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 Loblolly Pine Outperforms Slash Pine in Southeastern Georgia and Northern Florida

2000 ◽  
Vol 24 (1) ◽  
pp. 31-36 ◽  
Author(s):  
Barry D. Shiver ◽  
John W. Rheney ◽  
Kenneth L. Hitch
Keyword(s):  
Loblolly Pine ◽  
Species Interactions ◽  
Basal Area ◽  
Pinus Elliottii ◽  
Slash Pine ◽  
Stand Volume ◽  
Growing Seasons ◽  
The Difference ◽  
Stand Basal Area ◽  
Better Than

Abstract A total of 141 paired plot installations remain of the 160 that were planted with slash (Pinus elliottii Engelm.) and loblolly (P. taedaL.) pine across southeastern Georgia and northern Florida, after 14 growing seasons. Installations were evenly distributed across eight soil types. Analyses indicate that loblolly performed equal to or better than slash pine. There were no soil X species interactions. After 14 yr, loblolly pine had significantly higher survival (71% vs. 66%), stand basal area (98 vs. 81 ft2/ac), total stand volume (1857 vs. 1721 ft3/ac), merchantable stand volume (1497 vs. 1310 ft3/ac), total green weight (53 tons vs. 47 tons), and merchantable green weight (45 vs. 35 tons/ac) than slash pine. Growth over the period from age 11 to age 14 was also higher for loblolly than for slash indicating that the difference in the two species is diverging over time. South. J. Appl. For. 24(1): 31-36.

An Iterative Reweighting Procedure for Volume Equations Based on Diameter

1992 ◽  
Vol 16 (2) ◽  
pp. 64-67
Author(s):  
W. Rick Smith ◽  
Charles E. Thomas
Keyword(s):  
Censored Data ◽  
Parameter Estimates ◽  
Inventory Data ◽  
Diameter At Breast Height ◽  
Breast Height ◽  
Iterative Reweighting ◽  
Data Improvement ◽  
Volume Equations

Abstract An iterative reweighting scheme for regression with censored data is introduced. The method provides increased precision of parameter estimates for weighted linear or polynomial, diameter at breast height (dbh) based volume equations. This method can also improve equations that predict unreasonable volumes for trees with small dbh's. The technique was applied to highly heteroscedastic inventory data. Improvement in the precision of both softwood and hardwood, merchantable volume and sawtimber volume equations was achieved using this procedure. South. J. Appl. For. 16(2):64-67.

Modeling of aboveground tree stand-level biomass in Erukot Forest of Oban Division, Cross River National Park, Nigeria

2021 ◽  
Vol 18 (1) ◽  
Author(s):  
S.E. Bassey ◽  
S. Ajayi
Keyword(s):  
Carbon Dioxide ◽  
Aboveground Biomass ◽  
National Park ◽  
Basal Area ◽  
Tree Stand ◽  
Diameter At Breast Height ◽  
Total Height ◽  
Breast Height ◽  
Dry Biomass ◽  
Individual Trees

This research estimated aboveground tree stand level Biomass in Erukot Forest of Oban Division, Cross River National Park. A total of 872 individual trees were identified and measured for diameter at breast height and total height (dbh ≥ 5cm). The 872 individual trees spread across 51 species belonging to 25 different tree families. Simple random sampling was used with sampling intensity of 0.3% to lay 15 nested plots (7m x 7m, 25m x 25m and 35m x 35m). Diameter at breast height, total height and specific density of each wood species were used to determine aboveground biomass for each tree. Conversion factors were applied to estimate stand level green and dry biomass, sequestered carbon and carbon dioxide (CO2) emission in the study area. Simple linear regression models were fitted into the stand level growth data for the forest (basal area and volume). The mean diameter at breast height and mean total height were 38.5cm and 18.5m respectively. Mean basal area of 39.8 m2 ha-1 was obtained with a mean volume of 177.3 m3 ha-1 . Average green biomass, dry biomass, carbon stock and carbon-dioxide emission of 521.8113 ton ha-1 , 341.5880 ton ha-1 , 183.196 ton ha-1 and 694.2067 ton ha-1 respectively were obtained in the study area. Stand level biomass model developed for the forest showed that common logarithm of volume per hectare is significantly related to common logarithm of stand biomass (R2 = 58%). The actual and predicted biomasses were not significantly different (Paired T-test at p ˂ 0.05). Estimated bias of 0.10% for the stand biomass model means that the developed model can be used to predict the aboveground biomass of the study area without any adjustment. The research has provided easy to use regression model for determining aboveground biomass at stand level. This is very useful for carbon trade and assessment of carbon-dioxide emissions through deforestation in the study area. The model is also a tool for assessing the wood productivity of the study area and for better management of the park. Keyword: Sequestered carbon, aboveground biomass, dry biomass, conversion factor

