scholarly journals Multiple-pathway succession in coastal Tsuga heterophylla, Thuja plicata, and Abies amabilis forests on northeastern Vancouver Island, British Columbia

2014 ◽  
Vol 44 (10) ◽  
pp. 1145-1155 ◽  
Author(s):  
Adrian Weber ◽  
J.P. (Hamish) Kimmins ◽  
Benjamin Gilbert ◽  
Yueh-Hsin Lo ◽  
Juan A. Blanco
Keyword(s):  
Natural Disturbance ◽  
Vancouver Island ◽  
Tsuga Heterophylla ◽  
Thuja Plicata ◽  
Silver Fir ◽  
Frequency Distributions ◽  
Abies Amabilis ◽  
Forest Practices ◽  
Adult Trees ◽  
Disturbance Hypothesis

Sustainable forest practices are often designed to mimic natural disturbance and successional processes, yet succession is poorly understood in many ecosystems. On northeastern Vancouver Island, the “disturbance hypothesis” is a widely assumed succession model asserting that shade-tolerant western redcedar (Thuja plicata Donn ex D. Don) and the ericaceous shrub salal (Gaultheria shallon Pursh) invade and colonize highly productive western hemlock (Tsuga heterophylla (Raf.) Sarg.) – Pacific silver fir (Abies amabilis Douglas ex J. Forbes) stands (HA) on zonal sites in the absence of stand-replacing wind disturbance. This leads to the development of low-productivity, low-density, uneven-aged, open-crowned redcedar–hemlock–salal stands (CH). In conflict with this model, old, apparently stable HA stands lacking redcedar can be found on such sites as well. We sought evidence for the predicted transition to CH stands by examining stand composition, crown closure, tree size class frequency distributions, salal cover, and redcedar establishment on young HA (∼90 years old), old HA (>160 years), and CH (>160 years) stands. When adjacent to a redcedar stand, young HA stands had fewer redcedar seedlings but more redcedar adult trees than old HA stands. However, redcedar abundance did not differ between young and old HA stands at distances further than 10 m from adjacent redcedar stands. This could indicate that redcedar recruits into HA stands at stand establishment and that redcedar seedling establishment is low under the thick canopy of young HA stands. The chronosequence data also suggest that both old HA and CH stands are self-replacing stand types in these forests, contrary to the disturbance hypothesis. We develop a new, multipathway model for this ecosystem that is based on the chronosequence data and life-history traits of the focal tree species and suggest that disturbance plays a role opposite to the equilibrium model.

Factors limiting the early survivorship of Thuja plicata on northern Vancouver Island, British Columbia

2003 ◽  
Vol 33 (5) ◽  
pp. 854-861 ◽  
Author(s):  
Adrian Weber ◽  
Benjamin Gilbert ◽  
JP (Hamish) Kimmins ◽  
C E Prescott
Keyword(s):  
Forest Floor ◽  
Seedling Survival ◽  
Forest Edge ◽  
Vancouver Island ◽  
Tsuga Heterophylla ◽  
Thuja Plicata ◽  
Local Soil ◽  
Early Seedling ◽  
Successional Species ◽  
Thuja Plicata Donn

Western redcedar (Thuja plicata Donn ex D. Don), a late successional species on northern Vancouver Island, has a low seedling survival in mature hemlock (Tsuga heterophylla (Raf.) Sarg.) – amabilis fir (Abies amabilis (Dougl. ex Loud.) Dougl. ex J. Forbes) (HA) stands. Shade, moss competition, and substrate were tested as causes of low cedar establishment. Cedar seeds were sown on reference and local soils isolated from surrounding soil, on nonisolated local soil, and on forest floor with moss removed. Western hemlock, amabilis fir, and cedar seeded on forest floor acted as controls. Treatments were implemented in the HA interior and the HA–clearcut edge, with soil treatments also implemented in clearcuts. Germinants and very young seedlings of cedar have a low leaf area of needle-like primary foliage. Cedar development of secondary foliage (the scale foliage normally associated with this species) was correlated with greater vigour and growth. Secondary foliage developed in the rankings forest edge and clearcut > forest interior, and reference isolated soil > local isolated soil > nonisolated local soil. Seedling survival rankings were edge > interior, and amabilis fir > hemlock > cedar on soil and with moss removed > cedar on forest floor. Cedar and amabilis fir showed a smaller growth response to light than hemlock. The results indicate that cedar, normally considered a late successional species, needs disturbance for early seedling establishment and survival and thus has some characteristics of an early seral species.

