Picea Populations Research Articles

Spruce up your climate analysis: Dendroclimatology of Picea engelmannii and Picea pungens

AbstractWarming and more variable climates threaten to upend historical tree ranges, climatic sensitivity, and vigor. In western North America, the species Picea engelmannii var. engelmannii Parry ex Engelmann (Engelmann spruce) and Picea pungens Engelmann (Colorado blue spruce) are widespread spruce that act as foundational species in their montane to subalpine habitats. However, there is currently a lack of knowledge on P. pungens climatic responses, and how it differs from P. engelmannii. To address this gap, we assessed the climatic sensitivity and correlates of tree growth in a co‐occurring old‐growth stand of P. engelmannii and P. pungens, at high elevation in southern Utah, USA. We report the putative oldest cross‐dated P. pungens, with 457 rings, and sampled multiple P. pungens >400 years old. Both Picea populations had strongly positive growth responses to May–July precipitation and negative responses to maximum May–July temperature. Notably, October in the previous year had the strongest correlation with growth for both Picea species. Neither population exhibited signs of directional changes in climate–growth responses. Spectral analysis identified peaks associated with El Niño–Southern Oscillation at 3–4 years and quasi‐decadal oscillations (18–20 years) in both species. Cumulatively, our results highlight the growth–climate relationships of two frequently understudied subalpine tree species. In particular, P. pungens may warrant further study across its range and identification of other ancient populations.

Variability of leaf traits in natural populations of Picea omorika determines ignitability of fresh foliage

IntroductionA variety of plant traits, from architectural to the cellular level, have been connected to flammability, but intraspecific variability of plant traits (ITV) and components of flammability is poorly studied. The lack of knowledge about ITV of plant traits related to flammability appears to be a major shortcoming in further interpreting species flammability and fire behavior and incorporating the data into models.MethodsMorpho-ecophysiological traits (width, length, thickness, weight, area, volume, moisture content, flatness, specific leaf area, density of leaf tissue, ratio of area to volume) and time-to-ignition of fresh foliage were measured in seven populations of Picea omorika.ResultsAll leaf traits are presented along with their correlations to the flammability trait. The seven populations differed in terms of fresh leaves’ time-to-ignition. Differences among populations in morpho-ecophysiological traits were also significant but not consistent among populations. PCA classified 49 elements into three different groups, where three populations were clustered by higher leaf area-related traits, other three populations were clustered by higher leaf length, volume, thickness, time-to-ignition, density index, moisture content, width, weight, and one population was classified between the two main groups. The first two principal components accounted for 87% of the total variance: variability in leaf area- and leaf weight-derived parameters (specific leaf area and density index) and time-to-ignition primarily defined the formation of the first axis, while variability in leaf flatness (based on leaf weight and thickness) primarily contributed to the formation of the second axis.DiscussionResults suggest high ITV in natural populations of P. omorika regardless of site fire history.

Climate, fire and vegetation history at treeline east of Hudson Bay, northern Québec

This study investigates the spatio-temporal postglacial development of the vegetation in the northwestern part of the forest-tundra of northern Québec, Canada. Six lake sediment cores and 59 modern sediment samples were collected in an area of 16 by 7 km and analyzed for pollen and charcoal. Following a brief herb and shrub tundra period and a period with abundant Alnus, Picea mariana grew in the region for at least the past 4000 years, but there was a gradient across the area, with Picea growing to the west but not toward the east. The period of maximum Picea abundance varied between sites, but was generally between 1500 and 2500 years ago. Neoglacial cooling resulted in a decrease in Picea on the landscape, but the timing of the decline at any site depended on removal of Picea by fire. There was a gradient in Picea abundance across this study area, which resulted in a reconstructed spatial July temperature gradient of ∼1 °C across this 16 km region. In spite of the importance of fire in affecting local Picea populations around any lake, the paleoclimate reconstructions showed a long-term neoglacial cooling of ∼1 °C over the past 3800 cal yr BP, with superimposed century-scale fluctuations of ∼0.2 °C, corresponding to the Little Ice Age, the Medieval Warm Period, the Dark Ages Cold Period and the Roman Warm Period. High-resolution pollen records can therefore be used to reconstruct not only regional vegetation and climate history, but also local differences within small areas.

