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Canadian Journal of Forest Research
Journal Prestige (SJR): 0.969  Citation Impact (citeScore): 2 Number of Followers: 28  Hybrid journal * Containing 1  Open Access article(s) in this issue *ISSN (Print) 0045-5067 - ISSN (Online) 1208-6037 Published by NRC Research Press  [19 journals]
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- Modeling knot geometry from scanned images of Korean pine plantations
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Authors: Haotian Guo, Weiwei Jia, Dandan Li, Yuman Sun
Pages: 845 - 859
Abstract: Canadian Journal of Forest Research, Volume 52, Issue 5, Page 845-859, May 2022.
Based on 1038 knots from 42 sample trees from 14 standard plots in Korean pine (Pinus koraiensis Sieb. et Zucc.) plantations in Heilongjiang Province, China, we developed a knot profile model system. The concepts of growth inflection point and death inflection point were proposed. Depending on the growth conditions near the growth inflection point of the knot, we divided the knots into two types: curved knots and linear knots. A logistic regression model was constructed to predict the shape of the knots. The area under the curve of the logistic regression model was 0.699 (95% confidence interval 0.661∼0.736), and the prediction accuracy was 0.69. Our research shows that for middle-aged and young forests, the relative radial distances of the growth inflection points at the upper edge and bottom edge of curved knots were larger than those in linear knots. The curved knots did not bend at the death inflection point, but linear knots may bend at the death inflection point. Models were constructed separately for curved knots and linear knots. The results showed that the application of the mixed-effects model significantly improves the model fitting effect.
Citation: Canadian Journal of Forest Research
PubDate: 2022-03-07T08:00:00Z
DOI: 10.1139/cjfr-2021-0318
Issue No: Vol. 52, No. 5 (2022)
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- Decomposition differences between snags and logs in forests of Kenai
Peninsula, Alaska-
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Authors: Mikhail A. Yatskov, Mark E. Harmon, Becky Fasth, Jay Sexton, Toni L. Hoyman, Chana M. Dudoit
Pages: 1 - 16
Abstract: Canadian Journal of Forest Research, Ahead of Print.
Rising temperatures could increase forest ecosystem disturbance frequency and severity, transferring large amounts of live biomass to coarse woody debris (CWD) pools that emit carbon (C). The type of disturbance-created CWD influences the rate, amount, and duration of this C emission. We studied the effect of a large-scale disturbance on CWD dynamics in spruce-dominated forests of the Kenai Peninsula, Alaska, by determining CWD decomposition rate constants (k) using the chronosequence and decomposition-vectors methods and by modeling the hypothetical CWD dynamics occurring after a bark beetle outbreak versus a windthrow. Chronosequence-based k’s for mass ranged between 0.020 and 0.022 year−1 for logs and between 0.000 and 0.003 year−1 for snags. Decomposition-vectors-based k’s for log mass ranged between 0.022 and 0.045 year−1 among three decomposition phases and between 0.014 and 0.048 year−1 among five decay classes. Our analysis showed that snag-generating disturbances delayed C flux from CWD to the atmosphere, produced a smaller magnitude of C flux, and had the potential to store 10% to 66% more C in the system over time than disturbances generating logs. Thus, landscapes affected by disturbances creating snags (versus logs) may revert faster to C neutrality, suggesting forest management practices should reflect these differences.
Citation: Canadian Journal of Forest Research
PubDate: 2022-04-18T07:00:00Z
DOI: 10.1139/cjfr-2021-0208
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- Evaluation of UAS LiDAR data for tree segmentation and diameter estimation
in boreal forests using trunk- and crown-based methods-
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Authors: Mikko Kukkonen, Matti Maltamo, Lauri Korhonen, Petteri Packalen
Pages: 1 - 11
Abstract: Canadian Journal of Forest Research, Ahead of Print.
Very high point density laser scanning data from unmanned aerial systems (UAS) can be used to segment the trunks of individual trees. Such segmentation (e.g., individual trunk segmentation (ITS)) is useful, for example, in the estimation of diameter at breast height (DBH), which in turn is needed for the estimation of other tree and stand attributes, such as stem volume and diameter of the basal area median tree (DGM). In this paper, we assess the estimation of DBH directly from UAS LiDAR data in open and closed canopy conditions that represent the range of operational conditions encountered in boreal forests in Finland. We also compare trunk-based DBH estimates to corresponding estimates from individual tree crown segmentation (ITC) and fuse the results from the trunk- and crown-based estimates. The results showed that trunk segmentation performed slightly better than ITC in open canopy areas, whereas ITC performed better in closed canopy areas. The DBH prediction error was smaller for ITS (3.0 cm) than ITC (3.9 cm) when considering the trees that were recognized by both methods. We also conclude that a hybrid method, where both segmented tree trunks and tree crowns are fused, considerably increases the number of correctly segmented trees but does not decrease the prediction error associated with DGM compared to using either ITC or ITS individually.
