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Representations of fire in the U.S. are often tinged with nostalgia: for unburned landscapes, for less frequent fires, for more predictable fire behavior, or for a simpler, more harmonious relationship between human communities and wildfire. Our perspective piece identifies four prevalent nostalgic figures that recur in popular representations of wildfire: the Giant Sequoia, the Heroic Firefighter engaged in "the Good Fight", the Lone Frontiersman, and the "Noble Savage". We assess the affordances and constraints of each of these figures for helping and/or hindering fire management. We consider how some forms of nostalgia position particular humans as heroes and fire as a villain, how others prioritize the communities that come together to face catastrophic fire events, and how some romanticize Indigenous burning practices. Drawing on knowledge from fire science, human geography, and the environmental humanities, we suggest that a more nuanced understanding of nostalgia can be useful for fire management and for finding healthier ways of living with more fire in the future. [ABSTRACT FROM AUTHOR]

Premise: Trees in wet forests often have features that prevent water films from covering stomata and inhibiting gas exchange, while many trees in drier environments use foliar water uptake to reduce water stress. In forests with both wet and dry seasons, evergreen trees would benefit from producing leaves capable of balancing rainy‐season photosynthesis with summertime water absorption. Methods: Using samples collected from across the vertical gradient in tall redwood (Sequoia sempervirens) crowns, we estimated tree‐level foliar water uptake and employed physics‐based causative modeling to identify key functional traits that determine uptake potential by setting hydraulic resistance. Results: We showed that Sequoia has two functionally distinct shoot morphotypes. While most shoots specialize in photosynthesis, the axial shoot type is capable of much greater foliar water uptake, and its within‐crown distribution varies with latitude. A suite of leaf surface traits cause hydraulic resistance, leading to variation in uptake capacity among samples. Conclusions: Shoot dimorphism gives tall Sequoia trees the capacity to absorb up to 48 kg H2O h−1 during the first hour of leaf wetting, ameliorating water stress while presumably maintaining high photosynthetic capacity year round. Geographic variation in shoot dimorphism suggests that plasticity in shoot‐type distribution and leaf surface traits helps Sequoia maintain a dominate presence in both wet and dry forests. [ABSTRACT FROM AUTHOR]

SUMMARY: Drought is a major limitation for survival and growth in plants. With more frequent and severe drought episodes occurring due to climate change, it is imperative to understand the genomic and physiological basis of drought tolerance to be able to predict how species will respond in the future. In this study, univariate and multitrait multivariate genome‐wide association study methods were used to identify candidate genes in two iconic and ecosystem‐dominating species of the western USA, coast redwood and giant sequoia, using 10 drought‐related physiological and anatomical traits and genome‐wide sequence‐capture single nucleotide polymorphisms. Population‐level phenotypic variation was found in carbon isotope discrimination, osmotic pressure at full turgor, xylem hydraulic diameter, and total area of transporting fibers in both species. Our study identified new 78 new marker × trait associations in coast redwood and six in giant sequoia, with genes involved in a range of metabolic, stress, and signaling pathways, among other functions. This study contributes to a better understanding of the genomic basis of drought tolerance in long‐generation conifers and helps guide current and future conservation efforts in the species. Significance Statement: Climate change brings more frequent and severe drought events that challenge the survival of natural populations of plants. While most of our knowledge about drought tolerance comes from annual and domesticated plants, the genomic basis of drought tolerance in long‐generation trees is poorly understood. Here, we aim to fill this gap by identifying candidate genes in two conifer species, coast redwood and giant sequoia. [ABSTRACT FROM AUTHOR]

