Pinus Strobus Research Articles

Does forest tree species composition impact modelled soil recovery from acidic deposition?

Acidic deposition depleted soil base cation pools throughout central Ontario, particularly during the second half of the 20th century. While sulfur (S) and nitrogen (N) deposition have declined in recent decades, forest harvesting may continue to remove base cations from soils, highlighting the need for reliable soil chemistry forecasts. This study investigated whether differences in soil chemistry among forest plots dominated by different tree species affected predictions using a dynamic biogeochemical model, the Very Simple Dynamic model. Soil base saturation was modelled from 1850 to 2100 in plots dominated by balsam fir (Abies balsamea (L.) Mill.), eastern hemlock (Tsuga canadensis (L.) Carr.), white pine (Pinus strobus L.), sugar maple (Acer saccharum Marsh.), or yellow birch (Betula alleghaniensis Britt.). Three scenarios that manipulated future atmospheric S and N deposition and forest harvesting (2020–2100) were applied. When future atmospheric S and N deposition remained at 2020 levels and harvesting continued, base saturation increased marginally (2.0%–4.5%) in all plots. Further increases in base saturation were minor (∼1%) by 2100 when deposition reductions were implemented. When future forest harvesting was excluded, soil base saturation increased 3.4%–8.5% from 2020 to 2100. These results suggest that tree species composition has minimal influence on modelled soil chemistry forecasts in response to changes in acidic deposition, and such models can be broadly applied for regional predictions.

Determining the impact of sensor orientation on moisture content measurements in eastern white pine

As buildings become more airtight and insulated, the movement and accumulation of moisture within building envelopes become paramount in determining its resiliency. Current methods for quantifying the moisture content (MC) of wood species involve the measurement of electrical resistance between two installed electrodes and the use of existing empirical correlations to evaluate the MC. However, these correlations do not adequately consider the impact of sensor orientation within wall assemblies. The objective of this paper is to determine the impact of MC readings within a wood sample due to sensor orientation. A total of 126 eastern white pine samples were tested with electrodes placed along the grain of the wood (longitudinal), across the grain of the wood (tangential), and in a diamond pattern, using six different fasteners as electrodes. The samples were placed in a controlled environmental chamber until steady state was achieved at approximately 18% MC. Electrical resistances of the samples were measured in both directions at temperatures ranging from -10°C to 40°C. It was found that the tangential-to-longitudinal resistance ratio is 1.1-1.35 depending on the electrode type.

White-tailed deer herbivory impacts on tree seedling and sapling abundance in the Lake States Region of the USA

White-tailed deer (Odocoileus virginiana Zimmermann) browsing reduces seedling and sapling abundance of more palatable winter woody browse such as Tsuga canadensis L. Carrière, Thuja occidentalis L., Betula alleghaniensis Britton, and Pinus strobus L. across the Lake States Region of the USA. White-tailed deer consume buds and twigs of tree seedlings and saplings as forage. Deer populations in the Lake States Region of the USA have increased over recent decades due to a decrease in predators and an increase in habitat fragmentation. Higher deer population densities present challenges to regeneration of tree species. The objective of this work was to quantify the effects of deer browsing on tree seedling and sapling abundance and species richness of woody tree species which vary in deer browse palatability. Deer browsing impact measurements from the tree regeneration indicator from the US Department of Agriculture Forest Service’s Forest Inventory and Analysis program were used to predict seedling and sapling abundance from overstory basal area and a deer browsing index in the Lake States Region. Overstory basal area was important in predicting seedling and sapling abundance for all species (p < 0.05). Deer browsing affected seedling and sapling abundance differently across species, with the most palatable species showing lower stocking or negligible effects with browse. Results support the importance of quantifying impacts of deer browsing for use in determining the survival and abundance of palatable species in the smallest size cohorts.

