scholarly journals Diameter increment distribution along the stem of narrow-leaved ash in response to thinning intensity

2019 ◽  
Vol 143 (1-2) ◽  
pp. 45-51
Author(s):  
Ali Kemal Özbayram
Keyword(s):  
Rapid Development ◽  
Basal Area ◽  
Cross Sectional ◽  
Thinning Intensity ◽  
Tree Diameter ◽  
Diameter Increment ◽  
Breast Height ◽  
Sample Tree ◽  
Fraxinus Angustifolia ◽  
Different Parts

Narrow-leaved ash (NLA, Fraxinus angustifolia) is an important tree species due to its rapid development and valuable wood. In the pure NLA plantations in Turkey, little is known about the effects of thinning intensity on the diameter increment of different parts of the tree stem. In 2005, a thinning experiment with three thinning intensities (control: 0%; moderate: 19%; heavy: 28% of basal area removed) was established in an NLA plantation in Sakarya, Turkey. Seven years after thinning, a total of 25 sample trees representing dominant and co-dominant trees were felled, and cross-sectional stem samples were taken for analysis. The diameter at breast height (d<sub>1.30</sub>) and d<sub>1.30</sub> increments of the co-dominant trees with the moderate and heavy treatments were similar to each other and greater than in the controls. The seven-year d<sub>1.30</sub> increments of the dominant trees in the heavy-treatment plot were approximately 20% greater than in the other treatments plots. The highest diameter increments in both dominant and co-dominant trees for all treatments were determined at the 0.30 m and 17.30 m section heights. The sample tree diameter increments of between 1.30 m and 13.30 m were similar within their classes. In conclusion, heavy-intensity thinning of up to 28% did not cause tapering in the NLA plantation stems, and thus, heavy thinning can be recommended for NLA trees.

scholarly journals A Semi-empirical Approach Based on Genetic Programming for the Study of Biophysical Controls on Diameter-Growth of Fagus orientalis in Northern Iran

2019 ◽  
Vol 11 (14) ◽  
pp. 1680 ◽  
Author(s):  
Bayat ◽  
Noi ◽  
Zare ◽  
Bui
Keyword(s):  
Solar Radiation ◽  
Genetic Programming ◽  
Wind Velocity ◽  
Basal Area ◽  
Northern Iran ◽  
Tree Diameter ◽  
Diameter At Breast Height ◽  
Diameter Increment ◽  
Oriental Beech ◽  
Breast Height

This paper examines the possible ecological controls on the diameter increment of oriental beech (Fagus orientalis Lipsky) in a high altitude forest in northern Iran. The main objectives of the study are computer-generated abiotic surfaces and associated plot estimates of (i) growing-season-cumulated potential solar radiation, (ii) seasonal air temperature, (iii) topographic wetness index in representing soil water distribution, and (iv) wind velocity generated from the simulation of fluid-flow dynamics in complex terrain. Plot estimates of the tree growth are based on averaged plot measurements of diameter at breast height increment during a growing period of nine years (2003–2012). Biotic variables related to the tree diameter increment involve averaged 2003 tree diameter and basal area measured in individual forest plots. In the modelling data (144 plots), the assemblage of modelled and observed site variables explained 75% of the variance in plot-level diameter increment. In the validation data (32 plots), the degree of explained variance was 77%. Mean tree diameter at breast height showed the strongest correlation with diameter increment, explaining 32% of the variation between-plot, followed by the configuration of topography and re-distribution of surface water (19.5%) and plot basal area (16.9%). On average, localised estimates of solar radiation and wind velocity potentially contribute to about 20% of the control on plot-level mean increment in oriental beech of the area. The results of the genetic programming showed that controlling the stand basal area and tree size by thinning and/or selective harvesting can have a favourable impact on the future distribution of mean diameter in oriental beech.

