Effects of time since stand-replacing fire and overstory composition on live-tree structural diversity in the boreal forest of central Canada

2008 ◽  
Vol 38 (1) ◽  
pp. 52-62 ◽  
Author(s):  
Brian W. Brassard ◽  
Han Y.H. Chen ◽  
Jian R. Wang ◽  
Peter N. Duinker
Keyword(s):  
Boreal Forest ◽  
Coefficient Of Variation ◽  
Stand Structure ◽  
Diversity Index ◽  
Stand Development ◽  
Stand Volume ◽  
Diameter At Breast Height ◽  
Breast Height ◽  
Shaped Pattern ◽  
Mixedwood Stands

Stand structure diversity is hypothesized (i) to increase with stand development and (ii) to be greater in mixedwood stands than in conifer and broadleaf stands. We examined the effects of time since stand-replacing fire (TSF) and overstory type on stand volume, stand density, and tree-size variability, which is measured using Shannon’s diversity index (H′) and coefficient of variation, in fire-origin boreal forest stands. We sampled 36 stands representing conifer, mixedwood, and broadleaf overstory types, ranging in ages from 72 to 201 years TSF on upland mesic sites in northwestern Ontario, Canada. Stand volume decreased in older mixedwood and broadleaf stands, but followed a U-shaped pattern in conifer stands with TSF. Diameter-at-breast-height-based H′ followed an inverse U-shaped pattern with TSF for all overstory types. Height-based H′ decreased with TSF in conifer and mixedwood stands but peaked at the intermediate age class in broadleaf stands. Diameter-at-breast-height- and height-based coefficient of variation indices followed an inverse U-shaped distribution with TSF. Our results partially supported the two hypotheses, as (i) the 124- to 139-year-old stands were most diverse and (ii) mixedwood stands were more than or as equally diverse as conifer and broadleaf stands, depending on stand development stage and the diversity indices used.

scholarly journals Relative effects of dendrometers on the estimation of diameter at breast height, stand basal area and stand volume in uneven-aged northern hardwoods

2009 ◽  
Vol 85 (3) ◽  
pp. 446-452 ◽  
Author(s):  
François Guillemette ◽  
Marie-Claude Lambert
Keyword(s):  
Basal Area ◽  
Major Axis ◽  
Minor Axis ◽  
Northern Hardwoods ◽  
Parameter Estimates ◽  
Betula Alleghaniensis ◽  
Stand Volume ◽  
Diameter At Breast Height ◽  
Breast Height ◽  
Stand Basal Area

Four methods of estimating diameter at breast height (DBH) were used on 558 northern hardwood stems, located in 6, 0.25-ha plots, to compare their effects. The first method was a diameter tape reading and the second was a systematic reading, along a predefined axis, taken with a calliper. The last 2 methods were both obtained from the arithmetic mean of 2 different pairs of calliper readings taken at right angles. The first pair was directed along the major bole axis and the other pair along the minor axis. The 4 methods were compared in terms of mean tree diameter, plot basal area and plot volume. There were significant differences (p < 0.05) in parameter estimates among methods, and the differences varied according to species (Acer saccharum Marsh. and Betula alleghaniensis Britt.) and tree size class. Differences among methods were more evident for larger DBH classes, which contribute most to the significant differences observed for both the plot and stand basal area and volume. Overall, tree DBH, plot basal area and plot volume provided by these 4 methods ranked in this ascending order: mean calliper reading directed along the minor axis, systematic calliper reading, mean calliper reading directed along the major axis, and diameter tape. The difference in stand basal area or volume between the estimates obtained with a systematic calliper reading and a diameter tape was 1.1 m2/ha with a mean basal area of about 21 m2/ha, or 10.5 m3/ha with a mean stand volume of 169 m3/ha. Because of the magnitude of these differences, it is recommended the method of DBH estimation be specified in studies, to be careful when crossing databases or models using different methods of DBH estimation, and to always maintain the same method of DBH estimation when remeasuring a plot. Key words: northern hardwoods, dendrometer, diameter tape, calliper, caliper, DBH measurement, basal area, volume

scholarly journals Composição e estrutura da vegetação de caatinga no sul do Piauí, Brasil