Origin, development, and dynamics of coastal temperate conifer rainforests of southern Vancouver Island, Canada

2002 ◽  
Vol 32 (2) ◽  
pp. 353-372 ◽  
Author(s):  
K J Brown ◽  
R J Hebda
Keyword(s):  
Late Glacial ◽  
Vancouver Island ◽  
Tsuga Heterophylla ◽  
Fire Disturbance ◽  
Thuja Plicata ◽  
Quercus Garryana ◽  
Mixed Conifer Forests ◽  
Forested Ecosystems ◽  
Increasing Precipitation ◽  
Early Late

Pollen and charcoal from East Sooke Fen, Pixie Lake, and Whyac Lake were used to reconstruct the post glacial vegetation, climate, and fire-disturbance history across a precipitation gradient on southern Vancouver Island, British Columbia. An open Pinus woodland covered the landscape in the early late-glacial interval. Fires were absent under a cool and dry climate. Closed mixed conifer forests of Pinus, Picea, Abies, Tsuga heterophylla (Raf.) Sarg., and Tsuga mertensiana (Bong.) Carrière replaced the Pinus biogeochron in the late late-glacial interval. Fires became more common even though climate was cool and moist. Open Pseudotsuga menziesii (Mirb.) Franco forests expanded westward during the warm dry early Holocene, though closed Picea and Tsuga heterophylla forests grew in the wettest part of the area at Whyac Lake. Modern precipitation gradients likely originated at this time. Fires occurred in forested ecosystems, although East Sooke Fen at the driest end of the gradient experienced less fire. The middle and late Holocene was characterized by increasing precipitation and decreasing temperature, respectively. Quercus garryana Dougl. stands spread westward during the mid-Holocene. Extant closed Tsuga heterophylla and Cupressaceae (Thuja plicata Donn. ex D. Don) forests arose in the wetter part of the gradient, whereas Pseudotsuga forests occupied drier eastern areas. During this interval, fires were rare in wet western regions but apparently more common in dry eastern regions.

The phytogeography of Oxalis oregana in British Columbia

1984 ◽  
Vol 62 (7) ◽  
pp. 1561-1563
Author(s):  
R. T. Ogilvie ◽  
R. J. Hebda ◽  
Hans L. Roemer
Keyword(s):  
British Columbia ◽  
Vancouver Island ◽  
Tsuga Heterophylla ◽  
Picea Sitchensis ◽  
Native People ◽  
Thuja Plicata ◽  
Sea Levels ◽  
Island Populations ◽  
Queen Charlotte Islands ◽  
Polystichum Munitum

The occurrence of Oxalis oregana Nutt. in British Columbia is documented for five localities on the west coast of Vancouver Island and one locality in the Queen Charlotte Islands. The Oxalis populations grow in alluvial Tsuga heterophylla – Picea sitchensis – Thuja plicata – Polystichum munitum forest communities. Rhizomatous reproduction was recorded in all populations and flowering in two of the Vancouver Island populations. Three of the populations may be less than 3000 years old because they would have been inundated by higher sea levels during the middle Holocene. Possible introduction of plants by native people from the Olympic Peninsula, WA, is discussed.

Studies on periderm. II. Anthocyanidins in secondary periderm tissue of amabilis fir, grand fir, western hemlock, and western red cedar

1969 ◽  
Vol 47 (9) ◽  
pp. 1419-1422 ◽  
Author(s):  
D. B. Mullick
Keyword(s):  
Tsuga Heterophylla ◽  
Free State ◽  
Western Hemlock ◽  
Thuja Plicata ◽  
Abies Grandis ◽  
Abies Amabilis ◽  
Red Cedar ◽  
Western Red Cedar ◽  
Thuja Plicata Donn

By using a mild method, which precludes the possibility of pigment hydrolysis during extraction and processing, the occurrence of anthocyanidins in the free state has been detected in the normal secondary periderm tissues (rhytidomal region) of amabilis fir (Abies amabilis (Dougl.) Forbes), grand fir (Abies grandis (Dougl.) Lindl.), western hemlock (Tsuga heterophylla (Raf.) Sarg.), and western red cedar (Thuja plicata Donn.). Cyanidin was present in all species. Pelargonidin was present in western hemlock and most likely also in western red cedar.

Nitrogen fixation in coarse woody debris of Thuja plicata and Tsuga heterophylla forests on northern Vancouver Island

2003 ◽  
Vol 33 (9) ◽  
pp. 1670-1682 ◽  
Author(s):  
Andreas Brunner ◽  
J P Kimmins
Keyword(s):  
Nitrogen Fixation ◽  
Coarse Woody Debris ◽  
Forest Type ◽  
Nitrogenase Activity ◽  
Woody Debris ◽  
Vancouver Island ◽  
Tsuga Heterophylla ◽  
Thuja Plicata ◽  
Ambient Conditions ◽  
Old Growth Forest

