Palynology and paleoecology of postglacial sediments in an anoxic basin, Saanich Inlet, British Columbia

1983 ◽  
Vol 20 (5) ◽  
pp. 873-885 ◽  
Author(s):  
Linda E. Heusser
Keyword(s):  
British Columbia ◽  
Pinus Contorta ◽  
Tsuga Heterophylla ◽  
Douglas Fir ◽  
Western Hemlock ◽  
Thuja Plicata ◽  
Alnus Rubra ◽  
Red Cedar ◽  
Saanich Inlet ◽  
Anoxic Basin

Varved, black clayey silts deposited in the marine waters of Saanich Inlet yield unusually abundant and diverse pollen assemblages derived from the coastal Douglas-fir (Pseudotsuga) and western hemlock (Tsuga heterophylla) forests of southwestern British Columbia. The 12 000 year palynological record chronicles the development of vegetation since ice left Saanich Inlet: the succession of pine (Pinus contorta) and alder (Alnus rubra) woodlands by forests characterized by Douglas-fir and oak (Quercus) and later by western hemlock and red cedar (Thuja plicata). Rapid deposition of annual layers of pollen, charcoal, and other terrigenous particles provides detailed evidence of changes in land use during the past few hundred years: settlement, logging, farming, and urbanization. Vegetational and climatic changes inferred from pollen spectra in the marine sediments of Saanich Inlet compare favorably with changes inferred from correlative pollen assemblages previously described from adjacent parts of Vancouver Island and the Fraser River valley.

Life History and Habits of Pseudohylesinus nebulosus (Leconte) (Coleoptera: Scolytidae) in the Interior of British Columbia

1956 ◽  
Vol 88 (5) ◽  
pp. 197-202 ◽  
Author(s):  
J. Walters ◽  
L. H. McMullen
Keyword(s):  
British Columbia ◽  
Pinus Ponderosa ◽  
Tsuga Heterophylla ◽  
Douglas Fir ◽  
Western Hemlock ◽  
Thuja Plicata ◽  
Western North America ◽  
The West ◽  
Red Cedar ◽  
Yellow Pine

The Douglas-fir hylesinus, Pseudohylesinus nebulosus (Leconte), is a common bark beetle in western North America from British Columbia to Mexico. Although Douglas fir, Pseudotsuga menziesii (Mirb.) Franco, is the preferred host, the beetle has been collected also from western red cedar, Thuja plicata Donn, grand fir, Abies grandis (Dougl.) Lindl., amabilis fir, Abies amabilis (Dougl.) Forb., and western hemlock, Tsuga heterophylla (Raf.) Sarg., on the west coast of British Columbia, and from western hemlock and western yellow pine, Pinus ponderosa Laws., in the interior of the Province. Swaine (1918) describes Pseudohylesinus nebulosus (Lec.) as “a slender species, with strong colour-markings in dark and light reddish-brown; the male very densely clothed with stout scales; the epistomal lobe strongly developed; length, 2.8 mm.; width, 1.2 mm. The supposed female has interspace 9 on the declivity less strongly serrate, and the elytral scales decidedly elongate and becoming plumose towards the base.”

Hybrid biovars of Agrobacterium species isolated from conifer roots

1991 ◽  
Vol 37 (1) ◽  
pp. 34-41 ◽  
Author(s):  
C. R. Bell ◽  
W. D. Ramey
Keyword(s):  
Pseudotsuga Menziesii ◽  
Picea Glauca ◽  
Pinus Contorta ◽  
Heterotrophic Bacteria ◽  
Principal Component ◽  
Tsuga Heterophylla ◽  
Thuja Plicata ◽  
Discrete Groups ◽  
Red Cedar ◽  
Cluster 2