Genetic diversity comparative evaluation of Pinus Sylvestris L. and Picea x Fennica (regel) kom. native populations and clonal seed orchards in russian Karelia

Genetic diversity levels in 4 native populations of Finnish spruce and Scots pine each and 2 fields of conifer seed orchard growing in Karelia have been investigated using microsatellite loci. As a result high levels of basic genetic diversity parameters have been revealed for native populations of both species. It was found that expected heterozygosity figers calculated for the populations investigated were higher than the observed ones. This case thereby indicates a deficit of heterozygotes in the Karelian pine and spruce populations. Genetic diversity figures found for spruce seed orchard were much lower than for native populations of Picea x fennica. This fact, in our opinion, reflects the unsufficent representation of genetic pool both within the seed orchard field investigated and in spruce plus trees' breeding population on the whole. Scots pine seed orchard has been characterised by a high level of genetic diversity matched to native populations one.

Fine-scale environmental variation contributes to introgression in a three-species spruce hybrid complex

Hybridization is common for many forest trees, where weak barriers to reproduction obscure species boundaries. We characterized the genomic structure of Picea populations comprising three species s ...

Constraints on post‐glacial boreal tree expansion out of far‐northern refugia

AbstractAimTo use a variety of data sources to infer how northern boreal trees recovered their range upon deglaciation and/or Holocene warming.LocationScandinavia, Alaska/north‐west Canada (eastern Beringia).MethodsMapped fossil occurrences for Picea (spruce) were assessed against available palaeoenvironmental and phylogeographic information.ResultsFor Scandinavia, Last Glacial Maximum (LGM) evidence of Picea is confined to one DNA record, but late‐glacial and early‐Holocene records include scattered macrofossils. Holocene pollen data show a clear east–west increase to high values. A haplotype unique to the Scandinavian Peninsula is recognized. For eastern Beringia pre‐ and post‐LGM macrofossils occur, but the LGM fossil record comprises only scattered low pollen values. Early Holocene pollen values increase markedly c. 11 cal yr bp (north‐west Canada) and c. 10 kcal yr bp (central Alaska). Also at this time three sites on the Bering Land Bridge indicate the presence of Picea where it is now absent. Several unique regional haplotypes were recorded; while most are rare one is common in some modern populations.Main conclusionsSmall Picea populations probably occurred in pre‐Holocene Scandinavia, but pollen patterns argue against immediate expansion with the onset of warmer conditions. Despite relatively weak fossil evidence, refugial populations are also probable in eastern Beringia, particularly given the extent of unglaciated terrain. Post‐glacial pollen patterns are more nuanced, suggesting two spatially and temporally distinct expansions, one possibly consistent with a unique central Alaskan haplotype, and subsequent westerly ‘filling‐in’. The presence of macrofossils and/or neutral markers does not require that current northern populations are derived primarily from refugial ones, particularly where pollen patterns show delayed directional expansion of large populations though time. Refugial populations initially responded weakly to major post‐glacial environmental change; if subject to genetic isolation and strong selection pressure they may have had little potential to do otherwise, instead being largely replaced by in‐migrating populations with greater genetic diversity.

Genetic structure of the Black Bog Ant (Formica picea Nylander) in the United Kingdom

Social Hymenoptera have been relatively little studied in terms of conservation genetics even though their sociality and complementary sex determination potentially influence the interaction of genetics with extinction risk. Using microsatellite markers, we investigated the social and genetic structure of nests and populations of the Black Bog Ant Formica picea at four sites in the UK, where this habitat specialist has a localized and fragmented range. Nests were weakly polygynous (effective queen number, 4-27 per nest) with low worker relatedness. Isolation by distance tended to be present within sites, indicating limited dispersal, but inbreeding was rare. The four study sites fell into three main populations (two in South Wales, one in southern England). We conclude that, although UK F. picea populations are not at immediate risk from genetic factors, their limited dispersal abilities at both within- and between-site scales should inform conservation management decisions.

Rapid Lateglacial tree population dynamics and ecosystem changes in the eastern Baltic region

AbstractA growing body of evidence implies that the concept of 'treeless tundra' in eastern and northern Europe fails to explain the rapidity of Lateglacial and postglacial tree population dynamics of the region, yet the knowledge of the geographic locations and shifting of tree populations is fragmentary. Pollen, stomata and plant macrofossil stratigraphies from Lake Kurjanovas in the poorly studied eastern Baltic region provide improved knowledge of ranges of north‐eastern European trees during the Lateglacial and subsequent plant population responses to the abrupt climatic changes of the Lateglacial/Holocene transition. The results prove the Lateglacial presence of tree populations (Betula, Pinus and Picea) in the eastern Baltic region. Particularly relevant is the stomatal and plant macrofossil evidence showing the local presence of reproductive Picea populations during the Younger Dryas stadial at 12 900–11 700 cal. a BP, occurring along with Dryas octopetala and arctic herbs, indicating semi‐open vegetation. The spread of Pinus–Betula forest at ca. 14 400 cal. a BP, the rise of Picea at ca. 12 800 cal. a BP and the re‐establishment of Pinus–Betula forest at ca. 11 700 cal. a BP within a span of centuries further suggest strikingly rapid, climate‐driven ecosystem changes rather than gradual plant succession on a newly deglaciated land. Copyright © 2009 John Wiley & Sons, Ltd.

