Coniferous Stands Characterized with The Weibull Distribution

1974 ◽  
Vol 4 (4) ◽  
pp. 518-523 ◽  
Author(s):  
Hans T. Schreuder ◽  
Wayne T. Swank

The Weibull distribution, [Formula: see text], summarized diameter, basal area, surface area, biomass, and crown profile distribution data well for several different ages of white and loblolly pine plantations. The data for diameter, basal area, surface area, and biomass were easily summarized by this one distribution in a theoretically consistent fashion. This is not possible with the normal and the gamma distributions, and the lognormal gives less satisfactory results. The distribution function should prove useful in modeling tree stands since only the parameter values need to be changed over time for the above variables. The change in these parameters may be a good way to characterize and interpret changes in stands over time.

1999 ◽  
Vol 23 (3) ◽  
pp. 179-185 ◽  
Author(s):  
Stacey W. Martin ◽  
Graham H. Brister

Abstract Using 5 yr remeasurement data from even-aged natural loblolly pine (Pinus taeda L.) stands in the Georgia Piedmont, a system of growth equations was developed to project pine yield over time that accounts for hardwood competition. In this system, the increase in the proportion of hardwood basal area over time is estimated, then the projected pine basal area and trees per acre are adjusted inversely to account for this increase. The parameter estimates for this system ensure compatibility between volume prediction and projection equations and the proportion of hardwood basal area, pine basal area, dominant height, and trees per acre projection equations. The whole-stand growth and yield system developed here coupled with published merchantable yield equations allow for the evaluation of the impact of hardwoods on future stand yield and product distributions. The results indicate that the impact of hardwood competition on pine yield is substantial and occurs mainly as a reduction in sawtimber volume. South. J. Appl. For. 16(3):179-185.


2009 ◽  
Vol 33 (2) ◽  
pp. 69-76 ◽  
Author(s):  
Dean W. Coble

Abstract A new compatible whole-stand growth-and-yield model to predict total tree cubic-foot volume per acre yield (outside and inside bark) was developed for unmanaged loblolly pine (Pinus taeda) and slash pine (Pinus elliottii) plantations in East Texas. This model was compared with the noncompatible whole-stand model of Lenhart (<xref ref-type="bibr" rid="B15-2127">Lenhart, 1996</xref>, Total and partial stand-level yield prediction for loblolly and slash pine plantations in east Texas, South. J. Appl. For. 20(1):36–41) and the <xref ref-type="bibr" rid="B15-2127">Lenhart (1996)</xref> model refit to current data. For the two species, all three models were evaluated with independent observed data. The model developed in this study outperformed both Lenhart models in prediction of future yield and basal area per acre for all age classes combined and by 5-year age classes. The Lenhart models consistently overestimated yield and basal area per acre. All three models predicted surviving trees per acre similarly. An example is also provided to show users how to use the new whole-stand model.


1989 ◽  
Vol 19 (2) ◽  
pp. 247-256 ◽  
Author(s):  
V. C. Baldwin Jr. ◽  
D. P. Feduccia ◽  
J. D. Haywood

This study compared growth responses in planted loblolly pine (Pinustaeda L.) and slash pine (P. elliottii Engelm.) stands thinned by using three row-felling methods and at the same density levels, three selective felling methods. The study plots were in six plantations, aged 15–22 years, located in central Louisiana. Growth was measured 5 and 10 years after plot installation. Site index varied from 19.5 to 31.7 m (base age 50) and initial planting densities ranged from 1993 to 2989 trees/ha. Study results show there will likely be less diameter increment and less net basal area and cubic-metre volume per unit area growth and yield, and the growth will be in smaller-sized trees, if row thinning is used rather than selective thinning from below. These differences will probably be greater in slash pine plantations than in loblolly pine plantations.