Citation: Canadian Journal of Forest Research
PubDate: 2022-04-14T07:00:00Z
DOI: 10.1139/cjfr-2021-0217
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- Effects of interspecific competition on early growth of genetically
improved white spruce in mixedwood stands in northeastern Alberta-
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Authors: Dawei Luo, Phil G. Comeau, Barb R. Thomas
Pages: 1 - 15
Abstract: Canadian Journal of Forest Research, Ahead of Print.
While deployment of white spruce (Picea glauca (Moench) Voss) from seed orchards is increasing in Alberta, genetic gain is only considered in pure spruce stands due to uncertainties in measuring yields in mixedwood stands. To better understand the performance of improved spruce in mixedwood stands, we compared the effects of interspecific competition on growth of improved (1.9% height gain at a 100-year rotation) and unimproved spruce in northeastern Alberta. By age 8 years the improved spruce showed no advantage over the unimproved spruce in either height (1.36 ± 0.36 m vs. 1.42 ± 0.38 m) or diameter (23.68 ± 7.33 mm vs. 25.65 ± 6.85 mm), and the largest diameter trees were found in a nutrient-poor subxeric site. A distance-independent Lorimer’s index including tree size ratio, combined with a power function, accounted for most of the growth variation in diameter and height from 2016 to 2017. The unimproved and improved spruce had different growth-competition curves across ecosites, and their height growth was less sensitive to competition than diameter growth. These results highlight several considerations for managing improved spruce, including (i) deploying higher genetic worth seedlots, (ii) developing realized gain trials with a good statistical design, and (iii) developing growth and yield functions for improved spruce in mixedwood stands.
Citation: Canadian Journal of Forest Research
PubDate: 2022-03-14T07:00:00Z
DOI: 10.1139/cjfr-2021-0300
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- Additional biomass estimation alternatives: nonlinear two- and three-stage
least squares and full information maximum likelihood for slash pine-
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Authors: Dehai Zhao, Thomas B. Lynch, James A. Westfall, John W. Coulston
Pages: 1 - 14
Abstract: Canadian Journal of Forest Research, Ahead of Print.
A system of nonlinear biomass component equations was developed for slash pine (Pinus elliottii Engelm. var. elliottii) trees using an econometric approach in which endogenous right-hand-side variables were included in some equations. The system was fitted to component biomass data from 306 slash pine trees sampled in the southeastern United States with weighted two-stage (2SLS) and three-stage (3SLS) least squares and full information maximum-likelihood (FIML) estimation methods. The predictive performances of the system fitted with these three estimation methods were ranked based on an array of statistics, and the ranking follows the order of FIML> 3SLS> 2SLS. The new system performed as well or better than previously published biomass equation systems developed using the aggregation and disaggregation approaches and fitted to the same data. The results demonstrated that the econometric approaches such as FIML and 3SLS have the potential to be useful for tree biomass modeling.
Citation: Canadian Journal of Forest Research
PubDate: 2022-03-03T08:00:00Z
DOI: 10.1139/cjfr-2021-0335
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- Tree quality and value: results in northern conifer stands after 65 years
of silviculture and harvest-
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Authors: Maren Granstrom, Mindy S. Crandall, Laura S. Kenefic, Aaron R. Weiskittel
Pages: 1 - 14
Abstract: Canadian Journal of Forest Research, Ahead of Print.
