AN EVALUATION OF SEVERAL METHODS OF ESTIMATING SITE INDEX OF IMMATURE STANDS

1952 ◽  
Vol 28 (3) ◽  
pp. 63-74 ◽  
Author(s):  
John W. Ker
Keyword(s):  
Basal Area ◽  
Site Index ◽  
Site Quality ◽  
Average Height ◽  
Office Procedure ◽  
Minimum Sample ◽  
A Site ◽  
The University ◽  
Site Classes

The use of dominant heights for the estimation of site index is compared with the use of the average of dominant and codominant heights. Data collected on the University Research Forest are presented to illustrate the variability in tree heights and diameters within the two upper crown classes in well-stocked stands of immature Douglas fir.HeightIt is shown that the use of dominant heights reduces considerably the number of measurements required for a site index determination of given accuracy. Minimum sample sizes are given for three limits of accuracy for use in different site qualities. A general field and office procedure is outlined for the determination of minimum sample size in stands other than those described.DiameterThe use of diameter in site determination is discussed. Site indices based on the height of the tree of mean diameter, the height of the tree of mean basal area, and mean height are compared.ConclusionsQuick estimates of site quality can best be obtained by the measurement of total height of sample dominant trees, selected at random. For this purpose, tables are presented which list the average height of dominant trees by age and site classes for use in stands of Douglas fir, and western hemlock, respectively.

Growth of 20-Year-Old Virginia Pine Planted at Three Spacings in Tennessee

1985 ◽  
Vol 9 (1) ◽  
pp. 32-37
Author(s):  
Glendon W. Smalley
Keyword(s):  
Basal Area ◽  
Site Index ◽  
The Other ◽  
Average Height ◽  
Cumberland Plateau ◽  
Plantation Age ◽  
A Site ◽  
Pinus Virginiana Mill

Abstract Average height of dominant and codominant Virginia pines (Pinus virginiana Mill). on a Mid-Cumberland Plateau site was 46 feet at plantation age 20, equivalent to a site index (base age 50) of 75. Trees planted at a spacing of 8 x 8 feet had a merchantable yield (outside bark to a 4.0 inch top for all trees with a dbh of 4.6 inches and larger) of 1,987 ft³ per acre with a basal area of 114 ft² per acre. Comparative statistics on the other spacings tested were: 6 x 6 feet—2,067 ft³ and 123 ft² and 4 x 4 feet—2,155 ft³ and 141 ft². Survival on the plots was: 4 x 4 feet—38%; 6 x 6 feet—58%; and 8 x 8 feet—75%. Height to base of live crown averaged 25 feet, and dead branches remained nearly to the ground on most trees at all spacings.

scholarly journals La qualité des stations et la productivité des plantations de pin rouge (Pinus resinosa Ait.) au Québec.

1975 ◽  
Vol 51 (1) ◽  
pp. 16-20
Author(s):  
S. Popovich
Keyword(s):  
Basal Area ◽  
Pinus Resinosa ◽  
Site Index ◽  
Red Pine ◽  
Growth And Yield ◽  
Site Quality ◽  
Average Height ◽  
Stand Volume ◽  
Factors Affecting ◽  
The Relationship

This paper presents an evaluation of site quality based on the relationship between volume per square foot of basal area and age of plantation, for planted red pine (Pinus resinosa Ait.) in Quebec.A graph for the three site index classes is included with indication for its use. There is a table showing the values of volume per square foot of basal area as a function of average height and average form quotient of a stand, permitting a rapid evaluation of stand volume of a plantation. Finally, several factors affecting growth and yield of red pine plantations for various sites in Quebec are discussed.

scholarly journals A Carbon Management Diagram for Oak-hickory Forests in Southern Ohio

2011 ◽  
Vol 28 (3) ◽  
pp. 161-165 ◽  
Author(s):  
Roger A. Williams ◽  
Yuhua Tao
Keyword(s):  
Carbon Stock ◽  
Basal Area ◽  
Site Index ◽  
Tree Size ◽  
Total Carbon ◽  
Site Quality ◽  
Oak Forests ◽  
Carbon Management ◽  
Tree Diameter ◽  
Total Carbon Stock

