scholarly journals Biogeochemical survey of the Nechako River area using outer back of Lodgepole pine (NTS 93 F/9, 93 F/10, 93 F/15, 93 F/16 and parts of 93 F/11, 93 F/14, 93 K/1 and 93 K/2), alkali metals, alkaline earths, manganese and aluminum, central British Columbia

2000 ◽  
Author(s):  
C D Dunn ◽  
N L Hastings
Keyword(s):  
British Columbia ◽  
Alkali Metals ◽  
Lodgepole Pine ◽  
Alkaline Earths ◽  
F 14

scholarly journals Spore Dispersal by Dothistroma septosporum in Northwest British Columbia

2015 ◽  
Vol 105 (1) ◽  
pp. 69-79 ◽  
Author(s):  
Kennedy Boateng ◽  
Kathy J. Lewis
Keyword(s):  
British Columbia ◽  
Lodgepole Pine ◽  
Summer Precipitation ◽  
Disease Spread ◽  
Spore Dispersal ◽  
Mixed Species ◽  
Inoculum Sources ◽  
Pine Trees ◽  
Dothistroma Septosporum ◽  
Needle Blight

We studied spore dispersal by Dothistroma septosporum, causal agent of a serious outbreak of red band needle blight in lodgepole pine plantations in northwest British Columbia. Spore abundance was assessed at different distances and heights from inoculum sources and microclimatic factors were recorded during two consecutive years. Conidia were observed on spore traps from June to September during periods of rainfall. It was rare to detect spores more than 2 m away from inoculum sources. The timing and number of conidia dispersed were strongly tied to the climatic variables, particularly rainfall and leaf wetness. Should the trend toward increased spring and summer precipitation in the study area continue, the results suggest that disease spread and intensification will also increase. Increasing the planting distances between lodgepole pine trees through mixed species plantations and overall reduction in use of lodgepole pine for regeneration in wet areas are the best strategies to reduce the spread of the disease and enhance future productivity of plantations in the study area.

scholarly journals Identifying and Characterizing Important Trembling Aspen Competitors with Juvenile Lodgepole Pine in Three South-Central British Columbia Ecosystems

2012 ◽  
Vol 2012 ◽  
pp. 1-12
Author(s):  
Teresa A. Newsome ◽  
Jean L. Heineman ◽  
Amanda F. Linnell Nemec
Keyword(s):  
British Columbia ◽  
Lodgepole Pine ◽  
Geographic Range ◽  
Regression Analyses ◽  
Relative Height ◽  
Trembling Aspen ◽  
Ecosystem Productivity ◽  
Height Ratio ◽  
Critical Height ◽  
South Central

Critical height ratios for predicting competition between trembling aspen and lodgepole pine were identified in six juvenile stands in three south-central British Columbia ecosystems. We used a series of regression analyses predicting pine stem diameter from the density of neighbouring aspen in successively shorter relative height classes to identify the aspen-pine height ratio that maximizedR2. Critical height ratios varied widely among sites when stands were 8–12 years old but, by age 14–19, had converged at 1.25–1.5. MaximumR2values at age 14–19 ranged from 13.4% to 69.8%, demonstrating that the importance of aspen competition varied widely across a relatively small geographic range. Logistic regression also indicated that the risk of poor pine vigour in the presence of aspen varied between sites. Generally, the degree of competition, risk to pine vigour, and size of individual aspen contributing to the models declined along a gradient of decreasing ecosystem productivity.

scholarly journals CALCULATIONS OF BIOELECTRIC POTENTIALS

1939 ◽  
Vol 23 (1) ◽  
pp. 53-57 ◽  
Author(s):  
W. J. V. Osterhout
Keyword(s):  
Alkali Metals ◽  
Sea Water ◽  
Low Ph ◽  
Electrical Behavior ◽  
Low Concentrations ◽  
Alkaline Earths ◽  
Bioelectric Potentials

Interest in the study of Halicystis and of Valonia has been stimulated by discoveries of marked contrasts and striking similarities existing side by side. This is illustrated by new experiments with the alkali metals and alkaline earths. In Halicystis the apparent mobilities of K+, Rb+, Cs+, and Li+ (calculated by means of Henderson's equation from changes in P.D. produced by replacing sea water by a mixture of equal parts of sea water and 0.6 M of various chlorides) are as follows, uK, = 16, uRb = 16, uCs = 4.4, and uLi = 0.2; uNa is taken as 0.2. These values resemble those in Valonia except that in the latter uCs is about 0.2. No calculation is made for uNHNH4, because in these experiments even at low pH so much NH3 is present that the sign of the P.D. may reverse. This does not happen with Valonia. According to Blinks, NH4+ at pH 5 in low concentrations acts like K+. The calculation gives uMg = 1.9 which is similar to the value found for Valonia. No calculation can be made for CaCl2 since it produces protoplasmic alterations and in consequence Henderson's equation does not apply. This differs from Valonia. Evidently these plants agree closely in some aspects of electrical behavior but differ widely in others.

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