scholarly journals Accuracy and Precision of Commercial Thinning to Achieve Wildlife Management Objectives in Production Forests

Forests ◽  
2021 ◽  
Vol 12 (4) ◽  
pp. 411
Author(s):  
Kent Keene ◽  
William Gulsby ◽  
Allison Colter ◽  
Darren Miller ◽  
Kristina Johannsen ◽  
...  

Tree stocking and the associated canopy closure in production forests is often greater than optimal for wildlife that require an open canopy and the associated understory plant community. Although mid-rotation treatments such as thinning can reduce canopy closure and return sunlight to the forest floor, stimulating understory vegetation, wildlife-focused thinning prescriptions often involve thinning stands to lower tree densities than are typically prescribed for commercial logging operations. Therefore, we quantified the accuracy and precision with which commercial logging crews thinned pre-marked and unmarked mid-rotation loblolly pine (Pinus taeda) stands to residual basal areas of 9 (low), 14 (medium), and 18 (high) m2/ha. Following harvest, observed basal areas were 3.36, 1.58, and 0.6 m2/ha below target basal areas for the high, medium, and low basal area treatments, respectively. Pre-marking stands increased precision, but not accuracy, of thinning operations. We believe the thinning outcomes we observed are sufficient to achieve wildlife objectives in production forests, and that the added expense associated with pre-marking stands to achieve wildlife objectives in production forests depends on focal wildlife species and management objectives.

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.


Author(s):  
Kent Keene ◽  
William Gulsby ◽  
Allison Colter ◽  
Darren A. Miller ◽  
Kristina Johannsen ◽  
...  

Commercial thinning and prescribed fire can improve habitat quality for white-tailed deer (Odocoileus virginianus) in lobolly pine (Pinus taeda) stands by increasing coverage of forage plants. However, the relationships among thinning intensity, prescribed fire, and deer forage have not been quantified. We estimated percent cover of deer forage plants in 5 loblolly pine stands thinned to 11 (low), 14 (medium), and 18 (high) m2/ha basal areas during 2017 in Georgia, USA. We applied prescribed fire during 2018. From years 1-2 post-treatment, cover of total deer forage increased 26% and 29% in the low and medium basal area treatments, respectively, compared to 19% in the high basal area treatment. Similarly, the increase in forb coverage was greater for the medium (13%) and low (11%) basal area treatments than the high (6%) basal area treatment. Increases in vine and bramble coverage were greater in unburned medium basal area units. Woody browse was not affected by any treatment. Our results suggest thinning loblolly pine stands to 14 m2/ha can increase coverage of deer forage plants during the first two growing seasons post-thin, but deer forage was not greater in stands thinned to <14 m2/ha two years post-thin.


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.


Forests ◽  
2021 ◽  
Vol 12 (7) ◽  
pp. 935
Author(s):  
Mohammad Bataineh ◽  
Ethan Childs

The need for a comprehensive and mechanistic understanding of competition has never been more important as plants adapt to a changing environment and as forest management evolves to focus on maintaining and enhancing complexity. With the recent decline in shortleaf pine (Pinus echinata Mill.) land area, it is critical to determine the effects of competition on shortleaf pine and its performance against loblolly pine (Pinus taeda L.), the preferred planted replacement. We evaluate differences in shortleaf and loblolly pine 10 year mean basal area increment (BAI) and crown dimensions across a gradient of neighborhoods. Linear mixed-effects regression models were developed using BAI and several crown metrics as responses and crowding, competitor species abundance and identity, and initial size and species identity of focal tree as predictors. Crowding of focal trees negatively impacted BAI and crown size (p < 0.001, respectively). Although loblolly pine had three times higher BAI as compared to shortleaf pine within similar neighborhoods, BAI was variable, and the crowding effect did not differ between shortleaf and loblolly pine (p ranged from 0.51–0.99). Competitive impacts on focal trees did not differ by competitor identity (p ranged from 0.07–0.70). Distance-independent competition indices better explained the variation in BAI and horizontal crown metrics, while distance-dependent size ratios were more effective at evaluating vertical crown metrics. These findings highlight shortleaf pine competitive potential in mature, natural-origin stands and provide support for the restoration of pine–hardwood and hardwood–pine stratified mixtures as well as management of shortleaf pine at long rotations.


1997 ◽  
Vol 21 (4) ◽  
pp. 168-174
Author(s):  
Michael G. Shelton ◽  
Paul A. Murphy

Abstract Growth was monitored for 4 yr in a thinned stand in southern Arkansas with three pine basal areas (70, 85, and 100 ft2/ac) and three hardwood basal areas (0, 15, and 30 ft2/ac); pretreatment basal areas averaged 119 and 33 ft2/ac for pines and hardwoods, respectively. Treatments were arranged in a 3 X 3 factorial randomized complete block design with three replicates, yielding 27 permanent 0.20 ac plots. Growth variables were regressed with residual pine and hardwood basal areas. Pine basal area and volume growth increased with the pine stocking level after thinning and decreased with the level of retained hardwoods. For basal area and merchantable volume, hardwood growth largely compensated for losses in the pine component, and thus, hardwood retention had little net effect on the total growth of the stand. The greatest impact of hardwood retention was on the stand's sawtimber growth, because hardwoods did not contribute to this product class. Each 1 ft2/ac of retained hardwood basal area reduced pine sawtimber growth by 6 to 10 bd ft Doyle/ac/yr, depending on the pine stocking. Because large differences existed in the value of timber products, retaining 15 and 30 ft2/ac of hardwoods reduced the value of timber production by 13 and 24%, respectively, at 4 yr after thinning. South. J. Appl. For. 21(4):168-174.


