Genecology of Douglas Fir in Western Oregon and Washington

USDA Forest Service, Pacific Northwest Research Station, 3200 SW Jefferson Way, Corvallis, OR 97331, USA.
Annals of Botany (Impact Factor: 3.3). 01/2006; 96(7):1199-214. DOI: 10.1093/aob/mci278
Source: PubMed

ABSTRACT Genecological knowledge is important for understanding evolutionary processes and for managing genetic resources. Previous studies of coastal Douglas fir (Pseudotsuga menziesii var. menziesii) have been inconclusive with respect to geographical patterns of variation, due in part to limited sample intensity and geographical and climatic representation. This study describes and maps patterns of genetic variation in adaptive traits in coastal Douglas fir in western Oregon and Washington, USA.
Traits of growth, phenology and partitioning were measured in seedlings of 1338 parents from 1048 locations grown in common gardens. Relations between traits and environments of seed sources were explored using regressions and canonical correlation analysis. Maps of genetic variation as related to the environment were developed using a geographical information system (GIS).
Populations differed considerably for adaptive traits, in particular for bud phenology and emergence. Variation in bud-set, emergence and growth was strongly related to elevation and cool-season temperatures. Variation in bud-burst and partitioning to stem diameter versus height was related to latitude and summer drought. Seedlings from the east side of the Washington Cascades were considerably smaller, set bud later and burst bud earlier than populations from the west side.
Winter temperatures and frost dates are of overriding importance to the adaptation of Douglas fir to Pacific Northwest environments. Summer drought is of less importance. Maps generated using canonical correlation analysis and GIS allow easy visualization of a complex array of traits as related to a complex array of environments. The composite traits derived from canonical correlation analysis show two different patterns of variation associated with different gradients of cool-season temperatures and summer drought. The difference in growth and phenology between the westside and eastside Washington Cascades is hypothesized to be a consequence of the presence of interior variety (P. menziessii var. glauca) on the eastside.

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    • "The sampling design we used for collection of seeds were based on results from an earlier genecology study conducted across the study area (St Clair et al., 2005). Seeds were collected across seven regions in Washington, Oregon, and "
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    ABSTRACT: There is a general assumption that intraspecific populations originating from relatively arid climates will be better adapted to cope with the expected increase in drought from climate change. For ecologically and economically important species, more comprehensive, genecological studies that utilize large distributions of populations and direct measures of traits associated with drought-resistance are needed to empirically support this assumption because of the implications for the natural or assisted regeneration of species. We conducted a space-for-time substitution, common garden experiment with 35 populations of coastal Douglas-fir (Pseudotsuga menziesii var. menziesii) growing at three test sites with distinct summer temperature and precipitation (referred to as ‘cool/moist’, ‘moderate’ or ‘warm/dry’) to test the hypotheses that 1) there is large genetic variation among populations and regions in traits associated with drought-resistance, 2) the patterns of genetic variation are related to the native source-climate of each population, in particular with summer temperature and precipitation, 3) the differences among populations and relationships with climate are stronger at the warm/dry test site owing to greater expression of drought-resistance traits (i.e. a genotype × environment interaction). During mid-summer 2012, we measured the rate of water loss after stomatal closure (transpirationmin), water deficit (% below turgid saturation), and specific leaf area (SLA, cm2g−1) on new growth of sapling branches. There was significant genetic variation in all plant traits, with populations originating from warmer and drier climates having greater drought-resistance (i.e., lower transpirationmin, water deficit and SLA), but these trends were most clearly expressed only at the warm/dry test site. Contrary to expectations, populations from cooler climates also had greater drought-resistance across all test sites. Multiple regression analysis indicated that Douglas-fir populations from regions with relatively cool winters and arid summers may be most adapted to cope with drought conditions that are expected in the future.This article is protected by copyright. All rights reserved.
    Global Change Biology 08/2014; 21(2). DOI:10.1111/gcb.12719 · 8.22 Impact Factor
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    • "With adaptation of populations to the climate being unequivocal (see St Clair et al., 2005), a change in climate will have an effect on the growth and survival of individuals and populations. Yet, for provenance test results to be useful in assessing potential impacts of climate change (see Mátyás, 1994), geographic descriptors of clinal variation must be replaced by climatic descriptors (see St Clair et al., 2005; Rehfeldt and Jaquish, 2010; Joyce and Rehfeldt, 2013). The primary goal of the present study is to synthesize disparate provenance test data so that range-wide, climate-based clines in the sub-specific varieties of P. ponderosa and P. menziesii can be described statistically. "
    Forest Ecology and Management 01/2014; 324:138-146. · 2.67 Impact Factor
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    • "aptation of P. spicata populations to multivariate climates when compared to other species. R 2 values for traits regressed on climate were between 0.51 and 0.28 (Table 7), compared with Douglas-fir (Pseudotsuga menziesii), for example, which had R 2 values of 0.68 and 0.50 for the first two multivariate traits in a canonical correlation analysis (St. Clair et al. 2005), and is considered to be closely adapted to environments when compared with other conifer species (Rehfeldt 1994b). The R 2 values found in the current study are similar in magnitude to those found for two genecology studies of grass species over a more restricted area in the Blue Mountains: E. glaucus with R 2 values between 0.51 and "
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    ABSTRACT: A genecological approach was used to explore genetic variation in adaptive traits in Pseudoroegneria spicata, a key restoration grass, in the intermountain western United States. Common garden experiments were established at three contrasting sites with seedlings from two maternal parents from each of 114 populations along with five commercial releases commonly used in restoration. Traits associated with size, flowering phenology, and leaf width varied considerably among populations and were moderately correlated with the climates of the seed sources. Pseudoroegneria spicata populations from warm, arid source environments were smaller with earlier phenology and had relatively narrow leaves than those from mild climates with cool summers, warm winters, low seasonal temperature differentials, high precipitation, and low aridity. Later phenology was generally associated with populations from colder climates. Releases were larger and more fecund than most of the native ecotypes, but were similar to native populations near their source of origin. Differences among native populations associated with source climates that are logical for survival, growth, and reproduction indicate that genetic variation across the landscape is adaptive and should be considered during restoration. Results were used to delineate seed transfer zones and population movement guidelines to ensure adapted plant materials for restoration activities.
    Evolutionary Applications 09/2013; 6(6):933-48. DOI:10.1111/eva.12077 · 4.57 Impact Factor
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