Despite the importance of financial outcomes to stand-level forest management decision-making, long-term assessments are rare. We compared the quality and value of mixed, northern conifer (Picea–Abies–Tsuga) stands in Maine, USA, treated with a range of silvicultural systems and exploitive cuttings for 65 years. Ten replicated treatments — single-tree selection and uniform shelterwood systems, commercial clearcutting, fixed and guiding diameter-limit cutting, and no cutting — were assessed for quality and value of standing and harvested trees. Selection systems resulted in good tree quality and high stand value, particularly when applied on a short cutting cycle, but small harvest volumes were not always commercially operable. Shelterwood system resulted in good tree quality, but changes in species values over time influenced financial outcomes. In contrast, commercial clearcutting and fixed diameter-limit cutting resulted in poor tree quality and low residual stand value after multiple harvests. Guiding diameter-limit cutting resulted in high stand value and is more appropriately characterized as a silvicultural system than exploitive harvesting when applied with harvest volume limits and seed tree retention. Overall, treatments focused on short-term financial gain led to degraded stand conditions, while those that sought to grow high-quality trees resulted in desirable outcomes over the long term.
Citation: Canadian Journal of Forest Research
PubDate: 2022-02-25T08:00:00Z
DOI: 10.1139/cjfr-2021-0279
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- Intra-annual ring width and climate response of red pine in Itasca State
Park in north-central Minnesota-
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Authors: Kurt F. Kipfmueller, Evan E. Montpellier, Matthew L. Trumper, Daniel Griffin
Pages: 1 - 12
Abstract: Canadian Journal of Forest Research, Ahead of Print.
Red pine (Pinus resinosa Ait.) of northern Minnesota are part of a growing network of tree-ring chronologies aimed at understanding climate dynamics in the Upper Great Lakes Region. Red pine has been widely used in tree-ring studies of fire and climate variability across its range. Earlier studies have relied primarily on total annual ring width. Here we develop annual and subannual (i.e., earlywood, latewood, and adjusted latewood) chronologies from Itasca State Park to refine our understanding of red pine climate response. Our chronologies extend to the early 18th century and display common growth and cross-dating characteristics indicative of a significant common controlling mechanism. We found that total ring width contains dampened attributes reflective of both the temperature-limited earlywood and moisture-dependent latewood chronologies. The strongest relationship between climate and radial growth is between the adjusted latewood chronology and 3-month summer precipitation, suggesting that overall summer wetness rather than any single summer month primarily limits growth. The ability to disaggregate and improve upon the mixed climate signal of red pine highlights the potential of using intra-annual chronologies to strengthen future climate reconstructions. We hope the methodologies demonstrated here serve as a potential guide for future red pine chronology development in the region.
Citation: Canadian Journal of Forest Research
PubDate: 2022-02-22T08:00:00Z
DOI: 10.1139/cjfr-2021-0210
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- Differences in wood anatomy and chemistry of a Eucalyptus urophylla clone
explained by site climate conditions-
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Authors: Maria Naruna Felix Almeida, Graziela Baptista Vidaurre, José Luis Penetra Cerveira Louzada, José Eduardo Macedo Pezzopane, Jean Carlos Lopes Oliveira, Ana Paula Câmara, Maria Emilia Calvão Moreira Silva, Ana Isabel Ramos Novo Amorim Barros, Carlos da Costa Matos, Ana Maria Martins Alves, Otávio Camargo Campoe, Clayton Alcarde Alvares
Pages: 1 - 11
Abstract: Canadian Journal of Forest Research, Ahead of Print.
Environmental conditions can change both the quantity and quality of wood formation. This study aimed to evaluate anatomical and chemical changes in the wood of a Eucalyptus urophylla S.T. Blake clone cultivated in four sites of wide climatic conditions in Brazil. Radial samples were used to evaluate xylem anatomy along the growth cycles. Samples with a quarter of a disk were used to perform chemical analyses of extractives, total lignin (LG), syringyl/guaiacyl (S/G), holocellulose, and elemental analysis of wood. The elements Na, K, Ca, Mg, P, Mn, Fe, Zn, Ni, Cu, Cr, Cd, F, and Cl were also quantified. Correlations using the mean values of the variables per site were higher than those using values per tree growth cycle (years). Mean annual air temperature showed the highest correlations with wood density (r = −0.89) and the anatomical characteristics (vessel area: r = −0.68; fiber wall thickness: r = −0.70; vessel frequency: r = 0.74; and fiber lumen diameter: r = 0.90). Only LG and S/G showed significant correlations with the meteorological variables, with drier sites presenting a higher S/G. The anatomical characteristics change with regionwide climate features, while wood chemical characteristics showed weaker relations with climatic variations.