Seedling Response to Simulated Browsing and Reduced Water Availability: Insights for Assisted Migration Plantations

To facilitate forest transition to future climate conditions, managers can use adaptive silvicultural tools, for example the assisted translocation of tree species and genotypes to areas with suitable future climate conditions (i.e., assisted migration). Like traditional plantations, however, assisted migration plantations are at risk of failure because of browsing by ungulate herbivores. The ability of seedlings to tolerate browsing could also be hampered by low water availability, as is expected under climate change. Using a greenhouse experiment with five eastern North American tree species, we evaluated the effects of simulated winter browsing and reduced water availability on the growth (total biomass, shoot:root ratio), survival, and chemical composition (nitrogen, total phenolics, flavonoids) of seedlings. We compared seedlings from three geographic provenances representing three climate analogues, i.e., locations with a current climate similar to the climate predicted at the plantation site at a specific time (here: current, mid-century and end of the century). We hypothesized that seedlings would allocate resources to the system (shoots or roots) affected by the most limiting treatment (simulated browsing or reduced water availability). Additionally, we evaluated whether the combination of treatments would have an additive or non-additive effect on the growth, survival and chemical composition of the seedlings. Quercus rubra seedlings reacted only to the water reduction treatment (changes in biomass and N concentration, dependent on geographic provenance) while Pinus strobus reacted only to the simulated browsing treatment (biomass and chemical composition). We also observed non-additive effects of reduced water availability and simulated browsing on Prunus serotina, Acer saccharum and Thuja occidentalis. In general, shoot:root ratio and investment in chemical defense did not vary in response to treatments. The regrowth response observed in Q. rubra and A. saccharum suggests that these species could tolerate periodic browsing events, even when water availability is reduced. More information is required to understand their long-term tolerance to repeated browsing events and to harsher and more frequent water stress. We highlight the importance of species-specific growth and allocation responses that vary with geographic provenance, which should be considered by managers when planning climate-adapted strategies, such as assisted migration.

Cleaner production of flexographic ink by substituting carbon black with biochar

There is growing interest in making printing inks more sustainable, and lowering the overall carbon footprint of the printing industry. A recent surge of research activity has emerged to develop “green” inks with bio-based solvents and binders, but little attention has been given to replacing the pigments that give inks their distinctive color. In this study, flexographic inks were formulated by replacing carbon black with a more sustainable biochar pigment derived from recycled paper, and fast growth cycle wood pulp. Obtained from fossil fuel sources, carbon black imparts high quality black prints, but at a significant environmental cost. Biochar, derived from recycled and renewable resources, has the potential to replace carbon black in many applications. Canceled United States currency stock was pyrolyzed at 1600 °C to produce a black biochar. Eastern White Pine (Pinus strobus) was selected for comparison, and converted to biochar at 550 °C and 1600 °C. Each biochar was functionalized and formulated into a simple ink composition optimized for flexographic printing. Prints exhibiting reflective optical densities exceeding 1.0 with excellent tone reproduction were obtained. Comparable print quality was achieved on both coated and uncoated paper substrates. Although further work would be required to fully optimize a biochar ink to match current print industry standards, a viable pathway for sustainable black ink development with good black density derived from recycled resources has been demonstrated. Our results indicate that it is possible to replace fossil fuel-based carbon black with biomass derived biochar, potentially resulting in cleaner production of flexographic printing inks.

Detecting growth releases of mature retention trees in response to small-scale gap disturbances of known dates in natural-disturbance-based silvicultural systems in Maine

Disturbances play a fundamental role in shaping forest communities. It is therefore important to accurately quantify their frequency and magnitude in forest ecosystems. Tree-ring series are commonly used for relatively accurate detection of past disturbances. Currently, several dendroecological techniques exist that enable the detection of disturbances in tree-ring series. In this study, increment cores (n = 312) were collected from trees that were deliberately retained in harvested gaps of two natural-disturbance-based silvicultural systems in the Acadian Forest of Maine, USA. These systems were designed to approximate the gap-based natural disturbance regime of the region. Since the specific harvest dates and severities were known, we compared the efficacy of three predominant disturbance detection techniques in accurately detecting disturbance within two years of the harvest date across five common, yet ecologically distinct species -- Acer rubrum, Picea rubens, Pinus strobus, Thuja occidentalis, and Tsuga canadensis -- and the length of elapsed time prior to when maximum growth responses were experienced. We tested the growth-averaging method, the boundary-line method, and the combination of the growth-averaging and boundary-line methods (Splechtna method) using the TRADER R package. We found little variation among detection techniques in their -- relatively high success -- rate of detecting disturbance within two years of the harvest date (growth-averaging method: 69.9%, Splechtna method: 68.6%, and boundary-line method: 64.1%). We most frequently found negative correlations with pre-treatment growth rates and detection rates among detection techniques. Our estimates of disturbance severity did not influence the probability of detecting the year-of-harvest. Of the species tested, Tsuga canadensis (73.7% − 85.5%) and Thuja occidentalis (78.4% − 83.7%) had the greatest detection rates across the techniques while Pinus strobus was consistently the lowest (51%). Time-lags – defined as the number of years post-harvest before a tree reaches its peak growth rate – were also analyzed. Pre-disturbance basal area increment and crown ratio were marginally negatively correlated with the length of time-lags in response to harvest and Thuja occidentalis (7.2 ± 0.4) and Tsuga canadensis (6.8 ± 0.3) had significantly longer time-lags than Acer rubrum (5.4 ± 0.3). Overall, all techniques demonstrated relatively high detection rates (>60%), given the range of sizes and ages of the species tested and reduced two-year time window for detection. Absent from all models were variables that measured disturbance severity, which suggests tree responses to disturbance were more sensitive to tree-level attributes and local changes to the growing environment.