Sequencing, assembly, and annotation of the 26.5Gbp hexaploid genome of coast redwood (Sequoia sempervirens) was completed leading toward discovery of genes related to climate adaptation and investigation of the origin of the hexaploid genome. Deep-coverage short-read Illumina sequencing data from haploid tissue from a single seed were combined with long-read Oxford Nanopore Technologies sequencing data from diploid needle tissue to create an initial assembly, which was then scaffolded using proximity ligation data to produce a highly contiguous final assembly, SESE 2.1, with a scaffold N50 size of 44.9Mbp. The assembly included several scaffolds that span entire chromosome arms, confirmed by the presence of telomere and centromere sequences on the ends of the scaffolds. The structural annotation produced 118,906 genes with 113 containing introns that exceed 500Kbp in length and one reaching 2Mb. Nearly 19Gbp of the genome represented repetitive content with the vast majority characterized as long terminal repeats, with a 2.9:1 ratio of Copia to Gypsy elements that may aid in gene expression control. Comparison of coast redwood to other conifers revealed species-specific expansions for a plethora of abiotic and biotic stress response genes, including those involved in fungal disease resistance, detoxification, and physical injury/structural remodeling and others supporting flavonoid biosynthesis. Analysis of multiple genes that exist in triplicate in coast redwood but only once in its diploid relative, giant sequoia, supports a previous hypothesis that the hexaploidy is the result of autopolyploidy rather than any hybridizations with separate but closely related conifer species. [ABSTRACT FROM AUTHOR]

This research investigates the sub-annual climate response of ten Pinus lambertiana and eight Pinus jeffreyi from Yosemite, and ten Pinus monticola and ten Pinus jeffreyi from Sequoia. We investigate the potential of using resin ducts to measure the earlywood and latewood of P. lambertiana and P. monticola and compare this growth with co-occurring, traditionally measured P. jeffreyi. Correlation analyses of ring widths with average monthly temperature, vapor pressure deficit (VPD), and precipitation were conducted. Our results show that the resin duct method performed poorly at both sites but better with P. lambertiana at Yosemite. Species at both sites generally have a positive correlation with precipitation. Earlywood and latewood correlations with climate were relatively weak. Temperature and VPD correlations were generally positive in the spring and negative in the summer months at both sites for all three species. These results reveal that future increases in temperature and VPD will leave these trees vulnerable to future droughts. More samples are needed throughout the Sierras to determine if the resin duct method can be used for subannual climate reconstructions, if these results can be generalized, and if sub-annual reconstructions are possible for these three species. [ABSTRACT FROM AUTHOR]

The giant sequoia (Sequoiadendron giganteum) of California are massive, long-lived trees that grow along the U.S. Sierra Nevada mountains. Genomic data are limited in giant sequoia and producing a reference genome sequence has been an important goal to allow marker development for restoration and management. Using deep-coverage Illumina and Oxford Nanopore sequencing, combined with Dovetail chromosome conformation capture libraries, the genome was assembled into eleven chromosome-scale scaffolds containing 8.125 Gbp of sequence. Iso-Seq transcripts, assembled from three distinct tissues, was used as evidence to annotate a total of 41,632 protein-coding genes. The genome was found to contain, distributed unevenly across all 11 chromosomes and in 63 orthogroups, over 900 complete or partial predicted NLR genes, of which 375 are supported by annotation derived from protein evidence and gene modeling. This giant sequoia reference genome sequence represents the first genome sequenced in the Cupressaceae family, and lays a foundation for using genomic tools to aid in giant sequoia conservation and management.

Abstract Uncovering the genetic basis of local adaptation is a major goal of evolutionary biology and conservation science alike. In an era of climate change, an understanding of how environmental factors shape adaptive diversity is crucial to predicting species response and directing management. Here, we investigate patterns of genomic variation in giant sequoia, an iconic and ecologically important tree species, using 1,364 bi‐allelic single nucleotide polymorphisms (SNPs). We use an FST outlier test and two genotype–environment association methods, latent factor mixed models (LFMMs) and redundancy analysis (RDA), to detect complex signatures of local adaptation. Results indicate 79 genomic regions of potential adaptive importance, with limited overlap between the detection methods. Of the 58 loci detected by LFMM, 51 showed strong correlations to a precipitation‐driven composite variable and seven to a temperature‐related variable. RDA revealed 24 outlier loci with association to climate variables, all of which showed strongest relationship to summer precipitation. Nine candidate loci were indicated by two methods. After correcting for geographic distance, RDA models using climate predictors accounted for 49% of the explained variance and showed significant correlations between SNPs and climatic factors. Here, we present evidence of local adaptation in giant sequoia along gradients of precipitation and provide a first step toward identifying genomic regions of adaptive significance. The results of this study will provide information to guide management strategies that seek to maximize adaptive potential in the face of climate change.