Allozyme frequency distributions in four Swedish populations of Norway spruce (Picea abiesK.)

Allozyme variation in eleven loci was studied in four Swedish populations of Picea abies.For six of the loci, GDH-B, GOT-A, GOT-C, LAP-A, MDH-Aand MDH-Bthe inheritance of allozyme bands was ascertained from their distributions to female gametes within single trees. Significant divergence in gene frequencies among populations was demonstrated, which in four of the loci appears to be correlated to differences in altitude of the habitats. Estimates of genetic variability was, however, uniformly distributed among populations. The possible influence of different selection intensities and adaptation to microhabitat was discussed. It was, furthermore, demonstrated in analyses of linkage that three of the allozyme loci studied are situated on one chromosome sufficiently close to reduce the frequency of recombination in female gametes. Finally, from preliminary studies of the mating system were obtained maximum estimates of self-fertilization in three of the populations.

Younger Dryas to mid-Holocene environmental history of the lowlands of NW Transylvania, Romania

Pollen, micro-charcoal and total carbon analyses on sediments from the Turbuta palaeolake, in the Transylvanian Basin of NW Romania, reveal Younger Dryas to mid-Holocene environmental changes. The chronostratigraphy relies on AMS 14C measurements on organic matter and U/Th TIMS datings of snail shells. Results indicate the presence of Pinus and Betula open woodlands with small populations of Picea, Ulmus, Alnus and Salix before 12,000 cal yr BP. A fairly abrupt replacement of Pinus and Betula by Ulmus-dominated woodlands at ca. 11,900 cal. yr BP likely represents competition effects of vegetation driven by climate warming at the onset of the Holocene. By 11,000 cal yr BP, the woodlands were increasingly diverse and dense with the expansion of Quercus, Fraxinus and Tilia, the establishment of Corylus and the decline of upland herbaceous and shrubs taxa. The marked expansion of Quercus accompanied by Tilia between 10,500 and 8000 cal yr BP could be the result of low effective moisture associated with both low elevation of the site and with regional change towards a drier climate. At 10,000 cal yr BP, Corylus spread across the region, and by 8000 cal yr BP it replaced Quercus as a dominant forest constituent, with only little representation of Picea abies. Carpinus became established around 5500 cal yr BP, but it was only a minor constituent in local woodlands until ca. 5000 cal yr BP. Results from this study also indicate that the woodlands in the lowlands of Turbuta were never closed.

Fire history and tree species composition in managed Picea abies stands in southern Finland: Implications for restoration

We studied the fire history of 24 managed Picea abies-dominated stands in southern Finland using dendrochronological dating of fire scars in old stumps. Forests in the study area have been heavily utilized in many ways for centuries for swidden cultivation, tar burning, forest pasturage and pasture burning. Old charred stumps of Pinus sylvestris were found in every stand although in nine of them the stumps were too decayed to provide a sample that could be dated. In the 17th and 18th centuries, forests burned at intervals of ca. 50 years on average. The last fires in the study plots occurred in the latter half of the 19th century. Based on the presence of the old Pinus stumps, past frequent fires and historical documents, it can be judged that forests were Pinus-dominated in the 17th and 18th centuries. Around the middle of the 19th century a gap occurred in the annual tree ring chronologies of all study plots. This suggests that large coniferous trees were absent at that time. The currently dominating Picea populations regenerated at the beginning of the 20th century. Our results demonstrate that in an area where human impact on forests has been variable, pervasive and long-lasting, the goal of forest restoration can be very different depending on the choice of reference period. We conclude that for defining restoration goals, knowledge of local forest history is needed.