Efficacy of delayed entry low branch sanitation pruning in preventing mortality of western white pine infected with white pine blister rust

White pine blister rust, caused by the fungus Cronartium ribicola J. C. Fisch., is a virulent mortality agent of five-needle pines like western white pine (Pinus monticola D. Don.). For decades, low branch pruning has been recommended as a control by removing cankers that can migrate from infected branches to the tree stem and kill the host. These recommendations are mainly based on studies done on eastern white pine (Pinus strobus L.), or on western white pine growing primarily in the Interior Pacific Northwest of the United States. It is not clear whether these recommendations are transferable to geographically and climatically dissimilar Pacific coastal areas, where pruning often shows little benefit in commercial forest plantations. We summarize over 30 years of post-treatment data from coastal and interior sites in British Columbia. Sanitation pruning was done on 12–22-year-old stands using one or two pruning lifts and infection and mortality were tracked over the subsequent decades. Our results show that while pruning had little negative effect on treated tree height or diameter growth, mortality was not significantly different between treated and untreated groups across all sites. Cumulative mortality after three decades was >80% for coastal sites, and nearly 60% for the interior site, indicating a lack of treatment efficacy. Our results differ from earlier shorter duration studies and those from other jurisdictions. It is clear that delaying pruning until trees are older and carrying many existing branch and stem infections results in ineffective control of rust in coastal white pine stands.

Ecological analysis of intraspecific variability of eastern white pine (Pinus strobus) under climate change by combining provenance and demographic data

Ecological analysis of intraspecific variability of eastern white pine (Pinus strobus) under climate change by combining provenance and demographic data

Long-term development of transition hardwood and Pinus strobus - Quercus mixedwood forests with implications for future adaptation and mitigation potential

Uncertainty about global environmental change has led to increased emphasis on the climate adaptation and mitigation potential of forests. Given the linkages between adaptive capacity and ecosystem complexity, this increased emphasis has motivated evaluations of the compositional, functional, and structural conditions characterizing a given forest ecosystem in the context of future stressors; however, less is known about how these conditions develop over time or vary between secondary forests shaped by a history of land use. To address this need, we capitalize on a 69-year field experiment to examine the long-term structural and compositional dynamics of transition ecotone hardwood (forests containing species from both southern and northern communities) and Pinus strobus-Quercus mixedwood (stands characterized by hardwood and softwood species mixtures) forests, communities which are commonly found in the Northeastern US. As expected, we observed a general increase in biomass over time and increasing density and structural complexity, with live aboveground biomass greatest in structurally complex mixedwood systems dominated by large diameter P. strobus. While all forests trended toward greater shade tolerance with increasing stand age, the functional identities of hardwood stands were stable over time compared to mixedwoods, which were more transient and ultimately generated trait profiles resembling hardwood-dominated stands. Ingrowth on all sites favored shade-tolerant Fagus grandifolia and Tsuga canadensis, which have lower future climate compatibility and adaptability compared to overstory trees, with a noticeable absence of P. strobus and Quercus spp. regeneration. Although all forest types exhibited some conditions that foster adaptation potential, the compositional stability of hardwood-dominated systems highlight the capacity of these stands to maintain comparable levels of adaptive capacity into the future. Conversely, given that P. strobus-Quercus mixedwoods examined are largely an artifact of land use, the natural successional patterns of these forests may lead to a reduction in these mixed species communities and a depreciation of associated climate benefits without silvicultural intervention to favor recruitment of these constituent species.