2005 ◽  
Vol 22 (3) ◽  
pp. 170-174
Author(s):  
KaDonna C. Randolph ◽  
Robert S. Seymour ◽  
Robert G. Wagner

Abstract We describe an alternative approach to the traditional stand-density management diagrams and stocking guides for determining optimum commercial thinning prescriptions. Predictions from a stand-growth simulator are incorporated into multiple nomograms that graphically display postthinning responses of various financial and biological response variables (mean annual increment, piece size, final harvest cost, total wood cost, and net present value). A customized ArcView GIS computer interface (ThinME) displays multiple nomograms and serves as a tool for forest managers to balance a variety of competing objectives when developing commercial thinning prescriptions. ThinME provides a means to evaluate simultaneously three key questions about commercial thinning: (1) When should thinning occur? (2) How much should be removed? and (3) When should the final harvest occur, to satisfy a given set of management objectives? North. J. Appl. For. 22(3):170 –174.


2000 ◽  
Vol 24 (1) ◽  
pp. 31-36 ◽  
Author(s):  
Barry D. Shiver ◽  
John W. Rheney ◽  
Kenneth L. Hitch

Abstract A total of 141 paired plot installations remain of the 160 that were planted with slash (Pinus elliottii Engelm.) and loblolly (P. taedaL.) pine across southeastern Georgia and northern Florida, after 14 growing seasons. Installations were evenly distributed across eight soil types. Analyses indicate that loblolly performed equal to or better than slash pine. There were no soil X species interactions. After 14 yr, loblolly pine had significantly higher survival (71% vs. 66%), stand basal area (98 vs. 81 ft2/ac), total stand volume (1857 vs. 1721 ft3/ac), merchantable stand volume (1497 vs. 1310 ft3/ac), total green weight (53 tons vs. 47 tons), and merchantable green weight (45 vs. 35 tons/ac) than slash pine. Growth over the period from age 11 to age 14 was also higher for loblolly than for slash indicating that the difference in the two species is diverging over time. South. J. Appl. For. 24(1): 31-36.


Fire ◽  
2019 ◽  
Vol 2 (2) ◽  
pp. 25 ◽  
Author(s):  
David G. Ray ◽  
Deborah Landau

This case study documents the aftermath of a mixed-severity prescribed fire conducted during the growing season in a young loblolly pine forest. The specific management objective involved killing a substantial proportion of the overstory trees and creating an open-canopy habitat. The burn generated canopy openings across 26% of the 25-ha burn block, substantially altering the horizontal structure. Mortality of pines was high and stems throughout the size distribution were impacted; stem density was reduced by 60% and basal area and aboveground biomass (AGB) by ~30% at the end of the first growing season. A nonlinear regression model fit to plot data portrays a positive relationship between high stocking (i.e., relative density > 0.60) and postburn mortality. Survival of individual trees was reliably modeled with logistic regression, including variables describing the relative reduction in the size of tree crowns following the burn. Total AGB recovered rapidly, on average exceeding levels at the time of the burn by 23% after six growing seasons. Intentional mixed-severity burning effectively created persistent canopy openings in a young fire-tolerant precommercial-sized pine forest, meeting our objectives of structural alteration for habitat restoration.


1989 ◽  
Vol 13 (1) ◽  
pp. 12-16 ◽  
Author(s):  
Hewlette S. Crawford ◽  
R. Larry Marchinton

Abstract A habitat suitability index based on winter foods was designed to evaluate habitat changes affecting white-tailed deer (Odocoileus virginianus) in the Piedmont region of the southeastern United States. Habitat components incorporated in the index were (1) the standing crop of availableherbaceous vegetation and leaves of woody plants remaining green during late autumn and winter, (2) basal area of oak (Quercus spp.) 10" dbh and larger, (3) number of oak species in the stand ≥5% of total basal area, (4) site index of loblolly pine (Pinus taeda) or mixed oak, (5) percentageof agricultural land, and (6) distance from agricultural land to forest or shrub cover. The rationale for inclusion of each component of the index is given, and methods for sampling each habitat component are described. The index should be useful on private small landownerships as well ason larger private and public holdings. South. J. Appl. For. 13(1):12-16


2002 ◽  
Vol 26 (2) ◽  
pp. 85-92 ◽  
Author(s):  
Thomas J. Dean ◽  
S.Joseph Chang

Abstract This article presents a procedure to produce management regimes that not only maximize land value but also reflect stand development with simple marginal analyses of the accumulation and control of growing stock. An upper limit of growing stock is determined by translating management objectives into a future desired structure, and with this value as a guide for thinning age, marginal analysis is used to determine the planting density and the residual basal area after thinning. The procedure is demonstrated for a hypothetical loblolly pine plantation growing on land with a site index of 65 ft at 25 yr. The effects of various interest rates for a fixed rotation length and various rotation lengths for a fixed interest rate on initial planting density and residual growing stock after low thinning are analyzed. Optimal planting density decreased with increasing interest rate and rotation length. Thinning ages increased as initial planting density decreased, which caused optimal residual growing stock to increase with increasing interest rate and rotation age. According to this study, maximum land value is achieved when the growing stock limits are set to approximately the lower limit of full-site occupancy and the threshold of self-thinning. In terms of relative density, the ideal limits in growing stock for maximizing land value identified in this study are 35 and 55% of maximum SDI. South. J. Appl. For. 26(2):85–92.


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