Asymbiotic nitrogenase activity in coarse woody debris was measured using the acetylene reduction assay under ambient conditions in three different stand ages (5, 53, and 88 years old) of an unmanaged second-growth Tsuga heterophylla (Raf.) Sarg. – Abies amabilis (Dougl. ex Loud.) Dougl. ex J. Forbes forest type and a Thuja plicata Donn. ex D. Don – Tsuga heterophylla old-growth forest on northern Vancouver Island, British Columbia, Canada. Four different decay classes of coarse woody debris, different species in the early decay stages, and sapwood and heart wood were sampled separately. Mean nitrogenase activity ranged between 1.3 and 19.5 nmol C2H4·d–1·(g dry mass)–1, with an overall mean of 5.7. High variability of the activity rates between logs and within logs was observed in all four stands. Mean activity rates were, in most cases, significantly different between decay classes, with generally increasing nitrogenase activity with the progress of decay. Moisture content of the samples was a good predictor of nitrogenase activity and could explain differences between decay classes. Only minor differences in nitrogenase activity were found between the different stands. Estimates of nitrogen fixation ranged from 1.0 to 2.1 kg N·ha–1·year–1, the magnitude of these values depending more on the mass of coarse woody debris substrate available for asymbiotic nitrogen-fixing bacteria (103–158 t·ha–1 in this study) than on differences in nitrogenase activity rates. The measured nitrogenase activity and the resultant estimates of nitrogen fixation are among the highest values reported in the literature.

Old-Growth Douglas-Fir and Western Hemlock: A 36-Year Record of Growth and Mortality

1987 ◽  
Vol 2 (4) ◽  
pp. 111-114 ◽  
Author(s):  
Dean S. DeBell ◽  
Jerry F. Franklin
Keyword(s):  
Volume Growth ◽  
Tsuga Heterophylla ◽  
Douglas Fir ◽  
Western Hemlock ◽  
Thuja Plicata ◽  
Silver Fir ◽  
Pinus Monticola ◽  
White Pine ◽  
Old Growth ◽  
Stand Volume

Abstract Growth and mortality were measured at 6-year intervals in a 1,180-acre old-growth stand in southwestern Washington. Principal tree species were Douglas-fir (Pseudotsuga menziesii), western hemlock (Tsuga heterophylla), Pacific silver fir (Abies amabilis), western redcedar (Thuja plicata), and western white pine (Pinus monticola). They composed 59, 27, 6, 6, and 1%, respectively, of the total cubic volume (13,290 ft³) in 1947. Gross volume growth averaged 94 ft³ per acre per year, and mortality averaged 86 ft³ per acre per year. Net growth was therefore minimal, and total stand volume remained nearly constant for 36 years. Douglas-fir, which accounted for only one-third of the gross growth and nearly one-half of the mortality, is losing dominance to western hemlock, which provided nearly one-half the gross growth and only 28% of the mortality. Pacific silver fir increased in importance in the lower canopy and composed 60% of the in-growth. Thus, although net gain in timber volume was nil, substantial changes occurred in stand characteristics during the 1947-1983 period. West. J. Appl. For. 2(4):111-114, October 1987.

Late-glacial and postglacial vegetation history at Bear Cove Bog, northeast Vancouver Island, British Columbia

1983 ◽  
Vol 61 (12) ◽  
pp. 3172-3192 ◽  
Author(s):  
Richard J. Hebda
Keyword(s):  
British Columbia ◽  
Forest Canopy ◽  
Vegetation History ◽  
Late Glacial ◽  
Vancouver Island ◽  
Tsuga Heterophylla ◽  
Picea Sitchensis ◽  
Pteridium Aquilinum ◽  
Thuja Plicata ◽  
Blanket Bog

At 13 630 ± 310 BP (WAT-721) Port Hardy is the earliest area known to have been deglaciated at the end of the Fraser Glaciation on Vancouver Island. Pollen and macrofossil analyses of two cores from a basin–blanket bog show that about 14 000 years ago Pinus contorta, Alnus, and Pteridium aquilinum formed pioneering vegetation typical of post-ice environments on the Pacific Northwest coast. Climate is interpreted to have been relatively cool and dry. Picea sitchensis – Tsuga mertensiana forest succeeded at about 11 500 BP and persisted until about 10 000 BP. Climate was cool, moist, and maritime. Warming at about 10 000 BP permitted Tsuga heterophylla gradually to replace T. mertensiana. At 8800 BP Pseudotsuga menziesii migrated into the area and together with P. sitchensis dominated the forest. Abundant Pteridium aquilinum spores suggest forests were open. During the interval 8800 to 7000 BP the climate was warmer and drier than at present because today forests with Pseudotsuga do not extend as far north as Port Hardy. During this warm time, shallow ponds dried out. By 7000 BP Pseudotsuga declined and T. heterophylla and P. sitchensis dominated forests. Climate became wetter and cooler than in the preceding period but not as cool as today. About 3000 BP Cupressaceae, presumably both Thuja plicata and Chamaecyparis nootkatensis, shared the forest canopy with T. heterophylla. Sphagnum growth and bog development occurred after 7000 BP as climate became moister. The vegetation sequence described is a "maritime" type similar to sequences on the west coast of Washington State but unlike those from the Fraser Lowland. The xerothermic interval was of short duration between 8800 and 7000 BP but was expressed clearly in this area of moist maritime climate and therefore must have been of considerable amplitude. Vegetation differences between coastal and inland southwestern British Columbia were established by 11 500 BP.

