Silver fir and Douglas fir are more tolerant to extreme droughts than Norway spruce in south‐western Germany

Improving our understanding of the potential of forest adaptation is an urgent task in the light of predicted climate change. Long‐term alternatives for susceptible yet economically important tree species such as Norway spruce (Picea abies) are required, if the frequency and intensity of summer droughts will continue to increase. Although Silver fir (Abies alba) and Douglas fir (Pseudotsuga menziesii) have both been described as drought‐tolerant species, our understanding of their growth responses to drought extremes is still limited. Here, we use a dendroecological approach to assess the resistance, resilience, and recovery of these important central Europe to conifer species the exceptional droughts in 1976 and 2003. A total of 270 trees per species were sampled in 18 managed mixed‐species stands along an altitudinal gradient (400–1200 m a.s.l.) at the western slopes of the southern and central Black Forest in southwest Germany. While radial growth in all species responded similarly to the 1976 drought, Norway spruce was least resistant and resilient to the 2003 summer drought. Silver fir showed the overall highest resistance to drought, similarly to Douglas fir, which exhibited the widest growth rings. Silver fir trees from lower elevations were more drought prone than trees at higher elevations. Douglas fir and Norway spruce, however, revealed lower drought resilience at higher altitudes. Although the 1976 and 2003 drought extremes were quite different, Douglas fir maintained consistently the highest radial growth. Although our study did not examine population‐level responses, it clearly indicates that Silver fir and Douglas fir are generally more resistant and resilient to previous drought extremes and are therefore suitable alternatives to Norway spruce; Silver fir more so at higher altitudes. Cultivating these species instead of Norway spruce will contribute to maintaining a high level of productivity across many Central European mountain forests under future climate change.     

Tolerance to multiple climate stressors: a case study of Douglas‐fir drought and cold hardiness

相似文献   

Tree‐ring stable isotopes record the impact of a foliar fungal pathogen on CO2 assimilation and growth in Douglas‐fir

Swiss needle cast (SNC) is a fungal disease of Douglas‐fir (Pseudotsuga menziesii) that has recently become prevalent in coastal areas of the Pacific Northwest. We used growth measurements and stable isotopes of carbon and oxygen in tree‐rings of Douglas‐fir and a non‐susceptible reference species (western hemlock, Tsuga heterophylla) to evaluate their use as proxies for variation in past SNC infection, particularly in relation to potential explanatory climate factors. We sampled trees from an Oregon site where a fungicide trial took place from 1996 to 2000, which enabled the comparison of stable isotope values between trees with and without disease. Carbon stable isotope discrimination (Δ¹³C) of treated Douglas‐fir tree‐rings was greater than that of untreated Douglas‐fir tree‐rings during the fungicide treatment period. Both annual growth and tree‐ring Δ¹³C increased with treatment such that treated Douglas‐fir had values similar to co‐occurring western hemlock during the treatment period. There was no difference in the tree‐ring oxygen stable isotope ratio between treated and untreated Douglas‐fir. Tree‐ring Δ¹³C of diseased Douglas‐fir was negatively correlated with relative humidity during the two previous summers, consistent with increased leaf colonization by SNC under high humidity conditions that leads to greater disease severity in following years.     

Environmental variables associated with Nothophaeocryptopus gaeumannii population structure and Swiss needle cast severity in Western Oregon and Washington