2017 ◽  
Vol 12 (2) ◽  
pp. 210
Author(s):  
Mailson Pereira de Souza ◽  
Joxleide Mendes da Costa Pires Coutinho ◽  
Leovandes Soares da Silva ◽  
Felipe Silva Amorim ◽  
Allyson Rocha Alves
Keyword(s):  
Urban Area ◽  
Edge Effects ◽  
Forest Fires ◽  
Diversity Index ◽  
Good Condition ◽  
Diameter At Breast Height ◽  
Breast Height ◽  
Caatinga Vegetation ◽  
Composition And Structure ◽  
The City

<p>Visando contribuir para o conhecimento mais profundo a respeito da vegetação do sul do Piauí, e em especial às áreas de tensão ecológica, o presente trabalho objetivou inventariar, avaliando qualitativamente, o componente lenhoso de um trecho de Caatinga, no município de Bom Jesus, Piauí, Brasil. Para realização do levantamento foram alocadas 10 parcelas de 50x20 m (1000 m²), totalizando 1 ha de área amostrada, dispostas de forma contíguas para minimizar os possíveis efeitos de borda da área. Foram amostrados os indivíduos lenhosos vivos com diâmetro à altura do peito (DAP) ≥ 5 cm, independente da altura. No levantamento foram encontradas 11 famílias, 25 gêneros e 27 espécies. Destas, as que se destacaram com os maiores valores de IVI foram: <em>Cenostigma macrophyllum </em>Tul., <em>Combretum duarteanum</em> Cambess., <em>Erythroxylum</em> <em>laetevirens</em> O.E.Schulz, <em>Campomanesia pubescens</em> (Mart. ex DC.) O. Berg., e <em>Licania rigida</em> Benth. O índice de diversidade de Shannon-Wiener (H’) foi de 2,7 nats.ind<sup>-1</sup>. Para todos os efeitos de comparações, observou-se que a área estudada encontra-se em bom estado de conservação, não se constatando evidências diretas de exploração, tão pouco resquícios de incêndios florestais, apesar da proximidade da área de estudo com a zona urbana da cidade de Bom Jesus do Piauí.<strong> </strong>O fragmento é um ecótono vegetacional, com predomínio de espécies típicas da Caatinga.</p><p align="center"><strong><em>Composition and structure  caatinga vegetation in south Piauí, Brazil</em></strong><strong><em></em></strong></p><pre><strong>Abstract: </strong>To contribute to the deeper knowledge of the southern Piaui vegetation, especially the areas of ecological tension, this study aimed to inventory and qualitatively assess the woody component of a Caatinga stretch in the municipality of Bom Jesus / PI,  Brazil. To perform the survey plots were allocated 10 50x20 m (1000 m²) totaling 1 ha of sampled area, arranged contiguous way to minimize the possible edge effects area. They sampled the living woody individuals with diameter at breast height (DBH) ≥ 5 cm, regardless of height. In the survey we found 11 families, 25 genera and 27 species. Of these, those that stood out with the highest IVI values were.<em> </em><em>Cenostigma macrophyllum </em>Tul.,<em> Combretum duarteanum</em> Cambess., <em>Erythroxylum</em> <em>laetevirens</em> O.E.Schulz , <em>Campomanesia pubescens</em> (Mart. ex DC.) O. Berg and <em>Licania rigida</em> Benth. The diversity index Shannon-Wiener (H') was 2,7 nats.ind-1. For all purposes of comparison, it was observed that the study area is in good condition, not finding to direct exploration evidence, so little remains of forest fires, despite the proximity of the study area with the urban area the city of Bom Jesus do Piauí. The fragment is a vegetative ecotone, with predominance of species typical of the Caatinga. </pre><p><strong> </strong></p>

Stand structure and dynamics of Picea mariana on the northern border of the natural closed boreal forest in Quebec, Canada