Abstract A carbon management diagram for use in oak-hickory forests in southern Ohio has been developed to allow easier quantification of total forest carbon stock. The total carbon stock is positively correlated to basal area and average stand diameter but poorly correlated to the number of trees per acre. The total amount of carbon stored in these forests is going to be influenced by age and site quality to the extent that age and site influence basal area and the average tree size. Accordingly, not all stands considered to be fully to overstocked store the most carbon. Rather, it is a combination of basal area and average tree size that determines the total carbon stored, with the carbon stock in the forest increasing with an increase in both basal area and average tree diameter. Examples illustrating the use of the diagram are presented for two oak forests on oak site indexes 60 and 80. Both forests are overstocked at age 100 years, but the forest on site index 60 stores 77 tons/ac of total carbon compared with 103 tons/ac on site index 80.

scholarly journals EVOLUÇÃO DA ÁREA BASAL E DO VOLUME EM BRACATINGAIS NATIVOS SUBMETIDOS À DIFERENTES DENSIDADES INICIAIS E EM DIFERENTES SÍTIOS

FLORESTA ◽  
2002 ◽  
Vol 32 (1) ◽  
Author(s):  
Sebastião Do Amaral Machado ◽  
Ana Elizabete N. Tonon ◽  
Afonso Figueiredo Filho ◽  
Edilson Batista Oliveira
Keyword(s):  
Initial Density ◽  
Basal Area ◽  
Site Index ◽  
Metropolitan Region ◽  
Data Set ◽  
Permanent Sample Plots ◽  
Dominant Height ◽  
Site Classes ◽  
Volume Em ◽  
Area And Volume

Foram analisados os efeitos de quatro densidades iniciais (2, 4, 8 e 25,15 mil plantas por hectare) e de 3 classes de sítio, cujos índices de sítios são 10,2; 13,5 e 16,8 m de altura dominante aos 7 anos de idade, sobre a área basal e volume por hectare em povoamentos nativos de bracatinga (Mimosa scabrella Benth.) na região metropolitana de Curitiba. Os dados provieram de um experimento de densidades em blocos ao acaso medidos nas idades de 4,1; 5,1; 6,3 e 7,6 anos. Os efeitos da densidade inicial e do sítio sobre a área basal (G) e volume (V) por hectare foram verificados através de análise de variância seguida do teste de Tukey, quando pertinente. A densidade inicial de 4 mil plantas por hectare gerou maiores valores de G e V nas últimas idades de medição. A área basal/ha não sofreu efeitos significativos do sítio em nenhuma das medições, enquanto que o volume/ha foi afetado por este fator (sítio) até a idade de 6,3 anos. Evolution of Basal Area and Volume per Hectare in Native "Bracatingais" Submited to Different Initial Densities and Different Sites Abstract The objectives of this research were to study the effects of four initial densities (2000, 4000, 8000 and 25150 plants/ha) and three site classes (site index 10.2, 13.5 and 16.8 m of dominant height at age seven) on basal area (G) and volume per hectare (V) for native stands of bracatinga (Mimosa scabrella Benth.) in the Metropolitan Region of Curitiba, Brazil. The data set came from permanent sample plots of a density trial established in a random blocks design. These plots were measured at ages 4.1, 5.1, 6.3, and 7.6 years of age. The effects of initial density and site on basal area and volume per hectare were verified through graphics and analysis of variance followed by the Tukey test when necessary. The initial density of 4,000 plants/ha generated the highest values of basal area and volume in the last ages of measurement. The basal area/ha did not sufered significative effects of site at any one of the measurement ages, while volume/ha was affected by this factor (site) until the age of 6.3 years.

scholarly journals Generalized Nonlinear Mixed-Effects Individual Tree Diameter Increment Models for Beech Forests in Slovakia

Forests ◽  
2019 ◽  
Vol 10 (5) ◽  
pp. 451 ◽  
Author(s):  
Ram P. Sharma ◽  
Igor Štefančík ◽  
Zdeněk Vacek ◽  
Stanislav Vacek
Keyword(s):  
Basal Area ◽  
European Beech ◽  
Site Index ◽  
Development Stage ◽  
Mixed Effects ◽  
Site Quality ◽  
Stand Age ◽  
Sample Plot ◽  
Individual Tree ◽  
Diameter Increment