Distribution of leaf orientations in six conifer species

2001 ◽  
Vol 79 (4) ◽  
pp. 389-397 ◽  
Author(s):  
Hugh J Barclay
Keyword(s):  
Pseudotsuga Menziesii ◽  
Pinus Contorta ◽  
Goodness Of Fit ◽  
Tsuga Heterophylla ◽  
Picea Sitchensis ◽  
The Other ◽  
Thuja Plicata ◽  
Leaf Angle ◽  
Conifer Species ◽  
Abies Grandis

Leaf angle distributions are important in assessing both the flexibility of a plant's response to differing daily and seasonal sun angles and also the variability in the proportion of total leaf area visible in remotely sensed images. Leaf angle distributions are presented for six conifer species, Abies grandis (Dougl. ex D. Don) Lindl., Thuja plicata Donn. ex D. Don, Tsuga heterophylla (Raf.) Sarg., Pseudotsuga menziesii (Mirb.) Franco, Picea sitchensis (Bong.) Carr. and Pinus contorta Dougl. ex Loud. var. latifolia. The leaf angles were calculated by measuring four foliar quantities, and then the distributions of leaf angles are cast in three forms: distributions of (i) the angle of the long axis of the leaf from the vertical for the range 0–180°; (ii) the angle of the long axis of the leaf for the range 0–90°; and (iii) the angle of the plane of the leaf for the range 0–90°. Each of these are fit to the ellipsoidal distribution to test the hypothesis that leaf angles in conifers are sufficiently random to fit the ellipsoidal distribution. The fit was generally better for planar angles and for longitudinal angles between 0° and 90° than for longitudinal angles between 0° and 180°. The fit was also better for Tsuga heterophylla, Pseudotsuga menziesii, Picea sitchensis, and Pinus contorta than for Abies grandis and Thuja plicata. This is probably because Abies and Thuja are more shade tolerant than the other species, and so the leaves in Abies and Thuja are preferentially oriented near the horizontal and are much less random than for the other species. Comparisons of distributions on individual twigs, whole branches, entire trees, and groups of trees were done to test the hypothesis that angle distributions will depend on scale, and these comparisons indicated that the apparent randomness and goodness-of-fit increased on passing to each larger unit (twigs up to groups of trees).Key words: conifer, leaf angles, ellipsoidal distribution.

STUDIES IN FOREST PATHOLOGY: VII. DECAY IN WESTERN HEMLOCK AND FIR IN THE FRANKLIN RIVER AREA, BRITISH COLUMBIA

1949 ◽  
Vol 27c (6) ◽  
pp. 312-331 ◽  
Author(s):  
D. C. Buckland ◽  
R. E. Foster ◽  
V. J. Nordin
Keyword(s):  
British Columbia ◽  
Tsuga Heterophylla ◽  
Western Hemlock ◽  
Forest Pathology ◽  
Abies Amabilis ◽  
Armillaria Mellea ◽  
Forest Region ◽  
Volume Increment ◽  
Juan De Fuca

An investigation of decay in western hemlock (Tsuga heterophylla (Raf.) Sarg.) and fir (mainly Abies amabilis (Loud.) Forb.) in the Juan de Fuca forest region of British Columbia has shown that the major organisms causing root and butt rots are the same in both species. These are Poria subacida (Peck) Sacc., Fomes annosus (Fr.) Cke., Armillaria mellea Vahl ex Fr., Polyporus sulphureus Bull. ex Fr., and P. circinatus Fr. Those organisms causing trunk rots of western hemlock, in decreasing order of importance, are Fomes pinicola (Sw.) Cke., F. Pini (Thore) Lloyd, Stereum abietinum Pers., Fomes Hartigii (Allesch.) Sacc. and Trav., and Hydnum sp. (H. abietis). These same organisms causing trunk rots of fir, in decreasing order of importance, are Fomes pinicola, Stereum abietinum, Hydnum sp. (H. abietis), Fomes Pini, and Fomes Hartigii. The logs of 963 western hemlock were analyzed in detail. Maximum periodic volume increment was reached between 225 and 275 years of age. Maximum periodic volume increment was reached between 275 and 325 years of age in the 719 fir that were analyzed. Scars were the most frequent avenue of entrance for infection. In 59% of the cases of infection studied the fungus had entered through wounds.

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