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.

Expected decrease in diameter growth of even-aged red spruce

1987 ◽  
Vol 17 (3) ◽  
pp. 266-269 ◽  
Author(s):  
C. Anthony Federer ◽  
James W. Hornbeck
Keyword(s):  
New York ◽  
New England ◽  
Basal Area ◽  
Least Square ◽  
Red Spruce ◽  
Diameter Growth ◽  
Radial Increment ◽  
Breast Height ◽  
Second Growth ◽  
Stand Basal Area

Weibull functions provide close least square fits to tables for stand basal area and density versus age in even-aged, second-growth red spruce as reported by W. H. Meyer (USDA Tech. Bull. No. 142. 1929). The annual mean radial and basal area increments of the trees can be calculated from the two Weibull functions. For a stand following Meyer's tables and reaching breast height in 1915, mean tree basal area increment increases steadily to a maximum in the early 1960's and then declines; mean radial increment is constant from 1925 to 1955 and then declines rapidly. This behavior matches very closely the results from 3001 red spruce increment cores in New England and New York, which suggests that forest aging is an important cause of decreasing red spruce diameter growth.

Crown and basal area relationships of open-grown southern pines for modeling competition and growth

1992 ◽  
Vol 22 (3) ◽  
pp. 341-347 ◽  
Author(s):  
W.R. Smith ◽  
R.M. Farrar Jr. ◽  
P.A. Murphy ◽  
J.L. Yeiser ◽  
R.S. Meldahl ◽  
...  
Keyword(s):  
Loblolly Pine ◽  
Longleaf Pine ◽  
Basal Area ◽  
Growth And Yield ◽  
Predictive Equations ◽  
Diameter At Breast Height ◽  
Breast Height ◽  
Crown Width ◽  
Basal Area Growth ◽  
Area Growth

Data were collected on open-grown loblolly pine (Pinustaeda L.), longleaf pine (Pinuspalustris Mill.), and shortleaf pine (Pinusechinata Mill.) and analyzed to provide predictive equations of crown width and maximum potential basal area growth for crown competition and growth and yield models. The measurements were taken on 115 open-grown loblolly pine trees and 76 shortleaf pines in southeastern Arkansas. The longleaf pine data consisted of 81 open-grown trees from southern Alabama, Georgia, and Florida. A circle and an ellipse were tested as geometric models of the vertically projected crown. No significant differences between the tree shapes were found based on analyses of length and azimuth of the largest crown diameter, and the circle was chosen as an appropriate model. This indicated that only the distance between trees, not their orientation to one another, need be included in models of crown competition based on crown contact. Predictive equations of mean crown width based on diameter at breast height were fitted for each species for use in models of crown competition. A Chapman–Richards growth rate function with an intercept term was fit to periodic annual inside-bark basal area growth based on initial inside-bark basal area to provide empirical estimates of maximum basal area growth rates for growth and yield modeling of the given species. Additionally, equations to predict double bark thickness as a function of diameter at breast height were fit for each species to facilitate the use of the equations with outside-bark measurements of diameter.