Citation: Canadian Journal of Forest Research
PubDate: 2022-02-18T08:00:00Z
DOI: 10.1139/cjfr-2021-0261
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- Downed wood dynamics in the riparian and littoral zone of small lakes in
tolerant hardwood forests-
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Authors: Jennie L. Pearce, Elaine C. Mallory, Karen E. Smokorowski
Pages: 1 - 18
Abstract: Canadian Journal of Forest Research, Ahead of Print.
Large wood (LW) is an important structural feature in forested lake ecosystems, but little is known about the production of LW in riparian forests and its movement across the forest–lake ecotone, both of which we describe here for eight small (
Citation: Canadian Journal of Forest Research
PubDate: 2022-02-17T08:00:00Z
DOI: 10.1139/cjfr-2021-0245
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- Wood energy quality of Eucalyptus spp. clones established under different
soil types in the Brazilian Cerrado-
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Authors: Macksuel Fernandes da Silva, Pedro Augusto Fonseca Lima, Evandro Novaes, Carlos Roberto Sette, Ailton Teixeira do Vale
Pages: 1 - 8
Abstract: Canadian Journal of Forest Research, Ahead of Print.
The evaluation of wood energy quality of Eucalyptus clones planted in different edaphoclimatic conditions is fundamental to promote the sustainable expansion of energy forests to traditionally non-forest regions. This study aimed to evaluate the wood energy characteristics (proximate analysis, elemental analysis, higher heating value, basic and energy densities) from five Eucalyptus spp. clones planted in Latosol and Haplic Plinthosol soils in the Brazilian Cerrado (Savannah), considered a traditionally non-forest region. The wood basic and energetic densities are influenced by genotype (clone) but not influenced by the soil type (site). The higher heating value and the proximate analysis showed a significant effect of interaction between clone and soil type. Thus, for these wood energy variables, the clones behave differently depending on the growing location (soil type). Our results indicate that the clone with Eucalyptus cloeziana genes has the greatest energy potential because of the best wood quality: low ash (0.11%–0.09%), nitrogen contents (0.24%–0.31%), higher basic density (490.60–487.22 kg·m−1), and energy density (9720.5–9589.1 MJ·m−1), for soil types Latosol and Plinthosol.
Citation: Canadian Journal of Forest Research
PubDate: 2022-02-16T08:00:00Z
DOI: 10.1139/cjfr-2021-0234
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- A goal programming model for the optimization of log logistics considering
sorting decisions and social objective-
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Authors: Salar Ghotb, Taraneh Sowlati, Joel Mortyn, Dominik Roeser, Verena C. Griess
Pages: 1 - 11
Abstract: Canadian Journal of Forest Research, Ahead of Print.
Log logistics include sorting, processing, and transporting of logs from their place of harvest to demand locations. These activities account for a significant portion of the total log procurement costs; therefore, attempts were made in previous studies to optimize some aspects of log logistics. However, operational details, such as sorting decisions, truck compatibility requirements, and social objectives, are often disregarded in the optimization literature. Incorporating these details into the model makes the results more realistic and applicable. To address these gaps, a bi-objective mixed-integer programming model is developed in this paper to optimize log logistics. The first objective is to minimize total logistics costs, and the second objective is to provide a balanced workload for trucking contractors. The bi-objective model is solved using the goal programming approach. The model is applied to log logistics of a large Canadian forest company, where trucking contractors use heterogeneous fleet of trucks to carry various log sorts from cutblocks to sort yards for sorting. The planning horizon is 4 weeks with daily decisions. The goal programming model generates balanced workloads for the contractors with less than 0.4% increase in total costs compared to the single objective model where only the total cost is minimized.
Citation: Canadian Journal of Forest Research
PubDate: 2022-02-15T08:00:00Z
DOI: 10.1139/cjfr-2021-0203
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- Drag relationships for full-grown Scots pine trees
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Authors: Sergey A. Borisevich, Andrei N. Kamluk, Dmitry V. Rebko
Pages: 1 - 6
Abstract: Canadian Journal of Forest Research, Ahead of Print.
The wind force acting on full-grown pine trees as they free fall was calculated based on comparison of the results of the field experiment and numerical simulation using Borisevich and Vikhrenko’s 2018 model. A number of improvements were proposed to increase the accuracy of the method. Field experiments of the free fall of five pine trees previously cut were carried out. Then, computer simulations of their motion assuming the linear dependence of drag force on air velocity were performed. Comparisons of the data of the field experiments and computer simulations showed that the linear dependence with a constant scaling parameter gives a good approximation of the drag force at a wide range of air velocity values. Error analysis was carried out to assess the quality of the numerical model. At all times during the movement, the deviations in the center mass positions observed in the field experiment and obtained in the numerical experiment do not exceed the diameter of the tree stem. The scaling parameter for five full-grown Scots pines (Pinus sylvestris L.) growing in stands ranged between 25.5 and 90.0 kg/s.