The environment has a strong influence on the abundance and distribution of plant pathogenic organisms and plays a major role in plant disease. Climatological factors may also alter the dynamics of the interactions between plant pathogens and their hosts. Nothophaeocryptopus (=Phaeocryptopus) gaeumannii, the causal agent of Swiss needle cast (SNC) of Douglas‐fir, is endemic to western North America where it exists as two sympatric, reproductively isolated lineages. The abundance of this fungus and the severity of SNC are strongly influenced by climate. We used statistical and population genetic analyses to examine relationships between environment, pathogen population structure, and SNC severity. Although N. gaeumannii Lineage 2 in western Oregon and Washington was most abundant where SNC symptoms were most severe, we did not detect a significant relationship between Lineage 2 and disease severity. Warmer winter temperatures were inversely correlated with foliage retention (AFR) and positively correlated with the relative abundance of Lineage 2 (PL2). However when distance inland, which was strongly correlated with both AFR and PL2, was included in the model, there was no significant relationship between Lineage 2 and AFR. Spring/early summer dew point temperatures also were positively associated with total N. gaeumannii abundance (colonization index (CI)) and inversely correlated with AFR. Warmer summer mean temperatures were associated with lower CI and higher AFR. Our results suggest that the two lineages have overlapping environmental optima, but slightly different tolerance ranges. Lineage 2 was absent from more inland sites where winters are colder and summers are warm and dry, while Lineage 1 occurred at most sites across an environmental gradient suggesting broader environmental tolerance. These relationships suggest that climate influences the abundance and distribution of this ecologically important plant pathogen and may have played a role in the evolutionary divergence of these two cryptic fungal lineages.     

Assessment of Swiss Needle Cast Disease: Temporal and Spatial Investigations of Fungal Colonization and Symptom Severity

Increasing severity of Swiss needle cast (SNC), a foliar disease of Douglas‐fir caused by the fungus Phaeocryptopus gaeumannii, has become a matter of concern in forest plantations throughout coastal Oregon and Washington. This study monitored SNC disease in three Oregon Douglas‐fir plantations bi‐annually in 1998–1999, and compared differences in fungal colonization and symptom development in trees from north‐ and south‐facing plots at each plantation. Fungal colonization as quantified by ergosterol content, pseudothecia density and quantitative PCR was significantly correlated with symptom severity (needle retention and needle cholorosis). All three measures of fungal colonization were highly correlated with each other; and only the ergosterol–pseudothecia relationship differed between plots, presumably due to the non‐species specific nature of ergosterol measurements. Differences in symptom severity and fungal colonization between north‐ and south‐aspect plots were consistent with climate differences. At low to moderate levels of infection, trees growing on warmer (i.e. south slopes in the western, and north slopes in the eastern Coast Range) slopes had higher levels of colonization, particularly during the winter months. Plots with southern exposures, which received greater amounts of solar radiation, had greater amounts of needle abscission compared to north‐aspect plots with similar amounts of fungal colonization. As a result, greater fungal abundance and symptom expression developed on south‐aspect slopes within the Oregon Coast Range.     

Using a climatic niche model to predict the direct and indirect impacts of climate change on the distribution of Douglas‐fir in New Zealand

Climate change is likely to have major impacts on the distribution of planted and natural forests. Herein, we demonstrate how a process‐based niche model (CLIMEX) can be extended to globally project the potential habitat suitable for Douglas‐fir. Within this distribution, we use CLIMEX to predict abundance of the pathogen P haeocryptopus gaeumannii and severity of its associated foliage disease, Swiss needle cast. The distribution and severity of the disease, which can strongly reduce growth rate of Douglas‐fir, is closely correlated with seasonal temperatures and precipitation. This model is used to project how climate change during the 2080s may alter the area suitable for Douglas‐fir plantations within New Zealand. The climate change scenarios used indicate that the land area suitable for Douglas‐fir production in the North Island will be reduced markedly from near 100% under current climate to 36–64% of the total land area by 2080s. Within areas shown to be suitable for the host in the North Island, four of the six climate change scenarios predict substantial increases in disease severity that will make these regions at best marginal for Douglas‐fir by the 2080s. In contrast, most regions in the South Island are projected to sustain relatively low levels of disease, and remain suitable for Douglas‐fir under climate change over the course of this century.     

