Population-dependent selection strategies needed for 2-year-old black cottonwood clones

1994 ◽  
Vol 24 (8) ◽  
pp. 1704-1710 ◽  
Author(s):  
Don E. Riemenschneider ◽  
Bernard G. McMahon ◽  
Michael E. Ostry
Keyword(s):  
British Columbia ◽  
Leaf Morphology ◽  
Clonal Selection ◽  
Tree Height ◽  
Growing Season ◽  
Experimental Population ◽  
Black Cottonwood ◽  
Multiple Trait ◽  
Selection Strategies ◽  
Northern Idaho

We conducted a study to determine whether genotypic and phenotypic covariances among important traits differed between collections of black cottonwood (Populustrichocarpa Torn & Gray) from British Columbia and northern Idaho. We also determined how differences in estimated covariances could affect various multiple-trait clonal selection strategies. The experimental design consisted of 166 clones from British Columbia and northern Idaho intermixed at random in two replications of three-tree row plots. Measurements made during the second growing season included tree height, frequency and number of sylleptic branches, number of leaves, and the lengths and areas of leaf plastochron index 5, 10, and 15 leaves at the end of the growing season. The severity and extent of Melampsora leaf rust and Septoria leaf spot were also evaluated. We found high heritability for tree height, phenology, leaf morphology, and resistance to damaging agents. However, no advantage to using leaf morphology to improve genetic selection for tree height was demonstrable. Restricted selection indices had high potential utility for controlling increases in damaging agents. However, the relation between tree height and leaf diseases varied between the British Columbia and northern Idaho collections of black cottonwood, and between black cottonwood and an adjacent experimental population of balsam poplar (Populusbalsamifera L.). Such population-related variation in intertrait covariances suggests that selection strategies involving disease resistance may need to be evaluated on an individual population basis.

scholarly journals Conservation Evaluation of Lemmon's Holly Fern, Polystichum lemmonii, a Threatened Fern in Canada

2004 ◽  
Vol 118 (2) ◽  
pp. 164
Author(s):  
George W. Douglas
Keyword(s):  
British Columbia ◽  
Road Construction ◽  
Montane Forest ◽  
Mountain Area ◽  
Forest Road ◽  
South Central ◽  
Northern Idaho ◽  
Mining Exploration ◽  
Conservation Evaluation ◽  
Forest Road Construction

In Canada, Lemmon's Holly Fern, Polystichum lemmonii, is restricted to the Baldy Mountain area on the eastern side of the Okanagan River valley in south-central British Columbia. This population represents the northern limits of the species which ranges south through northern Idaho, Washington and Oregon to northern California. In British Columbia, P. lemmonii is associated with ultramafic rocky ridges within a montane forest at an elevation of 1900 m. The population in the Baldy Mountain area is relatively small, unprotected and potentially imperilled by mining exploration, forest road construction or wildfires.

Roost-site selection and roosting ecology of forest-dwelling bats in southern British Columbia

1996 ◽  
Vol 74 (10) ◽  
pp. 1797-1805 ◽  
Author(s):  
Maarten J. Vonhof ◽  
Robert M. R. Barclay
Keyword(s):  
British Columbia ◽  
Ponderosa Pine ◽  
Tree Height ◽  
Canopy Closure ◽  
Ambient Conditions ◽  
White Pine ◽  
Roosting Ecology ◽  
Site Preferences ◽  
Roost Trees ◽  
Lasionycteris Noctivagans

We used radiotelemetry to examine the roost-site preferences of four species of tree-roosting bats (Eptesicus fuscus, Lasionycteris noctivagans, Myotis evotis, and M. volans) in southern British Columbia, Canada, by radio-tracking bats to their day roosts. We found a total of 21 roost trees: 14 roosts were beneath loose bark, 5 were in cavities excavated by woodpeckers, and 2 were in natural cavities. Entrance height increased with tree height, but roost entrances tended to be situated below the level of the canopy. Of the 22 tree and site variables examined, only 3 significantly discriminated between roost trees and available trees: tree height, distance to the nearest available tree, and percent canopy closure. Bats preferred tall trees associated with low percent canopy closure and a short distance to the nearest available tree. Bats roosted in western white pine, and to a lesser extent ponderosa pine and western larch, in intermediate stages of decay more often than would be expected at random. Bats switched roosts frequently. The distance between subsequent roost trees was short, suggesting a degree of fidelity to a particular group of trees or area of forest. The number of days of rain during the roosting period significantly influenced the number of days spent in a particular roost, and thus ambient conditions may restrict the frequency with which bats can switch roosts.

