Interactive effects of light and stratification on the germination of some British Columbia conifers

1994 ◽  
Vol 72 (11) ◽  
pp. 1635-1646 ◽  
Author(s):  
X. J. Li ◽  
P. J. Burton ◽  
C. L. Leadem

Pregermination stratification treatment was generally more important than the effects of light on seed germination by 14 conifer species and varieties native to British Columbia. Nevertheless, there were some strong species differences in the response of germination to light. Final germination percentage after 21 days (28 days for Abies spp.) for both stratified and unstratified seeds of Picea glauca, Picea sitchensis, and Tsuga heterophylla showed no response to light during germination. Seed germination by Abies grandis, Pinus contorta var. contorta, Pinus contorta var. latifolia, Pinus ponderosa, Pseudotsuga menziesii var. glauca, and Pseudotsuga menziesii var. menziesii responded positively to light if unstratified but was not significantly affected by light when stratified. For Thuja plicata seeds, germination responded positively to light regardless of stratification pretreatment. Light appeared to reduce germination of stratified seeds of Abies amabilis, Abies lasiocarpa, Larix occidentalis, and Pinus monticola, although stratification conditions for these species were suboptimal. The germination rate of stratified seeds of all species and unstratified seeds of most species was increased by light. Results showed no significant relationship between germination response to light and shade-tolerance ranking or mean seed weight of the species. In six seed lots of Pinus contorta var. latifolia, however, we detected a weak negative correlation between mean seed weight and unstratified light responsivity measured after 1 week but a significant positive correlation when measured after 3 weeks. Very low light levels in closed-canopy forests or in the forest floor may prolong tree seed germination but are unlikely to constrain final germination levels after most seeds have been naturally stratified by moist, cool winter conditions. The importance of differences in the rate and timing of tree seed germination under natural conditions remains to be demonstrated. Key words: conifer biology, forest regeneration, light response, lodgepole pine, Pinus contorta, seed germination, stratification.

2001 ◽  
Vol 79 (4) ◽  
pp. 389-397 ◽  
Author(s):  
Hugh J Barclay

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.


1989 ◽  
Vol 4 (1) ◽  
pp. 10-13 ◽  
Author(s):  
Andrew C. Mason ◽  
David L. Adams

Abstract Bear damage was at least five times higher in thinned blocks than in adjacent unthinned blocks of western larch (Larix occidentalis), lodgepole pine (Pinus contorta), and Engelmann spruce (Picea engelmannii) on the Kootenai National Forest in northwest Montana. Western larch suffered the greatest damage (63% of all trees damaged and 92% of the trees killed). Damaged larch ranged from 4 to 13 in. dbh; the 4 to 8-in. dbh class accounted for 85% of the damage. Douglas-fir (Pseudotsuga menziesii), western redcedar (Thuja plicata), subalpine fir (Abies lasiocarpa), western white pine (Pinus monticola), and western hemlock (Tsuga heterophylla) were not damaged. Stand projections showed up to a 17% reduction in board-foot yield from bear damage, after 50 years, compared with hypothetical undamaged stands. West. J. Appl. For. 4(1):10-13, January 1989.


2013 ◽  
Vol 89 (03) ◽  
pp. 382-391 ◽  
Author(s):  
Alan Vyse ◽  
Michelle R. Cleary ◽  
Ian R. Cameron

We provide results from two trials comparing performance of species of known provenance planted on logged sites in the southern Interior Cedar Hemlock biogeoclimatic zone of southern British Columbia 20 and 26 years after establishment. The commonly used plantation species, lodgepole pine (Pinus contorta var. latifolia), interior spruce (a naturally occurring hybrid between Picea glauca and P. engelmannii) and Douglas-fir (Pseudotsuga menziesii var. glauca), survived as well as, but grew more slowly than, western larch (Larix occidentalis), western white pine (Pinus monticola) and ponderosa pine (Pinus ponderosa), and faster than western redcedar (Thuja plicata). Site index values were generally higher than published values for similar sites. Numerous pests affected all species in the trials. Mountain pine beetle (Dendroctonus ponderosae) caused heavy mortality in lodgepole pine in part of one trial, and Armillaria root disease caused widespread damage to western larch and Douglas-fir in the other trial. Western white pine from local seed sources were severely damaged by white pine blister rust (Cronartium ribicola) in both trials but a rust-resistant seed source used in one trial survived better. Frost damage reduced survival and growth of Douglas-fir in one trial and may have affected western white pine. Survival of two planted broadleaves (Betula papyrifera) and a hybrid of black cottonwood (Populus trichocarpa) and black poplar (Populus nigra) was severely reduced by drought. The results support ongoing efforts to broaden the number of species used in British Columbia reforestation programs.


