scholarly journals Analyse rétrospective de l'adaptation à la sécheresse chez le douglas

2012 ◽  
Vol 163 (3) ◽  
pp. 88-95 ◽  
Author(s):  
Philippe Rozenberg ◽  
Anne-Sophie Sergent ◽  
Guillermina Dalla-Salda ◽  
Alejandro Martinez-Meier ◽  
Sara Marin ◽  
...  
Keyword(s):  
Retrospective Analysis ◽  
Water Deficit ◽  
Wood Density ◽  
Pseudotsuga Menziesii ◽  
Hydraulic Properties ◽  
Douglas Fir ◽  
Ecological Preferences ◽  
Significant Relationships ◽  
Dry Conditions ◽  
The Relationship

Retrospective analysis of the adaptation of the Douglas-fir to drought For a number of years in certain regions of France the Douglas-fir trees (Pseudotsuga menziesii [Mirb.] Franco) have presented symptoms of withering which have been attributed to drought. Our results show that the hydraulic function of the wood plays a part in the resistance of the Douglas-fir to dry conditions. Narrower cellular conduits, and therefore a greater wood density, contribute to the survival of trees confronted with a period of a marked water deficit. This idea is confirmed by the existence of significant relationships between wood density and hydraulic properties of wood in which the raw sap circulates, and also by the relationships found between the ecological preferences of specimens in their area of origin and the density of their wood in regions of France where they have been introduced. Those coming from dry regions have a tendency to develop wood with characteristics similar to that of trees which have survived drought. While the relationship between wood density and survival has been demonstrated, the differences in the nature of this relationship between different sites show that the mechanisms involved are complex and to a large extent still not understood.

scholarly journals Adjacency to a harvest trail increases drought resistance of interior Douglas-fir (Pseudotsuga menziesii var. glauca) in partially harvested stands in central British Columbia

2018 ◽  
Vol 48 (7) ◽  
pp. 809-820 ◽  
Author(s):  
Neil P. Thompson ◽  
Kathy J. Lewis ◽  
Lisa M. Poirier
Keyword(s):  
British Columbia ◽  
Drought Tolerance ◽  
Pseudotsuga Menziesii ◽  
Growth Rates ◽  
Habitat Management ◽  
Odocoileus Hemionus ◽  
Douglas Fir ◽  
Ring Analysis ◽  
The Relationship

Drought tolerance of trees may be affected by competition, but most studies quantifying the relationship do not consider the effect of stem clustering. Trees are often clustered in interior Douglas-fir (Pseudotsuga menziesii var. glauca (Mayr) Franco) forests near the grassland interface in central British Columbia due to past harvesting practices or habitat management for mule deer (Odocoileus hemionus hemionus (Rafinesque, 1817)). Climate change projections indicate continued increases in temperature, an outcome that would stress trees growing in dry environments. Trees placed in different states of competition by mechanical harvesting in the 1970s were sampled to provide a 40-year comparison of three levels of competition during 1–2 year droughts. Tree-ring analysis was used to assess the reduction in growth during drought years and resumption of growth in subsequent years. A clear separation of growth rates was evident between open-growing trees, trees on the edge of harvesting trails, and trees within the unharvested interior. Edge trees had intermediate growth rates but no differences were found in the long-term climate–growth relationship compared with open-growing trees. Both Edge and Open classes showed less relative growth reduction during droughts than Interior trees growing between harvest trails. Precipitation throughfall rates and competition for resources are likely driving short-term drought tolerance in combination with other factors.

Seed lot, nursery, and bud dormancy effects on root electrolyte leakage of Douglas-fir (Pseudotsuga menziesii) seedlings

1999 ◽  
Vol 29 (8) ◽  
pp. 1269-1281 ◽  
Author(s):  
Raymund S Folk ◽  
Steven C Grossnickle ◽  
Paige Axelrood ◽  
Dave Trotter
Keyword(s):  
Pseudotsuga Menziesii ◽  
Height Growth ◽  
Douglas Fir ◽  
Bud Dormancy ◽  
Root Damage ◽  
Relative Height ◽  
Nursery Culture ◽  
Terminal Bud ◽  
Root Electrolyte Leakage ◽  
The Relationship

The effects of seed lot, nursery culture, and seedling bud dormancy status on root electrolyte leakage (REL) of Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) seedlings were assessed to determine if these factors should be considered when interpreting REL for seedling quality. The relationships of REL to survival, net photosynthesis (Pn), stomatal conductance (gwv), mid-day shoot water potential (Ψmid), root growth capacity (RGC), and relative height growth were determined for each factor. Nursery culture had no effect on the relationship between REL and all other measured attributes. Seed lot affected the relationship between REL and Pn, Ψmid, and survival. However, critical REL (i.e., lowest value associated with detectable root damage) and PS80 REL (i.e., level associated with an 80% probability for survival) were similar between seed lots. Bud dormancy status affected the relationship between REL and survival, RGC, and relative height growth. Control levels of REL, critical REL, and PS80 REL decreased as the number of days required for 50% terminal bud break declined. Thus, terminal bud dormancy status must be known before REL can be used to assess seedling quality. If the bud dormancy status of Douglas-fir populations is known, then critical and PS80 REL levels may be useful as indices of root damage.

The genus Rhabdocline Syd.

1969 ◽  
Vol 47 (10) ◽  
pp. 1533-1545 ◽  
Author(s):  
A. K. Parker ◽  
James Reid
Keyword(s):  
Pseudotsuga Menziesii ◽  
Douglas Fir ◽  
Disease Symptoms ◽  
Needle Cast ◽  
Imperfect Fungus ◽  
Thin Walled ◽  
Relationship Of ◽  
The Relationship ◽  
Iodine Reaction

The various entities included under the name Rhabdocline pseudotsugae Syd., the fungus causing a needle cast of Douglas fir (Pseudotsuga menziesii (Mirb.) Franco), have been placed into two species primarily on the basis of differences in structure of their ascus apices. The ascospores of Rhabdocline pseudotsugae (which includes R. pseudotsugae subsp. pseudotsugae and R. pseudotsugae subsp. epiphylla subsp. nov.) are ejected through variously ruptured thin-walled ascus apices, while ascospores of Rhabdocline weirii sp. nov. (which includes R. weirii subsp. weirii, R. weirii subsp. oblonga subsp. nov., and R. weirii subsp. obovata subsp. nov.) are ejected through distinct annular pores. An emendment to the diagnosis of Rhabdocline has been made. R. weirii subsp. weirii was the only entity found to be associated with the imperfect fungus Rhabdogloeum pseudotsugae Syd. The relationship of Rhabdocline to other members of the Hemiphacidiaceae, the significance of the constancy of the fungus and disease symptoms in Europe, the iodine reaction of asci, and spore maturity are discussed.

scholarly journals Wood density proxies of adaptive traits linked with resistance to drought in Douglas fir (Pseudotsuga menziesii (Mirb.) Franco)

Trees ◽  
2014 ◽  
Vol 28 (5) ◽  
pp. 1289-1304 ◽  
Author(s):  
Manuela Ruiz Diaz Britez ◽  
Anne-Sophie Sergent ◽  
Alejandro Martinez Meier ◽  
Nathalie Bréda ◽  
Philippe Rozenberg
Keyword(s):  
Wood Density ◽  
Pseudotsuga Menziesii ◽  
Douglas Fir ◽  
Adaptive Traits
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