Asymptotic Site-Index Curves, Fact or Artifact?

1984 ◽  
Vol 60 (3) ◽  
pp. 150-156 ◽  
Author(s):  
Victor G. Smith
Keyword(s):  
Black Spruce ◽  
Analysis Data ◽  
Site Index ◽  
Sample Plot ◽  
Stem Analysis ◽  
Permanent Sample Plots ◽  
Variable Site ◽  
Permanent Sample Plot ◽  
Regression Techniques ◽  
Curve Method

In the absence of permanent sample plot data, site-index curves and equations showing the height/age relationship for a tree species growing on a given site have been derived using stem analysis and temporary sample plot data. Initially the guide-curve method using temporary sample plot data (Bruce and Schumacher 1950) was employed to produce anamorphic site-index curves. More recently mensurationists (e.g. Heger 1968, and Payandeh 1978) have used stem analysis data and various regression techniques to produce polymorphic curves. This study suggests that the asymptotic site-index curves (i.e. curves that tend to level off within the life of the stand) that have been produced for black spruce may be the result of using mensurational and sampling techniques in forests where site-index is correlated with age. Also the regression techniques commonly used to estimate the parameters in site-index equations do not allow for error in both the dependent variable (height) and an independent variable (site). As a consequence the site-index curves produced by these techniques are asymptotic whereas height estimates obtained from 40 black spruce permanent sample plots do not exhibit any strong asymptotic height properties for stands up to 180 years of age.

A comparison of alternative data sources for modeling site index in loblolly pine plantations

2015 ◽  
Vol 45 (8) ◽  
pp. 1026-1033 ◽  
Author(s):  
Micky G. Allen ◽  
Harold E. Burkhart
Keyword(s):  
Loblolly Pine ◽  
Growth Pattern ◽  
Analysis Data ◽  
Site Index ◽  
Height Growth ◽  
Data Sources ◽  
Sample Plot ◽  
Stem Analysis ◽  
Permanent Sample Plots ◽  
Cost Constraints

Site index curves are generally developed from one of three data sources: (i) permanent sample plots, (ii) temporary sample plots, or (iii) stem analysis data. Permanent sample plots are considered to be the best data source for modeling height–age relationships; however, due to time and cost constraints, analysts may consider using temporary sample plots or stem analysis data for equation fitting. Temporary sample plot and stem analysis data, although more quickly obtained, require assumptions that are often not met when modeling site index. The question becomes how models developed from temporary sample plot or stem analysis data compare with models developed from permanent sample plot data. Data from a region-wide study in loblolly pine (Pinus taeda L.) plantations were used to develop site index curves from each of the three data sources. A form of the Chapman–Richards model was used for all three data sources to guard against confounding and to discern differences among the data sources when modeling height–age relationships. For the comparison and evaluation of behavior of different functions, the Schumacher model was also fitted to the three data sources. Curves developed from temporary sample plot and stem analysis data did not reproduce the height growth pattern exhibited in permanent sample plots, although curves derived from temporary plots were closer to the height growth pattern.

Preliminary Site Index Equations for Three Planted Species in Northern Ontario

1995 ◽  
Vol 12 (2) ◽  
pp. 57-63 ◽  
Author(s):  
Bijan Payandeh ◽  
Yonghe Wang
Keyword(s):  
Nonlinear Analysis ◽  
Black Spruce ◽  
Analysis Data ◽  
Site Index ◽  
Analysis Of Covariance ◽  
Stem Analysis ◽  
Northern Ontario ◽  
Natural Stand ◽  
Graphical Comparison ◽  
Similarities And Differences

Abstract Stem analysis data from plantations of black spruce, white spruce, and jack pine from northern Ontario were fitted to base-age specific and base-age invariant site index models. The resulting equations and their respective parameters were compared via nonlinear analysis of covariance. The base-age specific models produced a somewhat better fit to the data than their base-age invariant counterparts, although the latter are considered theoretically more elegant. Graphical comparison of plantation and natural stand site index curves for the three species showed both similarities and differences. North. J. Appl. For. 12(2):57-63.