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 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.

scholarly journals Estimating Structure and Biomass of a Secondary Atlantic Forest in Brazil Using Fourier Transforms of Vertical Profiles Derived from UAV Photogrammetry Point Clouds

2020 ◽  
Vol 12 (21) ◽  
pp. 3560 ◽  
Author(s):  
André Almeida ◽  
Fabio Gonçalves ◽  
Gilson Silva ◽  
Rodolfo Souza ◽  
Robert Treuhaft ◽  
...  
Keyword(s):  
Tropical Forests ◽  
Atlantic Forest ◽  
Fourier Transforms ◽  
Basal Area ◽  
Point Clouds ◽  
Tree Density ◽  
Vertical Profiles ◽  
Diameter At Breast Height ◽  
Breast Height ◽  
3D Point Clouds

Knowing the aboveground biomass (AGB) stock of tropical forests is one of the main requirements to guide programs for reducing emissions from deforestation and forest degradation (REDD+). Traditional 3D products generated with digital aerial photogrammetry (DAP) have shown great potential in estimating AGB, tree density, diameter at breast height, height, and basal area in forest ecosystems. However, these traditional products explore only a small part of the structural information contained in the 3D data, thus not leveraging the full potential of the data for inventory purposes. In this study, we tested the performance of 3D products derived from DAP and a technique based on Fourier transforms of vertical profiles of vegetation to estimate AGB, tree density, diameter at breast height, height, and basal area in a secondary fragment of Atlantic Forest located in northeast Brazil. Field measurements were taken in 30 permanent plots (0.25 ha each) to estimate AGB. At the time of the inventory, we also performed a digital aerial mapping of the entire forest fragment with an unmanned aerial vehicle (UAV). Based on the 3D point clouds and the digital terrain model (DTM) obtained by DAP, vertical vegetation profiles were produced for each plot. Using traditional structure metrics and metrics derived from Fourier transforms of profiles, regression models were fit to estimate AGB, tree density, diameter at breast height, height, and basal area. The 3D DAP point clouds represented the forest canopy with a high level of detail, regardless of the vegetation density. The metrics based on the Fourier transform of profiles were selected as predictors in all models produced. The best model for AGB explained 93% (R2 = 0.93) of the biomass variation at the plot level, with an RMS error of 9.3 Mg ha−1 (22.5%). Similar results were obtained in the models fit for the tree density, diameter at breast height, height, and basal area, with R2 values above 0.90 and RMS errors of less than 18%. The use of Fourier transforms of profiles with 3D products obtained by DAP demonstrated a high potential for estimating AGB and other forest variables of interest in secondary tropical forests, highlighting the value of UAV as a low-cost tool to assist the implementation of REDD+ projects in developing countries like Brazil.

scholarly journals Floristic Structure of Fire Experimental Plots of Olokemeji Forest Reserve, Ogun State, Nigeria

2020 ◽  
Vol 24 (11) ◽  
pp. 1861-1865
Author(s):  
DM Taiwo ◽  
OR Olatidoye ◽  
OR Jeminiwa ◽  
TO Oyebola ◽  
C Omonu
Keyword(s):  
Tree Species ◽  
Basal Area ◽  
Relative Importance ◽  
Importance Value ◽  
Forest Reserve ◽  
Diameter At Breast Height ◽  
Breast Height ◽  
Ogun State ◽  
Mean Diameter ◽  
Floristic Structure

Total enumeration of tree species was carried out fire experimental plot of Olokemeji forest reserve for relative importance value (RIV) mean heights, mean diameter at breast height and mean basal area. Three investigative plot (Plot A, B and C) were established. Plot A which represents Early Burn is burnt annually during the dry season while Plot B was burnt annually during the rainy season when the trees are still wet and Plot C serves as the protected area. Gmelina arborea had the highest relative importance value (28.31), this is followed by Dalbergia sissoo which had RIV of 10.94. Plot C recorded the highest frequency of trees with the highest tree heights, this is closely followed by Plot A and Plot B being the plot with the lowest mean height. Plot C has the highest mean diameter at breast height (DBH) of trees and it is followed by Plot B and Plot A with very close mean DBH. The highest mean basal area was also recorded in Plot C, the highest total basal area and tree volume was also recorded at Plot C as 32.2 m2 ha-1 and 188.8 m3. The size distribution of tree species depicts that Plot C has been protected just as expected Keywords: Forest, Structure, Flora, Dynamics, Fire

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