2007 ◽  
Vol 49 (1) ◽  
pp. 55-79 ◽  
Author(s):  
Richard J. Hebda

ABSTRACT British Columbia Holocene vegetation and climate is reconstructed from pollen records. A coastal Pinus contorta paleobiome developed after glacier retreat under cool and probably dry climate. Cool moist forests involving Picea, Abies, Tsuga spp., and Pinus followed until the early Holocene. Pseudotsuga menziesii arrived and spread in the south 10 000-9000 BP, and Picea sitchensis - Tsuga heterophylla forests developed in the north. T. heterophylla increased 7500-7000 BP, and Cupressaceae expanded 5000-4000 BP. Bogs began to develop and expland. Modern vegetation arose 4000-2000 BP. There were early Holocene grass and Artemisia communities at mid-elevations and pine stands at high elevations in southern interior B.C. Forests expanded downslope and lakes formed 8500-7000 BP. Modern forests arose 4500-4000 BP while lower and upper tree lines declined. In northern B.C. non-arboreal communities preceded middle Holocene Picea forests. Abies, Pinus and Picea mariana predominated at various sites after 4000 BP. At 6000 BP Tsuga heterophylla (south) and Picea sitchensis (north) dominated the coast and islands and Quercus garryana and Pseudotsuga on southeast Vancouver Island, but Thuja plicata was infrequent. Southern Interior Plateau vegetation at 6000 BP was more open than today at middle to lower elevations, whereas forests covered the Northern Interior Plateau. Picea forests occurred in northern B.C. Holocene climate phases were: 1) warm dry "xerothermic" ca. 9500-7000 BP, 2) warm moist "mesothermic" ca. 7000-4500 BP, 3) moderate and moist 4500-0 BP, with increasing moisture 8500-6000 BP and cooling (?increased moisture) 4500-3000 BP. B.Cs Hypsithermal had dry and wet stages; 6000 BP occurred in the warm and wet mesothermic stage.


1993 ◽  
Vol 8 (2) ◽  
pp. 67-70 ◽  
Author(s):  
E. E. Nelson ◽  
Rona N. Sturrock

Abstract Several species of conifers were outplanted around infected stumps in Oregon and British Columbia to measure their susceptibility to laminated root rot caused by Phellinus weirii. Grand fir (Abies grandis) experienced nearly 30% mortality caused by P. weirii. Douglas-fir (Pseudotsuga menziesii) mortality exceeded 20%. Noble fir (A. procera), Sitka spruce (Picea sitchensis), giant sequoia (Sequoiadendron giganteum), western hemlock (Tsuga heterophylla), and ponderosa pine (Pinus ponderosa) mortality averaged less than 10%. Western white pine (P. monticola) and lodgepole pine (P. contorta) mortality was less than 1%. Phellinus weirii did not cause mortality of western redcedar (Thuja plicata) or redwood (Sequoia sempervirens). Apparent susceptibility, based on mortality over 17-20 growing seasons, was similar to that recorded in past field observations. West. J. Appl. For. 8(2):67-70.


