scholarly journals Mechanisms by Which Pre-Commercial Thinning Increases Black Spruce Growth in Different Climates and Soil Types

Forests ◽  
2020 ◽  
Vol 11 (5) ◽  
pp. 599
Author(s):  
Amy Wotherspoon ◽  
Robert L. Bradley ◽  
Daniel Houle ◽  
Stéphane Tremblay ◽  
Martin Barrette ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Black Spruce ◽  
Canopy Openness ◽  
Soil N ◽  
Site Type ◽  
Commercial Thinning ◽  
Soil Moisture Availability ◽  
N Fertility ◽  
Competition For Resources ◽  
Site Types

In the province of Québec (Canada), pre-commercial thinning (PCT) is a common silvicultural practice applied to young black spruce (Picea mariana (Mill.) BSP) stands. PCT removes some of the competing vegetation and smaller black spruce stems, in order to improve growth rates and reduce forest rotation intervals. It is uncertain whether this positive response in black spruce growth is primarily due to lower competition for resources or to other mechanisms, which may vary according to climate or edaphic conditions. We sampled soils and black spruce needles in PCT-treated and non-treated control plots occurring in two climate regimes, as well as on two contrasting soil parent materials within one of these two climate regimes (i.e., three “site types”). We performed our sampling approximately 20 years after treatment. Paired treatment plots (i.e., PCT vs. control) were replicated at four independent sites in each of the three site types, for a total of 24 plots. Over two consecutive years, we measured stand structural characteristics, indices of soil N fertility, soil microbial activity, indices of soil moisture availability, canopy openness, and foliar characteristics in each plot. In each site type, PCT decreased total basal area but increased radial growth of individual trees. Across all plots, soil N mineralization rates measured in 2016 were positively related to foliar N concentrations of one-year-old needles collected in 2017. Annual precipitation, drainage class, potential evapotranspiration, and climate moisture index all indicated that plots occurring in the drier climate and on glacial till deposits were more prone to summer moisture deficits. Accordingly, PCT increased forest floor moisture only in this site type, which may benefit tree growth. In the wetter climate and on poorly drained soils, however, we found evidence that PCT reduces soil N fertility, presumably by increasing the spread of ericaceous shrubs in the understory. In the dry fertile site type, the range in canopy openness was substantially higher (12–37%) and correlated negatively with tree diameter, suggesting that greater light availability did not improve tree growth. Taken collectively, our data suggest that PCT increases black spruce growth across a broad range of site conditions found in Québec, presumably by lowering intraspecific competition for resources. However, on drier sites, PCT may also benefit trees by increasing soil moisture availability, whereas wetter climates may mitigate the beneficial effect of PCT due to a loss of soil N fertility.

Changes in DOC and DON fluxes in response to harvest intensity of black-spruce-dominated forest ecosystems in northwestern Ontario

2009 ◽  
Vol 89 (1) ◽  
pp. 67-79 ◽  
Author(s):  
Dave M Morris
Keyword(s):  
Dissolved Organic Nitrogen ◽  
Organic Nitrogen ◽  
Black Spruce ◽  
Site Type ◽  
Northwestern Ontario ◽  
Clearcut Harvesting ◽  
Second Year ◽  
Forest Floors ◽  
Source Sink ◽  
Site Types

The current study was conducted to quantify and compare dissolved organic carbon (DOC) and dissolved organic nitrogen (DON) fluxes through black-spruce-dominated forests, to compare the source/sink characteristics of sphagnum- versus feathermoss-dominated forest floors, and to identify changes in DOC and DON flow patterns occurring as a result of clearcut harvesting. After 2 yr of pre-harvest monitoring, replicated, experimental harvests of varying intensities of biomass removals were conducted followed by 4 yr of post-harvest sampling. Prior to harvest, the upland site type, dominated by feathermoss, was a significant source of DOC and DON, whereas, the wet-sphagnum-dominated sites exported minor amounts of these solutes. After harvest, DOC and DON fluxes peaked in the second year, but then dropped off significantly to at or below pre-harvest levels. On the upland site type, chipper debris appeared to be a major source of DOC and DON generating fluxes well above the pre-harvest levels. On the wetter site types, it appeared that microclimate differences between harvest treatments had a stronger influence on DOC and DON production than did the amount or type of harvest residue. Full-tree harvesting did not significantly alter the production of DOC and DON when compared with stem-only harvesting on the sites included in this study. Key words: DOC, DON, forest floor leachate, black spruce, harvesting response

scholarly journals Northeastern Ontario Forest Ecosystem Classification as a tool for managing marten habitat