A total of 377 heterotrophic bacteria were isolated on nonselective medium from the rhizoplanes of five species of conifer. The species were western hemlock (Tsuga heterophylla), Douglas-fir (Pseudotsuga menziesii), lodgepole pine (Pinus contorta), white spruce (Picea glauca), and western red cedar (Thuja plicata). Twenty-eight strains from this population were identified as presumptive agrobacteria. All proved nontumourigenic. Principal-component analysis indicated that the strains, which had clustered into two discrete groups, had intermediate biovar characteristics. Cluster 1 was predominately biovar 3/2 in character, cluster 2 was predominately biovar 2/3. All the presumptive agrobacteria were distributed randomly with respect to the tree species. This study demonstrates that agrobacteria, although atypical, do occur in forest soils and attests to the ubiquity of the genus in soil. Key words: Agrobacterium, biovars, crown gall, conifers.

Ionic balance and organic acids in western redcedar, western hemlock, and Douglas-fir seedlings grown in low- and high-N soils

1999 ◽  
Vol 29 (6) ◽  
pp. 669-678 ◽  
Author(s):  
J E Graff, Jr. ◽  
R K Hermann ◽  
J B Zaerr
Keyword(s):  
Organic Acids ◽  
Quinic Acid ◽  
Tsuga Heterophylla ◽  
Douglas Fir ◽  
Western Hemlock ◽  
Thuja Plicata ◽  
N Availability ◽  
Ionic Balance ◽  
Total N ◽  
Western Redcedar

Seedlings of western redcedar (Thuja plicata Donn ex. D. Don), western hemlock (Tsuga heterophylla (Raf.) Sarg.), and Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) were transplanted into soils with low and high levels of available NO3-(and total N). Current-year foliage was sampled after 10 weeks to determine the effect of N availability on foliar cation-anion balance (C-A) and the concentrations of low molecular weight organic acids of the three species. Carboxylate concentrations were estimated by using the difference between sums of cations and anions (C-A): 750 mequiv.·kg-1for western redcedar, 351 mequiv.·kg-1for western hemlock, and 266 mequiv.·kg-1for Douglas-fir. Quinic acid was a primary constituent, accounting for 40% of the total for western redcedar and 75% for western hemlock and Douglas-fir. Oxalic acid was present in greatest concentration in the foliage of western redcedar (65 mequiv.·kg-1) but was a minor constituent in western hemlock and Douglas-fir. The quantified acids accounted for only 15% of the C-A of western redcedar but >80% of the C-A of western hemlock and Douglas-fir. A considerable portion of the C-A balance not accounted for in redcedar may be associated with the accumulation of CaCO3. Litterfall deposition of CaCO3may lead to the consumption of H+ions and enrichment of exchangeable soil Ca in the rooting zone of long-lived western redcedar trees. No statistically significant differences among the soils were detected with regard to C-A or the concentration of organic acids.

Ectomycorrhizal mushroom distribution by stand age in western hemlock – lodgepole pine forests of northwestern British Columbia

2005 ◽  
Vol 35 (7) ◽  
pp. 1527-1539 ◽  
Author(s):  
J M Kranabetter ◽  
J Friesen ◽  
S Gamiet ◽  
P Kroeger
Keyword(s):  
British Columbia ◽  
Pinus Contorta ◽  
Nitrogen Availability ◽  
Lodgepole Pine ◽  
Natural Disturbance ◽  
Tsuga Heterophylla ◽  
Western Hemlock ◽  
Stand Age ◽  
Age Classes ◽  
Commercial Forest

