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

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.

1978 ◽  
Vol 54 (1) ◽  
pp. 39-41 ◽  
Author(s):  
Bijan Payandeh

Site index formulas were derived for peatland black spruce (Picea mariana [Mill.] B.S.P.) in northern Ontario based on stem analysis of 60 dominant and codominant trees. Nonlinear regression analysis and a biological growth function were employed to express both height as a function of site index and stand age and also site index as a function of stand height and age. Analysis of results indicates that peatland black spruce has a different pattern of height growth than that shown by Plonski's site index curves, particularly for site indices less than 8 m and stands older than 80 years.


1994 ◽  
Vol 24 (7) ◽  
pp. 1415-1418 ◽  
Author(s):  
Yonghe Wang ◽  
Bijan Payandeh

Extension of the Richards biological growth function has been applied extensively to describe height growth patterns or to develop site index equations. We introduce a linear filter model to achieve the same goals. Although derivation of the filter model involves more computation, it compares well with the Richards growth model in accuracy when applied to a black spruce (Piceamariana (Mill.) B.S.P) stem analysis data set from northern Ontario. The main advantage of the filter model, however, is that it can be used as a base-age invariant site index model.


1995 ◽  
Vol 12 (2) ◽  
pp. 57-63 ◽  
Author(s):  
Bijan Payandeh ◽  
Yonghe Wang

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.


FLORESTA ◽  
2002 ◽  
Vol 32 (1) ◽  
Author(s):  
Sebastião Do Amaral Machado ◽  
Ana Elizabete N. Tonon ◽  
Afonso Figueiredo Filho ◽  
Edilson Batista Oliveira

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.


1994 ◽  
Vol 70 (1) ◽  
pp. 65-74 ◽  
Author(s):  
P. F. Newton ◽  
G. F. Weetman

A stand density management diagram for managed black spruce (Picea mariana (Mill.) B.S.P.) stands was developed using data derived from 37 variable-size temporary and permanent sample plots, and 257 open-grown sample trees. The plots were situated within 15 plantations and 4 precommercially thinned stands located throughout central and western Newfoundland, north-western New Brunswick and northern Ontario. The basic components of the diagram included: (1) an approximate crown closure line (2) the self-thinning rule (3) expected size-density trajectories and (4) isolines for dominant height, relative density index, quadratic mean diameter and merchantability ratio. The utility of the diagram was demonstrated by deriving yields for various initial spacings by site class and subsequently evaluating various outcomes in terms of operability criteria. In addition, the potential of estimating the time of crown closure by initial spacing and site class is discussed in relation to minimizing the adverse effects of Kalmia angustifolia (L.) on black spruce growth and development. Key words: stand density management diagram, initial spacing, black spruce, operability, Kalmia angustifolia (L.)


2004 ◽  
Vol 80 (4) ◽  
pp. 495-506 ◽  
Author(s):  
V. Lacerte ◽  
G R Larocque ◽  
M. Woods ◽  
W J Parton ◽  
M. Penner

The Lake States variant of the FVS (Forest Vegetation Simulator) model (LS-FVS), also known as the LS-TWIGS variant of FVS, was validated for black spruce (Picea mariana (Mill.) BSP), white spruce (Picea glauca (Moench) Voss), jack pine (Pinus banksiana Lamb.) and trembling aspen (Populus tremuloides Michx.) forests in northern Ontario. Individual-tree data from 537 remeasured sample plots were used. This dataset included different combinations of site index, stand density and age. It was possible to compare observations and predictions for different projection length periods. The validation exercise included a biological consistency analysis, the computation of mean percent difference (MPD) for stand density, stand basal area, top height and quadratic mean diameter (QMD) and the comparison of observed and predicted individual-tree dbh. The biological consistency analysis indicated that LS-FVS logically predicted the effect of site index on top height, stand basal area and QMD for black spruce and jack pine. However, the decrease in stand basal area at young ages was inconsistent with the normal development pattern of the forest stands under study and was attributed to deficiencies in the prediction of mortality. LS-FVS was found to underpredict stand density, stand basal area and top height and to over-predict QMD. Even though there were large errors in the prediction of change in stand density, LS-FVS was nevertheless consistent in the prediction of the shape of the dbh size distribution. Key words: FVS, Forest Vegetation Simulator, validation, biological consistency analysis


1987 ◽  
Vol 17 (9) ◽  
pp. 1080-1091 ◽  
Author(s):  
V. G. Smith ◽  
M. Watts ◽  
D. F. James

Black spruce (Piceamariana (Mill.) B.S.P.) is an important pulpwood species that grows on peatland sites in the clay belt region of northern Ontario. The mechanical stability of spruce found on these sites is crucial in determining how tall a stand can grow before losses due to windthrow become excessive. In this study, the stability of a sample of 58 black spruce trees, in stands of various height and density classes, was measured by winching them over and determining their critical turning moment. Regression analysis was used to express critical turning moment as a function of tree height, dominant stand height, and stand stocking. An analysis was carried out to estimate turning moments due to static wind action on the sample trees and predicting the wind speeds required to produce the static force needed to cause windthrow. A comparison of the measured critical turning moments to the estimated wind-generated critical turning moments was used to identify the wind speeds that have enough static force to cause windthrow. A table of critical wind speeds, based on a reference wind, is given for black spruce stands of various heights and densities. Based on these wind speeds and winds associated with periodic storms, black spruce stands can be expected to become susceptible to windthrow once dominant stand height reaches 20 to 21 m. Stand stability increases with stand density owing to the greater ability of dense stands to dissipate incoming winds and the added stability of interlocking root systems. These results suggest that the black spruce stands growing on peatland sites in the clay belt should be harvested before dominant stand height reaches a maximum of 20 to 21 m to avoid excessive losses due to windthrow.


2008 ◽  
Vol 38 (7) ◽  
pp. 2003-2012 ◽  
Author(s):  
Hakim Ouzennou ◽  
David Pothier ◽  
Frédéric Raulier

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.


2013 ◽  
Vol 89 (04) ◽  
pp. 446-457 ◽  
Author(s):  
Doug G. Pitt ◽  
Len Lanteigne ◽  
Michael K. Hoepting ◽  
Jean Plamondon

The Green River precommercial thinning trials were established between 1959 and 1961 in naturally regenerating balsam fir (Abies balsamea [L.] Mill.)-dominated stands, an average of eight years after overstory removal. Three nominal spacings of 4 ft (1.2 m), 6 ft (1.8 m) and 8 ft (2.4 m) were compared to an unthinned control in six replicate blocks. In the fall of 2008, following completion of the ninth sequential evaluation of the study’s 48 permanent sample plots, three of the six replicates were clearcut harvested and data were collected on roundwood product recovery and value. These data were used to construct treatment-invariant (p ≥ 0.18) functions predicting product volume from tree diameter, allowing the volume of studwood, sawlogs and pulpwood to be predicted for the full Green River data set (all 6 replicates) through time. Mean annual increment of gross merchantable volume culminated in all treatments around stand age 45. Thinning to a nominal spacing of 6 ft, resulting in 1600 merchantable stems per ha by stand age 30, offered the best balance of individual tree and stand growth, producing 20% more gross merchantable volume and 26% more sawlog volume than unthinned stands, potentially increasing landowner stumpage revenues by 22% (p < 0.01). The sawlog volume produced in unthinned stands could be realized up to 15 years sooner in thinned stands, suggesting that PCT may offer substantive flexibility in balancing forest-level wood supply objectives.


1993 ◽  
Vol 23 (3) ◽  
pp. 558-562 ◽  
Author(s):  
Shongming Huang ◽  
Stephen J. Titus

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.


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