Taxol, a natural product derived from Taxus, is one of the most effective natural anticancer drugs and the biosynthetic pathway of Taxol is the basis of heterologous bio-production. Here, we report a high-quality genome assembly and annotation of Taxus yunnanensis based on 10.7 Gb sequences assembled into 12 chromosomes with contig N50 and scaffold N50 of 2.89 Mb and 966.80 Mb, respectively. Phylogenomic analyses show that T. yunnanensis is most closely related to Sequoiadendron giganteum among the sampled taxa, with an estimated divergence time of 133.4−213.0 MYA. As with most gymnosperms, and unlike most angiosperms, there is no evidence of a recent whole-genome duplication in T. yunnanensis. Repetitive sequences, especially long terminal repeat retrotransposons, are prevalent in the T. yunnanensis genome, contributing to its large genome size. We further integrated genomic and transcriptomic data to unveil clusters of genes involved in Taxol synthesis, located on the chromosome 12, while gene families encoding hydroxylase in the Taxol pathway exhibited significant expansion. Our study contributes to the further elucidation of gymnosperm relationships and the Taxol biosynthetic pathway. Song, Fu, Yang, Niu, Tian, et al. present a high-quality genome assembly and transcriptome data of Taxus yunnanensis, a plant belonging to the Taxus genus known for sources of traditional medicine and natural anticancer drugs. This study explores the Taxus evolutionary history and sheds light on the Taxol biosynthetic pathway. [ABSTRACT FROM AUTHOR]

Between 2012 and 2016, California suffered one of the most severe droughts on record. During this period Sequoiadendron giganteum (giant sequoias) in the Sequoia and Kings Canyon National Parks (SEKI), California, USA experienced canopy water content (CWC) loss, unprecedented foliage senescence, and, in a few cases, death. We present an assessment of the vulnerability of giant sequoia populations to droughts that is currently lacking and needed for management. We used a temporal trend of remotely sensed CWC obtained between 2015 and 2017, and recently georeferenced giant sequoia crowns to quantify the vulnerability of 7,408 individuals in 10 groves in the northern portion of SEKI. CWC is sensitive to changes in liquid water in tree canopies; therefore, it is a useful metric for quantifying the response of sequoia trees to drought. Temporal trends indicated that 9% of giant sequoias had a significant decline or consistently low CWC, suggesting these trees were likely operating at low photosynthetic capacity and potentially at high risk to drought stress. We also found that 20% of the giant sequoias had an increase or consistently high level of CWC, indicating these trees were at low risk to drought stress. These vulnerability categories were used in a random forest model with a combination of topographic, fire‐related, and climate variables to generate high‐resolution vulnerability risk maps. These maps show that higher risk is associated with lower elevation and higher climate water deficit. We also found that sequoias at higher elevations but located near meadows had higher vulnerability risk. These results and the vulnerability maps can identify vulnerable sequoias that may be difficult to save or locations of refugia to be protected, and thus may aid forest managers in preparation for future droughts. [ABSTRACT FROM AUTHOR]