Cooling in the Gulf of St. Lawrence and estuary region at 9.7 to 7.2 14C ka (11.2–8.0 cal ka): Palynological response to the PBO and 8.2 cal ka cold events, Laurentide Ice Sheet air-mass circulation and enhanced freshwater runoff

An examination of post-Younger Dryas (YD) pollen stratigraphies in the Gulf of St. Lawrence and St. Lawrence estuary region reveals features in the pollen records that represent breaks in the normal vegetation succession, widespread vegetation suppression, and a delay in migration of plant taxa between 9.7 and 7.2 14C ka (11.2 and 8.0 cal ka). The domination of Alnus crispa at sites bordering the St. Lawrence estuary–Gulf region in Gaspésie and northern New Brunswick within this timeframe represents a diversion from the typical vegetation progression from Picea and/or Populus or Picea/Betula to Pinus and/or Betula, and signifies a shift to a cooler, drier climate. Coinciding with the A. crispa expansion and domination in that region was the contraction of Picea populations in other areas. In southwestern New Brunswick and eastern and southeastern Nova Scotia, Picea was replaced by the first appearance of tree birch, B. papyrifera; whereas in western and southwestern Newfoundland, Picea gave way to a resurgence of shrub birch, Betula glandulosa. The Picea contraction and immediate resurgence of Betula represents cooling, and is reliably dated at 9720 ± 110 14C BP (10,800–11,240 cal BP) in southwest Newfoundland. This first post-YD episode of widespread cooling is correlated with the North Atlantic Preboreal Oscillation (PBO) centered around 9650 14C BP (10,900–11,180 cal BP) in the adjacent Great Lakes region. Sites exposed to winds from the Gulf of St. Lawrence in eastern New Brunswick, Prince Edward Island, and northern Nova Scotia show a lingering persistence of Picea and delay in arrival of Pinus to 8.0 and 7.7 14C ka (9.0 and 8.4 cal ka), yet Pinus was dominant as early as 9.4 14C ka (10.6 cal ka) in southwestern New Brunswick. At the same time, tundra vegetation persisted at high elevations in western and southwestern Newfoundland only to be replaced by upslope migration of shrub–birch heath by 8 14C ka. Prolonged broad-scale cooling to 8 14C ka and to as late as 7.7 14C ka extended up to 200 km inland in areas exposed to the St. Lawrence estuary and Gulf region and was in response to strong, cold, dry anticyclonic winds coming off the retreating Laurentide Ice Sheet in combination with enhanced freshwater runoff through the Gulf of St. Lawrence. The end of the period of prolonged cooling and onset of regional warming coincided with the diversion of western Canada runoff and Agassiz–Ojibway drainage to Hudson Bay and reduced effect or final break-up of the Laurentide Ice Sheet. Several sites document a subsequent cold shift, that interrupted regional warming at 7650 to 7200 14C BP (8400 to 8000 cal BP), and which is variously represented by the suppression of Pinus and resurgence of Picea, sometimes with A. crispa (Québec–Maritime region), or by an abrupt decrease of Picea and resurgence of Betula (western Newfoundland). This second post-YD cool interval is equated with the 8200 cal BP cold event registered in the Greenland ice isotopic record.

A high-resolution record of late-Holocene moisture variability from a Michigan raised bog, USA

We reconstructed the late-Holocene surface-moisture history and vegetation dynamics of a raised bog in Michigan using testate amoebae, peat humification, pollen, stomata and plant macrofossils. Our primary objective was to compare bog palaeohydrology with the water-level history of Lake Michigan, and to regional and local vegetation changes. Hydrologic histories inferred from testate amoebae and humification show similar trends, and correspond with records of past water-level variability in Lake Michigan. The bog clearly shows effective-moisture increases during the Algoma highstand (∼3200–2300 cal. BP) and a later unnamed highstand (∼1900–1300 cal. BP). Some higher-frequency fluctuations are also similar. The good correspondence indicates that bog hydrology and the water levels of Lake Michigan have been driven by changes in large-scale atmospheric circulation patterns for at least the past 3500 years. Climate during the Algoma highstand may have been spatiotemporally complex, with increasing moisture occurring several hundred years earlier in the northern portion of the western Great Lakes basin. Locally, the expansion and contraction of Picea populations on the bog surface was probably directly related to moisture conditions. The well-documented decline in Fagus populations in the central Great Lakes region after 1000 cal. BP is contemporaneous with a major shift towards drier conditions, suggesting that relative dryness caused the decline.

Tree species dynamics and disturbance in three Swedish boreal forest stands during the last two thousand years

Abstract. Data from three forest stands for the past 2000 yr show how the shade‐intolerant species Pinus sylvestris and Betula pubescens maintain significant populations in the Swedish boreal landscape. Age structure data from a northern stand close to the range limits of Picea abies and Pinus complement a local pollen diagram, and reveal cyclic population fluctuations which can be related to periods of climatic stress and fire. Pollen data from two southern stands show that high fire frequencies in the past prevented the expansion of Picea populations. Reduction of the fire frequency during the last 200 yr has favoured Picea. A long time perspective reveals the population dynamics of long‐lived species and indicates the controlling factors. Such knowledge permits assessment of the current status and likely future of forest stands.