Host‐specific thermal profiles affect fitness of a widespread pathogen

Host behavior can interact with environmental context to influence outcomes of pathogen exposure and the impact of disease on species and populations. Determining whether the thermal behaviors of individual species influence susceptibility to disease can help enhance our ability to explain and predict how and when disease outbreaks are likely to occur. The widespread disease chytridiomycosis (caused by the fungal pathogen Batrachochytrium dendrobatidis, Bd) often has species‐specific impacts on amphibian communities; some host species are asymptomatic, whereas others experience mass mortalities and population extirpation. We determined whether the average natural thermal regimes experienced by sympatric frog species in nature, in and of themselves, can account for differences in vulnerability to disease. We did this by growing Bd under temperatures mimicking those experienced by frogs in the wild. At low and high elevations, the rainforest frogs Litoria nannotis, L. rheocola, and L. serrata maintained mean thermal regimes within the optimal range for pathogen growth (15–25°C). Thermal regimes for L. serrata, which has recovered from Bd‐related declines, resulted in slower pathogen growth than the cooler and less variable thermal regimes for the other two species, which have experienced more long‐lasting declines. For L. rheocola and L. serrata, pathogen growth was faster in thermal regimes corresponding to high elevations than in those corresponding to low elevations, where temperatures were warmer. For L. nannotis, which prefers moist and thermally stable microenvironments, pathogen growth was fastest for low‐elevation thermal regimes. All of the thermal regimes we tested resulted in pathogen growth rates equivalent to, or significantly faster than, rates expected from constant‐temperature experiments. The effects of host body temperature on Bd can explain many of the broad ecological patterns of population declines in our focal species, via direct effects on pathogen fitness. Understanding the functional response of pathogens to conditions experienced by the host is important for determining the ecological drivers of disease outbreaks.     

Robust geographical determinants of infection prevalence and a contrasting latitudinal diversity gradient for haemosporidian parasites in Western Palearctic birds

Identifying robust environmental predictors of infection probability is central to forecasting and mitigating the ongoing impacts of climate change on vector‐borne disease threats. We applied phylogenetic hierarchical models to a data set of 2,171 Western Palearctic individual birds from 47 species to determine how climate and landscape variation influence infection probability for three genera of haemosporidian blood parasites (Haemoproteus, Leucocytozoon, and Plasmodium). Our comparative models found compelling evidence that birds in areas with higher vegetation density (captured by the normalized difference vegetation index [NDVI]) had higher likelihoods of carrying parasite infection. Magnitudes of this relationship were remarkably similar across parasite genera considering that these parasites use different arthropod vectors and are widely presumed to be epidemiologically distinct. However, we also uncovered key differences among genera that highlighted complexities in their climate responses. In particular, prevalences of Haemoproteus and Plasmodium showed strong but contrasting relationships with winter temperatures, supporting mounting evidence that winter warming is a key environmental filter impacting the dynamics of host‐parasite interactions. Parasite phylogenetic community diversities demonstrated a clear but contrasting latitudinal gradient, with Haemoproteus diversity increasing towards the equator and Leucocytozoon diversity increasing towards the poles. Haemoproteus diversity also increased in regions with higher vegetation density, supporting our evidence that summer vegetation density is important for structuring the distributions of these parasites. Ongoing variation in winter temperatures and vegetation characteristics will probably have far‐reaching consequences for the transmission and spread of vector‐borne diseases.     

Can the emergence of pine Diplodia shoot blight in France be explained by changes in pathogen pressure linked to climate change?

