Representatives of thePine Family (Pinaceae Lindl.) of the North American Flora in the Collection of the Dendrological Garden named after V.N. Nilov (NRIF)

The article presents the results of the introduction of the North American flora woody species of the pine family (Pinaceae Lindl.) to the European North of Russia. The research purpose is to select the most valuable specimens for introduction into northern conditions from the tree species collection. The research has involved experimental, calculation, analytical, and comparative methods. The conclusion on the result of the introduction of a particular plant was based on the materials of long-term phenological observations, which were carried out according to the method of botanical gardens improved for the conditions of the European North of Russia. As a result of the introduction of North American species of the Pinaceae Lindl. family to the region, a large-scale test of foreign conifers was carried out for the first time; a collection of 2 species of fir, 4 species and 3 forms of spruce, 2 species of pine, and 1 species of Douglas fir was created. Most attention was paid to the introduction of species of the genus Pinus. Positive results of cultivation of Pinus contorta Loud. var. latifolia S. Wats. in the Dendrological garden allowed us to select it for further introduction testing in experimental plantations of the region. On plantations located in the Arkhangelsk and Vologda regions and the Komi Republic, 104.2 ths seedlings were grown from the seed samples, mostly from the northern natural range of this pine. Unfortunately, not all of the breeding material for the North American pine species tested was derived from natural growth sites, which puts into question some of the unsatisfactory results. Therefore, for Jack pine and Weymouth pine, it is advisable to use in testing additional samples from the most northern regions of their natural ranges in Canada. Many of these species are of both scientific and practical interest for forestry. To assess the economic value of those introduced species, adaptive capabilities of which in the conditions of the European North according to the results of studies are not in doubt, it is advisable to lay out pilot plantations in the region, similar to the already created plantings of North American lodgepole pine (Pinus contorta Loud. var. latifolia S. Wats.). The concentration of different species like balsam fir (Abies balsamea Mill.), Fraser fir (Abies fraseri (Pursch.) Poir.), American larch (Larix laricina (Du Roi) K.Koch.), Canadian spruce (Picea glauca Voss.), Engelmann’s spruce (Picea engelmannii Engelm.), black spruce (Picea mariana Britt.), Jack pine (Pinus banksiana Lamb.), lodgepole pine (Pinus contorta Loud. var. latifolia S. Wats.), and Douglas fir (Pseudotsuga menziesii Mirb.), involving several seed origins from the most northern regions of its natural range for each, in 2-3 forest areas will allow creating a valuable introduction object; scientific and practical importance of those mentioned cannot be overestimated.

Lodgepole Pine Bole Wood Density and Decay Rate 1, 11, and 22 Years After Felling in Central Montana, United States

Estimates of dead and down woody material (DWM) biomass are important for nutrient cycling, wildlife habitat assessment, fire effects and climate change science. Most methods used to sample woody material initially assess volume then estimates of wood density are used to convert volume to biomass. To assess initial wood density and decomposition rate, this study examined in situ wood density of lodgepole pine logs at the Tenderfoot Creek Experimental Forest (TCEF), central Montana, United States, 1, 11, and 22 years after felling. Mean wood density decreased from 0.39 to 0.27 g cm–3 over 22 years and the single exponential decay rate was k = 0.012 yr–1 1 and 11-years post-felling and 0.022 yr–1 11 and 22 years post-felling. A common 5-category decay classification system was evaluated for estimating wood density by decay class, which identified significant difference in three of four observed classes.

Lodgepole pine and interior spruce radial growth response to climate and topography in the Canadian Rocky Mountains, Alberta

Climate change may have spatially variable impacts on growth of trees in topographically diverse environments, making generalizing across broad spatial and temporal extents inappropriate. Therefore, topography must be considered when analyzing growth response to climate. We address these topo-climatic relationships in the Canadian Rocky Mountains, focusing on lodgepole pine (Pinus contorta Douglas ex Louden) and interior spruce (Picea glauca (Moench) Voss × Picea engelmannii hybrid Parry) growth response to climate, Palmer drought severity index (PDSI), aspect, and slope angle. Climate variables correlate with older lodgepole pine growth on south- and west-facing slopes, including previous August temperature, winter and spring precipitation, and previous late-summer and current spring PDSI, but younger lodgepole pine were generally less sensitive to climate. Climate variables correlate with interior spruce growth on all slope aspects, with winter temperature and PDSI important for young and old individuals. Numerous monthly growth–climate correlations are not temporally stable, with shifts over the past century, and response differs by slope aspect and angle. Both species are likely to be negatively affected by moisture stress in the future in some, but not all, topographic environments. Results suggest species-specific and site-specific spatiotemporally diverse climate–growth responses, indicating that climate change is likely to have spatially variable impacts on radial growth response in mountainous environments.