RELATIVE PERFORMANCE OF CONIFER POPULATIONS IN VARIOUS TESTS FOR SENSTIVITY TO SO2, AND THE IMPLICATIONS FOR SELECTING TREES FOR PLANTING IN POLLUTED AREAS

SUMMARYThe sensitivity of five Pinus and three Picea populations to SO2 was compared in various types of fumigation experiment (i) > 9 months at 200 μg m−3, (ii) 6 h at 8000 μ m−3, (iii) 9 weeks at 800 μg m−3, (iv) 12 h (overnight) at 17 000 μg m−3 preceded by either 42 days or 6 h at 800 μg m−3. To complement the fumigation experiments the growth of four of the populations was compared at a polluted (London) and a control site (Silwood Park).There was no relationship between the relative sensitivity of the populations to 200 μg m−3(measured as relative growth rate) and the degree of acute injury at 8000 μg m−3. In general the populations of Picea were more sensitive to low concentrations of SO2 but more resistant to acute injury than those of Pinus. At 800 μg m−3 the initial symptoms were of acute injury, but later whole needles died and were shed. Populations prone to the initial injury were not necessarily sensitive to the later type, and vice versa.Leaf fall was accelerated and dry wt gain depressed at the polluted site compared with the control and these effects were much greater in Picea than in Pinus populations.It is concluded that the order of sensitivity obtained in screening experiments depends largely on the conditions used, and that short‐term experiments with high concentrations of SO2 cannot be used to predict the responses of conifers to low concentrations of SO2 in the field.

Nuclear DNA amounts in populations of Picea and Pinus species

There are numerous reports of a very wide range of variation in nuclear DNA amounts among populations within species of the Pinaceae, including Picea glauca, the White Spruce. Our survey of 26 provenances, covering almost the entire range of White Spruce in North America showed, in contrast, no significant variation in nuclear DNA amount within the species except for minor fluctuations due to B chromosomes. The DNA estimates, throughout, fall within the range of 37·4 to 40·4 × 10−12 g. The areas of the 2C nuclei measured at G1 from 12 provenances were also highly uniform. In addition, there was no significant variation in the chromosome volume between and within provenances. Both facts reinforce the conclusion that nuclear DNA amounts within the species are constant. There are no detectable differences in the nuclear DNA content between Picea glauca and P. engelmannii. In Pinus contorta as in P. glauca, nuclear areas and DNA amounts do not vary significantly between or within provenances and the mean DNA value of 2C nuclei is 40·34 × 10−12 g. White Spruce in North America alone ranges over 3000 miles of longitude and some 1000 miles of latitude. The constancy of the nuclear DNA amounts among provenances of White Spruce and of the other species growing in widely differing environments is both surprising and impressive. It provides further testimony to the pronounced inertia to quantitative DNA change within species.

Taxonomic and ecologie relationships between Picea glauca and Picea engelmannii

Comparisons have been made of the morphologic characters of 30-tree populations of Picea distributed from near the Arctic Circle in Alaska, to near the southern boundary of Arizona. Included are 7 populations of P. glauca beyond the geographic range of P. engelmannii, 12 populations of P. engelmannii beyond the geographic range of P. glauca, and 14 populations in the area of sympatry. Hybridization is evident in all populations in the area of sympatry, despite the appearance of many low-altitude trees as pure P. glauca and many high-altitude trees as pure P. engelmannii. The geographic range of P. glauca influence has been extended farther south than previously recognized—to eastern Washington and northern Wyoming. Distinguishing characters commonly given in taxonomic keys are less reliable than absolute measurements of the ovuliferous scales. The Holocene history of Picea is speculated upon.

A chemosystematic analysis of some hybrid spruce (Picea) populations in Montana

Much of the spruce occurring in western Montana is suspected of being hybrid derivatives from the introgression between Picea glauca and P. engelmannii whose botanical ranges overlap in Montana. These Montana populations were analyzed by chemosystematic methods; resins were collected from typical P. glauca (Manitoba) and typical P. engelmannii (Wyoming) populations and these were analyzed by vapor-phase chromatography, as were resins from western Montana populations. Monoterpene compositions were determined and through the calculation of ratios based on the percentages of limonene, myrcene, and beta phellandrene, a two-dimensional ordination was constructed of the typical and hybrid spruce populations. The methods provide a highly useful approach towards interpreting chemosystematic data collected from Picea populations in the northern Rocky Mountains.