Sphaeropsis shoot blight, caused by Diplodia pinea and Diplodia scrobiculata, damage conifers throughout the world. In France, the first disease outbreaks were reported during the 1990s. The factors associated with the pathogen presence in stands and the relationship between pathogen and disease distributions were analysed in order to understand the Sphaeropsis emergence. Eighty‐two stands of Pinus nigra, Pinus sylvestris, Pinus pinaster and Pinus radiata were visited. Cones were collected on the ground to assess the pathogen frequency. Diplodia spp were isolated and determined by a species‐specific PCR test. The role of potential explaining factors of D. pinea prevalence on cones was analysed by logistic regression. D. pinea was the dominant species in visited stands. The main factors influencing the pathogen presence selected in the models were host species (the pathogen being less frequent on P. pinaster than on P. nigra and P. sylvestris cones), winter temperature and summer rain, which were both positively correlated with cone colonization. The climate became more favourable to D. pinea presence within the last 15 years compared with the previous 30‐year period. By contrast, future climatic changes over the next 40 years should have far less impact on the pathogen presence.     

Uncommon southwest swells trigger sea urchin disease outbreaks in Eastern Atlantic archipelagos

Recurrent sea urchin mass mortality has recently affected eastern Atlantic populations of the barren‐forming sea urchin Diadema africanum. This new episode of die‐off affords the opportunity to determine common meteorological and oceanographic conditions that may promote disease outbreaks. The population dynamics of this sea urchin species are well known—urchin barrens have persisted for many decades along most of the coastlines off the archipelagos of Madeira, Selvages, and the Canary Islands, where they limit macroalgae biomass growth. However, this new and explosive mortality event decimated the sea urchin population by 93% on Tenerife and La Palma Islands. Two severe episodes of southwestern rough sea that led to winter storms, in February 2010 (Xynthia) and February 2018 (Emma), preceded both mass mortality events. The autumn and winter months of those years were anomalous and characterized by swells with an average wave height above 2 m that hit the south and southwest sides of the islands. The amoeba Paramoeba brachiphila was the only pathogen isolated this time from the moribund and dead sea urchins, suggesting that the amoeba was the primary cause of the mortality. This new sea urchin die‐off event supports the “killer‐storm” hypothesis that has been already described for western Atlantic coasts. These anomalous southwest storms during winters generate pronounced underwater sediment movement and large‐scale vertical mixing, detected in local tide gauge, which may promote paramoebiasis. This study presents valuable insights about climate‐mediated changes in disease frequency and its impacts on the future of coastal marine ecosystems in the Atlantic.     

Modeling climate impact on an emerging disease,the Phytophthora alni‐induced alder decline

Alder decline caused by Phytophthora alni is one of the most important emerging diseases in natural ecosystems in Europe, where it has threatened riparian ecosystems for the past 20 years. Environmental factors, such as mean site temperature and soil characteristics, play an important role in the occurrence of the disease. The objective of the present work was to model and forecast the effect of environment on the severity of alder Phytophthora outbreaks, and to determine whether recent climate change might explain the disease emergence. Two alder sites networks in NE and SW France were surveyed to assess the crown health of trees; the oomycete soil inoculum was also monitored in the NE network. The main factors explaining the temporal annual variation in alder crown decline or crown recovery were the mean previous winter and previous summer temperatures. Both low winter temperatures and high summer temperatures were unfavorable to the disease. Cold winters promoted tree recovery because of poor survival of the pathogen, while hot summer temperature limited the incidence of tree decline. An SIS model explaining the dynamics of the P. alni‐induced alder decline was developed using the data of the NE site network and validated using the SW site network. This model was then used to simulate the frequency of declining alder over time with historical climate data. The last 40 years' weather conditions have been generally favorable to the establishment of the disease, indicating that others factors may be implicated in its emergence. The model, however, showed that the climate of SW France was much more favorable for the disease than that of the Northeast, because it seldom limited the overwintering of the pathogen. Depending on the European area, climate change could either enhance or decrease the severity of the alder decline.     

