedar and western hemlock in the understorey of a
mid-seral Salmonberry – Red alder community ............................... 43
50 A windthrow-origin hemlock–Pacific silver fir stand on a zonal site in the
CWHvm subzone on northern Vancouver Island ............................ 43
51 An apparently truly old-growth western hemlock stand without redcedar on a
near-zonal site, and an apparently truly old-growth redcedar–hemlock stand on
a sloping zonal site in the CWHvm subzone on north Vancouver Island ........ 44
52 Chronology of redcedar age peaks and fire disturbance in the
Pacific Northwest ........................................................ 45
53 Redcedar occupying coarse talus deposits in the CWHvm subzone ............ 46
54 Responses function of redcedar residual chronology of ring-width indices
on 34 climatic parameters ................................................. 46
55 Redcedar dieback observed from highway near Qualicum Beach,
Vancouver Island ........................................................ 49
56 Understorey of Douglas-fir–dominated stand on a zonal site near
Qualicum Beach, Vancouver Island ........................................ 49
57 Root rot on redcedar, exposed by recent windthrow in association with
Douglas-fir and bigleaf maple .............................................. 49
viii
58 Vigorous saplings established as a pure stand on a water-surplus site
south of Bowser, Vancouver Island ......................................... 49
59 An advanced regeneration stage of a redcedar plantation on a poor,
CWHvm1/01 HwCw–Salal site in the Suquash basin ......................... 53
60 A naturally regenerated, seral redcedar–hemlock stand on a
water-deficient, rocky crest after cutting and fire; old-growth
redcedar–hemlock stands on rocky slope ................................... 58
61 Dieback of redcedar under prolonged very wet conditions at the
lake margin in the CWHvm subzone ....................................... 59
62 An open-canopy, old-growth stand of redcedar, yellow-cedar, and
western hemlock on a moist site in the CWHvh subzone ........................ 59
63 Projection of the zone of minimum growth suppression for western redcedar
under a canopy of 10-year-old black cottonwood for both black cottonwood
and redcedar and growth rates characteristic of the CWHxm/08 site type ....... 61
64 Height–age relationship for redcedar saplings stratified into two growing
zones at the 10-year-old cottonwood on moist and rich sites in the
CWHdm subzone ....................................................... 61
65 A pure, immature stand of redcedar that originated following fire on a
colluvial slope in the CWHvm subzone is one of many corroborating
adaptations of redcedar regeneration to fire disturbance ...................... 64
66 Dense natural regeneration of redcedar on the exposed mineral soil of a
roadcut ................................................................. 65
67 Standard stocktypes available for western redcedar and yellow-cedar,
with associated characteristics, coded designations, average height, and
root collar diameter ...................................................... 66
68 Canopy of a dense, naturally regenerated, fire-origin, immature stand of
western hemlock and redcedar on a sloping zonal site in the CWHvm1 variant. .. 69
69 Scattergram and fitted regression line of estimated shrub cover on estimated
canopy cover ............................................................ 70
70 Stand density management diagrams for both natural and planted stands
of redcedar ............................................................. 71
71 A half-shade crown and three-quarters shaded crown of immature
redcedar trees showing long, coarse, and persistent branches on the
unshaded portion of the stem ............................................. 74
72 Excellent stem form and high, narrow live-crowns of redcedar trees
that have developed in high-density conditions ............................. 74
73 A dense ericaceous shrub layer on one of the many salal- and
blueberry-dominated cedar-hemlock cutovers in the CWHvh subzone ......... 76
74 A low-productivity, open-canopy, old-growth western hemlock–redcedar
mixture on very moist, nutrient-poor sites .................................. 80
ix