Incorporating intertree competition into an ecosystem model

1995 ◽  
Vol 25 (3) ◽  
pp. 413-424 ◽  
Author(s):  
R.L. Korol ◽  
S.W. Running ◽  
K.S. Milner
Keyword(s):  
Process Model ◽  
Basal Area ◽  
Stand Density ◽  
Tree Height ◽  
Ecosystem Model ◽  
Growth And Yield ◽  
Maintenance Respiration ◽  
Tree Diameter ◽  
Diameter Increment ◽  
Individual Trees

Current research suggests that projected climate change may influence the growth of individual trees. Therefore, growth and yield models that can respond to potential changes in climate must be developed, TREE-BGC, a variant of the ecosystem process model FOREST-BGC, calculates the cycling of carbon, water, and nitrogen in and through forested ecosystems. TREE-BGC allocates stand-level estimates of photosynthesis to "each tree using a competition algorithm that incorporates tree height, relative radiation-use efficiency, and absorbed photosynthetically active radiation, TREE-BGC simulated the growth of trees grown in a dense and an open stand of interior Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) near Kamloops, B.C. The competition algorithm dynamically allocated stand estimates of photosynthesis to individual trees, and the trees were grown using an allometric relationship between biomass increment and height and diameter increment. Asymptotic height growth and the changes in the height–diameter relationship with competition were also incorporated in the model algorithms. Sapwood and phloem volume were used to calculate maintenance respiration. Predicted reductions in diameter growth with stand density were similar to those observed in the study stands. Although the carbon balance of individual trees was not tested, simulated tree diameter increments and height increments were correlated with the actual measurements of tree diameter increment (r2 = 0.89) and tree height increment (r2 = 0.78) for the 5-year period (n = 352). Although the model did not work well with trees that had diameters <5 cm, the model would be appropriate for a user who required an accuracy of ± 0.03 m3•ha−1 for volume, ± 0.02 m2•ha−1 for basal area, or ± 0.4 m for tree height over a 5-year period.

Modelling survival probability of individual trees in Norway spruce stands under different thinning regimes

2005 ◽  
Vol 35 (1) ◽  
pp. 113-121 ◽  
Author(s):  
Kjell Karlsson ◽  
Lennart Norell
Keyword(s):  
Norway Spruce ◽  
Goodness Of Fit ◽  
Basal Area ◽  
Site Index ◽  
Stand Age ◽  
Goodness Of Fit Test ◽  
Individual Tree ◽  
Thinning Intensity ◽  
Diameter At Breast Height ◽  
Breast Height

The probability that an individual tree will remain in even-aged Norway spruce (Picea abies (L.) Karst.) stands subjected to different thinning programmes was modelled, using data from a thinning experiment established in 25 localities in southern Sweden. A logistic regression approach was used to predict the probability and the Hosmer–Lemeshow goodness-of-fit test to evaluate the fit. Diameter at breast height (DBH), quadratic mean DBH, thinning intensity, thinning quotient, basal area, number of stems per hectare, stand age, number of thinnings, and site index were used as explanatory variables. Separate analyses for stands thinned from below, stands thinned from above, and unthinned stands were performed. The modelled probability graphs for trees not being removed, plotted against their diameter at breast height, had clear S-shapes for both unthinned stands and stands thinned from below. The graph for stands thinned from above was bell-shaped.

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.

scholarly journals Utjecaj intenziteta prorjeda na rast azijske bukve (Fagus orientalis Lipsky) u plantažama u Trabzonu na sjeveroistoku Turske

2019 ◽  
Vol 143 (5-6) ◽  
pp. 231-240
Author(s):  
Ayhan Usta ◽  
Ibrahim Turna ◽  
Esengül Genc ◽  
Yavuz Okunur Kocamanoglu ◽  
Selvinaz Yilmaz ◽  
...  
Keyword(s):  
Basal Area ◽  
Average Diameter ◽  
Average Height ◽  
Sample Plot ◽  
Fagus Orientalis ◽  
Thinning Intensity ◽  
Diameter Increment ◽  
Oriental Beech ◽  
Fagus Orientalis Lipsky ◽  
Area And Volume