1996 ◽  
Vol 72 (5) ◽  
pp. 529-532 ◽  
Author(s):  
J. C. Bowman ◽  
J.-F. Robitaille ◽  
W. R. Watt
Keyword(s):  
Key Words ◽  
Forest Ecosystem ◽  
Habitat Suitability ◽  
Black Spruce ◽  
Martes Americana ◽  
Forest Habitat ◽  
Site Type ◽  
Ecosystem Classification ◽  
Site Types ◽  
American Martens

In northeastern Ontario, the Forest Ecosystem Classification (NE-FEC) system has been used in a Habitat Suitability Matrix (NE-HSM) for forest wildlife. This paper examines whether American martens (Martes americana) responded significantly to different NE-FEC Site Types, and compares this response with suitability values in the NE-HSM. Use of Site Types by martens deviated significantly from availability; Site Type 5 (black spruce) was preferred and Site Type 7 (hardwood) was avoided. In general, the NE-HSM was consistent with field results; but it was concluded that some adjustments should be made to the suitability values for martens in the Northeastern Ontario Forest Habitat Suitability Matrix. Key words: Forest ecosystem classification, habitat suitability matrix, marten, Martes americana

scholarly journals Black spruce growth and foliar nutrient responses to drainage and fertilization: Wally Creek, Ontario

1998 ◽  
Vol 74 (1) ◽  
pp. 106-115 ◽  
Author(s):  
Brian E. McLaren ◽  
John K. Jeglum
Keyword(s):  
Growth Response ◽  
Black Spruce ◽  
Growth And Yield ◽  
Yield Response ◽  
Stem Analysis ◽  
Site Type ◽  
Foliar Nutrient ◽  
Poor Site ◽  
Npk Fertilization ◽  
Site Types

We report tenth-year growth and yield improvements in the Wally Creek area, an experimental, systematic drainage project established in 1984 and fertilized in 1986, in a forested Ontario peatland. We analyzed and compared results for dominant–codominant and intermediate black spruce in two site types. Response of trees to NPK-fertilization was more immediate than to drainage. Response to drainage took about five to seven years, whereas response to fertilization occurred earlier, from three to five years. Some indication of an asymmetric response, with larger trees experiencing higher growth increases, was observed for the OG 11 (Ledum) site type, while yield increases were potentially higher in the OG 12 (Alnus herb-poor) site type. Drainage was most effective in combination with fertilization. Consistent for both site types were increases in phosphorus associated with fertilization. The Wally Creek project is a benchmark in the analysis of growth and yield response from intensive peatland silviculture. Key words: black spruce, drainage, fertilization, foliar analysis, growth response, growth and yield, Lake Abitibi Model Forest, Ontario, stem analysis

scholarly journals Actinidia arguta Leaf as a Donor of Potentially Healthful Bioactive Compounds: Implications of Cultivar, Time of Sampling and Soil N Level

Molecules ◽  
2021 ◽  
Vol 26 (13) ◽  
pp. 3871
Author(s):  
Jan Stefaniak ◽  
Barbara Łata
Keyword(s):  
Antioxidant Capacity ◽  
Plant Development ◽  
Growing Season ◽  
Trolox Equivalent Antioxidant Capacity ◽  
Total Phenolic ◽  
Development Phase ◽  
Soil N ◽  
Actinidia Arguta ◽  
N Level ◽  
N Fertility

The aim of this study was to assess the enzymatic and non-enzymatic antioxidant status of kiwiberry (Actinidia arguta) leaf under different N regimes tested three times in field conditions during the 2015 growing season in two cultivars (‘Weiki’ and ‘Geneva’). Leaf total antioxidant capacity using ABTS, DPPH and FRAP tests was evaluated in the years 2015 to 2017, which experienced different weather conditions. Both cultivars exhibited a significant fall in leaf L-ascorbic acid (L-AA) and reduced glutathione (GSH) as well as global content of these compounds during the growing season, while total phenolic contents slightly (‘Weiki’) or significantly (‘Geneva’) increased. There was a large fluctuation in antioxidative enzyme activity during the season. The correlation between individual antioxidants and trolox equivalent antioxidant capacity (TEAC) depended on the plant development phase. The study revealed two peaks of an increase in TEAC at the start and end of the growing season. Leaf L-AA, global phenolics, APX, CAT and TEAC depended on the N level, but thiol compounds were not affected. Over the three years, TEAC decreased as soil N fertility increased, and the strength of the N effect was year dependent. The relationship between leaf N content and ABTS and FRAP tests was highly negative. The antioxidant properties of kiwiberry leaves were found to be closely related to the plant development phase and affected by soil N fertility.