Simulated winter warming has negligible effects on germination success of Acadian Forest tree species

Dormant seeds that require long periods of cold stratification to become germinable may be most sensitive to increases in winter temperatures caused by anthropogenic climate change. In this study, we used outdoor plots with infrared heaters to simulate the effects of projected winter warming (+6 °C) for Canada’s Acadian Forest Region and compared seed germination success of tree species with varying stratification requirements. We evaluated four seedlots each of balsam fir (Abies balsamea (L.) Mill.), red spruce (Picea rubens Sarg.), white pine (Pinus strobus L.), red maple (Acer rubrum L.), sugar maple (Acer saccharum Marshall), and yellow birch (Betula alleghaniensis Britton). Three central findings emerged from this study: (i) none of the tested species were significantly affected by warming; (ii) the random effect of seedlot explained more variation in germination success of deciduous species than it did for conifers; and (iii) balsam fir seedlots exhibited considerable differences in their response to warming, implying intraspecific variation in depth of dormancy. These results suggest seed germination success of the tested tree species may not be impeded by their individual seed characteristics under the magnitude of winter warming projected over the coming century in our study area.

Assessment of Air Pollution Tolerance and Particulate Matter Accumulation of 11 Woody Plant Species

High concentration of particulate matter (PM) threatens public health and the environment. Increasing traffic in the city is one of the main factors for increased PM in the air. Urban green spaces play an important role in reducing PM. In this study, the leaf surface and in-wax PM (sPM and wPM) accumulation were compared for 11 plant species widely used for landscaping in South Korea. In addition, biochemical characteristics of leaves (ascorbic acid chlorophyll content, leaf pH, and relative water content) were analyzed to determine air pollution tolerance. Plant species suitable for air quality improvement were selected based on their air pollution tolerance index (APTI) and anticipated performance index (API). Results showed a significant difference according to the accumulation of sPM and wPM and the plant species. PM accumulation and APTI showed a positive correlation. Pinus strobus showed the highest PM accumulation and APTI values, while Cercis chinensis showed the lowest. In 11 plants, API was divided into five groups. Pinus densiflora was classified as the best group, while Cornus officinalis and Ligustrum obtusifolium were classified as not recommended.

Additional carbon sequestration potential of abandoned agricultural land afforestation in the boreal zone: A modelling approach

Agricultural land abandonment is a widespread phenomenon that generally results in C accumulation due to natural establishment of woody vegetation. However, whether afforestation of abandoned agricultural lands (AAL) can sequester more C than AAL naturally reverting to woodlands is unclear. In this study, we used the CBM-CFS3 model to compare the additional C sequestration potential of afforested AAL (AR) with a reference scenario where AAL naturally returns to forest (NR). Simulations were performed for stands located in Quebec’s boreal zone (Canada) on podzolic soils. The AR scenario corresponded to stands afforested at a density of 2000 trees ha−1 with one of five commonly planted species in the region, namely black spruce (BS), white spruce (WS), eastern white pine (EWP), jack pine (JP) and tamarack (TK). The NR scenario corresponded to stands naturally reverting to natural forests of one of five species naturally occurring in the region, namely BS, WS, balsam fir (BF), trembling aspen (TA) and white birch (WB). The yield tables used for NR were phased out by 5, 10, 15 and 20 years to simulate various dynamics of colonization by woody plants following agricultural abandonment. Net C accumulation in AR stands varies depending on the planted species, from 127 to 255 Mg C ha−1 after 100 years with TK and WS, respectively. Net C accumulation in NR stands after 100 years ranges from 82 to 145 Mg C ha−1 for BS and TA, respectively, but these values are sensitive to both tree density and colonization time following abandonment. In both scenarios, the soil C pool shrinks by 6 to 12 Mg C ha−1 over the first 80–85 years, but the following soil C stock replenishment is faster in AR than in NR stands due to higher litter production (up to 50 Mg C ha−1). The additional C sequestration potential of AAL afforestation, i.e. the difference in net C accumulation between AR and NR stands, is the highest in stands afforested with WS and reaches a peak of 121–175 Mg C ha−1 80–87 years after afforestation depending on the NR scenario. Afterwards, additional C sequestration decreases due to a reduction in plantation growth combined with increasing natural regeneration growth. This modelling approach helps predict AAL additional C sequestration potential and suggests that AAL afforestation yields a more rapid C sequestration than natural regeneration, which could contribute to reaching net-zero emissions by 2050.

