Précisons sur les facteurs d'arbre utilisés lors d'inventaires par points d'échantillonnage des peuplements inéquiennes

1991 ◽  
Vol 67 (4) ◽  
pp. 389-392
Author(s):  
Yvon Grenier ◽  
France Lapointe
Keyword(s):  
Key Words ◽  
Traditional Method ◽  
Basal Area ◽  
Diameter Class ◽  
Point Sampling ◽  
Number Of Stems ◽  
Diameter Classes

This paper presents six tree factor tables, for basal area factors of 2, 3 and 4 m2/ha and diameter classes of 2 and 10 cm. They can be used for point sampling inventories of unevenaged stands while the purpose is to estimate the number of stems by diameter class. We used a method based on the fact that diameters in a diameter class do not have equal weights. One can calculate tree factor in a more precise manner that what could have been done with traditional method. Key words: diameter class, tree factor, unevenaged structure.

Cavity Trees in Sawtimber-Size Oak Stands in Central Massachusetts

1989 ◽  
Vol 6 (2) ◽  
pp. 61-65 ◽  
Author(s):  
William M. Healy ◽  
Robert T. Brooks ◽  
Richard M. DeGraaf
Keyword(s):  
Basal Area ◽  
Timber Production ◽  
Diameter Class ◽  
Silvicultural Treatment ◽  
Dead Trees ◽  
Tree Quality ◽  
Live Tree ◽  
Diameter Classes

Abstract Animals that use cavities in trees are an important component of hardwood ecosystems, but reserving cavity trees is often perceived as an impact on timber production. Cavities occurred in 4% of the live trees in even-aged, saw-timber-size oak stands with no previous silvicultural treatment. Cavity trees accounted for 8% of the total live tree basal area and occurred in all tree quality and diameter classes. Dead trees were well distributed by diameter class. On the average, unthinned stands had about 2.9 times as many cavity trees and 1.8 times as many dead trees per ha as thinned stands. It is possible to conduct thinnings that both improve stand quality and retain cavity trees because 89% of the rough cull, and 63% of the rotten cull trees did not contain cavities. North. J. Appl. For. 6:61-65, June 1989.

Nonlinear Models for Stand Table Projection in Northern Hardwood Stands

1974 ◽  
Vol 4 (1) ◽  
pp. 23-27 ◽  
Author(s):  
Alan R. Ek
Keyword(s):  
Nonlinear Models ◽  
Basal Area ◽  
Growth Period ◽  
Size Class ◽  
Diameter Class ◽  
Site Class ◽  
Northern Hardwood ◽  
Number Of Stems ◽  
A Site ◽  
Stand Basal Area

Nonlinear equation models were developed for prediction of periodic ingrowth, mortality, and survivor growth by 2-in. (5.1-cm) diameter classes in northern hardwood stands. Equations were constructed using 5 year growth records on 132 plots from stands with a broad range of age and size class distributions. The model for number of ingrowth trees in the smallest diameter class measured was [Formula: see text] where G and N are initial stand basal area and number of trees, respectively, on a per acre basis and the bi's are constants. Mortality in a diameter class expressed as trees per acre was described by the model [Formula: see text] where g and n indicate initial basal area and number of trees in a specified diameter class. Survivor growth was described by prediction of the number of trees in a class which grow into the next larger size class during the growth period. The model for the number of stems moving up was [Formula: see text] where S is a site class term. Considerations in the formulation of the models and a discussion of their utility and limitations are also presented.

scholarly journals Entwicklung der Baumarten im Schweizer Wald – methodische Überlegungen

2011 ◽  
Vol 162 (9) ◽  
pp. 326-336
Author(s):  
Philippe Duc ◽  
Urs-Beat Brändli ◽  
Fabrizio Cioldi ◽  
Adrian Lanz ◽  
Ulrich Ulmer
Keyword(s):  
Tree Species ◽  
Basal Area ◽  
National Forest Inventory ◽  
National Forest ◽  
Conifer Species ◽  
Tree Species Composition ◽  
Number Of Stems ◽  
Broadleaf Species ◽  
Methodological Considerations ◽  
Diameter Classes