Individual tree growth and yield models precisely describe tree growth irrespective of stand complexity and are capable of simulating various silvicultural alternatives in the stands with diverse structure, species composition, and management history. We developed both age dependent and age independent diameter increment models using long-term research sample plot data collected from both monospecific and mixed stands of European beech (Fagus sylvatica L.) in the Slovak Republic. We used diameter at breast height (DBH) as a main predictor and other characteristics describing site quality (site index), stand development stage (dominant height and stand age), stand density or competition (ratio of individual tree DBH to quadratic mean diameter), species mixture (basal area proportion of a species of interest), and dummy variable describing stand management regimes as covariate predictors to develop the models. We evaluated eight versatile growth functions in the first stage using DBH as a single predictor and selected the most suitable one, i.e., Chapman-Richards function for further analysis through the inclusion of covariate predictors. We introduced the random components describing sample plot-level random effects and stochastic variations on the diameter increment, into the models through the mixed-effects modelling. The autocorrelation caused by hierarchical data-structure, which is assumed to be partially reduced by mixed-effects modelling, was removed through the inclusion of the parameter accounting for the autoregressive error-structures. The models described about two-third parts of a total variation in the diameter increment without significant trends in the residuals. Compared to the age independent mixed-effects model (conditional coefficient of determination, R c 2 = 0.6566; root mean square error, RMSE = 0.1196), the age dependent model described a significantly larger proportion of the variations in diameter increment ( R c 2 = 0.6796, RMSE = 0.1141). Diameter increment was significantly influenced differently by covariate predictors included into the models. Diameter increment decreased with the advancement of stand development stage (increased dominant height and stand age), increasing intraspecific competition (increased basal area proportion of European beech per sample plot), and diameter increment increased with increasing site quality (increased site index) and decreased competition (increased ratio of DBH to quadratic mean diameter). Our mixed-effects models, which can be easily localized with the random effects estimated from prior measurement of diameter increments of four randomly selected trees per sample plot, will provide high prediction accuracies. Our models may be used for simulating growth of European beech irrespective of its stand structural complexity, as these models have included various covariate variables describing both tree-and stand-level characteristics, thinning regimes, except the climate characteristics. Together with other forest models, our models will be used as inputs to the growth simulator to be developed in the future, which is important for decision-making in forestry.

Growth basal area: a field method for appraising forest site potential for stockability

1983 ◽  
Vol 13 (1) ◽  
pp. 70-77 ◽  
Author(s):  
Frederick C. Hall
Keyword(s):  
Growth Rate ◽  
Basal Area ◽  
Site Index ◽  
Field Method ◽  
Stand Age ◽  
Diameter Growth ◽  
Forest Site ◽  
A Site

Growth basal area (GBA) is a field method for determining site potential limitations on stockability. It is defined as the basal area (BA) at which dominant trees grow 1 in. (25 mm) diameter per decade at age 100. Diameter growth is a constant used to compare sites; basal area is a variable used to express different site potentials for stockability. For example, a site with GBA = 220 ft2/acre (50 m2/ha) means dominants will grow 1 in. per decade (25 mm) in diameter at 220 ft2 BA. This is twice the stockability potential of a site with GBA = 110 ft2 (25 m2/ha). GBA is determined by relating current stand diameter growth rate and BA to a curve which permits adjustment of current BA to that for 1 in. per decade diameter growth. GBA is based on two assumptions: (i) rate of diameter growth decreases with increasing basal area and is an index of intertree competition. (ii) Change in GBA with age is related to stand age. GBA can be combined with site index (SI), shown as SI-GBA, to connote different productivities within an SI class. GBA is discussed in regard to concept of GBA curve development, assumptions made, applications, and constraints.

Site Classification From Air Photos in a Forest Inventory

1981 ◽  
Vol 57 (6) ◽  
pp. 265-266 ◽  
Author(s):  
G. M. Bonnor ◽  
K. C. Morrier
Keyword(s):  
Classification System ◽  
Forest Inventory ◽  
Site Index ◽  
Site Quality ◽  
Site Classification ◽  
Subsequent Test ◽  
Forest Inventories ◽  
Numerical Assessment ◽  
Eastern Ontario ◽  
A Site

A site classification system using 5-metre site index classes was applied in an inventory in eastern Ontario. ir photos and data on site index obtained from fiels work were used by photo interpreters to assign site index classes to individual stands. In a subsequent test of the procedures, the accuracy of the classification was found to be 76 percent. This accuracy, while acceptable, can be increased.The method is intended for use in extensive (regional, provincial) forest inventories and provides an objective (numerical) assessment of site quality.