1988 ◽  
Vol 12 (4) ◽  
pp. 270-273 ◽  
Author(s):  
Charles R. Blinn ◽  
Al Lyons ◽  
Edward R. Buckner

Abstract Color aerial photography was used to assess crown color classes in loblolly pine (Pinus taeda L.) plantations. Three distinct Munsell color classes were delineated on the resulting photographs. Foliar N levels and, to a lesser degree, foliar K levels were directly related to color. Significant relationships between color and site index and color and basal area were shown. Application of color aerial photography, combined with Munsell color coding, could expedite land classification and also make possible more efficient use of fertilizers. South J. Appl. For. 12(4):270-273.


2003 ◽  
Vol 27 (4) ◽  
pp. 237-252 ◽  
Author(s):  
James H. Miller ◽  
Bruce R. Zutter ◽  
Shepard M. Zedaker ◽  
M. Boyd Edwards ◽  
Ray A. Newbold

Abstract Loblolly pine (Pinus taeda L.) plantations were studied across 13 southeastern sites grown for 15 yr with near-complete control of woody, herbaceous, and woody plus herbaceous components during the first 3–5 yr. This multiple objective experiment (the COMProject) documents stand dynamics at the extreme corners of the response surface that encompasses most competition conditions common to pine plantations. This is the second of two companion reports. Merchantable pine volume after 15 yr with early, near complete competition control reached 2,350–4,415 ft3/ac by site compared to 1,132–2,965 ft3/ac on the no controls. With control of both woody and herbaceous competition, 15 yr volumes were increased by 23–121% and gains increased as hardwoods and shrubs increased on the no controls. Early woody control increased merchantable pine volume on 11 sites by 14–118%, while herbaceous control yielded somewhat less on average, a 17–50% increase on ten sites. No gains and some volume losses occurred when control of one component released severe competition from an enhanced remaining component, otherwise gains were generally additive for control of both components. Pine volume was decreased by about 1% for each 1 ft2/ac of hardwood basal area (BA) present at age 15. Annual measurements determined that culmination of current annual increment (CAI) with control of both competition components occurred in yr 8–11 at 250–470 ft3/ac/yr. CAIs for pine height, BA, and volume were decreased by about 5–27% when growing season rainfall (March–October) was less than 36 in. Mean annual increment had not culminated for any treatment at any location by yr 15 and ranged from 195–250 ft3/ac/yr with both woody and herbaceous control. Fusiform rust mainstem galls [Cronartium quercuum (Berk.) Miyabe ex Shirai f. sp. fusiforme (Hedge. & Hunt) Burdsall & Snow] in high severity areas increased additively with control of both components, more so with herb control. Contrary to the widespread assumption that hardwood out-compete pine, the hardwood proportion of stand BA decreased from yr 5–15 on sites where hardwood BA in yr 5 exceeded 10 ft2. South. J. Appl. For. 27(4):237–252.


1996 ◽  
Vol 20 (4) ◽  
pp. 188-193 ◽  
Author(s):  
James C. Fortson ◽  
Barry D. Shiver ◽  
Lois Shackelford

Abstract A series of paired plots was installed in loblolly pine plantations at 42 locations in Georgia's Piedmont and Alabama's Piedmont and Coastal Plain. One plot of each pair had all competing vegetation eliminated. The other plot was left as an uncontrolled check. Locations were stratified over two age classes (5-9 and 12-16 yr old) and three slope positions (top, midslope, and bottom). Analysis of 33 surviving locations 8 yr after treatment revealed a positive treatment effect for both individual tree (dbh and total height) and stand characteristics (basal area per acre, total volume per acre, and merchantable volume per acre). There was no difference in volume response between age classes. Slope position was not significant for the individual tree variables, but was significant for the stand variables, with midslopes responding most positively followed by bottom and then top slope positions. Over all locations, the average treatment response was approximately ½ cord/ac/yr. Economic analyses indicate that the magnitude of the response will be economical for many stumpage prices, particularly on midslope and bottom slope positions, in plantations where access and species composition make herbicide spraying possible. South J. Appl. For. 20(4):188-192.


