More Like this

1. Differential defoliation and mortality of white spruce and balsam fir by eastern spruce budworm

   https://doi.org/10.1016/j.foreco.2022.120042  

   Corona, Cristian ; Leeper, Abigail C. ; LaMontagne, Jalene M. ( March 2022 , Forest Ecology and Management)
2. Western Spruce Budworm Outbreaks Did Not Increase Fire Risk over the Last Three Centuries: A Dendrochronological Analysis of Inter-Disturbance Synergism

   https://doi.org/10.1371/journal.pone.0114282  

   Flower, Aquila ; G. Gavin, Daniel ; Heyerdahl, Emily K. ; Parsons, Russell A. ; Cohn, Gregory M. ; Carcaillet, Christopher ( December 2014 , PLoS ONE)
3. Ethanol exposure can inhibit red spruce ( Picea rubens ) seed germination

   https://doi.org/10.15258/sst.2018.46.2.07  

   Butnor, John R. ; Verrico, Brittany M. ; Vankus, Victor ; Keller, Stephen R. ( June 2018 , Seed Science and Technology)

   Flotation of seeds in solvents is a common means of separating unfilled and filled seeds. While a few protocols for processing red spruce (Picea rubens) seeds recommend ethanol flotation, delayed and reduced germination have been reported. We conducted an ethanol bioassay on seeds previously stored at -20°C to quantify the concentration required to separate red spruce seeds and the effects on germination. We used seeds from Canada (CAN) that had been exposed to ethanol during processing, and seeds from the United States (USA) that had not been exposed to ethanol during processing. Seeds were exposed to 10 ethanol concentrations (10-100%) and deionised water was used as a control. The effective concentration of ethanol for 50% (EC50) of the seeds to sink ranged by source from 70.9 to 90.7%, with all seeds sinking in 100% ethanol. The use of less than 100% ethanol is not adequate for seed separation, as some filled seeds could float and be mistakenly categorised as unfilled. The mean EC50 of ethanol that inhibits germination was significantly higher for USA sources (52.7%), than for CAN sources (40.8%; P < 0.05). Ethanol concentrations that inhibited germination coincided with delays in germination. The mechanism of phytotoxity was not determined;more »however, damage during extraction, desiccation and storage at -20°C are potential sources. We recommend separating red spruce seeds by physical means rather than ethanol flotation to avoid potential negative impacts on germination.« less
4. Whole‐exome sequencing reveals a long‐term decline in effective population size of red spruce ( Picea rubens )

   https://doi.org/10.1111/eva.12985  

   Capblancq, Thibaut ; Butnor, John R. ; Deyoung, Sonia ; Thibault, Ethan ; Munson, Helena ; Nelson, David M. ; Fitzpatrick, Matthew C. ; Keller, Stephen R. ( May 2020 , Evolutionary Applications)

   Understanding the factors influencing the current distribution of genetic diversity across a species range is one of the main questions of evolutionary biology, especially given the increasing threat to biodiversity posed by climate change. Historical demographic processes such as population expansion or bottlenecks and decline are known to exert a predominant influence on past and current levels of genetic diversity, and revealing this demo‐genetic history can have immediate conservation implications. We used a whole‐exome capture sequencing approach to analyze polymorphism across the gene space of red spruce (Picea rubens Sarg.), an endemic and emblematic tree species of eastern North America high‐elevation forests that are facing the combined threat of global warming and increasing human activities. We sampled a total of 340 individuals, including populations from the current core of the range in northeastern USA and southeastern Canada and from the southern portions of its range along the Appalachian Mountains, where populations occur as highly fragmented mountaintop “sky islands.” Exome capture baits were designed from the closely relative white spruce (P. glauca Voss) transcriptome, and sequencing successfully captured most regions on or near our target genes, resulting in the generation of a new and expansive genomic resource for studying standing geneticmore »variation in red spruce applicable to its conservation. Our results, based on over 2 million exome‐derived variants, indicate that red spruce is structured into three distinct ancestry groups that occupy different geographic regions of its highly fragmented range. Moreover, these groups show small Ne , with a temporal history of sustained population decline that has been ongoing for thousands (or even hundreds of thousands) of years. These results demonstrate the broad potential of genomic studies for revealing details of the demographic history that can inform management and conservation efforts of nonmodel species with active restoration programs, such as red spruce.« less
5. High frequency growth variability of White spruce clones does not differ from non-clonal trees at Alaskan treelines

   https://doi.org/10.1016/j.dendro.2017.05.005  

   Wilmking, Martin ; Buras, Allan ; Eusemann, Pascal ; Schnittler, Martin ; Trouillier, Mario ; Würth, David ; Lange, Jelena ; van der Maaten-Theunissen, Marieke ; Juday, Glenn Patrick ( June 2017 , Dendrochronologia)