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.

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.

scholarly journals Twenty-five years' growth in a young red pine stand

1993 ◽  
Vol 69 (1) ◽  
pp. 57-63 ◽  
Author(s):  
R. M. Newnham
Keyword(s):  
Volume Growth ◽  
Pinus Resinosa ◽  
Site Index ◽  
Red Pine ◽  
Weibull Function ◽  
Growth Data ◽  
Site Class ◽  
Growth Site ◽  
Natural Stand ◽  
Class 1

Growth data are presented by 5-year intervals from age 20 to 45 years for a natural stand of red pine (Pinus resinosa Ait.) in eastern Ontario. At age 45 years, the top height (100 largest trees/ha) was 21.3 m and the volume 448 m3/ha, with little evidence of any decline in either height or volume growth. Site index was approximately 24 m (at age 50 years) which is considerably superior to Plonski's site class 1 (Plonski 1974). Growth appears to be comparable to that of unmanaged plantations growing on the best sites on the Petawawa Research Forest. Height-diameter regressions are calculated for each plot measurement and compared with a combined regression for all plot measurements. The Weibull function was used to fit diameter distributions.

scholarly journals Variable stocking yield functions for the boreal mixedwood in Ontario

1996 ◽  
Vol 72 (4) ◽  
pp. 416-419 ◽  
Author(s):  
Bijan Payandeh ◽  
Yonghe Wang
Keyword(s):  
Basal Area ◽  
Site Index ◽  
Eastern United States ◽  
Site Productivity ◽  
Area Index ◽  
Permanent Sample Plots ◽  
Index Model ◽  
Index Site ◽  
Yield Functions ◽  
Site Index Model

A measure of utilized site productivity, "basal area index" was recently developed and used to construct variable stocking yield functions and tables for the boreal mixedwood of northcentral Ontario. Data from 197 permanent sample plots supplied by the James River/Marathon Paper Company Ltd. were used. The resulting yield equations compare favourably with previous ones and are more appropriate for the boreal mixedwood. In addition, the basal area index employed has several advantages: 1) it serves as a valid measure of utilized site productivity which is better correlated with the main stand attributes than site index; 2) it produces variable stocking yield tables suitable for uneven-aged mixed species cover types; 3) unlike the site index, the basal area index may be estimated quickly, easily and inexpensively. The basic improvement in mixedwood yield estimation via basal area index should have broad applications for other stand types particularly for the disturbed hardwoods of southern Ontario and those in eastern United States. Key words: Basal area index, site index model, numerical method

scholarly journals Developing and Evaluating Tree Height-Diameter Models at Three Geographic Scales for Black Spruce in Ontario

2004 ◽  
Vol 21 (2) ◽  
pp. 83-92 ◽  
Author(s):  
Changhui Peng ◽  
Lianjun Zhang ◽  
Xiaolu Zhou ◽  
Qinglai Dang ◽  
Shongming Huang
Keyword(s):  
Growth Model ◽  
Tree Species ◽  
Black Spruce ◽  
Tree Height ◽  
Permanent Sample Plots ◽  
Central Regions ◽  
Geographic Regions ◽  
Richards Growth Model

Abstract A total of 11,612 black spruce trees were measured from permanent sample plots across the boreal and central regions of Ontario and were used to fit the well-known Chapman-Richards growth model at provincial, regional, and ecoregional scales. The results suggest that the height-diameter relationships of black spruce vary with different geographic regions and scales. There were significant variations in height-diameter relationships for black spruce between boreal and central regions as well as among some of the seven ecoregions. The ecoregion-based height-diameter models presented here will provide more accurate predictions for tree height and, consequently, tree volume than these models developed at both provincial and regional scales. Furthermore, the heterogeneity of tree species should be considered in developing and applying ecoregion-based height-diameter models for predicting local tree height.

Base-Age Invariant Polymorphic Site Index Curves for Black Spruce and Balsam Fir Within Central Newfoundland

1992 ◽  
Vol 9 (1) ◽  
pp. 18-22 ◽  
Author(s):  
Peter F. Newton
Keyword(s):  
Black Spruce ◽  
Predictive Ability ◽  
Site Index ◽  
Polymorphic Site ◽  
Balsam Fir ◽  
Growth And Yield ◽  
Parameter Estimates ◽  
Prediction Errors ◽  
Site Class ◽  
Permanent Sample Plots

Abstract Increasing management intensity within Newfoundland requires that regional site index equations be species-specific and base-age invariant. Accordingly, base-age invariant polymorphic site index curves for black spruce and balsam fir were developed for use on upland mineral sites within central insular Newfoundland. Specifically, employing mean dominant height and breast-height age data derived from 129, 0.081 ha permanent sample plots situated in pure black spruce (n = 71) and mixed black spruce/balsam fir (n = 58) stands, site index equations were calibrated by species and stand type. In addition, given the approximate numeric equivalence of the resultant parameter estimates, data for both species and stand types were combined and a pooled equation calibrated. The equations were evaluated on their bias and predictive ability over 10-, 20-, and 30-year projection periods. Results indicated that the predictions were positively biased averaging +1.29 m, +2.36 m, and +3.15 m for 10-, 20-, and 30-year projection periods, respectively. Corresponding 95% prediction error intervals for these periods were -0.56 to +3.14 m, -0.88 to +5.44 m, and -1.27 to +6.56 m. These biases and prediction errors are within acceptable limits for site-class designations; however, explicit use of the site-index equations with growth and yield models would depend on error tolerances specified by individual users. North. J. Appl. For. 9(1):18-22

scholarly journals Draining an unproductive black spruce peatland stand: 18-year post-treatment tree growth and stand productivity estimation