Commercial forest rotations are usually shorter than natural disturbance return intervals, which could affect the distribution of ectomycorrhizal fungal (EMF) species dependent on late-seral stands. We examined this potential reduction in species richness by comparing ectomycorrhizal mushroom communities across four age-classes (pole stage, young, mature, and old growth) of western hemlock (Tsuga heterophylla (Raf.) Sarg.) – lodgepole pine (Pinus contorta Dougl. ex Loud.) stands on submesic sites in northwestern British Columbia. Almost 130 species of ectomycorrhizal mushrooms were identified over the 12 sites during the 3-year study period. EMF richness was lowest in pole stands and almost twice as high in the older age-classes. Species composition and abundance were related to stand age, with relatively large differences in communities between the ages of 20 and 120 and relatively smaller differences between 120 and 225 years. Twelve species, including the economically important pine mushroom (Tricholoma magnivelare (Peck) Redhead), were late-seral stand dependent, fruiting in forests that are at least older than 85 years. This distribution of ectomycorrhizal mushrooms across stand ages suggests EMF succession is primarily an accumulation of species and is likely affected by differences in dispersal by ectomycorrhizal fungi, soil properties (increased soil acidity and reduced nitrogen availability), and the rate of stand development. The evidence for EMF species limited to late-seral stands supports the maintenance of some mature forests within these landscapes to conserve EMF richness.

Quaternary Palynology of the Pacific Slope of Washington

1977 ◽  
Vol 8 (3) ◽  
pp. 282-306 ◽  
Author(s):  
Calvin J. Heusser
Keyword(s):  
Pinus Contorta ◽  
Meteorological Data ◽  
Tsuga Heterophylla ◽  
Douglas Fir ◽  
Western Hemlock ◽  
Olympic Peninsula ◽  
The Holocene ◽  
Pollen Stratigraphy ◽  
The Pacific ◽  
Pacific Slope

Quaternary deposits on the Pacific slope of Washington range in age from the earliest known interglaciation, the Alderton, through the Holocene. Pollen stratigraphy of these deposits is represented by 12 major pollen zones and is ostensibly continuous through Zone 8 over more than 47,000 radiocarbon yr. Before this, the stratigraphy is discontinuous and the chronology less certain. Environments over the time span of the deposits are reconstructed by the comparison of fossil and modern pollen assemblages and the use of relevant meteorological data. The Alderton Interglaciation is characterized by forests of Douglas fir (Pseudotsuga menziesii), alder (Alnus), and fir (Abies). During the next younger interglaciation, the Puyallup, forests were mostly of pine, apparently lodgepole (Pinus contorta), except midway in the interval when fir, western hemlock (Tsuga heterophylla), and Douglas fir temporarily replaced much of the pine. Vegetation outside the limits of Salmon Springs ice (>47,00034,000 yr BP) varied chiefly between park tundra and forests of western hemlock, spruce (Picea), and pine. The Salmon Springs nonglacial interval at the type locality records early park tundra followed by forests of pine and of fir. During the Olympia Interglaciation (34,000–28,000 yr BP), pine invaded the Puget Lowland, whereas western hemlock and spruce became manifest on the Olympic Peninsula. Park tundra was widespread during the Fraser Glaciation (28,000–10,000 yr BP) with pine becoming more important from about 15,000 to 10,000 yr BP. Holocene vegetation consisted first of open communities of Douglas fir and alder; later, closed forests succeeded, formed principally of western hemlock on the Olympic Peninsula and of western hemlock and Douglas fir in the Puget Lowland. Over the length of the reconstructed environmental record, climate shifted between cool and humid or relatively warm, semihumid forest types and cold, relatively dry tundra or park tundra types. During times of glaciation, average July temperatures are estimated to have been at least 7°C lower than today. Only during the Alderton Interglaciation and during the Holocene were temperatures higher for protracted periods than at present.

scholarly journals Height prediction equations using diameter and stand density measures

2000 ◽  
Vol 76 (2) ◽  
pp. 303-309 ◽  
Author(s):  
Christie Staudhammer ◽  
Valerie LeMay
Keyword(s):  
Weibull Distribution ◽  
Predictor Variable ◽  
Stand Density ◽  
Tsuga Heterophylla ◽  
Douglas Fir ◽  
Thuja Plicata ◽  
Red Cedar ◽  
Non Linear Equation ◽  
Height Prediction ◽  
Thuja Plicata Donn