Michael "Nick" Nichols's 2012 portrait of the 3200-year old, 247-foot tall giant sequoia named the President, the second largest tree known, for National Geographic, comprised of 126 separate photographs which have been digitally combined to make one image, challenges cultural plant-blindness and confronts the ethics of representation of plants, in particular trees, when the images are printed on plant-based paper. Neither art nor scientific illustration, the photojournalistic image draws connections between trees and photography, and both individualizes the tree and metaphorically references the biocommunity in which it participates. Nichols's approach to the portrait, which recognized the intimacy between himself, his team, and the tree, draws attention to plant sentience. The materiality of the image, published as a fold-out poster printed on paper that includes tree content, has the capacity to alert the viewer to the ethics of plant representation. [ABSTRACT FROM AUTHOR]

We used a prescribed fire study to demonstrate the concept of pyrosilviculture, defined here as (i) using prescribed fire to meet management objectives or (ii) altering nonfire silvicultural treatments explicitly in order to optimize the incorporation of prescribed fire in the future. The study included implementation of relatively hot prescribed burns in mixed-conifer forests that have been managed with gap-based silviculture. The fires burned through 12-, 22-, 32-, and 100-year-old cohorts, thus enabling an analysis of stand age influences on fire effects. Mastication and precommercial thinning were assessed as prefire treatments in the 12-year-old stands. Postburn mortality and crown scorch declined with stand age. There was a clear tradeoff between fuel consumption and high rates of tree damage and mortality in the 12-year-old stands. Masticated stands had higher levels of mean crown scorch (78%) compared with precommercially thinned stands (52%). Mortality for all 12-year-old stands was high, as nearly half of the trees were dead 1 year after the fires. Giant sequoia and ponderosa pine had relatively high resistance to fire-related mortality. When applying the concept of pyrosilviculture, there may be opportunities to combine prescribed fire with regeneration harvests that create a variety of gap sizes to sustain both low fire hazard and promote structural heterogeneity and sustainable age structures that may not be achieved with prescribed fire alone. [ABSTRACT FROM AUTHOR]

The cones of the giant sequoia contain red, water-soluble crystalline substances known as cone crystals. The inhibitory effect of this extracted material on Norway spruce, Scots pine and European larch germination was newly examined. Sown seed representative samples without and with added cone crystals were compared after their incubation in the same appropriate conditions. All these cases have brought compelling evidence that cone crystals totally inhibit germination. However, the chemically inhibited seeds being rinsed afterwards germinated very well. This switch effect caused by the cone crystals of the three above-mentioned conifers proved to be a nonspecific tool. Seeds of the giant sequoia, naturally affected by the cone crystals, were sown as rinsed and non-rinsed samples. Both the samples, grown on a wet peat substrate in appropriate conditions for 16 weeks, exhibited an equal, yet very low viability of 1.3% at the same time. This low number, fixed in seeds of the tree being far from the ecological optimum, does not allow any disputation with other authors.

The first dendroclimatic reconstruction of May 1 snow water equivalent (SWE) was developed from a Sequoiadendron giganteum regional tree-ring chronology network of 23 sites in central California for the period 90–2012 CE. The reconstruction is based on a significant relationship between May 1 SWE and tree-ring growth and shows climate variability from interannual to intercentennial time scales. A regression-based reconstruction equation explains up to 55% of the variance of SWE for 1940–2012. Split-sample validation supports our use of a reconstruction model based on the full period of reliable observational data (1940–2012). Thresholds for May 1 SWE low (15 percentile) and high (80 percentile) years were selected based on the exploratory scatterplots relationship between observed and reconstructed data for the period 1940–2012. The longest period of consecutive low-SWE years in the reconstruction is 2 years and the frequency of the lowest SWE years is highest during the period 710–809 CE. The longest high-SWE period, defined by consecutive wet years, is 3 years (558–560 CE). SWE and its reconstruction positively correlate with northeastern Pacific sea surface temperatures, the low-frequency variability of which may provide some predictive ability. Ultimately, the instrumental record and reconstruction suggest that unlike other sites in the region, twentieth century SWE variability in these Sequoia groves has remained within historical boundaries and relatively buffered from extremes and severe declines, though this is likely to change in coming decades with potentially negative effects on water availability for these trees. [ABSTRACT FROM AUTHOR]