Development of tree species in Swiss forests – some methodological considerations Swiss forests have been subject to more stress in recent decades due to increased climatic and biogenic disturbances. Some tree species, such as Norway spruce, have been more severely affected than others. How the tree species composition of the Swiss forest has changed during this time has been assessed with data from the Swiss National Forest Inventory (NFI). The four indicators, presence, dominance, number of stems and basal area, were examined to see: whether the changes in the most important tree species are significant; whether the indicators have developed in the same way in the two diameter classes, D1 (12–36 cm DBH) and D2 (> 36 cm DBH); and how different diameter thresholds (12 or 36 cm DBH) and different circular sample plot sizes (200 m2 or 500 m2) affect the development and significance of the indicators. All the values were estimated for the 5370 NFI forest plots that were accessible in all three inventories, NFI1 (1983–85), NFI2 (1993–95) and NFI3 (2004–06). Only in a minority of tree species did changes in the presence, dominance, number of stems and basal area develop in the same way. Most indicators for the conifer species spruce, fir and pine decreased significantly, whereas for the broadleaf species, maple and ash, as well as larch and the other conifers, they increased significantly. The basal area increased during the period investigated for all tree species except pine and spruce. The different development of the indicators number of stems and basal area can be attributed to a different development within the DBH classes D1 and D2. The inventory diameter threshold strongly affects the development of the indicator number of stems, but not that of the indicator basal area.

Le système radiculaire dans les érablières du Québec. I. Nouvelle méthode d'estimation du volume et de la masse des radicelles

1992 ◽  
Vol 22 (10) ◽  
pp. 1562-1567 ◽  
Author(s):  
Fernand Pagé ◽  
Bady Badibanga ◽  
Annie Sauvesty ◽  
Colette Ansseau
Keyword(s):  
Standard Deviation ◽  
Sugar Maple ◽  
Soil Samples ◽  
Diameter Class ◽  
Thin Sections ◽  
Truncated Cone ◽  
The Mean ◽  
Diameter Classes

A method for rapidly estimating the rootlet volume and mass in sugar maple groves was developed in relation with the rootlet size. Soil samples were obtained with corers and cut in 2-cm thick slices. The number of rootlets of diameter classes <0.3, 0.3–0.5, 0.5–0.8, and 0.8–1.0 mm were determined under microscope (× 150) on the upper surface of slices. Rootlet surface for each class was measured on thin sections of soil, with an optic microscope connected to a digitalizing board. Mean rootlet surface [Formula: see text] showed a small standard deviation within each diameter class. The rootlet surface (S) on a surface of soil St can be estimated as [Formula: see text], where N is the number of rootlets observed in nc fields of observation, each field having a surface So. If two soil slices are located at depths h1 and h2, respectively, and if the rootlet surfaces of those slices are S1 and S2, the rootlet volume V of the first slice corresponds approximately to the volume of a truncated cone, and can be calculated as V = [S1 + S2 + (S1S2)0,5] (h2–h1)/3. The rootlet density (g•cm−3 of root) was also determined for each diameter class. The standard deviation from [Formula: see text], the mean density for each diameter class was small. Thus, the rootlet mass M was determined as [Formula: see text]. Estimated and real rootlet volume and mass values were compared. A difference of about 10% was found between estimated and real values.

scholarly journals Zur Auswirkung der Hangneigungskorrektur auf Schätzwerte im Schweizerischen Landesforstinventar (LFI) | Investigation of the effect of the slope correction method as applied in the Swiss National Forest Inventory of estimates

2001 ◽  
Vol 152 (6) ◽  
pp. 215-225 ◽  
Author(s):  
Michael Köhl ◽  
Peter Brassel
Keyword(s):  
Forest Inventory ◽  
Basal Area ◽  
Correction Method ◽  
National Forest Inventory ◽  
National Forest ◽  
Average Deviation ◽  
Forest Inventories ◽  
Slope Correction ◽  
Number Of Stems ◽  
Elliptical Area

For forest inventories on slopes, it is necessary to correct the test areas, because the circular areas, when projected, become elliptical. Based on 93 samples from the Swiss National Forest Inventory (FNI), it was determined whether the simplified method, which increases the radius to match that of the elliptical area, leads to a distortion of the results. An average deviation of 2% was found between the FNI estimated values and the actual values for the basal area and the number of stems. For estimations of smaller units, greater distortions of the results are expected.

