scholarly journals The characteristics of diameter growth and increment of introduced North American ash species at the sites of common alder

2012 ◽  
Vol 51 (No. 6) ◽  
pp. 237-243
Author(s):  
D. Kremer ◽  
J. Čavlović ◽  
I. Anić
Keyword(s):  
Growth Curve ◽  
Ring Width ◽  
Basal Area ◽  
Alnus Glutinosa ◽  
Diameter Growth ◽  
Mixed Stands ◽  
Increment Core ◽  
The Mean ◽  
The Difference ◽  
Individual Trees

Research was conducted into diameter growth and increment of introduced American ash species at the sites of common alder (Alnus glutinosa[L.] Gaertn.) in three mixed stands of introduced ash and common alder in the lowland part of Croatia. About 10 samples of increment cores of each species were taken from trees in the diameter class of the mean basal area. In the process, an attempt was made to reach the centre of the trees with the purpose of getting an insight into the development of the trees over a long period, i.e. from the moment when the trees reached breast height. The increment cores were analysed by measuring the width of each individual ring to the tenth of the millimetre. Bark thickness was also measured. The results obtained from the analysis of the increment cores yielded trends of ring widths for individual trees as well as trends of the average ring widths for each species within a locality. On the basis of the increment core analysis, parts of the diameter growth curve of the mean stand tree were obtained. The increment curve of mean stand diameter was obtained by deriving the growth curve of mean stand diameter. Introduced ash was found to have average ring widths from 0.92 to 4.21 mm. The measured minimal and maximal values of ring widths in total were 0.2 and 6.5 mm, respectively. Consequently, introduced ash may have significantly large ring widths in conditions of prolonged flooding as well. Therefore, its pioneering role is not irrelevant at poor sites naturally inhabited by common alder. The average ring width of introduced ash is the highest up to the age of 30 years, after which it retains the value of 2 mm or less. In common alder, the average ring width in the studied stand ranged from 1.40 to 4.59 mm. The measured minimal and maximal values of ring widths in total were 0.4 and 7.0 mm, respectively. A comparison of average ring widths of introduced ash and common alder revealed that in Draganić locality common alder had a statistically significantly larger average ring width than introduced ash. In the localities Karlovac and Đurđevac the difference was not statistically significant.

Evaluating growth responses to fertilization

1985 ◽  
Vol 15 (5) ◽  
pp. 877-880 ◽  
Author(s):  
L. R. Auchmoody
Keyword(s):  
Basal Area ◽  
Uniform Field ◽  
Growth Responses ◽  
Basal Area Growth ◽  
Nutrient Effects ◽  
Area Growth ◽  
The Mean ◽  
The Difference ◽  
Individual Trees ◽  
Area Response

When fertilizers increase radial growth rates, they also increase the diameter of trees that will be used to compute future basal area responses. If the mean basal area growth per tree is computed for fertilized trees that are larger than the unfertilized trees, the length of time that fertilizers directly affect growth can be overestimated. In this paper, a model that describes mean basal area responses per tree over time as a function of direct nutrient effects and indirect tree-size effects is suggested. Application of the model to a uniform field fertilization experiment shows that after the 1st year, some or all of the average basal area response of individual trees is due to the difference in size between fertilized and unfertilized trees. To evaluate direct fertilizer responses properly, mean basal area growth per tree must be adjusted for the unequal size of fertilized and unfertilized trees.

Use of diameter increment and basal area increment in tree growth studies

1980 ◽  
Vol 10 (1) ◽  
pp. 71-77 ◽  
Author(s):  
P. W. West
Keyword(s):  
Weighted Least Squares ◽  
Basal Area ◽  
Basal Area Increment ◽  
Regression Equations ◽  
Least Squares Regression ◽  
Mixed Stands ◽  
Diameter Increment ◽  
Growth Studies ◽  
Initial Diameter ◽  
Individual Trees

Growth of diameter of individual trees can be expressed as diameter increment or basal area increment. Little work has been done to determine which of these parameters is preferable for use in growth studies. This paper examines growth of trees in pure and mixed stands of even-aged, regrowth forest of Eucalyptusregnans, E. obliqua, and E. globulus, aged 6-80 years, thinned and unthinned, in southeastern Tasmania. Weighted least squares regression equations are developed to relate diameter and basal area increments, over 1- to 6-year increment periods, to initial tree diameter in 29 growth plots. The correlation between basal area increment and initial diameter was always greater than that between diameter increment and initial diameter in these relationships. Despite this, the precision of estimates of future diameter in each plot is shown to be the same whether diameter or basal area increment equations are used. Data from a thinning experiment in 38- to 85-year-old, even-aged Acersaccharum, Fraxinusamericana, and Prunusserotina stands in southern Ontario are also examined and similar results obtained. It is concluded that no apriori reason exists for expressing growth as diameter increment or basal area increment in studies of these types.