1996 ◽  
Vol 20 (2) ◽  
pp. 110-113 ◽  
Author(s):  
Roger A. Williams

Abstract Stand Density Index (SDI) equations and diagrams were developed and presented for loblolly pine (Pinus taeda L.) plantations in north Louisiana. Two different SDI diagrams are presented—one that utilizes the number of trees per acre and average stand diameter, and a second that uses the number of trees per acre and the basal (ft²) per acre. Basal area is presented as a second alternative to average stand diameter since many practicing foresters commonly use basal area for density management. South. J. Appl. For. 20(2):110-113.


2005 ◽  
Vol 29 (3) ◽  
pp. 158-162 ◽  
Author(s):  
Ralph L. Amateis ◽  
Harold E. Burkhart

Abstract Data from a long-term, region-wide thinning study were used to examine the proportion of pulpwood, sawtimber, and peeler quality trees in unthinned, once-thinned, and twice-thinned plantations. Results suggest that the thinning treatments have had a significant influence on the product distribution in these stands over the 21-year history of the study. Proportional odds modeling methods were used to develop equations for predicting product proportions from dbh, the basal area before and after thinning (thinning intensity), and the number of thinnings imposed. South. J. Appl. For. 29(3):158–162.


2015 ◽  
Vol 50 (8) ◽  
pp. 707-717 ◽  
Author(s):  
Antonio Carlos Ferraz Filho ◽  
José Roberto Soares Scolforo ◽  
Antonio Donizette de Oliveira ◽  
José Márcio de Mello

Abstract:The objective of this work was to develop and validate a prognosis system for volume yield and basal area of intensively managed loblolly pine (Pinus taeda) stands, using stand and diameter class models compatible in basal area estimates. The data used in the study were obtained from plantations located in northern Uruguay. For model validation without data loss, a three-phase validation scheme was applied: first, the equations were fitted without the validation database; then, model validation was carried out; and, finally, the database was regrouped to recalibrate the parameter values. After the validation and final parameterization of the models, a simulation of the first commercial thinning was carried out. The developed prognosis system was precise and accurate in estimating basal area production per hectare or per diameter classes. There was compatibility in basal area estimates between diameter class and whole stand models, with a mean difference of -0.01 m2ha-1. The validation scheme applied is logic and consistent, since information on the accuracy and precision of the models is obtained without the loss of any information in the estimation of the models' parameters.


1988 ◽  
Vol 12 (3) ◽  
pp. 208-214 ◽  
Author(s):  
R. Scott Cameron ◽  
Ronald F. Billings

Abstract An inventory of 167,316 ac of 5- to 15-year-old plantations of slash pine (Pinus elliottii Engelm.) or loblolly pine (P. taeda L.) or both in east Texas revealed that infestations (spots) of the southern pine beetle, Dendroctonus frontalis Zimm., occurred in plantations of all ages greater than 5 years. Infestation frequency ranged from 0.1 spots/1000 ac for 6-year-old plantations to 6 to 8 spots/1000 ac for 12- to 15-year-old plantations in 1985. Analyses of subsets of plantation inventories revealed that spots were more frequent in loblolly pine plantations than in slash pine plantations, and more frequent in plantations that had been prescribed-burned. An intensive study of 34 individual spots showed that spot initiation was often associated with stand disturbance but not with intraplantation variations in stand parameters. In turn, regression analyses revealed that the initial number of active trees (spot size) was directly correlated with pine basal area/ac. Rate of summer spot growth in uncontrolled infestations was most strongly correlated with number of active (brood) trees and weakly correlated with tree height and pine basal area/ac. Spots tended to grow faster in loblolly plantations than in those with slash pine. Mean spot growth rates were markedly less within young plantations than rates documented in earlier studies for natural pulpwood and sawtimber stands. A field guide for setting control priorities for beetle infestations in young plantations is provided. South. J. Appl. For. 12(3):208-214.


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