2000 ◽  
Vol 132 (6) ◽  
pp. 811-823 ◽  
Author(s):  
Thomas W. Phillips ◽  
Gerald N. Lanier

AbstractHost specificity of Pissodes strobi (Peck) from different geographic regions and genetic divergence of local host-associated weevil populations were studied in a series of experiments. Pacific coast P. strobi reared from Sitka spruce, Picea sitchensis (Bong.) Carr (Pinaceae), were unable to successfully colonize either eastern white pine, Pinus strobus L. (Pinaceae), or western white pine, Pinus monticola Dougl. ex D. Don., in a forced-infestation study on interplanted trees in New York. Reproductively mature field-collected P. strobi from British Columbia did not oviposit on eastern white pine in New York, but field-collected New York weevils successfully reproduced in Sitka spruce leaders in British Columbia. Unacceptability of eastern white pine for western P. strobi was shown to be under genetic control, rather than influenced by prior host experience on Sitka spruce. Pissodes strobi originating from Sitka spruce but reared one generation in the laboratory on the exotic Norway spruce, Picea abies (L.) Karst., were also unable to utilize eastern white pine as a host in a forced-infestation experiment in the field. Population genetic studies using allozyme electrophoresis found that P. strobi populations occurring on different host species within 2 km of each other had significant differences in allele frequencies in three out of four cases. These results suggest that P. strobi can exist as small breeding populations that can facilitate host specialization. Applied research on host resistance against P. strobi could target mechanisms that prevent western P. strobi from utilizing nonhosts such as eastern and western white pines.


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.


2001 ◽  
Vol 79 (11) ◽  
pp. 1349-1357 ◽  
Author(s):  
Cameron G Lait ◽  
Sarah L Bates ◽  
Karen K Morrissette ◽  
John H Borden ◽  
Allison R Kermode

Radiography is a valuable tool for assessing quality of conifer seeds, but it cannot differentiate between aborted seeds and seeds that have been emptied by western conifer seed bug (Leptoglossus occidentalis Heidemann) feeding. We tested three biochemical marker-based assays that were developed to identify L. occidentalis damage to seeds of Douglas-fir, Pseudostuga menziesii (Mirb.) Franco, for their use in lodgepole pine, Pinus contorta var. latifolia Engelmann. The three assays included measurement of storage protein reserve depletion, immunodetection of fragments of insoluble (crystalloid) storage proteins, and immunodetection of L. occidentalis salivary proteins. Aborted seeds contained significantly less soluble and insoluble protein than seeds that were fed on by L. occidentalis. Polyclonal antibodies raised against 11S globulin crystalloid proteins or L. occidentalis salivary gland extracts only immunoreacted with proteins in seeds exposed to L. occidentalis feeding. In a single-blind test, antibody raised against salivary-gland extracts correctly distinguished between undamaged full seeds, unfilled aborted seeds, and seeds fed on by L. occidentalis. Immunodetection of L. occidentalis salivary proteins was also performed on seeds of Abies amabilis Dougl. ex J. Forbes, Tsuga heterophylla (Raf.) Sarg., Picea sitchensis Bong (Carr.), Pinus ponderosa Lawson, and Pinus monticola Dougl. ex D. Don. For all species, immunoreactive polypeptides were only detected in seeds fed on by L. occidentalis. These biochemical marker-based techniques could help researchers and seed orchard managers estimate seed losses caused by L. occidentalis in commercial seed orchards and natural forest stands.Key words: Leptoglossus occidentalis, saliva, biochemical markers, polyclonal antibody, immunodetection, Pinus contorta.


1991 ◽  
Vol 37 (1) ◽  
pp. 34-41 ◽  
Author(s):  
C. R. Bell ◽  
W. D. Ramey

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.


Author(s):  
D. N. Pegler

Abstract A description is provided for Inonotus weirii. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOSTS: On Abies amabilis, A. grandis, A. lasiocarpa, Chamaecyparis spp., Larix occidentalis, Picea engelmannii, P. sitchensis, Pinus contorta, P. monticola, P. ponderosa, Pseudotsuga menziesii, Thuja plicata, Tsuga heterophylla. DISEASE: Laminated butt rot and yellow ring rot of conifers. GEOGRAPHICAL DISTRIBUTION: North America (Western Canada, Oregon, Washington); Japan. TRANSMISSION: The disease is spread by root contact with infected material in the soil; there appears to be little spread of the fungus by growth through the soil. It is likely that infection of freshly exposed wounds takes place through airborne basidiospores.


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