Genetic Diversity, Structure and Effective Population Size of Old-Growth vs. Second-Growth Populations of Keystone and Long-Lived Conifer, Eastern White Pine (Pinus strobus): Conservation Value and Climate Adaptation Potential.

Whether old-growth (OG) forests have higher genetic diversity and effective population size, consequently higher conservation value and climate adaptive potential than second-growth (SG) forests, remain an unresolved issue. We have tested the hypothesis that old-growth forest tree populations have higher genetic diversity, effective population size (NE), climate adaptive potential and conservation value and lower genetic differentiation than second-growth forest tree populations, employing a keystone and long-lived conifer, eastern white pine (EWP; Pinus strobus). Genetic diversity and population structure of old-growth and second-growth populations of eastern white pine (EWP) were examined using microsatellites of the nuclear and chloroplast genomes and single nucleotide polymorphisms (SNPs) in candidate nuclear genes putatively involved in adaptive responses to climate and underlying multilocus genetic architecture of local adaptation to climate in EWP. Old-growth and second-growth EWP populations had statistically similar genetic diversity, inbreeding coefficient and inter-population genetic differentiation based on nuclear microsatellites (nSSRs) and SNPs. However, old-growth populations had significantly higher chloroplast microsatellites (cpSSRs) haploid diversity than second-growth populations. Old-growth EWP populations had significantly higher coalescence-based historical long-term NE than second-growth EWP populations, but the linkage disequilibrium (LD)-based contemporary NE estimates were statistically similar between the old-growth and second-growth EWP populations. Analyses of population genetic structure and inter-population genetic relationships revealed some genetic constitution differences between the old-growth and second-growth EWP populations. Overall, our results suggest that old-growth and second-growth EWP populations have similar genetic resource conservation value. Because old-growth and second-growth EWP populations have similar levels of genetic diversity in genes putatively involved in adaptive responses to climate, old-growth, and second-growth populations may have similar adaptive potential under climate change. Our results could potentially be generalized across most of the boreal and temperate conifer forest trees. Our study contributes to address a long-standing issue, advances research field and knowledge about conservation and ecological and climate adaptation of forest trees.

Tree assisted migration in a browsed landscape: Can we predict susceptibility to herbivores?

To promote the sustainability of forest ecosystems and maintain ecosystem services to human populations in the context of climate change, forest managers are considering several adaptation tools. One of those, assisted migration, consists of displacing tree species and/or populations to locations with suitable future climate conditions. Assisted migration plantations, however, could fail to produce viable forests under high herbivory pressure from mammalian herbivores. Thus, selecting species and genotypes with low susceptibility to herbivores could be a key condition for the recruitment of translocated seedlings. We developed an approach to predict susceptibility to mammalian herbivores, based on the seedlings’ chemical content (a proxy of phytochemical defence and susceptibility to herbivores). We used the approach on eight North American tree species of three climate analogues regions each (i.e. locations where the current climate is similar to the future climate at plantation site). We built chemical profiles and ranked species and climate analogue based on their potential susceptibility. To assess the reliability of our approach, we compared the chemical profiles to a systematic review of these species’ chemistry and of mammalian browsing throughout their native geographic range. For most species, our chemical profiles and browse susceptibility rankings were congruent with information available in the literature, both for phytochemical defence and for browsing. Two of the eight species (Pinus strobus and Thuja occidentalis) were more susceptible than predicted based on their chemical profile. These discrepancies could be linked to specific mammalian herbivores, that were unaffected by the phytochemical defence of these species. We observed a generally higher susceptibility of broadleaf species, which could be taken into account when devising adaptive silvicultural strategies. Furthermore, we propose the chemical profiling approach as a preliminary screening tool to identify species more resistant to mammalian herbivores, but also potentially to other herbivores and pathogens. Our chemical profile approach, based on the objective assessment of multivariate analyses results, could be replicated to compare the potential susceptibility of other species. This approach could be especially useful when contending with novel plant-herbivore relationships, such as forestry and conservation assisted migration or species invasion.