In this study, the effects of first thinnings having different intensities in oriental beech (Fagus orientalis Lipsky) plantation areas were investigated in terms of diameter and height growth of trees. Sample plots were chosen from oriental beech plantation areas which are within the boundaries of Maçka–Yeşiltepe and Vakf&#305;kebir districts of Trabzon province, Turkey. With removing of 0%, 10%, 25% and 40% of basal area in a hectare of stands which are in sapling stage, sample plots were established by applying thinnings which are in four different intensities (control, light, moderate, strong). After the thinning applications, basal areas were calculated by measuring diameters and heights of trees in established sample plots in order to reveal stand growth. The effects of thinnings were revealed related to some stand characteristics (average diameter, basal area, average height, relative diameter increment, etc.) and determined chosen trees. The effect of thinning intensity on average diameter, basal area, and volume values is statistically important in every two plantations. 2-year results showed that thinning increased the diameter increment significantly, and the increase in diameter increment was positively correlated with the thinning intensity in both experiments. Moreover, increments of diameter, height, basal area, and volume were higher in Maçka-Yeşiltepe experiment than in Vakf&#305;kebir experiment. But, the values of moderate and strong thinning intensities applied in Vakf&#305;kebir were close to each other. When all the results are evaluated, application of strong thinning intensity for Yeşiltepe sample plot, the moderate thinning intensity for Vakf&#305;kebir sample plot is seen appropriate by us in terms of both stand development.

An antithetic variate to facilitate upper-stem height measurements for critical height sampling with importance sampling

2013 ◽  
Vol 43 (12) ◽  
pp. 1151-1161 ◽  
Author(s):  
Thomas B. Lynch ◽  
Jeffrey H. Gove
Keyword(s):  
Importance Sampling ◽  
Basal Area ◽  
Cross Sectional Area ◽  
Sample Point ◽  
Sectional Area ◽  
Critical Height ◽  
Cross Sectional ◽  
Individual Tree ◽  
Sample Tree ◽  
The Cross

Critical height sampling (CHS) estimates cubic volume per unit area by multiplying the sum of critical heights measured on trees tallied in a horizontal point sample (HPS) by the HPS basal area factor. One of the barriers to practical application of CHS is the fact that trees near the field location of the point-sampling sample point have critical heights that occur quite high on the stem, making them difficult to view from the sample point. To surmount this difficulty, use of the “antithetic variate” associated with the critical height together with importance sampling from the cylindrical shells integral is proposed. This antithetic variate will be u = (1 − b/B), where b is the cross-sectional area at “borderline” condition and B is the tree’s basal area. The cross-sectional area at borderline condition b can be determined with knowledge of the HPS gauge angle by measuring the distance to the sample tree. When the antithetic variate u is used in importance sampling, the upper-stem measurement will be low on tree stems close to the sample point and high on tree stems distant from the sample point, enhancing visibility and ease of measurement from the sample point. Computer simulations compared HPS, CHS, CHS with importance sampling (ICHS), ICHS and an antithetic variate (AICHS), and CHS with paired antithetic varariates (PAICHS) and found that HPS, ICHS, AICHS, and PAICHS were very nearly equally precise and were more precise than CHS. These results are favorable to AICHS, since it should require less time than either PAICHS or ICHS and is not subject to individual-tree volume equation bias.

Use of Small Plots Can Overestimate Upper Limits to Basal Area and Biomass

1975 ◽  
Vol 5 (3) ◽  
pp. 503-505 ◽  
Author(s):  
J. Harry G. Smith
Keyword(s):  
Unit Area ◽  
Basal Area ◽  
Cross Sectional Area ◽  
Sectional Area ◽  
Cross Sectional ◽  
Subalpine Fir ◽  
Good Relationship ◽  
Breast Height ◽  
Plot Size ◽  
Upper Limits

Measurements of cross-sectional area outside bark at breast height in a spruce – subalpine fir forest were studied to determine the effects of plot size on minimum and maximum amounts of basal area sampled per unit area. Assuming a good relationship between basal area and biomass of trees, the need for careful interpretation of stand weight estimates on small plots is illustrated.