2007 ◽  
Vol 83 (5) ◽  
pp. 723-732 ◽  
Author(s):  
Sylvain Jutras ◽  
Jean Bégin ◽  
André P Plamondon ◽  
Hannu Hökkä
Keyword(s):  
Tree Growth ◽  
Black Spruce ◽  
Site Index ◽  
Site Productivity ◽  
Individual Tree ◽  
Diameter Increment ◽  
Stand Productivity ◽  
The Individual ◽  
Canadian Boreal Forest ◽  
Forest Drainage

In the eastern Canadian boreal forest, drainage of unproductive black spruce peatlands is an infrequently used silvicultural treatment. The sparse scientific literature concerning its influence on tree growth is, however, relatively positive about the possibility of using drainage to convert unproductive stands into productive ones. This study aimed to address this issue by assessing the individual tree growth and by estimating the future stand productivity on a drained black spruce peatland stand. Results showed larger mean annual post-drainage stump diameter increment with increasing ditch proximity but they also showed the lack of effect of the treatment at distances greater than 15 m from the ditch. Small-sized trees reacted more strongly to the treatment than larger ones. Estimated site productivity was also influenced by the ditch proximity. The presence of excavating mounds on only one side of the ditch greatly influenced tree growth and site productivity. Considering the obtained results, intensive drainage operations, utilizing narrow ditch spacing, would be necessary in order to transform the type of unproductive sites studied into productive ones. Key words: diameter growth, site index, forested peatland, forest drainage, Picea mariana

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.

Modelling knot morphology as a function of external tree and branch attributes

2013 ◽  
Vol 43 (3) ◽  
pp. 266-277 ◽  
Author(s):  
E. Duchateau ◽  
F. Longuetaud ◽  
F. Mothe ◽  
C. Ung ◽  
D. Auty ◽  
...  
Keyword(s):  
Tree Growth ◽  
Pinus Banksiana ◽  
Black Spruce ◽  
Three Dimensional ◽  
Tree Height ◽  
Jack Pine ◽  
Weibull Function ◽  
Data Set ◽  
External Branch ◽  
Tree Characteristics

Existing models for describing knot morphology are typically based on polynomial functions with parameters that are often not biologically interpretable. Hence, they are difficult to integrate into tree growth simulators due to the limited possibilities for linking knot shape to external branch and tree characteristics. X-ray computed tomography (CT) images taken along the stems of 16 jack pine (Pinus banksiana Lamb.) trees and 32 black spruce (Picea mariana (Mill.) B.S.P.) trees were used to extract the three-dimensional shape of 3450 and 11 276 knots from each species, respectively. Using a nonlinear approach, we firstly fitted a model of knot geometry adapted from a Weibull function. Separate equations were used to describe both the curvature and the diameter of the knot along its pith. Combining these two equations gave an accurate representation of knot shape using only five parameters. Secondly, to facilitate the integration of the resulting model into a tree growth simulator, we extracted the parameters obtained for each knot and modelled them as functions of external branch and tree characteristics (e.g., branch diameter, insertion angle, position in the stem, tree height, and stem diameter). When fitted to a separate data set, the model residuals of the black spruce knot curvature equation were less than 2.9 mm in any part of the knot profile for 75% of the observations. The corresponding value from the diameter equation was 2.8 mm. In jack pine, these statistics increased to 5.4 mm and 3.2 mm, respectively. Overall, the ability to predict knot attributes from external tree- and branch-level variables has the potential to improve the simulation of internal stem properties.

Height development of Scots pine on peatlands: describing change in site productivity with a site index model

2004 ◽  
Vol 34 (5) ◽  
pp. 1081-1092 ◽  
Author(s):  
Hannu Hökkä ◽  
Risto Ojansuu
Keyword(s):  
Scots Pine ◽  
Site Index ◽  
Stand Age ◽  
Variance Component Model ◽  
Moderate Increase ◽  
Site Productivity ◽  
Permanent Sample Plots ◽  
Index Model ◽  
Site Water ◽  
Site Index Model

The effect of site properties and forest drainage on the dominant height development of Scots pine (Pinus sylvestris L.) stands in peatland sites was studied using data from permanent sample plots located in natural and drained sites in northern Finland. The Korf model was used to describe the height development of dominant trees in natural sites. The effect of drainage on height development was accounted for by a term giving a nonlinear height increase for drained sites as a function of the time elapsed since drainage. The variance component model was applied to account for the hierarchical data structure. Natural height development after 30 years of age at DBH was significantly slower in PF sites (sparsely forested pine fens) than in PS sites (genuine forested pine swamps). Within PF sites, there were further differences in relation to nutrient availability. Temperature sum explained the variation in the intercept. In PS sites, drainage resulted in a moderate increase in the maximum attainable height, while in PF sites, drainage improved site productivity by 80%–85% in terms of the attainable height. The asymptote for drained stands was dependent on stand age at the time of drainage. Differences between the two major groups were assumed to be due to initial differences in site water regime.

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