Modeling relative error in stem basal area estimates

1990 ◽  
Vol 20 (5) ◽  
pp. 496-502 ◽  
Author(s):  
T. G. Gregoire ◽  
S. M. Zedaker ◽  
N. S. Nicholas
Keyword(s):  
Basal Area ◽  
Field Measurements ◽  
Mean Square ◽  
Interval Estimates ◽  
Tree Diameter ◽  
Diameter At Breast Height ◽  
Breast Height ◽  
The Mean ◽  
The Difference ◽  
Relative Errors

The computed estimate of basal area was the focus of this investigation into the accuracy of tree diameter measurements. Diameter at breast height was measured on 101 trees, the breast height disc was removed from the stem, and each disc outline was then digitized to determine its actual area. Actual areas were compared with the basal areas computed with the field measurements of diameter by expressing the deviations as a proportion of the actual areas. These relative errors averaged 3.1% when basal area was computed with a taped diameter at breast height, and they averaged −2.5% when the mean of two calipered, perpendicular diameter at breast height measurements were used. Noncircularity accounted for about 2.6% of the bias, on average, in basal areas from taped diameters. Root mean square error of relative basal area errors ranged from 7.3 to 7.9% among these methods. The difference between basal areas computed with a taped diameter at breast height and with calipered diameter at breast height was computed and expressed as a proportion of the actual basal area. On average, a difference of 5% was observed. Interval estimates for these differences are presented.

Basal area and diameter growth in high-graded eastern temperate mixedwood forests: the influence of acceptable growing stock, species, competition and climate

2019 ◽  
Vol 92 (5) ◽  
pp. 659-669 ◽  
Author(s):  
Hugues Power ◽  
Patricia Raymond ◽  
Marcel Prévost ◽  
Vincent Roy ◽  
Frank Berninger
Keyword(s):  
Abies Balsamea ◽  
Basal Area ◽  
Balsam Fir ◽  
Diameter Growth ◽  
Yellow Birch ◽  
Mixed Stands ◽  
Growing Stock ◽  
Mixedwood Forests ◽  
Stem Quality ◽  
History Of

AbstractHarvesting practices in temperate mixedwoods of eastern North America have a history of diameter-limit cuts, which have often resulted in degraded residual stands. In this study, we examined the factors influencing stand basal area (BA) and tree diameter growth in previously high-graded mixedwood forests, to understand which stands are more likely to recover from high-grading. Over 15 years, we monitored tree growth, recruitment and stem quality of 532 sample plots that were located in high-graded stands of Quebec’s mixedwood forest. We found that diameter growth rates were positively correlated with precipitation-related variables for balsam fir (Abies balsamea) and for yellow birch (Betulla alleghaniensis) but opposing trends for temperature-related variables were found. Conversely to balsam fir, yellow birch growth was positively correlated to temperature variables. Our results also show that BA growth was greater for plots with a larger acceptable growing stock (AGS: trees with potential sawlog production) and that the increase in AGS was greater for plots with larger amount of conifer BA. These result highlights the importance to maintain a proportion of conifer trees in these mixed stands. Moreover, the significant effect of asymmetric competition in our study underscores the relevance of considering the spatial distribution when choosing crop trees.

scholarly journals Density of juvenile and mature wood of selected coniferous species

2011 ◽  
Vol 57 (No. 3) ◽  
pp. 123-130 ◽  
Author(s):  
V. Gryc ◽  
H. Vavrčík ◽  
K. Horn
Keyword(s):  
Wood Density ◽  
Scots Pine ◽  
Juvenile Wood ◽  
Ring Width ◽  
Mature Wood ◽  
European Larch ◽  
The Czech Republic ◽  
Coniferous Species ◽  
The Mean ◽  
The Difference

The objective of research was to determine the density of juvenile (JW) and mature wood (MW) of selected coniferous species growing in the Czech Republic. The research included the wood of Norway spruce (Picea abies (L.) Karst.), Scots pine (Pinus sylvestris L.) and European larch (Larix decidua Mill.). The juvenile wood density close to the pith was 410 kg&middot;m<sup>&ndash;3</sup> for spruce, 391 kg&middot;m<sup>&ndash;3</sup> for pine and 573 kg&middot;m<sup>&ndash;3</sup> for larch with 12% water content. Mature wood in the peripheral parts had the higher density in all species &ndash; spruce 516 kg&middot;m<sup>&ndash;3</sup>, pine 552 kg&middot;m<sup>&ndash;3</sup> and larch 652 kg&middot;m<sup>&ndash;3</sup>. The highest difference, the difference of 161 kg&middot;m<sup>&ndash;3</sup>, between juvenile and mature wood was found out in Scots pine. The large difference in the wood density of pine is caused by a considerable difference in the mean ring width of its juvenile and mature wood. Further, it was proved that wood density decreases with the increasing ring width while wood density increases with the increasing proportion of latewood.