Citation: Canadian Journal of Forest Research
PubDate: 2022-02-11T08:00:00Z
DOI: 10.1139/cjfr-2021-0043
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- Effects of artificial nitrogen deposition on the forest floor and soil
chemistry in chestnut-leaved oak (Quercus castaneifolia) plantation in
northern Iran-
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Authors: Azam Nouraei, Hamid Jalilvand, Seyed Mohammad Hojjati, Patrick Schleppi, Seyed Jalil Alavi
Pages: 1 - 11
Abstract: Canadian Journal of Forest Research, Ahead of Print.
Human demand for food and energy has led to significant changes in the level of reactive nitrogen (N) released to the atmosphere and then deposited in the biosphere. This study aimed to investigate the impact of the deposition of artificial N on the forest floor and on the soil chemical properties in an oak (Quercus castaneifolia C.A. Mey.) plantation in northern Iran. Twelve plots of 200 m2 (20 m × 10 m) were set up in the study area. Four N treatments were considered: zero (control), 50 (low), 100 (medium), and 150 (high) kg N·ha−1·year−1. N in the form of NH4NO3 solution was manually sprayed onto the understory plots monthly for 1 year. The total N, phosphorus (P), potassium (K), and organic carbon (OC) of the forest floor were measured. Soil N, available P, available K, pH, EC (electrical conductivity), OC, microbial biomass C (MBC), and urease enzyme activity were measured in the 0–10 cm depth. The concentration of total N and P of the forest floor was significantly higher in the high-N treatment. The total concentration of N (+36%), the urease activity (+44%), and EC (+12%) of soil increased with raising the high-N treatment compared to the control, but the MBC (−20%), available P (−28%), and available K (−15%) were significantly reduced in the high-N treatment. Our results were obtained with simulated deposition rates that exceed ambient fluxes, but ambient N deposition is nevertheless high in our study area.
Citation: Canadian Journal of Forest Research
PubDate: 2022-02-01T08:00:00Z
DOI: 10.1139/cjfr-2021-0331
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- An alternative simulation framework to evaluate the sustainability of
annual harvest on large forest estates-
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Authors: Mathieu Fortin, Derek Sattler, Robert Schneider
Pages: 1 - 12
Abstract: Canadian Journal of Forest Research, Ahead of Print.
Sustainability is central to forest management. To determine the sustainable annual harvest, practitioners rely on a simulation framework that combines inventory data, growth models, and optimization software. Because this standard simulation framework is based on model predictions aggregated into yield tables, it may not properly capture natural dynamics. In this paper, we designed an alternative simulation framework that does not require aggregated model predictions. However, the growth model must implement a harvest submodel and produce stochastic predictions. To showcase this alternative simulation framework, we used a forest management unit in southwestern Quebec, Canada, and compared our simulation results with those of the standard simulation framework. Our alternative simulation framework showed that the standing volume of most coniferous species would decrease, whereas that of maple species would increase over the 21st century. The annual harvest of one species as determined through the standard simulation framework was found to be unsustainable in the alternative simulation framework. Being much lighter in terms of computation, this alternative simulation framework can be used as a complement to the standard simulation framework, notably for checking if the optimization-based annual harvest is sustainable.
Citation: Canadian Journal of Forest Research
PubDate: 2022-02-01T08:00:00Z
DOI: 10.1139/cjfr-2021-0255
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- Root adaptations of black spruce growing in water-saturated soil
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Authors: Cornelia Krause, Audrey Lemay
Pages: 1 - 9
Abstract: Canadian Journal of Forest Research, Ahead of Print.