2009 ◽  
Vol 39 (12) ◽  
pp. 2307-2318 ◽  
Author(s):  
Sergio Rossi ◽  
Marie-Josée Tremblay ◽  
Hubert Morin ◽  
Valérie Levasseur
Keyword(s):  
Boreal Forest ◽  
Picea Mariana ◽  
Stand Structure ◽  
Tree Age ◽  
Stand Dynamics ◽  
Stand Development ◽  
Economic Potential ◽  
Structure And Dynamics ◽  
Northern Border ◽  
Ecological Importance

The boreal forest of higher latitudes constitutes a reservoir of trees of great ecological importance and unknown economic potential, but the stand dynamics in these regions still remain essentially unexplored. This paper examines the change in age and size structures during stand development on the northern border of the natural closed boreal forest in Quebec, Canada. Height, diameter, and age of trees were measured in 18 plots with stand ages between 77 and 340 years. The occurrence, size, and origin (layer or seed) of seedlings and saplings were assessed in subplots. Tree density ranged from 600 to 3750 trees·ha–1. Picea mariana (Mill.) BSP was the dominant species, mainly originating by layering. A cluster analysis segregated plots into even-aged and uneven-aged stands according to tree age, but size distribution of trees, saplings, and seedlings did not differ statistically between the two groups. Even-aged stands exhibited a 60% probability of assuming an uneven-aged structure between 120 and 200 years after stand initiation. At high latitudes, the closed boreal forest of P. mariana appears homogeneously sized, with similar distributions of diameter and height across all stages of stand development.

Individual tree biomass estimation equations for plantation-grown white spruce in northern Minnesota

1985 ◽  
Vol 15 (4) ◽  
pp. 738-739 ◽  
Author(s):  
R. B. Harding ◽  
D. F. Grigal
Keyword(s):  
Stand Structure ◽  
White Spruce ◽  
Biomass Estimation ◽  
Prediction Equations ◽  
Tree Biomass ◽  
Eastern Canada ◽  
Individual Tree ◽  
Diameter At Breast Height ◽  
Breast Height ◽  
Estimation Equations

Prediction equations for biomass of white spruce (Piceaglauca (Moench) Voss) were developed for 115 sample trees using the allometric models Y = ADB and Y = ADBHC, where Y is mass, D is diameter at breast height, and H is total height. The addition of height to the model reduced the Sy•x for all estimates except that for biomass of branches and needles. Comparison of results to other estimation equations developed in eastern Canada showed that biomass estimates were variable. Variations in stand structure and age between natural and plantation-grown trees are possible reasons for these differences.

Cone serotiny in jack pine: ontogenetic, positional, and environmental effects

1993 ◽  
Vol 23 (3) ◽  
pp. 394-401 ◽  
Author(s):  
Sylvie Gauthier ◽  
Yves Bergeron ◽  
Jean-Pierre Simon
Keyword(s):  
Boreal Forest ◽  
Life Span ◽  
Environmental Effects ◽  
Thermal Environment ◽  
Jack Pine ◽  
Time Interval ◽  
Diameter At Breast Height ◽  
Breast Height ◽  
Pine Trees ◽  
Environmental Causes

The main objective of this study was to determine empirically if the absence of serotinous (seed retaining) cones in young jack pine (Pinusbanksiana Lamb.) was due to environmental causes, particularly to ground-radiated heat, or to the juvenility of the trees. Twenty-five jack pine populations were sampled in the southern part of the boreal forest, in Abitibi, Quebec. The age, diameter at breast height (DBH), and number of serotinous and nonserotinous cones per branch were determined for 30 trees per population. A subset of 10 other trees per population was felled to determine the number of serotinous and nonserotinous cones per cone age-class and per branch. DBH, age, and height of these trees were also measured. The results showed that DBH is more strongly related than age or height to the appearance of the first serotinous cone. Most trees that did not bear any serotinous cones had not reached a DBH of 7 cm. Until individuals had reached a DBH of 10 cm, the proportion of serotinous cones increased from year to year. The proportion of serotinous cones ≥4 years old was significantly lower than that of younger cones, indicating that old cones tended to open, particularly on those trees with a DBH greater than 10 cm. The proportion of serotinous cones on branches below 260 cm was significantly lower than that of cones situated above that height. The same trends were observed for cones where serotiny was determined in the laboratory, suggesting that the thermal environment is not entirely responsible for serotinous cone opening. We suggest that the age of branches affects the opening of cones and that the absence of serotinous cones in small trees is related to their juvenility. Seed release resulting from the absence of serotiny in small jack pine trees and the opening observed in old cones may play an important role in serotinous populations when the time interval between two fires is longer than the life-span of one jack pine generation.