Eastern white pine and eastern hemlock growth: possible tradeoffs in response of canopy trees to climate

A warming climate and extended growing season may confer competitive advantages to temperate conifers that can photosynthesize across seasons. Whether this potential translates into increased growth is unclear, as is whether pollution could constrain growth. We examined two temperate conifers — eastern white pine (Pinus strobus L.) and eastern hemlock (Tsuga canadensis (L.) Carrière) — and analyzed associations between growth (476 trees in 23 plots) and numerous factors, including climate and pollutant deposition variables. Both species exhibited increasing growth over time and eastern white pine showed greater maximum growth. Higher spring temperatures were associated with greater growth for both species, as were higher autumnal temperatures for eastern hemlock. Negative correlations were observed with previous year (eastern hemlock) and current year (eastern white pine) summer temperatures. Spring and summer moisture availability were positively correlated with growth for eastern white pine throughout its chronology, whereas for hemlock, correlations with moisture shifted from being significant with current year’s growth to previous year’s growth over time. The growth of these temperate conifers might benefit from higher spring (both species) and fall (eastern hemlock) temperatures, though this could be offset by reductions in growth associated with hotter, drier summers.

Earlier and more variable spring phenology projected for eastern Canadian boreal and temperate forests with climate warming

Climate change affects timing and variability of spring phenology, as well as occurrence of spring frosts, and therefore influences forest structure, function, and management practices. In this study, we evaluated changes in budburst timing, sequential order of budburst, budburst temperatures, and frosts, from 1981–2010 baseline to different future climates (+2, +4, and +6 °C for moderate, high, and extremely high warming) for selected boreal and temperate species in eastern Canada. We used species-specific budburst models that are developed from large-scale forcing experiments.Budburst averaged 10–15 days earlier per 2 °C increase of temperatures, except for temperate yellow birch and eastern white pine that slowed down to 5–7 days in budburst advancement from +4 to +6 °C. Earlier budburst was associated with greater annual and interspecific variations in budburst timing, lower budburst temperatures, more frosts, and less annual variations in sequential order of budburst. Compared to temperate trees, boreal trees had greater budburst advances and annual variations, but less interspecific variations in timing and sequential order of budburst. Early flushing species had greater phenological changes and annual variations, as well as more frosts. Our results suggest that budburst advance that has occurred will continue with greater among years/species variability but is unlikely to converge between boreal and temperate regions in eastern Canada under anticipated levels of climate warming.

Представители семейства сосновые (Pinaceae Lindl.) североамериканской флоры в коллекции дендрологического сада ФБУ «СевНИИ ЛХ»

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.

Chlorophyll pigment and needle macronutrient responses and interactions to soil moisture and atmospheric CO2 treatments of eight pine and spruce species

Key messageLarge differences were detected between genera and among species in chlorophyll pigment and macronutrient concentrations. Pines have greater variances than spruces and showed less downregulation of chlorophyll pigment concentrations than spruces in response to eCO2 and DRT. There was strong genetic control of chlorophyll pigments and most macronutrients.Chlorophyll pigment and needle macronutrient concentrations were quantified for eight tree species in two commercially important genera, Pinus and Picea grown in a 2 × 2 factorial of atmospheric CO2 (370 and 740 ppm) and soil moisture stress (− 0.1 to − 0.5 and − 0.7 to − 1.0 MPa) treatments. Four of the pines and three of the spruces are native to eastern North America, while a fourth spruce, Norway spruce (NS: Picea abies), is from Europe but has been widely used for reforestation in northeastern North America. Overall, spruces had significantly greater chlorophyll a, b, (CHLa, CHLb), and total chlorophyll concentration (TCC) and carotenoid concentration (CAR) than pines. Ambient CO2 (aCO2) had significantly greater TCC than in response to elevated CO2 (eCO2), and TCC and CAR was significantly downregulated more in spruces than in pines in response to eCO2. Pines had equal or greater TCC and CAR in response to drought treatment (DRT) than well-watered treatment, whereas spruces had significantly lower values in response to DRT. Needle N, P and Ca concentrations were greater for spruces than pines. Needle N concentrations declined in response to both eCO2 and DRT. Needle P increased in response to eCO2 but declined in response to DRT. Using total biomass as a covariate, needle N showed no response in pines; whereas spruces showed a slight positive response to increasing total biomass. Covariate analysis showed that TCC had a significant positive relationship to needle N and Mg, with greater TCC in spruces than in pines for a given needle N. Photosynthetic quantum efficiency (QE), derived from light response curves, had a significant positive relationship to TCC that was greater in pines than in spruces for a given TCC. Photosynthetic light convexity had a significant positive relationship to TCC that was also greater in pines than in spruces for a given TCC, indicating a sharper curvature compared to a more progressive curve for spruce. Pine species have greater variances than spruce species. While Pinus strobus (white pine, subgenus Strobus) stands out as having greater chlorophyll and nutrient concentrations than the other three pines (subgenus Pinus). Overall, pines showed less downregulation of chlorophyll pigment concentrations than spruces in response to eCO2 and DRT. There was strong genetic control for chlorophyll pigments and most macronutrients.