Black spruce (Picea mariana (Mill.) BSP) is the main tree species growing within peatlands. The difficult growing conditions within peatlands are associated with low individual wood productivity, and only tree species tolerant to high ground water level can survive. We examine the effect of water-saturated soil on the growth potential of black spruce trees and specific adaptation of the root system. Experimental mesocosms were constructed with two drainage regimes (saturated and well-drained soil conditions). We measured biomass, height, and diameter at stem base of 55 black spruce saplings and noted the location of each horizontal root. Black spruce exhibited a very shallow root system located above saturated commercial peat 19 years after the experiment was initiated. Most roots were adventitious in the water-saturated mesocosms. Overall aerial and root biomass accumulation of the black spruce trees growing under saturated soil conditions was significantly lower than that of the well-drained mesocosms. Interestingly, root–shoot ratios were similar across the two drainage regimes. Soil conditions induced adaptation of the root system in black spruce trees, and physiological stress affected the entire individual with lower biomass productivity in all components (stem, branches, root system). However, biomass distribution remained similar to that of trees growing in well-drained mesocosms.
Citation: Canadian Journal of Forest Research
PubDate: 2022-01-28T08:00:00Z
DOI: 10.1139/cjfr-2021-0310
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- Long-term effect of elevated air humidity on seasonal variability in
diurnal leaf conductance and gas exchange in silver birch-
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Authors: Priit Kupper, Gristin Rohula-Okunev, Arvo Tullus, Ingmar Tulva, Ebe Merilo, Arne Sellin
Pages: 1 - 8
Abstract: Canadian Journal of Forest Research, Ahead of Print.
Environmental conditions and photoperiod length drive the seasonal variability of gas exchange in plants. Still, little is known about trees’ adaptation to climate change, expressed as a delay in decreasing photosynthetic capacity at the end of the growing season. We investigated the effect of elevated air humidity (RH) and sampling period (from July to September) on the variability of net photosynthesis (An), dark respiration (R), daytime (gl_day) and night-time (gl_night) leaf conductance, an index of leaf chlorophyll content (SPAD), and An:SPAD ratio in cut shoots of silver birch (Betula pendula Roth). Measurements of cut shoots were conducted in a climate chamber to eliminate the direct effect of field conditions. The An, An:SPAD ratio, and gl_day were higher in the humidification treatment (H) than in the control (C) (P < 0.05) in autumn. The R was higher in the control than in the humidification treatment across the study period. The gl_night increased considerably in September in both treatments (P < 0.05) and was significantly correlated with R. Our findings suggest that autumnal leaf conductance and gas exchange in silver birch are considerably influenced by long-term exposure to elevated RH and are probably related to a complex of leaf senescence processes, including nitrogen retranslocation.
Citation: Canadian Journal of Forest Research
PubDate: 2022-01-25T08:00:00Z
DOI: 10.1139/cjfr-2021-0236
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- Quantitative magnetic resonance imaging of Scots pine seeds and the
assessment of germination potential-
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Authors: Teemu V. Tuomainen, Katri Himanen, Pekka Helenius, Mikko I. Kettunen, Mikko J. Nissi
Pages: 1 - 11
Abstract: Canadian Journal of Forest Research, Ahead of Print.
The availability of Scots pine seeds (Pinus sylvestris L.) with high germinability is necessary for artificial forest regeneration. In this work, Scots pine seed orchard seeds were magnetic resonance (MR) imaged to noninvasively investigate the association of the anatomical images and quantitative relaxation times with the structure and germinability of the seeds. Relaxation time differences compared to the germination day were also investigated. The average whole seed relaxation times T1 (two methods), T2, and [math] were 430 ± 59, 660 ± 20, 14 ± 1.7, and 0.83 ± 0.33 ms, respectively. It was observed that the seed structures had statistically significant (p < 0.05) differences in relaxation times, while no differences could be observed in relation to the rate of seed germination. Furthermore, the obtained data were compared to radiographs. Empty seeds were observed to provide a minimal MRI signal, whereas intact and mechanically damaged seeds provided a profound signal with distinguishable structures. The mechanically hardest region, i.e., the seed coat, was not visible in MRI as opposed to radiographs. Some seeds determined to be mechanically damaged by radiography were able to germinate, and mechanical faults could be distinguished in MRI. As such, MRI can be seen complementary to the currently used methods to optimize seed sorting and to interpret germination potential.
Citation: Canadian Journal of Forest Research
PubDate: 2022-01-25T08:00:00Z
DOI: 10.1139/cjfr-2021-0273
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- Feature selection by genetic algorithm in nonlinear taper model
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Authors: Talles Hudson Souza Lacerda, Evandro Nunes Miranda, Isáira Leite e Lopes, Guilherme Rodrigues Fonseca, Luciano Cavalcante de Jesus França, Lucas Rezende Gomide
Pages: 1 - 11
Abstract: Canadian Journal of Forest Research, Ahead of Print.