Predicting tree crown ratio for unthinned and thinned Scots pine stands

1995 ◽  
Vol 25 (1) ◽  
pp. 57-62 ◽  
Author(s):  
Jari Hynynen
Keyword(s):  
Scots Pine ◽  
Basal Area ◽  
Tree Height ◽  
Tree Crown ◽  
Thinning Intensity ◽  
Tree Diameter ◽  
Dominant Height ◽  
The Difference ◽  
Thinning Effect ◽  
Experimental Plots

A nonlinear model that yields logical predictions for tree crown ratio is presented. The model is based on data from permanent experimental plots located in even-aged Scots pine (Pinussylvestris L.) stands in southern and central Finland. Regressor variables in the model are stand dominant height, stand basal area, tree diameter, and tree height. The effect of thinning on tree crown ratio is modelled by incorporating a thinning response variable into the model. Thinning effect is dependent on thinning intensity and time elapsed from thinning, the latter of which is represented by the difference between current stand dominant height and dominant height at the time of thinning.

Thinning and nitrogen fertilization effects on sapwood development and relationships of foliage quantity to sapwood area and basal area in Douglas-fir

1983 ◽  
Vol 13 (3) ◽  
pp. 384-389 ◽  
Author(s):  
H. Brix ◽  
A. K. Mitchell
Keyword(s):  
Nitrogen Fertilization ◽  
Basal Area ◽  
Douglas Fir ◽  
Annual Rings ◽  
Cross Sectional ◽  
Sapwood Area ◽  
Breast Height ◽  
Linear Relationships ◽  
Regression Slopes ◽  
Fertilization Effects

A 24-year-old Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) stand was treated with various levels and combinations of nitrogen fertilization and thinning. Over a period of 5–9 years after treatments, trees were sampled to determine effects on foliage quantity and sapwood characteristics at different stem heights together with their relationships. Sapwood width remained relatively constant up the stem where heartwood was present, but the number of annual rings it contained decreased with height. The sapwood width at breast height (bh) increased with stem diameter; treatments had little effect on percent sapwood at bh. The ratio of foliage mass to sapwood cross-sectional area changed for different portions of the crown and was lower when based on sapwood area at bh than at base of live crown. Significant linear relationships of foliage mass and area to sapwood area at bh were found, but relationships of foliage to basal area (bh) were just as close for all treatments; treatments significantly affected these relationships with control trees having the lowest regression slopes.

scholarly journals Evaluacion De Dos Instrumentos De Medicion En La Determinación Del Área Basal En Pinus Radiata

2017 ◽  
Vol 13 (24) ◽  
pp. 10
Author(s):  
Norma Lara Vásconez ◽  
Janneth Morocho ◽  
Santiago Lara ◽  
Oscar Guadalupe ◽  
Keilly Chavez ◽  
...  
Keyword(s):  
Pinus Radiata ◽  
Forest Inventory ◽  
Basal Area ◽  
Measuring Instruments ◽  
Cross Sectional ◽  
Stand Volume ◽  
Breast Height ◽  
Measurement Tools ◽  
Pine Trees ◽  
Parallel Measurement

This study compares the diameter of data obtained from utilizing two measuring instruments (the caliper and diameter tape). This instrument is the two most commonly used instruments for measuring tree diameters in forest inventory procedures. The measurement of diameter has a high implication in the estimation of the basal area and stand volume. It is therefore imperative to ensure accurate measurement of the diameter of trees in a stand. This work evaluated data taken with these two diameter measuring instruments. In order to evaluate the performance of the measuring instruments, parallel measurement of the diameter at breast height (DBH) of a sample of Pinus radiata trees in a plantation were measured. Also, the basal area of the stand was determined for both instruments. It was concluded through the analysis of variance (ANOVA) that there is no significant (p =0.958) difference between the averages of the calculated basal areas from the diameter measurements obtained by the diameter tape and the caliper. The estimated value from the diameter tape was 0,04190829, while the caliper was 0,04145599. Thus, the use of the two measurement tools led to similar results in the calculation of the cross-sectional areas of pine trees measured at breast height.

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