Up-regulation of a photosystem II core protein phosphatase inhibitor and sustained D1 phosphorylation in zeaxanthin-retaining, photoinhibited needles of overwintering Douglas fir

Overwintering needles of the evergreen conifer Douglas fir exhibited an association between arrest of the xanthophyll cycle in the dissipating state (as zeaxanthin + antheraxanthin; Z + A) with a strongly elevated predawn phosphorylation state of the D1 protein of the photosystem II (PSII) core. Furthermore, the high predawn phosphorylation state of PSII core proteins was associated with strongly increased levels of TLP40, the cyclophilin-like inhibitor of PSII core protein phosphatase, in winter versus summer. In turn, decreases in predawn PSII efficiency, F_v/F_m, in winter were positively correlated with pronounced decreases in the non-phosphorylated form of D1. In contrast to PSII core proteins, the light-harvesting complex of photosystem II (LHCII) did not exhibit any nocturnally sustained phosphorylation. The total level of the D1 protein was found to be the same in summer and winter in Douglas fir when proteins were extracted in a single step from whole needles. In contrast, total D1 protein levels were lower in thylakoid preparations of overwintering needles versus needles collected in summer, indicating that D1 was lost during thylakoid preparation from overwintering Douglas fir needles. In contrast to total D1, the ratio of phosphorylated to non-phosphorylated D1 as well as the levels of the PsbS protein were similar in thylakoid versus whole needle preparations. The level of the PsbS protein, that is required for pH-dependent thermal dissipation, exhibited an increase in winter, whereas LHCII levels remained unchanged.     

Quantifying nutrient inputs by gulls to a fluctuating lake,aided by movement ecology methods

相似文献   

Differences in seasonal survival suggest species‐specific reactions to climate change in two sympatric bat species

Long‐lived animals with a low annual reproductive output need a long time to recover from population crashes and are, thus, likely to face high extinction risk, if the current global environmental change will increase mortality rates. To aid conservation of those species, knowledge on the variability of mortality rates is essential. Unfortunately, however, individual‐based multiyear data sets that are required for that have only rarely been collected for free‐ranging long‐lived mammals. Here, we used a five‐year data set comprising activity data of 1,445 RFID‐tagged individuals of two long‐lived temperate zone bat species, Natterer's bats (Myotis nattereri) and Daubenton's bats (Myotis daubentonii), at their joint hibernaculum. Both species are listed as being of high conservation interest by the European Habitats Directive. Applying mixed‐effects logistic regression, we explored seasonal survival differences in these two species which differ in foraging strategy and phenology. In both species, survival over the first winter of an individual's life was much lower than survival over subsequent winters. Focussing on adults only, seasonal survival patterns were largely consistent with higher winter and lower summer survival but varied in its level across years in both species. Our analyses, furthermore, highlight the importance of species‐specific time periods for survival. Daubenton's bats showed a much stronger difference in survival between the two seasons than Natterer's bats. In one exceptional winter, the population of Natterer's bats crashed, while the survival of Daubenton's bats declined only moderately. While our results confirm the general seasonal survival pattern typical for hibernating mammals with higher winter than summer survival, they also show that this pattern can be reversed under particular conditions. Overall, our study points toward a high importance of specific time periods for population dynamics and suggests species‐, population‐, and age class‐specific responses to global climate change.     

Strong “bottom‐up” influences on small mammal populations: State‐space model analyses from long‐term studies