Comparison and Development of Height Growth and Site Index urves for Douglas-Fir in the Inland Northwest

1989 ◽  
Vol 4 (3) ◽  
pp. 85-88
Author(s):  
James L. Vander Ploeg ◽  
James A. Moore
Keyword(s):  
Pseudotsuga Menziesii ◽  
Model Development ◽  
Analysis Data ◽  
Site Index ◽  
Height Growth ◽  
Douglas Fir ◽  
Western Montana ◽  
Stem Analysis ◽  
Inland Northwest ◽  
Central Idaho

Abstract Stem analysis data from Douglas-fir (Pseudotsuga menziesii) collected throughout the inland Northwest were used for testing height growth and site index equations. The equations performed well in northern and central Idaho, northeast Oregon, and northeast Washington on vegetative types similar to those sampled in model development. However, if the equations were applied on drier sites outside the original geographic study area, overestimates of height growth and under-estimates of site index could result. Therefore, revised height growth and site index equations are presented for western Montana and central Washington. West. J. Appl. For. 4(3):85-88, July 1989.

Site Index Curves for Loblolly Pine Plantations on Cutover Site-Prepared Lands

1985 ◽  
Vol 9 (3) ◽  
pp. 166-169 ◽  
Author(s):  
Ralph L. Amateis ◽  
Harold E. Burkhart
Keyword(s):  
Differential Equation ◽  
Pinus Taeda ◽  
Loblolly Pine ◽  
Analysis Data ◽  
Site Index ◽  
Height Growth ◽  
Pine Plantations ◽  
The South ◽  
Stem Analysis ◽  
Natural Range

Abstract Stem analysis data collected from dominant and codominant loblolly pine (Pinus taeda) trees in cutover, site-prepared plantations were used to develop site index curves. The data were collected over much of the natural range of loblolly pine. A separable differential equation which expresses height growth as a function of both height and age was used to develop the site index curves. These site index curves should be applicable to loblolly pine plantations on cutover, site-prepared lands through much of the South.1

Tarifs de cubage paramétrés: application à l'épinette noire de Lebel-sur-Quévillon

1990 ◽  
Vol 20 (9) ◽  
pp. 1471-1478 ◽  
Author(s):  
Chhun-Huor Ung
Keyword(s):  
Black Spruce ◽  
Standing Stock ◽  
Analysis Data ◽  
Volume Estimation ◽  
Allometric Model ◽  
Stem Analysis ◽  
Forest Region ◽  
Spruce Stands ◽  
The Mean ◽  
The Cost

The mean ratio of height to diameter at breast height of dominant trees in a stand resulted in more accurate one-entry volume tables than general two-entry volume tables. These parametrical one-entry volume tables were established with the allometric model and Hummel's line. The values of their coefficients were estimated from stem analysis data of felled trees in black spruce stands at Lebel-sur-Quévillon. In the search for simple and effective methods to increase the reliability of standing stock estimation for managing a relatively homogeneous forest region, parametrical one-entry volume tables reduce the cost of estimating standing volume and increase the accuracy of volume estimation compared with general two-entry volume tables.

An assessment of the structural method of deriving a black spruce site equation

1987 ◽  
Vol 17 (10) ◽  
pp. 1181-1189 ◽  
Author(s):  
Victor G. Smith ◽  
Martin Watts
Keyword(s):  
Black Spruce ◽  
Nonlinear Models ◽  
Site Index ◽  
Stand Age ◽  
Structural Method ◽  
Northern Ontario ◽  
Data Set ◽  
Permanent Sample Plots ◽  
Stochastic Error ◽  
Stand Height

To date, methods of deriving site index (S) equations assume that stochastic error is only present in the regressor. This paper develops a method, termed the "structural method," which recognizes that both dominant stand height (H) and S measurements contain stochastic error. To achieve this, the structural method utilizes the structural relationship that exists between H and S to derive an S equation. S equations are derived for black spruce, Piceamariana (Mill.) B.S.P., using the structural method and various other methods, with linear and nonlinear models that are currently in use. Data used in the study consist of 56 black spruce permanent sample plots, containing a total of 382 observations, from north central Ontario and the Clay Belt Region of northern Ontario. This data set is split into 36 plots (260 observations) for deriving S equations and 20 plots (122 observations) for testing the equations for accuracy in predicting H, S, and future H. The equations are also examined for bias over stand age. Results show that height development of black spruce is not asymptotic and is best described by a linear model. Overall, the structural method provides the most accurate S equation within the range of the data. It predicted 90% of the H test observations with an error of 0.4 m or less, 89% of the S test observations with an error of 0.4 m or less, and 90% of the future H test observations with an error of 0.7 m or less. The structural method also has the advantage of producing only one equation for predicting both H and S. This enables estimates of both H and S to be made from one graph of H over age by S classes.