Thinning Increases Loblolly Pine Vigor and Resistance to Bark Beetles¹

1987 ◽  
Vol 11 (1) ◽  
pp. 28-31 ◽  
Author(s):  
M. W. Brown² ◽  
T. E. Nebeker ◽  
C. R. Honea
Keyword(s):  
Loblolly Pine ◽  
Bark Beetles ◽  
Basal Area ◽  
Height Growth ◽  
Diameter Growth ◽  
Southern Pine ◽  
Pine Beetle ◽  
The Difference ◽  
Southern Pine Beetles ◽  
Pine Beetles

Abstract Twenty-seven 1-ac plots were thinned to a basal area of 70, 100, or 130 ft²/ac, and 9 plots were left unthinned to be used as a control. Changes in diameter growth, height growth, and oleoresin exudation pressure (OEP) are presented for the first 3 years following thinning. Height growth was lower in the thinned plots, but diameter growth in plots thinned to 70 and 100 ft²/ac was significantly greater than the unthinned plots and those thinned to 130 ft²/ac. OEP was also greater in thinned plots in the first two years; the difference was not significant in the third year. Introductions of southern pine beetles into the plots resulted in a significantly lower proportion of successful attacks in thinned plots in the first two years following thinning. It was concluded that increased tree vigor along with the increase in tree spacing following thinning does reduce susceptibility to southern pine beetle attack when stands are thinned to a basal area of 100ft²/ac or less. South. J. Appl. For. 11(1):28-31

scholarly journals Deciduous Broad-Leaved Species (Quercus Robur, Tilia Cordata, Acer Platanoides and Ulmus Laevis) Forest Stand Productivity in Latvia

2021 ◽  
Vol 75 (4) ◽  
pp. 239-247
Author(s):  
Guntars Šņepsts ◽  
Jānis Donis ◽  
Dārta Kaupe ◽  
Māris Laiviņš
Keyword(s):  
Basal Area ◽  
High Volume ◽  
Forest Stand ◽  
Growth Potential ◽  
Mixed Stands ◽  
Growing Stock ◽  
Volume Yield ◽  
Mean Diameter ◽  
The Mean ◽  
Broad Leaved Species

Abstract Climate forecasts indicate that in the future the climate will become more and more suitable for growth of broad-leaved tree species in Latvia. It is therefore very important to recognise and understand the growth potential of these broad-leaved stands in Latvia and the factors affecting the increment of growing stock. The results of the study showed high volume yield, as already 60- to 80-year-old stand stock could reach 500–600 m3·ha-1, and in later years even 700–1000 m3·ha-1. Similarly, the results of our study showed that the increment of the stock and growth potential of individual forest elements varied significantly between the various broad-leaved species. Significant factors were the age of the forest stand or forest element (a set of trees of the same species, in one layer and belonging to one generation), the indicators of competition (basal area and/or relative density) and the indicators of the social status of the forest element, namely, the ratio of the mean diameter of the forest element and the mean diameter of the dominant species of the upper layer of the stand and the sum of the basal area of the larger forest elements). No significant differences were found in growing stock and growth potential between monospecies and mixed stands and between simple and complex stands, neither at the level of the stands, nor at the level of the individual forest element.

The Effect of Vocabulary Intervention on Text Comprehension: Who Benefits?

2019 ◽  
Vol 50 (4) ◽  
pp. 562-578 ◽  
Author(s):  
Dawna Duff
Keyword(s):  
Middle School ◽  
Reading Comprehension ◽  
Text Comprehension ◽  
Classroom Instruction ◽  
Vocabulary Instruction ◽  
Clinical Intervention ◽  
Vocabulary Knowledge ◽  
Vocabulary Intervention ◽  
The Mean ◽  
The Difference