Edmund Schulman is rightly honored for quantifying the age of bristlecone pines and discovering individuals significantly older than giant sequoias (Sequoiadendron gigantea), previously thought to be the oldest living things. However, George Engelmann inferred the potential for great age in his description of bristlecone pine (Pinus aristata) almost a century before, in 1863. Staff from Inyo National Forest re-made Engelmann's inference, and publically asserted that White Mountain bristlecones might outlive giant sequoias before Schulman had published any results of his bristlecone research. Schulman sampledWhiteMountains pines after seeing a photograph and caption associated with an article by founders of the University of California White Mountain Research Station. Although Schulman's correspondence and publications make this clear, incorrect theories regarding his decision to come to theWhite Mountains have been published and are promulgated at the Schulman Grove Visitor Center in the White Mountains. This paper places Schulman's work in its historic context by recovering forgotten information about attempts by Inyo National Forest staff and White Mountain Research Station to call attention to the trees. It also recovers details of Schulman's and C. Wesley Ferguson's activities in the White Mountains range as documented in field notes and Thomas Harlan's Bristlecone Pine Project database. [ABSTRACT FROM AUTHOR]

The properties of Giant Sequoia (Sequoiadendron giganteum (Lindley) Buchholz) seeds originating from a single cultivated Sequoia tree in the second gene strain in the Czech Republic were examined. The maximum germination level was set at 1.8%. This type is a pyrophyte, but nonetheless the short-term effects of a temperature of 100°C simulating a natural fire are still lethal. The seeds were planted with the same success in one case using a fungicide, which is routine practice in nurseries, and in another case using a "biological method" relying on the positive effect of soil microflora. Both stratified and non-stratified seeds can germinate, but stratification increases the number of germinating individual trees to at least double.

The article focuses on General Sherman who is talking about the American Civil War general. It mentions he is credited to General Sherman an attempt to eradicate the Sioux Indians, applying the tactic of the scorched earth in the war against the southern states, and an opportunistic view of slavery. It also mentions giant sequoia in Giant Forest, which is part of the California Sequoia National Park and parking lot where visitors enter General Sherman's grove.

The giant sequoia (Sequoiadendron giganteum) of California are massive, long-lived trees that grow along the U.S. Sierra Nevada mountains. Genomic data are limited in giant sequoia and producing a reference genome sequence has been an important goal to allow marker development for restoration and management. Using deep-coverage Illumina and Oxford Nanopore sequencing, combined with Dovetail chromosome conformation capture libraries, the genome was assembled into eleven chromosome-scale scaffolds containing 8.125 Gbp of sequence. Iso-Seq transcripts, assembled from three distinct tissues, was used as evidence to annotate a total of 41,632 protein-coding genes. The genome was found to contain, distributed unevenly across all 11 chromosomes and in 63 orthogroups, over 900 complete or partial predicted NLR genes, of which 375 are supported by annotation derived from protein evidence and gene modeling. This giant sequoia reference genome sequence represents the first genome sequenced in the Cupressaceae family, and lays a foundation for using genomic tools to aid in giant sequoia conservation and management. [ABSTRACT FROM AUTHOR]

Uncovering the genetic basis of local adaptation is a major goal of evolutionary biology and conservation science alike. In an era of climate change, an understanding of how environmental factors shape adaptive diversity is crucial to predicting species response and directing management. Here, we investigate patterns of genomic variation in giant sequoia, an iconic and ecologically important tree species, using 1,364 bi‐allelic single nucleotide polymorphisms (SNPs). We use an FST outlier test and two genotype–environment association methods, latent factor mixed models (LFMMs) and redundancy analysis (RDA), to detect complex signatures of local adaptation. Results indicate 79 genomic regions of potential adaptive importance, with limited overlap between the detection methods. Of the 58 loci detected by LFMM, 51 showed strong correlations to a precipitation‐driven composite variable and seven to a temperature‐related variable. RDA revealed 24 outlier loci with association to climate variables, all of which showed strongest relationship to summer precipitation. Nine candidate loci were indicated by two methods. After correcting for geographic distance, RDA models using climate predictors accounted for 49% of the explained variance and showed significant correlations between SNPs and climatic factors. Here, we present evidence of local adaptation in giant sequoia along gradients of precipitation and provide a first step toward identifying genomic regions of adaptive significance. The results of this study will provide information to guide management strategies that seek to maximize adaptive potential in the face of climate change. [ABSTRACT FROM AUTHOR]