Spatial dynamics of soil moisture and temperature in a black spruce boreal chronosequence

2006 ◽  
Vol 36 (11) ◽  
pp. 2794-2802 ◽  
Author(s):  
Ben Bond-Lamberty ◽  
Karen M Brown ◽  
Carol Goranson ◽  
Stith T Gower
Keyword(s):  
Soil Moisture ◽  
Spatial Variability ◽  
Sampling Design ◽  
Black Spruce ◽  
Structural Characteristics ◽  
Spatial Dynamics ◽  
Spherical Model ◽  
Local Scale ◽  
Spatial Dependencies ◽  
The Mean

This study analyzed the spatial dependencies of soil moisture and temperature in a six-stand chronosequence of boreal black spruce (Picea mariana (Mill.) BSP) stands. Spatial variability of soil temperature (TSOIL) was evaluated twice during the growing season using four transects in each stand, employing a cyclic sampling design with measurements spaced 2–92 m apart. Soil moisture (θg) was measured on one occasion. A spherical model was used to analyze the geostatistical correlation structure; θg and TSOIL at the 7- and 21-year-old stands did not exhibit stable ranges or sills. The fits with stable ranges and sills modeled the spatial patterns in the older stands reasonably well, although unexplained variability was high. Calculated ranges varied from 3 to 150 m for these stands, lengths probably related to structural characteristics influential in local-scale energy transfer. Transect-to-transect variability was significant and typically 5%–15% of the mean for TSOIL and 10%–70% for θg. TSOIL and θg were negatively correlated for most stands and depths, with TSOIL dropping 0.5–0.9 °C for every 1% rise in θg. The results reported here provide initial data to assess the spatial variability of TSOIL and θg in a variety of boreal forest stand ages.

scholarly journals Standortkartierung im Lehr- und Forschungswald der ETH in Sedrun | Site mapping in the ETH Research Forest of Sedrun

2009 ◽  
Vol 160 (2) ◽  
pp. 27-36
Author(s):  
Jacques Doutaz ◽  
Hans-Ulrich Frey ◽  
Harald Bugmann
Keyword(s):  
Classification System ◽  
Sustainable Forest Management ◽  
Structural Characteristics ◽  
Site Classification ◽  
Classification Methods ◽  
Site Type ◽  
Forest Sites ◽  
Site Mapping ◽  
A Site ◽  
Site Types

Phytosociology has advanced in various respects since the fundamental groundwork was laid, which was mainly concerned with developing a classification system of vegetation units. Current site classification methods for forests consider not only floristic aspects, but also pedological, topographic and structural characteristics of forest stands. During the summer of 2007, a site mapping was carried out in the ETH Research Forest near Sedrun (Switzerland). This paper describes the methods employed, and it evaluates the applicability thereof based on case studies. Site mapping is based on expert opinion, and as such it includes a certain degree of generalization and subjectivity in the evaluation of stands and their assignment to a site type. However, we propose that site classification constitutes a suitable tool for describing and characterizing the complexity of forest sites. The accurate description of site types strongly facilitates the interpretation and the applicability of a classification system in decision support for sustainable forest management.

scholarly journals Early Height Growth and Site Index of Lodgepole Pine Under Wet and Dry Soil Moisture Regimes in British Columbia

1997 ◽  
Vol 12 (1) ◽  
pp. 5-8
Author(s):  
Gordon D. Nigh
Keyword(s):  
Soil Moisture ◽  
Pinus Contorta ◽  
Lodgepole Pine ◽  
Site Index ◽  
Height Growth ◽  
Moisture Regimes ◽  
Indicator Variables ◽  
Soil Moisture Availability ◽  
A Site ◽  
Growth Intercept

Abstract The objective of this study was to determine whether the relationship between site index and early height growth of lodgepole pine (Pinus contorta var. latifolia) is the same on wet and dry sites. If the height growth/site index relationship is the same for different site types, then only one growth intercept model is required to estimate site index. Indicator variables in nonlinear regression were used to incorporate soil moisture availability into a growth intercept model. One set of parameters in a site index/early height growth model was adequate for both wet and dry sites. This result was supported graphically. Therefore, only one growth intercept model is necessary for the sites examined in this study. West. J. Appl. For. 12(1):5-8.

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