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1. Juvenile morphology of the large Antarctic canopy-forming brown alga, Desmarestia menziesii J. Agardh

   https://doi.org/10.1007/s00300-019-02584-3  

   Küpper, Frithjof C.; Amsler, Charles D.; Morley, Simon; de Reviers, Bruno; Reichardt, Aurelia; Peck, Lloyd S.; Peters, Akira F. (November 2019, Polar Biology)
2. Prefire Drought Intensity Drives Postfire Recovery and Mortality in Pinus monticola and Pseudotsuga menziesii Saplings

   https://doi.org/10.1093/forsci/fxae013  

   Sparks, Aaron M; Blanco, Alexander S; Lad, Lauren E; Smith, Alistair M; Adams, Henry D; Tinkham, Wade T (March 2024, Forest Science)

   Abstract Increasing frequency of droughts and wildfire are sparking concerns that these compounded disturbance events are pushing forested ecosystems beyond recovery. An improved understanding of how compounded events affect tree physiology and mortality is needed given the reliance of fire management planning on accurate estimates of postfire tree mortality. In this study, we use a toxicological dose-response approach to quantify the impact of variable-intensity drought and fire on the physiology and mortality of Pinus monticola and Pseudotsuga menziesii saplings. We show that the dose-response relationship between fire intensity and mortality shifts toward increased vulnerability under drought, indicating higher mortality with increasing drought at any fire intensity. The trajectory we observed in postfire chlorophyll fluorescence, an indicator of photosynthetic efficiency and stress, was an effective early warning sign of impending tree death. Postfire mortality modeling shows that accurate mortality classification can be achieved using prefire physiology and morphology metrics combined with fire intensity. Variable importance measures indicate that physiological condition and fire intensity have greater influence on the classification accuracy than morphological metrics. The wide range in drought and fire responses observed between this study and others highlights the need for more research on compound disturbance effects. Study Implications: An improved understanding of how drought and fire affect tree physiology and mortality is needed by natural resource managers looking to predict postfire tree mortality. This study advances our compound disturbance understanding by subjecting conifer saplings to variable drought and fire intensities and quantifying and modeling moderate-term recovery and mortality. The results show reduced physiological recovery and amplified mortality in saplings exposed to greater drought and fire intensity. Overall, this study highlights the importance of physiological condition when modeling tree mortality and could potentially be used to inform current postfire tree mortality models. 

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3. The Curious Douglas-Fir ( Pseudotsuga Menziesii ) Trees in Schulman Grove, Mesa Verde National Park, Southwestern Colorado, USA

   https://doi.org/10.1017/aaq.2021.4  

   Nash, Stephen E.; Towner, Ronald H.; Dean, Jeffrey S. (July 2021, American Antiquity)

   En 1954, los arqueólogos James Allen Lancaster y Don Watson, y el dendrocronólogo Edmund Schulman afirmaron que una pequeña arboleda de árboles de abeto Douglas ( Pseudotsuga menziesii [Mirb.] Franco var. glauca [Beissen.] Franco), en el Cañón Navajo en el lado oeste de Chapin Mesa, en el Parque Nacional de Mesa Verde, al suroeste de Colorado, EE. UU., contenía evidencia de ramas de árboles cortadas con una hacha de piedra. En 1965, los arqueólogos Robert Nichols y David Smith publicaron un artículo titulado “Evidencia del cultivo prehistórico de árboles de abeto Douglas en Mesa Verde,” en el que apoyan la afirmación de Lancaster/Watson/Schulman sobre la evidencia de ramas de árboles cortadas con una hacha de piedra. Ellos utilizaron las fechas en los anillos de árboles de las presuntas ramas de árboles cortadas con una hacha de piedra. Nichols y Smith, documentaron los únicos tres árboles Douglas en el Parque Nacional de Mesa Verde que contienen tallos cortados con una hacha de piedra, presentando evidencia de un manejo forestal precolombino. Nosotros intentamos replicar el trabajo de Nichols y Smith. Revisamos los documentos archivados, incluida toda la correspondencia, analizamos las muestras de anillos de árboles que estaban archivadas y muestras colectadas recientemente. Hicimos un análisis controlado y comparamos los registros archivados y publicados. Nosotros no pudimos confirmar sus resultados, por lo cual rechazamos la afirmación de que en la arboleda de Schulman ocurrió una manipulación precolombina de árboles por parte de los habitantes ancestrales de Mesa Verde. 

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4. A long-read and short-read transcriptomics approach provides the first high-quality reference transcriptome and genome annotation for Pseudotsuga menziesii (Douglas-fir)

   https://doi.org/10.1093/g3journal/jkac304  

   Velasco, Vera Marjorie; Ferreira, Alyssa; Zaman, Sumaira; Noordermeer, Devin; Ensminger, Ingo; Wegrzyn, Jill L (December 2022, G3 Genes|Genomes|Genetics)

   Holland, J. (Ed.)

   Abstract Douglas-fir (Pseudotsuga menziesii) is native to western North America. It grows in a wide range of environmental conditions and is an important timber tree. Although there are several studies on the gene expression responses of Douglas-fir to abiotic cues, the absence of high-quality transcriptome and genome data is a barrier to further investigation. Like for most conifers, the available transcriptome and genome reference dataset for Douglas-fir remains fragmented and requires refinement. We aimed to generate a highly accurate, and complete reference transcriptome and genome annotation. We deep-sequenced the transcriptome of Douglas-fir needles from seedlings that were grown under nonstress control conditions or a combination of heat and drought stress conditions using long-read (LR) and short-read (SR) sequencing platforms. We used 2 computational approaches, namely de novo and genome-guided LR transcriptome assembly. Using the LR de novo assembly, we identified 1.3X more high-quality transcripts, 1.85X more “complete” genes, and 2.7X more functionally annotated genes compared to the genome-guided assembly approach. We predicted 666 long noncoding RNAs and 12,778 unique protein-coding transcripts including 2,016 putative transcription factors. We leveraged the LR de novo assembled transcriptome with paired-end SR and a published single-end SR transcriptome to generate an improved genome annotation. This was conducted with BRAKER2 and refined based on functional annotation, repetitive content, and transcriptome alignment. This high-quality genome annotation has 51,419 unique gene models derived from 322,631 initial predictions. Overall, our informatics approach provides a new reference Douglas-fir transcriptome assembly and genome annotation with considerably improved completeness and functional annotation. 

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