Bacterioplankton, Phytoplankton, and Zooplankton Communities in a British Columbia Coastal Lake Before and After Nutrient Reduction

1986 ◽  
Vol 43 (8) ◽  
pp. 1504-1514 ◽  
Author(s):  
F. Joan Hardy ◽  
Ken S. Shortreed ◽  
John G. Stockner
Keyword(s):  
British Columbia ◽  
Sockeye Salmon ◽  
Inorganic Nitrogen ◽  
Size Fraction ◽  
Growing Season ◽  
Nutrient Reduction ◽  
Nitrogen And Phosphorus ◽  
Coastal Lake ◽  
Before And After ◽  
High Concentrations

Inorganic nitrogen and phosphorus were applied weekly during the growing season from 1980 to 1982 and twice weekly in 1983 to Hobiton Lake, a warm monomictic coastal lake in British Columbia. The lake was not fertilized in 1984. Average numbers of bacteria during the growing season decreased from a high of 1.53 × 106∙mL−1 in the fertilized condition to 0.84 × 106∙mL−1 in the unfertilized condition. Chlorophyll a concentrations decreased from a maximum seasonal average of 2.69 μg∙L−1 (1981) to 1.30 μg∙L−1 (1984), and algal numbers decreased from 5.83 × 104∙mL−1 (1983) to 2.29 × 104∙mL−1 (1984). Although the numbers of phytoplankton in each size fraction (picoplankton, nanoplankton, or microplankton) decreased in the unfertilized condition, the greatest change was an almost fourfold decrease in picoplankton, which consisted of 90% cyanobacteria (primarily Synechococcus spp.). Abundance of the large diatoms Rhizosolenia spp. and Melosira spp. increased in 1984, resulting in an increase in average seasonal algal volume. Average densities of medium (0.15–0.84 mm) and large (0.85–1.5 mm) zooplankton were greatest in 1982, while rotifers and small zooplankton (0.10–0.14 mm) were most dense in 1984 following nutrient reduction. The lake had relatively high concentrations of planktivorous juvenile sockeye salmon (Oncorhynchus nerka) that appeared to minimize any direct effect of nutrient additions on zooplankton densities.

The millipede family Striariidae Bollman, 1893. II. New records and species of the genus Amplaria Chamberlin, 1941 (Diplopoda, Chordeumatida, Striarioidea)

Zootaxa ◽  
2021 ◽  
Vol 4908 (2) ◽  
pp. 205-224
Author(s):  
WILLIAM A. SHEAR
Keyword(s):  
British Columbia ◽  
New Species ◽  
North America ◽  
New Records ◽  
Western North America ◽  
San Luis ◽  
Senior Synonym ◽  
Northern Idaho

The millipede genus Amplaria Chamberlin, 1941 (senior synonym of Vaferaria Causey, 1958 and Speostriaria Causey, 1960) is endemic to western North America, from Mt. Palomar and San Luis Obispo, California, north to southwestern British Columbia, Canada, and east to northern Idaho. Seven species names are currently assigned to the genus. Below I describe ten additional new species: Amplaria crawfordi, Amplaria fontinalis, Amplaria rykkenae, Amplaria arcata, Amplaria baughi, Amplaria staceyi, Amplaria umatilla, Amplaria cervus, Amplaria mendocino and Amplaria flucticulus, and provide new records of Amplaria nazinta Chamberlin. 

Characteristics of Multiple-Seeded Cocklebur: A Biotype of Common Cocklebur (Xanthium strumariumL.)

1999 ◽  
Vol 13 (2) ◽  
pp. 257-263 ◽  
Author(s):  
Hamed K. Abbas ◽  
Dan J. Pantone ◽  
Rex N. Paul
Keyword(s):  
Leaf Morphology ◽  
Growing Season ◽  
Large Round

A new biotype of common cocklebur, called multiple-seeded cocklebur (MSC), was found in Bell County, TX, in 1994. MSC has up to 25 seeds per bur, usually producing up to nine seedlings, whereas normal common cocklebur (NCC) has two seeds per bur which usually produce only one seedling. MSC burs are large, round, covered with hairy spines or prickles, and flattened on one end, with each seed terminated by a beak. Leaf morphology differs among the biotypes, and stems of MSC are straighter and smoother than NCC. Apomixis occurred with MSC but not with NCC. Both biotypes have potential dormancy with germination occurring in the second growing season. MSC produces increased numbers of seedlings which increases the difficulty in controlling common cocklebur.

scholarly journals Nest site characteristics of cavity-nesting birds on a small island, in Haida Gwaii, British Columbia, Canada