A note on the relationship between the quadratic mean stand diameter and harmonic mean basal area under size-biased distribution theory

2003 ◽  
Vol 33 (8) ◽  
pp. 1587-1590 ◽  
Author(s):  
J H Gove
Keyword(s):  
Size Distribution ◽  
Graphical Representation ◽  
Basal Area ◽  
Distribution Theory ◽  
Harmonic Mean ◽  
Quadratic Mean ◽  
Point Sampling ◽  
The Relationship ◽  
Horizontal Point Sampling ◽  
Biased Distribution

This note seeks to extend the utility of size-biased distribution theory as applied to forestry through two relationships regarding the quadratic mean stand diameter. First, the quadratic mean stand diameter's relationship to the harmonic mean basal area for horizontal point sampling, which has been known algebraically from early on, is proved under size-biased distribution theory. Second, a new result, which may prove most valuable in viewing the graphical representation of assumed distributions, is also derived. The results are also shown to apply to the basal area – size distribution, providing a unique duality between the two means.

scholarly journals BITTER HERBS OF EASTERN NIGERIA (GONGRONEMA LATIFOLIUM, VERNONIA AMYGDALINA AND VITEX DONIANA): A REVIEW

2018 ◽  
Vol 15 (3) ◽  
pp. 47
Author(s):  
Asuzu Chinwe U.
Keyword(s):  
Key Words ◽  
Traditional Method ◽  
Human Consumption ◽  
Vernonia Amygdalina ◽  
South Eastern ◽  
Electronic Search ◽  
Anti Cancer ◽  
Large Audience ◽  
Vitex Doniana ◽  
Gongronema Latifolium

Background: The article is a review of three bitter vegetables consumed in South-eastern Nigeria (Gongronema latifolium, Vernonia amygdalina and Vitex doniana). These vegetables are not very palatable to taste but are highly famed because of the myriad of illnesses that they are reputed to cure and manage. The different aspects of these vegetables reviewed are their ethnobotany, zoo pharmacology, bioactivity, phytochemistry and toxicity. Materials and method: The literatures consulted were searched using electronic search engines (Google, Google scholar and Pubmed). Substantial amount of literature was consulted but only those directly related to the main review were selected. Result: The review revealed that the three bitter vegetables possessed phytochemicals like saponins, flavonoids, alkaloids among others that justify the claims of curing and managing many of the illnesses that traditional folks attribute to them. From literature, antimicrobial, antinflammatory, antidiabetic, antioxidant and anti cancer activities were attributed to these three bitter herbs. Antinutritional substances like phytate and oxalate reported in these herbs were not regarded as harmful for human consumption because of the traditional method of processing the vegetables by squeeze washing in several changes of water. Conclusion: The three bitter herbs are regarded as beneficial for human consumption and the information should be disseminated to a large audience. Key words: V. amygdalina, V. doniana, G.

scholarly journals Bayesian Evaluation of Smartphone Applications for Forest Inventories in Small Forest Holdings

Forests ◽  
2020 ◽  
Vol 11 (11) ◽  
pp. 1148
Author(s):  
Andrej Ficko
Keyword(s):  
Mobile Applications ◽  
Mobile Application ◽  
Basal Area ◽  
Small Enterprises ◽  
Private Forest ◽  
P Values ◽  
Forest Inventories ◽  
The Difference ◽  
Number Of Stems ◽  
Small Forest

There are increasingly advanced mobile applications for forest inventories on the market. Small enterprises and nonprofessionals may find it difficult to opt for a more sophisticated application without comparing it to an established standard. In a small private forest holding (19 ha, 4 stands, 61 standing points), we compared TRESTIMA, a computer vision-based mobile application for stand inventories, to MOTI, a smartphone-based relascope, in measuring the number of stems (N) and stand basal area (G). Using a Bayesian approach, we (1) weighted evidence for the hypothesis of no difference in N and G between TRESTIMA and MOTI relative to the hypothesis of difference, and (2) weighted evidence for the hypothesis of overestimating versus underestimating N and G when using TRESTIMA compared to MOTI. The results of the Bayesian tests were then compared to the results of frequentist tests after the p-values of paired sample t-tests were calibrated to make both approaches comparable. TRESTIMA consistently returned higher N and G, with a mean difference of +305.8 stems/ha and +5.8 m2/ha. However, Bayes factors (BF10) suggest there is only moderate evidence for the difference in N (BF10 = 4.061) and anecdotal evidence for the difference in G (BF10 = 1.372). The frequentist tests returned inconclusive results, with p-values ranging from 0.03 to 0.13. After calibration of the p-values, the frequentist tests suggested rather small odds for the differences between the applications. Conversely, the odds of overestimating versus underestimating N and G were extremely high for TRESTIMA compared to MOTI. In a small forest holding, Bayesian evaluation of differences in stand parameters can be more helpful than frequentist analysis, as Bayesian statistics do not rely on asymptotics and can answer more specific hypotheses.