Adjustment of the age–height relationship for uneven-aged black spruce stands

2008 ◽  
Vol 38 (7) ◽  
pp. 2003-2012 ◽  
Author(s):  
Hakim Ouzennou ◽  
David Pothier ◽  
Frédéric Raulier
Keyword(s):  
Black Spruce ◽  
Information Criterion ◽  
Diversity Indices ◽  
Site Index ◽  
Diameter Distribution ◽  
Large Network ◽  
Permanent Sample Plots ◽  
Dominant Height ◽  
Spruce Stands ◽  
Height Model

Site index (SI) is commonly used in natural stands, even when their diameter distribution deviates from that of the monospecific, even-aged, fully stocked stands used to develop basic age–height relationships. Since deviations from basic age–height trajectories can be reflected in deviations of stand diameter distribution from a bell shape, we incorporated different diameter diversity indices into an age–height equation to help improve height predictions and determine which index is best related to stand dominant height. This procedure was performed using black spruce ( Picea mariana (Mill.) BSP) stands from a large network of permanent sample plots established across the province of Quebec, Canada. The age–height model that minimized the Akaike’s information criterion used the Shannon evenness index (ESh) as an equation modifier accounting for the diameter diversity variable. The model showed that for stands established on relatively poor sites (SI = 9), no substantial differences in dominant height were found between two contrasting ESh values. For SI = 15, however, the larger ESh value increased the dominant height by as much as 1 m at 80 years. These results suggest that introduction of ESh into an age–height model can improve calculation of site index, particularly in regions characterized by the presence of numerous uneven-aged stands.

An index of site productivity for uneven-aged or mixed-species stands

1993 ◽  
Vol 23 (3) ◽  
pp. 558-562 ◽  
Author(s):  
Shongming Huang ◽  
Stephen J. Titus
Keyword(s):  
Black Spruce ◽  
Tree Height ◽  
Site Index ◽  
Weibull Function ◽  
Growth Data ◽  
Site Productivity ◽  
Mixed Species ◽  
Quick Method ◽  
Permanent Sample Plots ◽  
Productivity Measure

A site productivity measure based on the relationship between total tree height and diameter at breast height of dominant and codominant trees was presented for four major tree species (white spruce (Piceaglauca (Moench) Voss), lodgepole pine (Pinuscontorta Dougl.), trembling aspen (Populustremuloides Michx.), and black spruce (Piceamariana (Mill.) B.S.P.)) growing in boreal mixed-species stands in Alberta. The measure is based on a three-parameter modified Weibull function fitted to growth data from permanent sample plots using the difference-equation method; R2-values ranged from 0.90 to 0.97. The measure has many logical properties similar to those of the site-index approach and produces curves that are polymorphic and reference-diameter invariant. It can be used as a simple and quick method of quantifying site productivity for uneven-aged and (or) mixed-species stands.

scholarly journals Height growth of black spruce in British Columbia

2002 ◽  
Vol 78 (2) ◽  
pp. 306-313 ◽  
Author(s):  
Gordon D Nigh ◽  
Pavel V Krestov ◽  
Karel Klinka
Keyword(s):  
British Columbia ◽  
Black Spruce ◽  
Site Index ◽  
Logistic Function ◽  
Height Growth ◽  
Growth Patterns ◽  
Growth And Yield ◽  
Stem Analysis ◽  
Yield Information ◽  
Northern Half

Black spruce (Picea mariana (Mill.) B.S.P.) is a boreal species that occurs extensively across the northern half of British Columbia. Forest managers require better growth and yield information for black spruce given the anticipated increase in demand for wood in the northern part of the province. The purpose of this study was to develop height-age models for black spruce. Ninety-one stem analysis plots were established in the BWBS and SBS biogeoclimatic zones. Three black spruce site trees from each plot were stem analyzed and the data were converted into height-age data. A conditioned log-logistic function was fit to the data. Indicator variables were used to test for differences in height growth between the sampled subzones. Although the warm subzones had different height growth patterns than the cool subzones, there was general agreement among the height-age models from British Columbia, Alberta, and New Brunswick up to about age 100. Key words: biogeoclimatic zones, height-age models, logistic function, site index, stem analysis

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