2020 ◽  
Vol 133 (4) ◽  
pp. 352-363
Author(s):  
Neil G. Pilgrim ◽  
Joanna L. Smith ◽  
Keith Moore ◽  
Anthony J. Gaston
Keyword(s):  
British Columbia ◽  
Nest Site ◽  
Bird Species ◽  
Tree Height ◽  
Small Island ◽  
Haida Gwaii ◽  
Cavity Nesting ◽  
Site Characteristics ◽  
The Mean ◽  
Brown Creeper

Many studies of cavity-nesting birds in North America are conducted in large continental forests and much less is known about them in island ecosystems. We describe a 29-year study of tree species, nest site characteristics, and fledge dates of cavity-nesting birds on a small island in Haida Gwaii, British Columbia (BC). Seven cavity-nesting bird species were documented on East Limestone Island and 463 nests were found in 173 different trees. Nest trees were significantly taller and had a greater diameter than a random sample of snags. Tree height did not differ among bird species but diameter at breast height was larger for trees used by Brown Creeper (Certhia americana) than for other species. Cavity-nesters selected tree decay classes 2–7 (all dead/near dead [snags]), with 85% in decay class 4 (35%) or 5 (50%), similar to the random snag sample (class 4, 32%; class 5, 42%). Cavity height ranged from 2.6 to 44.9 m and for all species, except Brown Creeper, the mean nest height was >60% of the mean tree height. Nest heights were generally greater than observed elsewhere in BC. Nest cavity orientation was random except for Red-breasted Sapsuckers (Sphyrapicus ruber), for which only 13% of the cavity entrances faced southeast. Median fledging dates ranged from 7 June (Chestnut-backed Chickadee [Poecile rufescens]) to 28 June (Northern Flicker [Colaptes auratus]). Estimated median dates of clutch completion were similar for all species. Our results show that large snags provide habitat for a high diversity of cavity-nesting birds on Haida Gwaii.

Above- and be Bow-ground biomass of precompetitive red pine in northern Michigan

1995 ◽  
Vol 25 (7) ◽  
pp. 1064-1069 ◽  
Author(s):  
David D. Reed ◽  
Glenn D. Mroz ◽  
Hal O. Liechty ◽  
Elizabeth A. Jones ◽  
Peter J. Cattelino ◽  
...  
Keyword(s):  
Aboveground Biomass ◽  
Growth Index ◽  
Tree Height ◽  
Growing Season ◽  
Height Growth ◽  
Red Pine ◽  
Basal Diameter ◽  
Total Height ◽  
Ground Biomass ◽  
Northern Michigan

In 1984, red pine (Pinusresinosa Ait.) plantations were established at three sites in northern Michigan. From 1985 through 1992, 3083 individual trees from these stands were destructively sampled to determine aboveground biomass. The root systems were excavated on a subset of these trees (975 individuals). There were no significant differences in the relationships between either above- or below-ground biomass and groundline diameter and tree height across the range of biomass (3–6720 g for aboveground biomass and 1–319 g for belowground biomass), basal diameter (0.3–10.1 cm), or height (10–417 cm) of the sampled trees. There were also no significant differences in these relationships among the three sites. Relative height growth (the ratio of total height increment in a year and the total height at the beginning of the growing season) was found to have a very well defined maximum that was a function of total height at the beginning of the growing season. This maximum relative growth rate was used to develop a new height growth index that can be used to identify precompetitive red pine that are approaching their potential height growth in field situations.

An analysis of climatic environments for plant-breeding purposes

1976 ◽  
Vol 27 (1) ◽  
pp. 19 ◽  
Author(s):  
WJR Boyd ◽  
NA Goodchild ◽  
WK Waterhouse ◽  
BB Singh
Keyword(s):  
Plant Breeding ◽  
Regional Distribution ◽  
Central Zone ◽  
Growing Season ◽  
Short Term ◽  
Yield Variation ◽  
Selection Strategies ◽  
Marginal Areas ◽  
Highly Correlated

Variations in the regional means of a number of growing-season climatic variables, and combinations of them, are not highly correlated with the long-term regional distribution of mean wheat yields in Western Australia or with their variation between years. The data suggest that the growing season is characterized by a cyclical alternation of favourable and unfavourable conditions for crop growth. This oscillating pattern varies in amplitude and wavelength as a result of unpredictable 'between'- and 'within'-season variation in the regional distribution of rainfall. In the central zone of the study area, wheat production is subject mainly to between-season variation whilst in more marginal areas yield variation is confounded by opposing and reciprocating within-season effects. The consequences for plant breeding are that specific regional environments expected on the basis of climate do not occur predictably in the short term. It is argued that breeding objectives, selection strategies and regional testing should initially avoid complications associated with specific marginal environments by concentrating on general adaptability within the central zone, which monitors between-season variation only. Subsequent evaluation for additional adaptive features specific to marginal areas should be undertaken.

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