Effectiveness of Oil-Based Denture Dentifrices-Organoleptic Characteristics, Physicochemical Properties and Antimicrobial Action.

Denture dentifrices must be effective and not deleterious to prosthetic devices. This study formulated and evaluated dentifrices based on oils of Copaifera officinalis, Eucalyptus citriodora, Melaleuca alternifolia, Pinus strobus, and Ricinus communis. Organoleptic characteristics (appearance, color, odor, taste), physicochemical properties (pH, density, consistency, rheological, abrasiveness, weight loss, and surface roughness) and antimicrobial (Hole-Plate Diffusion–HPD)/anti-biofilm (Colony Forming Units–CFU) action against Staphylococcus aureus, Streptococcus mutans, and Candida albicans were evaluated. Formulations were compared with water (negative control) and a commercial dentifrice (positive control). The data were analyzed by Kruskal-Wallis and Dunn tests (α = 0.05). The organoleptic and physicochemical properties were adequate. All dentifrices promoted weight losses, with high values for C. officinalis and R. communis, and an increase in surface roughness, without differing from each other. For antimicrobial action, C. officinalis and E. citriodora dentifrices were similar to positive control showing effectiveness against S. mutans and C. albicans and no dentifrice was effective against S. aureus; regarding the anti-biofilm action, the dentifrices were not effective, showing higher CFU counts than positive control for all microorganisms. The dentifrices presented satisfactory properties; and, although they showed antimicrobial action when evaluated by HPD, they showed no effective anti-biofilm action on multispecies biofilm.

Inferences on the Susceptibility of Wood of Different Tree Species to Heterobasidion annosum Sensu Lato Primary Infections and on the Range of Pathogen Spores Dispersal

Stumps play a pivotal role in the epidemiology of the fungal forest pathogens Heterobasidion spp. because they are the main courts of primary airborne infections. The aims of this study were (i) to determine the susceptibility of seven tree species (i.e., Larix sibirica, Picea abies, Picea sitchensis, Pinus contorta, Pinus strobus, Pinus sylvestris and Pseudotsuga menziesii) to primary infection by H. annosum and H. parviporum through comparative inoculation experiments of conidia on wood discs in controlled conditions; (ii) to compare the susceptibility of wood discs of the same tree species to natural airborne infections in two Latvian Norway spruce forest stands infested either by H. annosum or H. parviporum; (iii) to explore the rates of infection of wood discs at increasing distances from spore sources in these two forests to make inferences on the range of spores dispersal. Results obtained by spraying wood discs with conidial suspensions in controlled conditions are in agreement with those obtained by exposing wood discs to the natural airborne inoculum in the forests, as clearly supported by the significant correlation (r = 0.79; p &lt; 0.05) between the two sets of data. Susceptibility was highest in Pinus species, followed by P. abies and P. sitchensis. Susceptibility was lowest for L. sibirica and P. menziesii. The area colonized by Heterobasidion spp. in the sapwood of wood discs was much greater than that colonized in the heartwood. A sharp decrease in the rate of infection of wood discs with distance from spore sources (i.e., fruiting bodies) was observed, further confirming the importance of local spore sources in the epidemiology of Heterobasidion spp. Taken together, these findings could help designing tactics to manage these fungal forest pathogens.