“Bottom‐up” influences, that is, masting, plus population density and climate, commonly influence woodland rodent demography. However, “top‐down” influences (predation) also intervene. Here, we assess the impacts of masting, climate, and density on rodent populations placed in the context of what is known about “top‐down” influences. To explain between‐year variations in bank vole Myodes glareolus and wood mouse Apodemus sylvaticus population demography, we applied a state‐space model to 33 years of catch‐mark‐release live‐trapping, winter temperature, and precise mast‐collection data. Experimental mast additions aided interpretation. Rodent numbers in European ash Fraxinus excelsior woodland were estimated (May/June, November/December). December–March mean minimum daily temperature represented winter severity. Total marked adult mice/voles (and juveniles in May/June) provided density indices validated against a model‐generated population estimate; this allowed estimation of the structure of a time‐series model and the demographic impacts of the climatic/biological variables. During two winters of insignificant fruit‐fall, 6.79 g/m² sterilized ash seed (as fruit) was distributed over an equivalent woodland similarly live‐trapped. September–March fruit‐fall strongly increased bank vole spring reproductive rate and winter and summer population growth rates; colder winters weakly reduced winter population growth. September–March fruit‐fall and warmer winters marginally increased wood mouse spring reproductive rate and September–December fruit‐fall weakly elevated summer population growth. Density dependence significantly reduced both species' population growth. Fruit‐fall impacts on demography still appeared after a year. Experimental ash fruit addition confirmed its positive influence on bank vole winter population growth with probable moderation by colder temperatures. The models show the strong impact of masting as a “bottom‐up” influence on rodent demography, emphasizing independent masting and weather influences; delayed effects of masting; and the importance of density dependence and its interaction with masting. We conclude that these rodents show strong “bottom‐up” and density‐dependent influences on demography moderated by winter temperature. “Top‐down” influences appear weak and need further investigation.     

Seasonal variation in epifaunal communities associated with giant kelp (Macrocystis pyrifera) at an upwelling‐dominated site

Kelp forests are highly productive and species‐rich benthic ecosystems in temperate regions that provide biogenic habitat for numerous associated species. Diverse epifaunal communities inhabit kelp sporophytes and are subject to variations in the physical environment and to changes experienced by the kelp habitat itself. We assessed seasonal variations in epifaunal invertebrate communities inhabiting giant kelps, Macrocystis pyrifera, and their effects on this seaweed. Six seasonal samplings were conducted over a year at an upwelling‐dominated site in northern‐central Chile where physical conditions are known to fluctuate temporally. More than 30 taxa were identified, among which peracarid crustaceans stood out in both diversity and abundance. Species richness and abundance differed among sporophyte sections (holdfast and fronds) and throughout the year. The frond community was dominated by two grazers (the amphipod Peramphithoe femorata and the isopod Amphoroidea typa), while suspension feeders, grazers, and omnivores (the amphipod Aora typica, the isopod Limnoria quadripunctata, and polychaetes) dominated the holdfasts. Abundances of the dominant species fluctuated throughout the year but patterns of variation differed among species. The most abundant grazer (P. femorata) had highest densities in summer, while the less abundant grazer (A. typa) reached its peak densities in winter. Interestingly, the area of kelp damaged by grazers was highest in autumn and early winter, suggesting that grazing impacts accumulate during periods of low kelp growth, which can thus be considered as ‘vestiges of herbivory past.’ Among the factors determining the observed seasonal patterns, strong variability of environmental conditions, reproductive cycles of associated fauna, and predation by fishes vary in importance. Our results suggest that during spring and early summer, bottom‐up processes shape the community structure of organisms inhabiting large perennial seaweeds, whereas during late summer and autumn, top‐down processes are more important.     

Soil CO2 efflux measurements in a mixed forest: impact of chamber disturbances,spatial variability and seasonal evolution