scholarly journals Tree mortality in the dynamics and management of uneven-aged Norway spruce stands in southern Finland

2020 ◽  
Vol 139 (6) ◽  
pp. 989-998
Author(s):  
Sauli Valkonen ◽  
Lucie Aulus Giacosa ◽  
Juha Heikkinen
Keyword(s):  
Tree Mortality ◽  
Stand Structure ◽  
Basal Area ◽  
Repeated Measurements ◽  
Common Causes ◽  
Single Tree Selection ◽  
Spruce Stands ◽  
Causes Of Mortality ◽  
Number Of Stems ◽  
Adverse Influence

Abstract This study focused on tree mortality in spruce-dominated stands managed using the single-tree selection method in southern Finland. Together with regeneration and tree growth, mortality is one of the basic elements of the stand structure and dynamics in selection stands. The study was based on data acquired from a set of 20 permanent experimental plots monitored with repeated measurements for 20 years. The average mortality in the number of stems (N) was 4.45 trees ha−1a−1, in basal area (G) 0.07 m2 ha−1a−1, and in stemwood volume (V) 0.56 m3 ha−1a−1. In relative terms it was 0.50% of N, 0.30% of G and 0.27% of V, respectively. Wind and snow were the most common causes of mortality, while deaths by biotic causes (mammals, insects, pathogens) were extremely rare. Some 6–10% of the total loss in the number of stems and volume was attributable to the loss or removal of trees that sustained serious damage in harvesting. Most of the mortality occurred in the smallest diameter classes of up to 20 cm. Such a high mortality among small trees can have an adverse influence on the sustainability of selection structures if not successfully checked in harvesting and management.

scholarly journals Controlling Beech Root and Stump Sprouts Using the Cut-Stump Treatment

2006 ◽  
Vol 23 (3) ◽  
pp. 155-165 ◽  
Author(s):  
Jeffrey D. Kochenderfer ◽  
James N. Kochenderfer ◽  
Gary W. Miller
Keyword(s):  
Radial Distance ◽  
Basal Area ◽  
Fagus Grandifolia ◽  
Complete Control ◽  
Growing Seasons ◽  
Control Root ◽  
Stump Sprouting ◽  
Number Of Stems ◽  
Cut Stump ◽  
Stump Sprouts

Abstract Application costs and efficacy were determined for cut-stump treatments applied to American beech (Fagus grandifolia Ehrh.) to control root and stump sprouts in central West Virginia. Glyphosate as Glypro (53.8%) was applied to the outer 2 in. of beech stumps from trees >6.0-in. dbh within 1 hour after cutting. In addition to treatment plots, individual beech stumps were treated to determine mortality patterns. The treatments were applied in early September 2001 and evaluated 12 months after treatment. A rating system ranging from 1 to 7 (0 to 100% crown affected) based on visual estimates of symptoms was used to evaluate the efficacy of the treatments. Trees with a rating of 5 (75% crown control or greater) were considered controlled. After 12 months, more than 90% of beech root sprouts ≥1-ft tall to 5.9-in. dbh on treated plots were controlled. Complete control of stump sprouting also was achieved. An average of 93 beech stems was controlled around each treated stump. Mortality around treated stumps declined as the radial distance from stumps increased and stump size decreased. Average application cost (chemical and labor) ranged from $39.43 to 62.34 per acre depending on the basal area and number of stems treated. After two growing seasons, the number of beech root sprouts on more than 90% of the treated regeneration plots remained below levels considered as interfering according to guidelines for Allegheny hardwoods. This study demonstrated that herbicide is readily translocated from the surfaces of freshly cut beech stumps via parent root systems to attached live beech stems. The cut-stump method can be applied in areas where beech is the primary species interfering with the establishment and development of desirable regeneration.

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