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Effects of spacing on growth,yield and wood properties of Tectona grandis at Longuza forest plantation, Tanzania
No full textMSc DissertationIn forest management, understanding the influence of spacing on
tree growth is crucial, as it goes hand in hand with stand growth as
well as yield at the final harvest. Also, spacing, especially narrow
spacing, has been used to control the stem quality of trees, as it
influences the stem straightness as well as the branching behaviour.
On the other hand, tree growth, particularly radial growth, means an
increase in wood materials such as cell wall substances, latewood,
and earlywood. Those wood materials influence the physical and
mechanical properties of wood. Behind those influences, an
understanding of the influence of spacing on the final harvest is
required to decide on appropriate spacing to economize the value of
the final harvest. However, information on the spacing influence on
growth, yield, and wood properties of Tectona grandis at an older
age in Tanzania is limited. Thus, this study is intended to evaluate
the influence of spacing on the growth, yield, and wood properties of
24-year-old Tectona grandis at Longuza Forest plantation, Tanzania.
Data were collected from a spacing trial with a randomized complete
block design with three treatments, namely 2 x 2 m, 3 x 3 m, and 4 x
4 m, replicated three times. For growth and stem quality, all trees'
diameter at breast height (dbh), height, and stem quality were
evaluated. Then, dbh data were used to obtain basal area (Ba),
volume, and the mean annual increment (MAI). Furthermore, three
trees from each spacing were sampled for physical and mechanical
properties.
The basic density (BD) was determined using
over-dry weight and green volume, while the heartwood (HW)
percentage was calculated using the cross-sectional area of the HW
and disk underbark. Moreover, all mechanical properties were tested
using a Monsanto tensiometer machine. An analysis of variance
(ANOVA) was used to evaluate the influence of spacing. Then,
Tukey’s Honest Significant Difference test (p = 0.05) was used for
multiple comparisons of means. Results revealed that at the older
age of 24 years, spacing did not statistically influence all growth and
yield parameters studied. A 4 x 4 m spacing produced trees with
higher dbh and height, while higher Ba, volume, and MAI values
were observed at 3 x 3 m. Stem quality was statistically different in
some spacings, where only 2 x 2 m differed statistically from 4 x 4
m. All physical and mechanical properties evaluated were not
statistically influenced by spacing except CLST to grain, whereby the
spacings of 2 x 2 m and 3 x 3 m had significantly higher values than
a spacing of 4 x 4 m. In conclusion, results showed that despite the
growth and yield parameters not being statistically influenced by
spacing, a spacing of 3 x 3 m could ensure a higher yield compared
to other spacings. Also, it produces trees with high stem quality,
similar to closer spacing, without affecting both physical and
mechanical properties. This is because the values of those
properties appear to have slight differences among the spacings.
Keywords: Tectona grandis, Spacing, Volume, Stem quality, Basic
density, Heartwood percentageForest Services Agency (TFS
Effects of spacing on growth,yield and wood properties of Tectona grandis at Longuza forest plantation, Tanzania
No full textMSc DissertationIn forest management, understanding the influence of spacing on
tree growth is crucial, as it goes hand in hand with stand growth as
well as yield at the final harvest. Also, spacing, especially narrow
spacing, has been used to control the stem quality of trees, as it
influences the stem straightness as well as the branching behaviour.
On the other hand, tree growth, particularly radial growth, means an
increase in wood materials such as cell wall substances, latewood,
and earlywood. Those wood materials influence the physical and
mechanical properties of wood. Behind those influences, an
understanding of the influence of spacing on the final harvest is
required to decide on appropriate spacing to economize the value of
the final harvest. However, information on the spacing influence on
growth, yield, and wood properties of Tectona grandis at an older
age in Tanzania is limited. Thus, this study is intended to evaluate
the influence of spacing on the growth, yield, and wood properties of
24-year-old Tectona grandis at Longuza Forest plantation, Tanzania.
Data were collected from a spacing trial with a randomized complete
block design with three treatments, namely 2 x 2 m, 3 x 3 m, and 4 x
4 m, replicated three times. For growth and stem quality, all trees'
diameter at breast height (dbh), height, and stem quality were
evaluated. Then, dbh data were used to obtain basal area (Ba),
volume, and the mean annual increment (MAI). Furthermore, three
trees from each spacing were sampled for physical and mechanical
properties.
The basic density (BD) was determined using
over-dry weight and green volume, while the heartwood (HW)
percentage was calculated using the cross-sectional area of the HW
and disk underbark. Moreover, all mechanical properties were tested
using a Monsanto tensiometer machine. An analysis of variance
(ANOVA) was used to evaluate the influence of spacing. Then,
Tukey’s Honest Significant Difference test (p = 0.05) was used for
multiple comparisons of means. Results revealed that at the older
age of 24 years, spacing did not statistically influence all growth and
yield parameters studied. A 4 x 4 m spacing produced trees with
higher dbh and height, while higher Ba, volume, and MAI values
were observed at 3 x 3 m. Stem quality was statistically different in
some spacings, where only 2 x 2 m differed statistically from 4 x 4
m. All physical and mechanical properties evaluated were not
statistically influenced by spacing except CLST to grain, whereby the
spacings of 2 x 2 m and 3 x 3 m had significantly higher values than
a spacing of 4 x 4 m. In conclusion, results showed that despite the
growth and yield parameters not being statistically influenced by
spacing, a spacing of 3 x 3 m could ensure a higher yield compared
to other spacings. Also, it produces trees with high stem quality,
similar to closer spacing, without affecting both physical and
mechanical properties. This is because the values of those
properties appear to have slight differences among the spacings.
Keywords: Tectona grandis, Spacing, Volume, Stem quality, Basic
density, Heartwood percentageForest Services Agency (TFS
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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