scholarly journals Assessment of Open Grown Trees Composition and Diversity in Selected Research Institutes in Peri-Urban Ibadan, Oyo state, Nigeria

2021 ◽  
Vol 25 (7) ◽  
pp. 1263-1269
Author(s):  
B.L. Olajiire-Ajayi ◽  
R.T. Ibode ◽  
A.A. Tunde-Francis ◽  
S.O. Okeleke
Keyword(s):  
Tree Species ◽  
Diversity Index ◽  
Growth Characteristics ◽  
Shannon Diversity Index ◽  
Species Dominance ◽  
Diameter At Breast Height ◽  
Breast Height ◽  
Shannon Diversity ◽  
A Value ◽  
Research Institutes

Urban green spaces are rapidly deteriorating in most parts of Nigeria. The study assessed open grown trees composition and diversity in selected Research Institutes within Ibadan Region with the aim of comparing the ecological diversity in the study locations. This was achieved through species identification and mensuration of all open grown trees species that were accessible in the study areas. Open grown trees with Diameter at breast height ≥ 10cm were assessed for growth characteristics of total height and diameter at breast height. Basal area and volume were estimated from measured growth characteristics. Tree species were identified by a taxonomist at Federal Herbarium in Ibadan. Biodiversity indices of Shannon diversity index, species evenness and species dominance were computed to see variation in tree community of the areas. The Shannon diversity index calculated was higher in IITA with a value of 3.04 compared to that of CRIN with a value of 2.36. A dominance value of 0.15 and 0.05 was obtained for CRIN and IITA respectively. The study concludes that both institutes are repository of large diversity of tree species thereby, helping in the conservation of biodiversity while ameliorating weather. It is recommended that educational institutions from all levels located within the region as well as private organizations and individuals should plant trees within their domains in order to create conducive green environments that would promote sustainable environment in the region. This is possible when government provide adequate incentive and annual rewards for establishments with the best green environments.

scholarly journals Success Factors for Experimental Partial Harvesting in Unmanaged Boreal Forest: 10-Year Stand Yield Results

Forests ◽  
2020 ◽  
Vol 11 (11) ◽  
pp. 1199
Author(s):  
Louiza Moussaoui ◽  
Alain Leduc ◽  
Miguel Montoro Girona ◽  
Annie Claude Bélisle ◽  
Benoit Lafleur ◽  
...  
Keyword(s):  
Boreal Forest ◽  
Tree Mortality ◽  
Stand Structure ◽  
Black Spruce ◽  
Organic Layer ◽  
Stand Development ◽  
Partial Harvesting ◽  
Site Characteristics ◽  
Spruce Stands ◽  
Stand Yield

Over the past two decades, partial harvesting has been increasingly used in boreal forests as an alternative to clearcutting to promote irregular stand structures and maintain a balance between biodiversity preservation and continued timber production. However, relatively little is still known about the silvicultural potential of partial harvesting in Canada’s boreal forest, especially in areas prone to organic matter accumulation (paludification), and most prior research has focused on biodiversity responses. In this study, we assess the effects of partial harvesting on stand development (recruitment, growth, and mortality) ten years after harvesting in previously unmanaged black spruce stands and quantify its effectiveness in reducing the impacts on ecosystem structures. Our analyses revealed that pre-harvest stand structure and site characteristics, especially initial basal area, sapling density, tree diameter, and organic layer thickness (OLT) were major factors involved in stand development ten years following these partial harvesting treatments. Depending on pre-harvest structure and site characteristics, partial harvesting can result in either an increase in post-harvest tree recruitment and growth or a loss of stand volume because of standing tree mortality. To increase the chances of partial harvesting success in ensuring an increase in decennial stand yield after harvest in black spruce forest stands, sites prone to paludification (i.e., where OLT >17 cm) should be left unharvested. This study illustrates the importance of taking into account pre-existing structure and site characteristics in the selection of management strategies to maximize the potential of partial harvesting to achieve sustainable forest management in black spruce stands.