The growth and yield responses of a high site quality red pine plantation to seven thinning treatments and two thinning intervals

1986 ◽  
Vol 16 (3) ◽  
pp. 513-520 ◽  
Author(s):  
Hal O. Liechty ◽  
Glenn D. Mroz ◽  
David D. Reed
Keyword(s):  
Volume Growth ◽  
Basal Area ◽  
Site Index ◽  
Red Pine ◽  
Growth And Yield ◽  
Site Quality ◽  
Pine Plantation ◽  
High Site ◽  
Yield Responses ◽  
Lower Site

Seven thinning treatments with residual densities between 60 and 160 ft3/acre (13.8 and 36.8 m2/ha) of basal area were applied to a highly productive (site index, 81 ft (24.7 m); base age, 50 years) red pine (Pinusresinosa Ait.) plantation. After 10 years, periodic basal area growth was maximized over a lower and much broader range of residual densities than previously found in lower site quality stands. Total and merchantable cubic foot volume growth for the 10 year period was not significantly different between treatments. Application of these thinning treatments on a 6- compared with a 10-year interval reduced total and merchantable cubic foot volume growth while increasing the average stand diameter.

scholarly journals GROWTH AND YIELD OF EVEN-AGED Cupressus lusitanica PLANTATIONS IN SOUTHERN BRAZIL

FLORESTA ◽  
2021 ◽  
Vol 51 (4) ◽  
pp. 980
Author(s):  
Mário Dobner Jr.
Keyword(s):  
Basal Area ◽  
Site Index ◽  
Growth And Yield ◽  
Site Quality ◽  
Timber Species ◽  
Southern Brazil ◽  
Cupressus Lusitanica ◽  
Dominant Height ◽  
Dominant Height Growth ◽  
Quality Variation

Plantation forestry in southern Brazil demands additional timber species to a higher market differentiation by providing high quality timber and exploitation of market niches. Cupressus lusitanica has long been recognized for this purpose but, until now, it was not properly region-wide quantified in terms of growth and yield. The present study delivers the lacking quantitative approach, which may encourage the commercial use of the species. With this study it was aimed at collecting and processing quantitative data from all known C. lusitanica stands in southern Brazil. Inventories were carried out (60 ha, 6-39 years of age) in order to model the development of dominant height (h100), basal area, volume and dominant diameter (d100). Dominant height was the basis for site quality evaluation, delivering site index curves, which, together with the commercial volume of the stands, allowed yield modelling. A wide amplitude of dominant height growth was detected (10-30 m at 20 years), indicating a great site quality variation. At age of 20 years, commercial volumes of 110 and 620 m³ ha-1 were observed for site indexes of 14 and 26, respectively, equivalent to a maximum of 6-31 m³ ha-1 year-1 at ages between 16-18 years. Results demonstrated in a robust manner that C. lusitanica has a high potential for cultivation in southern Brazil. Thus, offering the opportunity of market differentiation by promoting market niches whose demands timber for special solid end-uses.

Building a dynamic growth model for trembling aspen in western Canada without age data

2013 ◽  
Vol 43 (3) ◽  
pp. 256-265 ◽  
Author(s):  
Oscar García
Keyword(s):  
Populus Tremuloides ◽  
Site Occupancy ◽  
Basal Area ◽  
Site Index ◽  
Growth And Yield ◽  
Site Quality ◽  
Diameter Distribution ◽  
Stand Age ◽  
Parameter Estimates ◽  
Trembling Aspen

A biologically inspired whole-stand growth and yield model was developed for even-aged thinned or unthinned stands dominated by trembling aspen (Populus tremuloides Michx.). The estimation used permanent sample plot data from British Columbia, Alberta, Saskatchewan, and Manitoba, supplemented by published site index and young stand information. An ingrowth imputation procedure was devised to facilitate the use of plot measurements where small trees are not measured. Two published site index models were closely approximated by a simple age-base invariant equation. Good parameter estimates for mortality and basal area growth were obtained without using age observations, which were unreliable or missing. Four differential equations describe the dynamics of top height, trees per hectare, basal area, and a site occupancy factor. Current values of these variables are used to estimate total and merchantable volumes up to any diameter limit and diameter distribution parameters. When an independent source of site quality estimates is available, the final model does not require stand age knowledge for making growth and yield predictions.

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