A Tree Survival Equation and Diameter Growth Model for Loblolly Pine Based on the Self-Thinning Rule

1994 ◽  
Vol 31 (4) ◽  
pp. 693 ◽  
Author(s):  
Quang V. Cao
2019 ◽  
Vol 49 (5) ◽  
pp. 440-446 ◽  
Author(s):  
Shuaichao Sun ◽  
Quang V. Cao ◽  
Tianjian Cao

Competition indices play a significant role in modeling individual-tree growth and survival. In this study, six distance-independent competition indices were evaluated using 200 permanent plots of loblolly pine (Pinus taeda L.). The competition indices were classified into three families: (1) size ratios, which include diameter ratio and basal area ratio; (2) relative position indices, which include basal area of larger trees (BAL) and tree relative position based on the cumulative distribution function (CDF); and (3) partitioned stand density index and relative density. Results indicated that different families of competition indices were suitable for different tree survival or diameter growth prediction tasks. The diameter ratio was superior for predicting tree survival, whereas the relative position indices (BAL and CDF) performed best for predicting tree diameter growth, with CDF receiving the highest rank.


Forests ◽  
2021 ◽  
Vol 12 (5) ◽  
pp. 556
Author(s):  
Mauricio Zapata-Cuartas ◽  
Bronson P. Bullock ◽  
Cristian R. Montes ◽  
Michael B. Kane

Intensive loblolly pine (Pinus taeda L.) plantation management in the southeastern United States includes mid-rotation silvicultural practices (MRSP) like thinning, fertilization, competitive vegetation control, and their combinations. Consistent and well-designed long-term studies considering interactions of MRSP are required to produce accurate projections and evaluate management decisions. Here we use longitudinal data from the regional Mid-Rotation Treatment study established by the Plantation Management Research Cooperative (PMRC) at the University of Georgia across the southeast U.S. to fit and validate a new dynamic model system rooted in theoretical and biological principles. A Weibull pdf was used as a modifier function coupled with the basal area growth model. The growth model system and error projection functions were estimated simultaneously. The new formulation results in a compatible and consistent growth and yield system and provides temporal responses to treatment. The results indicated that the model projections reproduce the observed behavior of stand characteristics. The model has high predictive accuracy (the cross-validation variance explained was 96.2%, 99.7%, and 98.6%; and the prediction root mean square distance was 0.704 m, 19.1 trees ha−1, and 1.03 m2ha−1 for dominant height (DH), trees per hectare (N), and basal area (BA), respectively), and can be used to project the current stand attributes following combinations of MRSP and with different thinning intensities. Simulations across southern physiographic regions allow us to conclude that the most overall ranking of MRSP after thinning is fertilization + competitive vegetation control (Fert + CVC) > fertilization only (Fert) > competitive vegetation control only (CVC), and Fert + CVC show less than additive effect. Because of the model structure, the response to treatment changes with location, age of application, and dominant height growth as indicators of site quality. Therefore, the proposed model adequately represents regional growth conditions.


2007 ◽  
Vol 22 (4) ◽  
pp. 269-277
Author(s):  
D. Pascual ◽  
D.A. Maguire ◽  
F. Bravo

Abstract Evaluations of response to variable silvicultural treatments play a key role in developing sustainable forest management. To evaluate silvicultural response, a growth and yield model is needed. A comparison between similar species could act as a logical first step toward building a growth and yield model and to test the efficiency of the calibration of an existing ponderosa pine (Pinus ponderosa Dougl. ex Laws.) growth model to a Mediterranean maritime pine (Pinus pinaster Ait. ssp. mesogeensis) growth model. This study aimed at (1) comparing the diameter growth pattern between ponderosa and Mediterranean maritime pine, and (2) assessing the potential of ORGANON for simulating Mediterranean maritime pine growth and yield. The first objective was addressed by fitting a diameter growth equation for Mediterranean maritime pine and comparing it with patterns in ponderosa pine growth represented by the corresponding equation in ORGANON. The second objective was addressed by growing Mediterranean maritime pine as ponderosa pine in ORGANON, conditional on observed diameter growth rates of Mediterranean maritime pine in Spain. The results emphasized the unsuitability of ORGANON for predicting diameter growth of Mediterranean maritime pine in Spain. Mediterranean maritime pine diameter growth depended on basal area in trees with a diameter larger than the subject tree, (BAL) which, in our context is a subrogate of competition from above.


1982 ◽  
Vol 6 (4) ◽  
pp. 215-217 ◽  
Author(s):  
G. L. Wheeler ◽  
F. M. Meade ◽  
M. W. Russell

Abstract A thinning and fertilizing study was established in an 11-year-old loblolly pine (Pinus taeda L.) plantation. Half of the plots were row thinned, removing 50 percent of the trees; plots were split and half were fertilized at a per acre rate of 100 pounds nitrogen, 50 pounds phosphorous and 50 pounds potassium. There was no response of height, d.b.h. or volume growth to fertilizer. Thinning increased diameter growth but decreased volume growth. The trees have shown exceptional growth. At age 17 the height was 49 feet, d.b.h. 7.3 inches and stocking 2,490 cubic feet on the thinned plots. The respective values for the unthinned plots were 48 feet, 6.7 inches, and 3,960 cubic feet.


1986 ◽  
Vol 16 (2) ◽  
pp. 330-334 ◽  
Author(s):  
N. J. Smith ◽  
D. W. Hann

A two-staged stand growth model is developed to describe the relationship between biomass or volume and numbers of stems in even-aged, monospecific plant populations undergoing self-thinning. The model is tested on red alder (Alnusrubra Bong.) seedlings and red pine (Pinusresinosa Ait.) stands grown over a range of site qualities and initial spacings. First, survival rate is modelled as a Weibull distribution. This is then fit to an analytical size–density model to give growth estimates. Crown closure is estimated to occur at a relative density of 0.09 for red alder, while initial mortality is estimated to occur at a relative density of 0.12 for red pine. Net stand growth rates peaked at a relative density of 0.54 for red alder biomass and from relative densities from 0.40 (widest initial spacing) to 0.55 (densest initial spacing) for red pine total stem volume. Site quality merely shifted the magnitude of these relationships. The model adds a dynamic component to the self-thinning rule and also generalizes and extends the rule to stand development between crown closure and the self-thinning asymptote.


2013 ◽  
Vol 59 (1) ◽  
pp. 27-37 ◽  
Author(s):  
Nilesh Timilsina ◽  
Christina L. Staudhammer

1987 ◽  
Vol 17 (6) ◽  
pp. 534-538 ◽  
Author(s):  
Peter T. Sprinz ◽  
Harold E. Burkhart

Empirical and theoretical relationships between tree crown, stem, and stand characteristics for unthinned stands of planted loblolly pine (Pinustaeda L.) were investigated. Readily measured crown variables representing the amount of photosynthetic area or distance of the translocation process were identified. Various functions of these variables were defined and evaluated with regard to efficacy in predicting stem and stand attributes. Linear models were used to evaluate the contribution of the crown variables in predicting stem and stand characteristics. The stem attributes modeled included basal area, basal area growth, diameter at breast height, and diameter growth, while the stand attributes modeled were basal area, basal area growth, arithmetic mean diameter, and mean diameter growth. Crown diameter and crown projection area were particularly important in contributing to model fit and prediction of individual stem characteristics, while sum of crown projection areas was found especially important in stand level equations. As these crown measures developed over time so did corresponding stem and stand attributes.


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