Tree stem profile results from a complex structure of shapes and dimensions determined by ecological processes within the forest. However, the feature selection in the development of taper models has been underinvestigated to date. We propose a genetic algorithm (GA) to assess factors that affect the stem taper and volume of Eucalyptus urograndis trees at different ages (2, 7, and 14 years) in Brazil. A total of 213 sample trees were measured in diameter and height along the stem, crown width, crown base height, crown length, and crown ratio. These variables and the stand age were supplied to the GA that selects variables, replacing those of Kozak’s 2004 model. The performance of models was evaluated using error statistics and residual plots. The GA model was efficient in predicting diameters and volumes, mainly by increasing the accuracy of the estimates in the extreme portions of the trees. This was attributed to the selection of morphometric variables as predictors of stem taper and volume, making them understandable in ecological terms. We highlight GA as a robust tool, since it incorporated the morphometric variables in Kozak’s model that contribute to the estimates.
Citation: Canadian Journal of Forest Research
PubDate: 2022-01-20T08:00:00Z
DOI: 10.1139/cjfr-2021-0265
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- Bacterial community of reindeer lichens differs between northern and
southern lichen woodlands-
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Authors: Marta Alonso-García, Juan Carlos Villarreal A.
Pages: 1 - 12
Abstract: Canadian Journal of Forest Research, Ahead of Print.
Lichens cover nearly 7% of the earth’s surface, and in eastern Canada, lichen woodlands occupy over 300 000 km2. Reindeer lichens (genus Cladonia) are the main component of lichen woodlands and they play a crucial role in boreal forest ecology. We study, for the first time, the bacterial community of four species of reindeer lichens from eastern North America’s boreal forests. Using the 16S rRNA gene, we characterize the bacterial community of 189 lichen samples. We aim to analyse the effect of geography and host identity in the bacterial community composition and structure, verify the presence of a common core bacteria, and identify the most abundant core taxa. Our results suggest that host-lichen identity does not determine bacterial community composition and structure in reindeer lichens, but we confirm the influence of geography in shaping the diversity and abundance of bacteria associated with Cladonia stellaris. We also reveal that reindeer lichens share a reduced common core bacteria composed exclusively by Alphaproteobacteria. Northern lichen woodlands exhibit a significantly higher diversity and abundance of bacteria associated with C. stellaris than southern lichen woodlands do. The presence of the species Methylorosula polaris in the core bacteria is evident and may have a particular importance for reindeer lichens.
Citation: Canadian Journal of Forest Research
PubDate: 2022-01-18T08:00:00Z
DOI: 10.1139/cjfr-2021-0272
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- Effects of overstory tree density, site preparation, and ground vegetation
on natural Scots pine seedling emergence and survival in northern boreal
pine forests
Open Access Article-
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Authors: M.J. Kyrö, V. Hallikainen, S. Valkonen, M. Hyppönen, P. Puttonen, U. Bergsten, H. Winsa, P. Rautio
Pages: 1 - 10
Abstract: Canadian Journal of Forest Research, Ahead of Print.
Natural regeneration is a commonly used forest regeneration method in northern Finland. It is not known, however, what would be the optimal overstory density and ground vegetation composition for seedling emergence and survival, and if site preparation is needed to accompany overstory density manipulation. We studied the effects of overstory density (unthinned control and thinning to 50, 150, and 250 trees·ha−1) and ground vegetation removal (mechanical site preparation with disc trenching) on the number of naturally germinated pine seedlings and survival of individual seedlings over a period of 8 to 11 years. Bare mineral soil was a superior seedbed compared to intact vegetation cover, even though the mortality rate was high on mineral soil. Greater cover of lingonberry, crowberry, and slash had a negative effect on seedling number. Seedling mortality was initially high (60% died during the first 2 years) but decreased throughout the first 5 years. The survival rate of seedlings located in the mineral soil of the upper part of the disc trencher track was twice as high as that of seedlings located in the lower part of the track. High coverage of hair mosses (Polytrichum spp.) was associated with poorer seedling survival. An overstory density of 50–150 trees·ha−1 with site preparation seems to be an efficient treatment to promote regeneration under these circumstances.
Citation: Canadian Journal of Forest Research
PubDate: 2021-11-11T08:00:00Z
DOI: 10.1139/cjfr-2021-0101
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