scholarly journals Estimation of Genetic Parameters and Wood Yield Selection Index in a Clonal Trial of Korean Pine (Pinus koraiensis) in Northeastern China

2021 ◽  
Vol 13 (8) ◽  
pp. 4167
Author(s):  
David Kombi Kaviriri ◽  
Huan-Zhen Liu ◽  
Xi-Yang Zhao
Keyword(s):  
Selection Index ◽  
Tree Height ◽  
Stem Volume ◽  
Korean Pine ◽  
Branch Number ◽  
Basal Diameter ◽  
Diameter At Breast Height ◽  
Breast Height ◽  
Stem Straightness ◽  
Clonal Trial

In order to determine suitable traits for selecting high-wood-yield Korean pine materials, eleven morphological characteristics (tree height, basal diameter, diameter at breast height, diameter at 3 meter height, stem straightness degree, crown breadth, crown height, branch angle, branch number per node, bark thickness, and stem volume) were investigated in a 38-year-old Korean pine clonal trial at Naozhi orchard. A statistical approach combining variance and regression analysis was used to extract appropriate traits for selecting elite clones. Results of variance analysis showed significant difference in variance sources in most of the traits, except for the stem straightness degree, which had a p-value of 0.94. Moderate to high coefficients of variation and clonal repeatability ranged from 10.73% to 35.45% and from 0.06% to 0.78%, respectively. Strong significant correlations on the phenotypic and genotypic levels were observed between the straightness traits and tree volume, but crown breadth was weakly correlated to the volume. Four principal components retaining up to 80% of the total variation were extracted, and stem volume, basal diameter, diameter at breast height, diameter at 3 meter height, tree height, and crown height displayed high correlation to these components (r ranged from 0.76 to 0.98). Based on the Type III sum of squares, tree height, diameter at breast height, and branch number showed significant information to explain the clonal variability based on stem volume. Using the extracted characteristics as the selection index, six clones (PK105, PK59, PK104, PK36, PK28, and K101) displayed the highest Qi values, with a selection rate of 5% corresponding to the genetic gain of 42.96% in stem volume. This study provides beneficial information for the selection of multiple traits for genetically improved genotypes of Korean pine.

scholarly journals Carbon stocks of homestead forests have a mitigation potential to climate change in Bangladesh

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Tarit Kumar Baul ◽  
Tajkera Akhter Peuly ◽  
Rajasree Nandi ◽  
Lars Holger Schmidt ◽  
Shyamal Karmakar
Keyword(s):  
Species Diversity ◽  
Stand Structure ◽  
Diversity Index ◽  
Carbon Stocks ◽  
Small Scale ◽  
Species Diversity Index ◽  
C Stocks ◽  
Homestead Forests ◽  
C Stock ◽  
Low Altitude

AbstractA total of 176 homestead forests at three altitudes in the Chittagong Hill Tracts, Bangladesh were randomly surveyed to estimate carbon (C) stocks and how stand structure affects the biomass C. All woody vegetations were measured, and litter and soil (0–30 cm depth) were sampled. The tree biomass C stock in the top two altitude forests was up to 37–48% higher than in low altitude, owing to significantly higher tree density and species diversity. An increase in species diversity index by one unit increased the biomass stock by 23 Mg C ha−1. The C stock of litterfall in low altitude forests was 22–28% higher than in the top two altitude due to the deposition of litters downslope and deliberate use of mulch for soil improvement and conservation, resulting in up to 5% higher total soil C. The topsoil C was 10–25% higher than the deeper soil, depending on the altitude. The forest stored 89 Mg C ha−1, indicating a potential for C sequestration in trees outside forest. This study would help policymakers to strengthen the recognition of small-scale forests for mitigation in REDD + (reducing emissions from deforestation and forest degradation, the role of conservation, sustainable management of forests, and enhancement of forest carbon stocks) and support owners through C credits from sustainably managed forests.

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