Stand Density Management Diagram for Jack Pine Stands in Eastern Canada

A stand density management diagram was developed for jack pine (Pinus banksiana Lamb.) stands using the data obtained from 125 permanent sample plots (PSPs) established in Ontario and 232 PSPs in Quebec, Canada. The diagram was evaluated using data from 40 PSPs established in Ontario. Recently developed and efficient models have been used in constructing the diagram to estimate diameters and heights for the trees for which no diameters or heights were recorded at the time of stand inventory. Relative density indices of 0.15, 0.40, and 0.55 were used, corresponding to the line of approximate crown closure, the limit of productive zone, and the lower limit of competition-related mortality, respectively. If two stand characteristics are known, including mean total tree volume, quadratic mean diameter, trees per hectare, and average dominant height, the others can be readily obtained using the diagram. The consequences of various thinning scenarios can be plotted and visualized in the field without the need for computer simulation.

A parameter recovery model for estimating black spruce diameter distributions within the context of a stand density management diagram

The objectives of this study were to develop and subsequently demonstrate a parameter prediction approach for estimating black spruce (Picea mariana (Mill. ) BSP) diameter frequency distributions within the context of a stand density management diagram (SDMD). The approach consisted of three sequential steps: (1) obtaining maximum likelihood estimates for the location, scale and shape parameters of the Weibull probability density function for 153 empirical diameter frequency distributions; (2) developing and evaluating parameter prediction equations in which the Weibull parameter estimates were expressed as functions of stand-level variables based on step-wise regression and seemingly unrelated regression techniques; and (3) explicitly incorporating the parameter prediction equations into the SDMD modelling framework. The results indicated that the Weibull function was successful in characterizing the diameter distributions within the sample stands: the fitted distributions exhibited no significant (p ≤ 0. 05) differences in relation to their corresponding observed distributions, based on the Kolmogorov-Smirnov test. The parameter prediction equations described 94, 94 and 89% of the variation in the location, scale and shape parameter estimates, respectively. Furthermore, evaluation of the recovered distributions in terms of prediction error indicated minimal biases and acceptable accuracy. As demonstrated, incorporating the parameter prediction equations into an algorithmic version of the SDMD enabled the prediction of the temporal dynamics of the diameter frequency distribution by initial density regime and site quality. Additionally, an executable version of the resultant algorithm with instructions on acquiring it via the Internet is provided. Key words: 3-parameter Weibull probability density function, stepwise and seemingly unrelated regression, predictive error, product value, algorithm, Internet

Regional-Specific Algorithmic Stand Density Management Diagram for Black Spruce

A regional-specific algorithmic stand density management diagram was developed for managed upland black spruce (Picea mariana [Mill.] B.S.P.) stands applicable to Newfoundland, New Brunswick, Quebec, and Ontario. Specifically, the IBM-compatible PC-based algorithm (1) graphically illustrates site-specific size-density trajectories for 8 user-specified initial density regimes, (2) calculates and subsequently tabulates periodic yield estimates from 5-50 yr by 5 yr intervals for mean dominant height, density, mean volume, total volume, total merchantable volume, quadratic mean diameter, and basal area, (3) given (2), graphically illustrates empirically derived yield production curves for total merchantable volume per hectare and number of stems per cubic meter with user-specified operability criteria superimposed, and (4) given (3), calculates and subsequently tabulates the minimum time required to attain operability status. The utility of the algorithm is demonstrated within the context of determining site-specific initial densities required to attain user-specified operability criteria. Procedures for acquiring the executable version via the Internet are also included. North. J. Appl. For. 15(2):94-97.

Stand density management diagram for managed black spruce stands

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.)