Height equations for western hemlock (Tsuga heterophylla (Raf.) Sarg.), western red cedar (Thuja plicata Donn), Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco), and alder (Alnus rubra Bong. and Alnus tenuifolia Nutt.) were fitted using dbh as the predictor variable. A simple, non-linear equation gave very similar results to the Weibull distribution, except for hemlock, which was better modelled using the more flexible Weibull distribution function. Introducing stand density variables into the base equations resulted in increased accuracy for predicting heights of alder. Smaller improvements were found for Douglas-fir, cedar, and hemlock. Key words: estimating height, Coastal BC, Weibull estimation, stand density measures

A New Approach in Measuring Rainfall Interception by Urban Trees in Coastal British Columbia

2009 ◽  
Vol 44 (1) ◽  
pp. 16-25 ◽  
Author(s):  
Yeganeh Asadian ◽  
Markus Weiler
Keyword(s):  
British Columbia ◽  
Green Infrastructure ◽  
Douglas Fir ◽  
Urban Trees ◽  
Thuja Plicata ◽  
Storm Events ◽  
Canopy Interception ◽  
Red Cedar ◽  
Western Red Cedar ◽  
Interception Loss

Abstract Interception loss plays an important role in controlling the water balance of a watershed, especially where urban development has taken place. The aim of this study was to illustrate the importance of urban trees as a form of ‘green infrastructure’ where they reduce stormwater runoff and rainwater intensity. In addition, trees cause a delay in precipitation reaching the ground. Interception loss was studied in the North Shore of British Columbia. We applied a unique methodology for measuring throughfall under six different urban trees using a system of long polyvinyl chloride pipes hung beneath the canopy capturing the throughfall and draining it to a rain gauge attached to a data logger. Different tree species (Douglas-fir [Pseudotsuga menziesii] and western red cedar [Thuja plicata]) in variable landscape sites (streets, parks, and natural forested areas) and elevations were selected to ensure that the system adequately captured the throughfall variability. Interception and throughfall were monitored over a one year cycle for which the results of seven discrete storm events for coniferous trees from the District of North Vancouver during 2007 to 2008 are presented. Cumulative gross precipitation for seven selected events was 377 mm. Average canopy interception during these events for Douglas-fir and western red cedar were 49.1 and 60.9%, where it corresponded to average net loss of 20.4 and 32.3 mm, respectively. The interception loss varied depending on canopy structure, climatic conditions, and rainfall characteristics.

Overturning resistance of western redcedar and western hemlock in mixed-species stands in coastal British Columbia

2007 ◽  
Vol 37 (5) ◽  
pp. 931-939 ◽  
Author(s):  
Kenneth E. Byrne ◽  
Stephen J. Mitchell
Keyword(s):  
British Columbia ◽  
Tsuga Heterophylla ◽  
Western Hemlock ◽  
Thuja Plicata ◽  
Specific Information ◽  
Mixed Species ◽  
Stem Form ◽  
Western Redcedar ◽  
Applied Forces ◽  
Coastal British Columbia

Specific information about the applied forces that cause trees to fail is required to validate mechanistic models of windthrow in different forest types. Static tree-pulling tests were conducted to examine the overturning resistance of western redcedar ( Thuja plicata Donn ex D. Don) and western hemlock ( Tsuga heterophylla (Raf.) Sarg.) in a mixed species second-growth stand in coastal British Columbia. Although widely used, tree-pulling techniques are not standardized. Data from three inclinometers were used to estimate stem deflection, which was found to increase with tree slenderness. Differing methods of fitting stem curvature had a small effect on estimates of self-loading at failure. The distance of the pivot point from the centre of the stem base increased with tree diameter. Accounting for the correct self-loading at failure produced a small difference in the overall turning moment regressions but did not improve the fit of these regressions. However, this difference increased with tree size and warrants consideration in future tree-pulling tests with large or plate-rooted trees. The stem mass – overturning resistance relationship had the best fit and was not significantly different for these species in spite of their differences in wood density and stem form.