Purpose Vocabulary intervention can improve comprehension of texts containing taught words, but it is unclear if all middle school readers get this benefit. This study tests 2 hypotheses about variables that predict response to vocabulary treatment on text comprehension: gains in vocabulary knowledge due to treatment and pretreatment reading comprehension scores. Method Students in Grade 6 ( N = 23) completed a 5-session intervention based on robust vocabulary instruction (RVI). Knowledge of the semantics of taught words was measured pre- and posttreatment. Participants then read 2 matched texts, 1 containing taught words (treated) and 1 not (untreated). Treated texts and taught word lists were counterbalanced across participants. The difference between text comprehension scores in treated and untreated conditions was taken as a measure of the effect of RVI on text comprehension. Results RVI resulted in significant gains in knowledge of taught words ( d RM = 2.26) and text comprehension ( d RM = 0.31). The extent of gains in vocabulary knowledge after vocabulary treatment did not predict the effect of RVI on comprehension of texts. However, untreated reading comprehension scores moderated the effect of the vocabulary treatment on text comprehension: Lower reading comprehension was associated with greater gains in text comprehension. Readers with comprehension scores below the mean experienced large gains in comprehension, but those with average/above average reading comprehension scores did not. Conclusion Vocabulary instruction had a larger effect on text comprehension for readers in Grade 6 who had lower untreated reading comprehension scores. In contrast, the amount that children learned about taught vocabulary did not predict the effect of vocabulary instruction on text comprehension. This has implications for the identification of 6th-grade students who would benefit from classroom instruction or clinical intervention targeting vocabulary knowledge.

Efficacy and Safety of Oral Ivermectin and Topical Permethrin in the Treatment of Scabies

2020 ◽  
Vol 33 (1) ◽  
pp. 41-47
Author(s):  
Mohsena Akhter ◽  
Ishrat Bhuiyan ◽  
Zulfiqer Hossain Khan ◽  
Mahfuza Akhter ◽  
Gulam Kazem Ali Ahmad ◽  
...  
Keyword(s):  
Skin Diseases ◽  
Close Contact ◽  
Randomized Study ◽  
Sarcoptes Scabiei ◽  
Efficacy And Safety ◽  
Common Skin ◽  
Group A ◽  
The Mean ◽  
The Difference ◽  
Group B

Background: Scabies is one of the most common skin diseases in our country. It is caused by the mite Sarcoptes scabiei var hominis, which is an ecto-parasite infesting the epidermis. Scabies is highly contagious. Prevalence is high in congested or densely populated areas. Individuals with close contact with an affected person should be treated with scabicidal which is available in both oral and topical formulations. The only oral but highly effective scabicidal known to date is Ivermectin. Amongst topical preparations, Permethrin 5 % cream is the treatment of choice. Objective: To evaluate the efficacy & safety of oral Ivermectin compared to topical Permethrin in the treatment of scabies. Methodology: This prospective, non-randomized study was conducted at the out-patient department of Dermatology and Venereology of Shaheed Suhrawardy Medical College & Hospital over a period of 6 months, from August 2016 to January 2017. The study population consisted of one hundred patients having scabies, enrolled according to inclusion criteria. They were divided into two groups. group A was subjected to oral Ivermectin and the group B to Permethrin 5% cream. Patients were followed up on day 7 and 14 for assessment of efficacy and safety. Result: The mean scoring with SD in group A (Ivermectin) and group B (Permethrin) were 8.26 ± 2.22 and 7.59 ± 2.01 respectively at the time of observation. The difference between the mean score of the two group is not significant (p=0.117) the mean scoring with SD in group A and group B were 4.54 ± 2.05 and 1.64 ± 1.84 respectively at 7thdays. The difference between the mean score of the two group is significant (p<0.001). The mean scoring with SD in group A and group B were 2.68± 2.35 and .36± 1.10 respectively at 14th day difference between the mean score of the group is significant (p<0.001). Conclusion: Topical application of permethrin 5% cream is more effective and safer than oral Ivermectin in the treatment of scabies. TAJ 2020; 33(1): 41-47

EFFECTS OF SYNTHETIC LH/FSH-RELEASING HORMONE (LRH) ON PLASMA LH AND FSH IN AMENORRHOEIC WOMEN

1974 ◽  
Vol 75 (4) ◽  
pp. 647-652 ◽  
Author(s):  
G. Rannevik ◽  
J. Thorell
Keyword(s):  
Urinary Excretion ◽  
Initial Response ◽  
Releasing Hormone ◽  
The Mean ◽  
The Difference ◽  
Serial Measurements

ABSTRACT Eight amenorrhoeic women were given 100 μg synthetic LRH (Hoechst) iv and im, respectively, at an interval of 2 weeks. Four of the women received the iv injection first and four the im injection. The urinary excretion of oestrogens and pregnanediol was low and unaltered throughout the test weeks. The effects of LRH were compared by serial measurements of the plasma LH and FSH during 8 h. The initial response of LH for up to 25 min and that of FSH for up to 60 min were equal whether LRH was given iv or im. The difference appeared later. Four hours after the injection the mean increase of LH to iv injection was 0.5 ng/ml (N. S.), while that to im injection was 1.9 ng/ml (P < 0.01). The corresponding values for FSH were 1.3 (P < 0.05) and 3.2 (P < 0.001). The effect of LRH administration im was thus found to be larger and more prolonged.

Sign in / Sign up

Export Citation Format

Share Document