A closed‐dynamic‐chamber system (CDCS) was used to measure the spatial and seasonal variability of the soil CO₂ efflux (F_s) in beech and in Douglas fir patches of the Vielsalm forest (Belgium). First the difference between natural and measured soil CO₂ efflux induced by the presence of the CDCS was studied. The impact on the measurements of the pressure difference between the outside (natural condition) and the inside of the chamber was found to be small (0.4%). The influence of wind disturbance in the closed chamber was tested by comparison with an open‐chamber system characterized by a different wind distribution. A very good correlation between the two systems was found (r² = 0.99) but the open system yielded slightly lower fluxes than the closed one (slope = 0.88 ± 0.05). A measurement procedure has been developed to minimize the effect of the other sources of perturbation. The spatial and seasonal evolution of the soil CO₂ efflux was obtained by performing regular measurements on 29 spots in the beech patch over a period of 12 months and on 24 spots in the Douglas fir patch over 8 months. For each spot, the experimental relationship between Fs and soil temperature was compared with the fitted line for an Arrhenius relationship with a soil temperature‐dependent activation energy. Soil temperature explains 73% of the seasonal variation for all the data. The spatial average of the soil CO₂ efflux at 10 °C (Fs₁₀) in the beech patch is 2.57 ± 0.41 μmol m^?2 s^?1, approximately twice the average in the Douglas fir patch recorded at 1.42 ± 0.22 μmol m^?2 s^?1. The litter fall analysis seems to indicate that soil organic matter quality and quantity may be one the reasons for this difference. Finally the annual soil CO₂ efflux was calculated for the beech and Douglas fir patches (870 ± 140 and 438 ± 68 gC m^?2 y^?1, respectively). The beech value would represent 92 ± 15% of the annual ecosystem respiration estimated from the eddy covariance measurements.     

Diversity and succession of epiphytic macrolichen communities in low‐elevation managed conifer forests in Western Oregon

Abstract. We examined epiphytic macrolichen communities in Pseudotsuga menziesii (Douglas‐fir) forests across the western Oregon landscape for relationships to environmental gradients, stand age and structure, and commercial thinning. We used a retrospective, blocked design through the Coast and the western Cascade ranges of Oregon. Each of our 17 blocks consisted of a young, unthinned stand (age 50–110 yr); an adjacent, thinned stand of equivalent age; and an old‐growth stand (age > 200 yr). We found 110 epiphytic macrolichen taxa in the stands. Forage‐providing alectorioid lichens and the nitrogen‐fixing cyanolichen Lobaria oregana associated strongly with old‐growth stands and remnant old trees in younger stands (unthinned + thinned). Relative to unthinned stands, thinned stands had a slightly higher abundance of alectorioid lichens and a greater presence of Hypogymnia imshaugii. However, thinned stands hosted a lower landscape‐level (γ) diversity, lacking many species that occurred infrequently in the unthinned stands. Patterns in the lichen community composition correlated strongly with climatic gradients; the greatest variation in composition was between the Coast and Cascade ranges. The difference in communities between mountain ranges was greatest among stands 70–110 yr old, suggesting a difference in lichen successional dynamics between the ranges.     

Geographic variation in growth response of Douglas‐fir to interannual climate variability and projected climate change

We used 179 tree ring chronologies of Douglas‐fir [Pseudotsuga menziesii (Mirb.) Franco] from the International Tree‐Ring Data Bank to study radial growth response to historical climate variability. For the coastal variety of Douglas‐fir, we found positive correlations of ring width with summer precipitation and temperature of the preceding winter, indicating that growth of coastal populations was limited by summer dryness and that photosynthesis in winter contributed to growth. For the interior variety, low precipitation and high growing season temperatures limited growth. Based on these relationships, we chose a simple heat moisture index (growing season temperature divided by precipitation of the preceding winter and current growing season) to predict growth response for the interior variety. For 105 tree ring chronologies or 81% of the interior samples, we found significant linear correlations with this heat moisture index, and moving correlation functions showed that the response was stable over time (1901–1980). We proceeded to use those relationships to predict regional growth response under 18 climate change scenarios for the 2020s, 2050s, and 2080s with unexpected results: for comparable changes in heat moisture index, the most southern and outlying populations of Douglas‐fir in Mexico showed the least reduction in productivity. Moderate growth reductions were found in the southern United States, and strongly negative response in the central Rocky Mountains. Growth reductions were further more pronounced for high than for low elevation populations. Based on regional differences in the slope of the growth–climate relationship, we propose that southern populations are better adapted to drought conditions and could therefore contain valuable genotypes for reforestation under climate change. The results support the view that climate change may impact species not just at the trailing edges but throughout their range due to genetic adaptation of populations to local environments.