scholarly journals Stocktype and Vegetative Competition Influences on Pseudotsuga menziesii and Larix occidentalis Seedling Establishment

Forests ◽  
2018 ◽  
Vol 9 (5) ◽  
pp. 228 ◽  
Author(s):  
Jeremiah Pinto ◽  
Bridget McNassar ◽  
Olga Kildisheva ◽  
Anthony Davis

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.



2021 ◽  
Vol 97 (01) ◽  
pp. 43-51
Author(s):  
Michael P. Murray ◽  
Adrian Leslie

Tree root disease caused by the pathogen Armillaria ostoyae (Romagn.) Herink has notable influence on bio-economic systems of southern British Columbia (BC) and the northwestern United States. Annual radial growth and mortality trends of regeneration associated with A. ostoyae during the first 21 years of a plantation were investigated. Our dendrochronological approach focused on a plantation established in 1991 with Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco), western larch (Larix occidentalis Nutt.), and lodgepole pine (Pinus contorta Dougl. ex Loud. var. latifolia Engelm. ex S. Wats.). We examined tree rings for reduced growth onset (RGO) to estimate infection periods. Among trees studied, we found that the number of RGO events peaked in 2006 followed by a steady decline in frequency. A similar trend was seen in annual mortality rates which reached maximum values in 2007 followed by an uninterrupted decrease. The average number of years from RGO to death based on host species ranged from 2.3 to 3.6 years. According to on logistic regression modeling, values associated with drought codes and duff moisture codes were significant in determining the year of death for infected trees. The predicted increase in frequency of summer droughts may lead to elevated mortality associated with A. ostoyae in young plantations.



1960 ◽  
Vol 38 (1) ◽  
pp. 87-91
Author(s):  
L. Gilbertson

Poria zonata Bres., a wood-rotting fungus known only from the western United States and British Columbia, is reported to be widely distributed within that area on recently fallen trees of Abies grandis, A. concolor, A. lasiocarpa, Larix occidentalis, Pseudotsuga menziesii, and Tsuga heterophylla. A description of the sporophores of the fungus, its cultural characteristics, and the white pocket rot caused by it are given.



1991 ◽  
Vol 6 (4) ◽  
pp. 105-108 ◽  
Author(s):  
Rene I. Alfaro ◽  
Liang Qiwei ◽  
John Vallentgoed

Abstract The diameter growth of western larch, Larix occidentalis, was studied in two stands defoliated by the larch casebearer, Coleophora laricella. Before defoliation, the growth pattern of larch was highly synchronized (correlation coefficient ≥0.82) with that of Douglas-fir, Pseudotsuga menziesii, a nonhost for the casebearer on the same site, indicating that both species were under the influence of the same environmental factors. During the defoliation years, the growth of larch was only loosely related to the growth of Douglas-fir. A model which predicted growth of larch based on growth of Douglas-fir indicated that defoliation caused a loss of approximately 29% in the breast height diameter growth of larch. West. J. Appl. For. 6(4):105-108.



2014 ◽  
Vol 114 (5) ◽  
pp. 973-980 ◽  
Author(s):  
Estelle Arbellay ◽  
Markus Stoffel ◽  
Elaine K. Sutherland ◽  
Kevin T. Smith ◽  
Donald A. Falk


1998 ◽  
Vol 8 (2) ◽  
pp. 397-410 ◽  
Author(s):  
Karen A. Kainer ◽  
Mary L. Duryea ◽  
Nazaré Costa de Macêdo ◽  
Kimberlyn Williams


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