Forest history of the last 12 000 years based on plant macrofossil analysis of sediment from Marion Lake, southwestern British Columbia

1987 ◽  
Vol 65 (11) ◽  
pp. 2179-2187 ◽  
Author(s):  
Newton Wainman ◽  
Rolf W. Mathewes

The forest history around Marion Lake in southwestern British Columbia is reconstructed using plant macrofossil analysis. A comparison with a previous reconstruction based on pollen and spore analysis reveals a good correspondence between pollen and macrofossil zones. Significant improvements in the reconstruction of forest history are possible by combining the study of pollen and macrofossils. Thuja plicata macrofossils do not appear at Marion Lake until 6000 BP, contradicting previous suggestions of red cedar presence as early as 10 000 BP. Although not common at present, Taxus brevifolia may have been an important component of the forest prior to the arrival of Thuja. Fluvial input of macrofossils is important at Marion Lake. Charcoal also appears to enter the lake primarily during periods of high runoff and erosion in the watershed, suggesting the need for caution in the interpretation of charcoal data from stream-fed lakes. Increases in total influx coincide with evidence for increased precipitation after 7000 BP. Marked reductions in macrofossil influx coincide with periods of peat deposition upstream from the present lake. Relative percentages of conifer needles are unaffected by changes in influx.

1983 ◽  
Vol 20 (5) ◽  
pp. 873-885 ◽  
Author(s):  
Linda E. Heusser

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.


2007 ◽  
Vol 139 (5) ◽  
pp. 685-689
Author(s):  
Regine Gries ◽  
Robb G. Bennett ◽  
Grigori Khaskin ◽  
Gerhard Gries

AbstractIn a field trapping experiment in an abandoned seed orchard of western red-cedar, Thuja plicata Donn × D. Don, in British Columbia, we show that attraction of male red-cedar cone midges, Mayetiola thujae (Hedlin), to the pheromone blend (2S,12S)-, (2S,13S)-, and (2S,14S)-diacetoxyheptadecane is reduced in the presence of a blend of all other stereoisomers, or of the three SR- or RR-stereoisomers. The three RS-stereoisomers, in contrast, had no significant effect. Thus, synthetic pheromone for monitoring M. thujae populations must not contain the SR- or RR-stereoisomers of 2,12-, 2,13-, and 2,14-diacetoxyheptadecane. This result will allow development of a less expensive design for synthesizing the pheromone.


1946 ◽  
Vol 24c (5) ◽  
pp. 158-181 ◽  
Author(s):  
D. C. Buckland

Investigations of decay in Thuja plicata D. Don. in British Columbia have shown that the major heart-rotting fungi of living western red cedar on the Coast, in decreasing order of importance, are Poria asiatica (Pilát) Overh. (brown cubical pocket and butt rot), Poria albipellucida Baxter (white ring rot), Fomes Pini (Thore) Lloyd (white pitted trunk rot), Merulius sp. (brown crumbly butt rot), and Poria subacida (Peck) Sacc. (spongy white rot). In the Interior of the Province they are Poria asiatica, P. Weirii Murr. (yellow ring rot), Fomes Pini, Polyporus balsameus Peck (brown cubical butt rot), Merulius sp., and Poria subacida. Other fungi attacking the heartwood of living trees less extensively are Fomes annosus (Fr.) Cke., F. nigrolimitatus (Romell) Egel., F. pinicola (Sw.) Cke., Armillaria mellea (Fr.) Quél., Omphalia campanella (Fr.) Quél., Polyporus Schweinitzii Fr., and Coniophora cerebella Pers.On the areas investigated, loss through decay in stands 50 to 450 years of age never exceeded growth increment. It was indicated that decay in younger stands was of importance. Loss through decay and incidence of infection was appreciably higher in the Interior than on the Coast. No reliable external indications of decay in the standing tree were found.Deterioration in felled trees was caused by Poria Weirii, P. albipellucida, P. subacida, Armillaria mellea, Omphalia campanella, Fomes annosus, F. nigrolimitatus, and F. pinicola. Polyporus cuneatus (Murr.) Overh., and Hymenochaete tabacina (Sow.) Lév. were the major decay organisms of cedar sapwood and slash. Polyporus abietinus (Dicks.) Fr., P. versicolor (L.) Fr., P. semipileatus Peck, P. hirsutus (Wulf.) Fr., and Poria isabellina (Fr.) Overh. were restricted in distribution or of irregular occurrence.To assist in the identification of cultures all the major heart-rotting organisms were grown on tannic and gallic acid media. Seventy-seven species of Basidiomycetes were collected on living and dead Thuja plicata in British Columbia from 1943 to 1945.


2009 ◽  
Vol 44 (1) ◽  
pp. 16-25 ◽  
Author(s):  
Yeganeh Asadian ◽  
Markus Weiler

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.


2005 ◽  
Vol 83 (1) ◽  
pp. 14-21 ◽  
Author(s):  
Mark Landry ◽  
Les C Cwynar

We used the techniques of plant macrofossil analysis and radiocarbon dating to determine the minimum residence time of the endangered thread-leaved sundew (Drosera filiformis Raf.) in three bogs of southern Nova Scotia. The minimum residence times are 4240 cal. year BP for Swain's Road Bog, 2050 cal. year BP for Villagedale Bog, and very recent (modern radiocarbon age) for Port La Tour Bog, indicating that the species has likely been in the region for the past 4240 years. Analysis of nearby Old School Road Bog, which lacks D. filiformis today, failed to find any evidence that it formerly occurred there, suggesting that it may not have been more widespread in the past than it is today.Key words: Drosera filiformis, thread-leaved sundew, plant macrofossil analysis, radiocarbon dating, bogs, minimum residence time.


1956 ◽  
Vol 88 (5) ◽  
pp. 197-202 ◽  
Author(s):  
J. Walters ◽  
L. H. McMullen

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.”


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