Bayesian Predictions of Bark Beetle Attack and Mortality of Three Conifer Species During Epidemic and Endemic Population Stages

Bark beetles naturally inhabit forests and can cause large-scale tree mortality when they reach epidemic population numbers. A recent epidemic (1990s–2010s), primarily driven by mountain pine beetles (Dendroctonus ponderosae), was a leading mortality agent in western United States forests. Predictive models of beetle populations and their impact on forests largely depend on host related parameters, such as stand age, basal area, and density. We hypothesized that bark beetle attack patterns are also dependent on inferred beetle population densities: large epidemic populations of beetles will preferentially attack large-diameter trees, and successfully kill them with overwhelming numbers. Conversely, small endemic beetle populations will opportunistically attack stressed and small trees. We tested this hypothesis using 12 years of repeated field observations of three dominant forest species (lodgepole pine Pinus contorta, Engelmann spruce Picea engelmannii, and subalpine fir Abies lasiocarpa) in subalpine forests of southeastern Wyoming paired with a Bayesian modeling approach. The models provide probabilistic predictions of beetle attack patterns that are free of assumptions required by frequentist models that are often violated in these data sets. Furthermore, we assessed seedling/sapling regeneration in response to overstory mortality and hypothesized that higher seedling/sapling establishment occurs in areas with highest overstory mortality because resources are freed from competing trees. Our results indicate that large-diameter trees were more likely to be attacked and killed by bark beetles than small-diameter trees during epidemic years for all species, but there was no shift toward preferentially attacking small-diameter trees in post-epidemic years. However, probabilities of bark beetle attack and mortality increased for small diameter lodgepole pine and Engelmann spruce trees in post-epidemic years compared to epidemic years. We also show an increase in overall understory growth (graminoids, forbs, and shrubs) and seedling/sapling establishment in response to beetle-caused overstory mortality, especially in lodgepole pine dominated stands. Our observations provide evidence of the trajectories of attack and mortality as well as early forest regrowth of three common tree species during the transition from epidemic to post-epidemic stages of bark beetle populations in the field.

Effects of SO2 emissions in Alberta, Canada on lodgepole pine climate-growth relationships

<p>The growth response of trees to climate can be altered by other environmental changes that a tree may face including pollution or fertilization. In this study, the effect of spatial and temporal patterns sulfur dioxide (SO<sub>2</sub>) emissions on climate-growth relationships of lodgepole pine (Pinus contorta) in two areas of Alberta, Canada was assessed. Twenty tree cores were collected in each of four stands per study area: two near a source of SO<sub>2</sub> emissions (sour gas processing facility) and two far from the source of emissions. To select important climate variables, the average standardized tree ring width of all trees in each area were first compared to monthly average temperature and total precipitation variables. For each important climate variable, response function analysis was conducted between standardized tree ring widths and climate in each of three SO<sub>2</sub> exposure time periods: a period pre-dating any emissions, a period of high emissions, and a more recent period of reduced emissions. Linear mixed models were used to compare response coefficients of tree ring widths to climate between exposure space (near or far from the source of emissions) and exposure time (no emissions, high emissions, reduced emissions) and the interaction between them. The absolute values of predicted ring widths in each exposure space and exposure time in each area were used as a response variable in a linear mixed effects model to assess the effects of SO<sub>2</sub> exposure on the magnitude of tree growth response to climate. SO<sub>2</sub> exposure time was a significant term in all climate-growth relationship models. Exposure space was significant in 13 out of 20 models, and the interaction between exposure time and exposure space was significant in 14 out of 20 models. The effects of exposure time and exposure space on climate-growth relationships were not consistent between climate variables. Overall, tree growth responded most strongly to climate in the high exposure time period. The increase in magnitude of climate-growth relationships in the high SO<sub>2</sub> exposure time period may indicate that trees stressed by sulfur deposition are not able to buffer the effects of climate, and are more susceptible to extreme weather conditions such as drought. However, the response to climate during the high emission period was greater far from the source of emissions than near the source of emissions; This could be because the historical addition of lime to stands near the sour gas processing facilities resulted in less sulfur stress. SO<sub>2</sub> emissions in Alberta may alter climate-growth relationships of lodgepole pine.  </p>