Litter decomposition in western red cedar and western hemlock forests on northern Vancouver Island, British Columbia

1996 ◽  
Vol 74 (10) ◽  
pp. 1626-1634 ◽  
Author(s):  
R. J. Keenan ◽  
C. E. Prescott ◽  
J. P. Kimmins ◽  
J. Pastor ◽  
B. Dewey
Keyword(s):  
Litter Decomposition ◽  
Litter Quality ◽  
Tsuga Heterophylla ◽  
N Cycling ◽  
Western Hemlock ◽  
Thuja Plicata ◽  
N Availability ◽  
Forest Types ◽  
Red Cedar ◽  
Western Red Cedar

Litter decomposition and changes in N and organic chemicals were studied for 2 years in two forest types: old-growth western red cedar (Thuja plicata Donn) and western hemlock (Tsuga heterophylla (Raf.) Sarge) and 85-year-old stands of western hemlock and amabilis fir (Abies amabilis (Dougl.) Forbes) that developed after a major windstorm. We tested the hypothesis that lower rates of mass loss and different patterns of nutrient release in decomposing litter could explain lower nutrient availability in the cedar–hemlock type. Decomposition rate of a standard litter substrate, lodgepole pine needles, was almost identical in the two forest types indicating that each type had similar microenvironmental conditions for decomposers. Salal leaves had a lower lignin to N ratio and decomposed and released N more rapidly than the conifer litters. Among the conifers, cedar had poorer litter quality (higher lignin to N ratio), decomposed more slowly, and released considerably less N during the study. Cedar litter contributes to lower N availability in cedar–hemlock forests, but other factors, such as lower external N cycling and complexing of N with secondary carbon compounds during later stages of decomposition, are also likely to have a major influence on N availability. Keywords: Thuja plicata, Tsuga heterophylla, decomposition, litter quality, N cycling.

Trees are larger on southern slopes in late-seral conifer stands in northwestern British Columbia

2019 ◽  
Vol 49 (11) ◽  
pp. 1349-1356
Author(s):  
Nathan J. Kuyek ◽  
Sean C. Thomas
Keyword(s):  
British Columbia ◽  
Picea Glauca ◽  
Pinus Contorta ◽  
Tree Height ◽  
Tsuga Heterophylla ◽  
Snow Accumulation ◽  
Western Hemlock ◽  
Stem Volume ◽  
Published Data ◽  
Canopy Tree

Mid-latitude forests commonly show increased productivity and ultimately produce larger trees on shaded, northern aspects compared with those on sunny, southern aspects. Little research has been conducted on this phenomenon at higher latitudes where solar radiation is less available. We examined patterns of canopy tree size in a set of 142 naturally regenerated, late-seral conifer stands in northwestern British Columbia, Canada, at latitudes of 54°N–56°N. The height, diameter, and total stem volume of three shade-tolerant conifers (western hemlock (Tsuga heterophylla (Raf.) Sarg.), subalpine fir (Abies lasiocarpa (Hook.) Nutt.), and hybrid spruce (Picea glauca × engelmannii (Moench) Voss)) and shade-intolerant lodgepole pine (Pinus contorta var. latifolia Engelm. ex S. Watson) were analyzed. In contrast to most previous studies, mean canopy tree height, diameter, and volume were greatest on southern aspects and lowest on northern aspects for the subset of sites with pronounced slopes (≥30%). There was some variation in patterns among species, with western hemlock responding most strongly to topography, and species-specific effects of topography on height–diameter allometry. We suggest that decreased levels of radiation at northern latitudes and increased light and warmer temperatures on steeper, southern aspects promote growth. In contrast, colder, shaded, northern aspects with increased snow accumulation, delayed snowmelt, and decreased nitrogen mineralization inhibit growth. Our results, together with published data, suggest that a latitudinal shift from higher forest productivity on northern aspects to higher productivity on southern aspects typically occurs between 40°N and 50°N.

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