Giant sequoia (Sequoiadendron giganteum) is an iconic conifer that lives in relict populations on the western slopes of the California Sierra Nevada. In these settings, it is unusual among the dominant trees in that it associates with arbuscular mycorrhizal fungi rather than ectomycorrhizal fungi. However, it is unclear whether differences in microbial associations extend more broadly to nonmycorrhizal components of the soil microbial community. To address this question, we used next‐generation amplicon sequencing to characterize bacterial/archaeal and fungal microbiomes in bulk soil (0–5 cm) beneath giant sequoia and co‐occurring sugar pine (Pinus lambertiana) individuals. We did this across two groves with distinct parent material in Yosemite National Park, USA. We found tree‐associated differences were apparent despite a strong grove effect. Bacterial/archaeal richness was greater beneath giant sequoia than sugar pine, with a core community double the size. The tree species also harbored compositionally distinct fungal communities. This pattern depended on grove but was associated with a consistently elevated relative abundance of Hygrocybe species beneath giant sequoia. Compositional differences between host trees correlated with soil pH and soil moisture. We conclude that the effects of giant sequoia extend beyond mycorrhizal mutualists to include the broader community and that some but not all host tree differences are grove‐dependent. [ABSTRACT FROM AUTHOR]

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Giant sequoia are endemic to the western slope of the Sierra Nevada, confined to approximately seventy groves spared from 19th century timber harvests. While nearly half of these groves were afforded protections through early National Park designations, only recently at the turn of the 21st century have the remainder of these been given protections on multiple use National Forest land. However, these megaflora continue to be impacted by forces exogenous to the groves themselves, including climatic change, high severity wildfire, exurban land use pressures, and industrial levels of tourism. The history, designation and current management of Giant Sequoia National Monument is emblematic of this shift from proximate impacts to a recognition of more systemic, landscape-level phenomena. We explain this shift in the scale of management through political-legal mandates, climatic and ecological complexity, and permissible recreational activities. The landscape unifies these processes across a monument on forest land, adjoined by parks. [ABSTRACT FROM AUTHOR]

Premise: Patterns of genetic structure across a species' range reflect the long‐term interplay between genetic drift, gene flow, and selection. Given the importance of gene flow in preventing the loss of diversity through genetic drift among spatially isolated populations, understanding the dynamics of gene flow and the factors that influence connectivity across a species' range is a major goal for conservation of genetic diversity. Here we present a detailed look at gene flow dynamics of Sequoiadendron giganteum, a paleoendemic tree species that will likely face numerous threats due to climate change. Methods: We used microsatellite markers to examine nineteen populations of S. giganteum for patterns of genetic structure and to estimate admixture and rates of gene flow between eight population pairs. Also, we used Generalized Dissimilarity Models to elucidate landscape factors that shape genetic differentiation among populations. Results: We found minimal gene flow between adjacent groves in the northern disjunct range. In most of the southern portion of the range, groves showed a signal of connectivity which degrades to isolation in the extreme south. Geographic distance was the most important predictor of genetic dissimilarity across the range, with environmental conditions related to precipitation and temperature explaining a small, but significant, portion of the genetic variance. Conclusions: Due to their isolation and unique genetic composition, northern populations of S. giganteum should be considered a high conservation priority. In this region, we suggest germplasm conservation as well as restoration planting to enhance genetic diversity. [ABSTRACT FROM AUTHOR]