Modeling the Effects of Initial Spacing on Stand Basal Area Development of Loblolly Pine

2012 ◽  
Vol 58 (2) ◽  
pp. 95-105
Author(s):  
Clara Antón-Fernández ◽  
Harold E. Burkhart ◽  
Ralph L. Amateis
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.


1999 ◽  
Vol 29 (7) ◽  
pp. 979-984 ◽  
Author(s):  
Dwight K Lauer ◽  
Glenn R Glover

The relationship between age-5 pine height and vegetation cover was estimated for loblolly pine (Pinus taeda L.) and slash pine (Pinus elliottii Engelm.) stands using regression analysis. This paper utilizes results from four locations of a vegetation control study that included herbicide treatments to control woody shrub and herbaceous vegetation. Age-5 average dominant height was predicted from first-year herbaceous cover, untreated first-year shrub cover, and fifth-year shrub cover. Dominant height increased 0.5 m for each decrease of about 30% in either first year herbaceous cover, untreated first-year shrub cover, or year-5 shrub cover. Lack of vegetation control on beds where vegetation was allowed to recolonize before planting reduced dominant height an additional 0.5 m. A competition index was constructed that estimates the difference between "potential" and actual age-5 pine height. Stand-level models were developed to link age-5 pine height and occupancy of competing vegetation to quadratic mean DBH, specific DBH percentiles, and stand basal area. The effects of interspecific competition on stand basal area and diameter percentiles could be accounted for through the effects of competing vegetation on dominant height except for treatments that did not control woody shrubs.


1988 ◽  
Vol 18 (7) ◽  
pp. 851-858 ◽  
Author(s):  
B. M. Cregg ◽  
P. M. Dougherty ◽  
T. C. Hennessey

A 10-year-old stand of loblolly pine (Pinustaeda L.) in southeastern Oklahoma was thinned to three target basal-area levels: 5.8, 11.5, and 23 m2•ha−1 (control). Specific gravity, latewood percentage, date of transition from earlywood to latewood, growth, and climate variables were measured for 2 years after thinning. Variation in the measured wood properties was more influenced by climatic variation than by the thinning treatments. Diameter growth and per-tree basal-area growth were significantly greater on the thinned treatments both years after thinning. However, stand basal-area growth was greatest on the unthinned treatment. Basal-area growth rates were significantly related to stand basal area, tree size, soil water potential, and air temperature. Early in the summer, growth was positively related to mean daily temperature, while later in the summer, growth was negatively related to mean daily temperature, reflecting the influence of high-temperature stress on growth. A year with high summer rainfall (1984) resulted in wood with a higher percentage of latewood and higher specific gravity than wood produced in a year with low summer rainfall (1985). The date of latewood initiation was significantly related to tree size, soil moisture, and evaporative demand. The date of transition from earlywood to latewood occurred 10–14 days sooner on the unthinned plots in both years. However, annual ring latewood percentage and specific gravity were not significantly affected by thinning. Increased late-season growth rates compensated for the later transition date on the thinned treatments, resulting in no net change in ring latewood percentage due to thinning. The results indicate that individual tree basal-area growth can be increased by thinning without reducing wood density.


2020 ◽  
Vol 66 (5) ◽  
pp. 623-633
Author(s):  
Y H Weng ◽  
J Grogan ◽  
D W Coble

Abstract Growth response to thinning has long been a research topic of interest in forest science. This study presents the first 3–4 years of response of loblolly pine (Pinus taeda L.) growth to thinning at different intensities. Data were collected from the East Texas Pine Research Project’s region-wide loblolly pine thinning study, which covers a wide variety of stand conditions. Four treatments, light, moderate, and heavy thinning, respectively having 370, 555, and 740 residual trees per hectare after thinning, and an unthinned control, were included. Individual tree diameter at breast height (dbh) and total height were recorded annually for the first 3–4 years after thinning. Results indicate significant differences between treatments in dbh growth in each year after thinning, as well as for all years combined. Each thinning treatment had significantly greater dbh growth than the control in the first growing season with this positive response being more evident in the case of the heavier thinning or at the later years post-thinning. Conversely, the thinning effect on tree height growth was initially negligibly negative, then becoming positive after 2–4 years, with the heavier thinning becoming positive sooner. Tree size class, assigned based on prethinning dbh, had a significant effect on both dbh and height growth responses. Compared to the control, small trees had a greater response both in dbh and in height growth than the medium and large trees over the measurement period. At the stand level, the heavier thinning had significantly less stand basal area per hectare, but the difference in stand basal area per hectare between the thinned and the unthinned plots decreased with years post-thinning. Results from this study can improve our understanding in thinning effects and help forest managers make accurate decisions on silvicultural regimes.


1993 ◽  
Vol 23 (10) ◽  
pp. 2126-2132 ◽  
Author(s):  
Glenn R. Glover ◽  
Bruce R. Zutter

A site-preparation study installed in 1959 in Fayette County, Alabama, U.S.A., provides data to evaluate long-term effects of varying densities of hardwood on loblolly pine (Pinustaeda L.) plantation growth, yield, and stand structure. Six treatments (hand girdle; bulldoze scarification; herbicide applied to axe frill, chain frill, and with an injector; and an untreated check) were installed as a randomized complete block with five replications. Periodic measurements of pine and hardwood size and density show that higher hardwood densities existing early in the pine plantation had a substantial negative effect on loblolly pine survival and basal area yield, with the bulldoze and herbicide treatments having less hardwood and higher survival and stand basal area. Pine total height and diameter at breast height were reduced by increasing hardwood density early in the life of the plantation, but size of surviving trees differed little among treatments at later ages, except on plots where most pine trees were suppressed by hardwoods. Strong relationships between pine basal area per hectare at age 27 and both number of hardwood stems at age 3 and percentage of stand basal area in hardwood at age 6 were noted. These relationships indicate promise for predicting long-term growth and yield of loblolly pine plantations from early measures of hardwood interference.


2002 ◽  
Vol 26 (1) ◽  
pp. 32-36 ◽  
Author(s):  
Stacey W. Martin ◽  
Barry D. Shiver

Abstract A designed experimental study was installed at 25 separate locations in the Piedmont and Upper Coastal Plain regions of South Carolina, Georgia, and Alabama with the objective of evaluating the effects of different site preparation treatments, both chemical and mechanical, on growth and yield of cutover site-prepared loblolly pine (Pinus taeda L.) plantations. The following six site preparation treatments were included: (1) burn, (2) chop and burn, (3) shear, pile and disk, (4) chop, herbicide and burn, (5) herbicide and burn, and (6) herbicide, burn and complete vegetation control. The herbicide, burn and complete vegetation control treatment significantly increased mean dbh, mean height, stand basal area, and total and merchantable volume compared to all other treatments. The burn-only treatment consistently ranked worst compared to all other treatments. There were significant differences in mean dbh, mean height, stand basal area, and total and merchantable volume between: (1) the herbicide and burn, which is an operational chemical treatment, and (2) the average of the chop and burn treatment and the shear, pile and disk treatment, which are operational mechanical treatments. In all cases the operational chemical treatment performed significantly better than the average of the two operational mechanical treatments. Average 12-yr-old merchantable volumes (ft3/ac) across all locations by treatment were: burn (846), chop and burn (1,445), shear, pile and disk (1,740), chop, herbicide and burn (1,669), herbicide and burn (1,919), and herbicide, burn and complete vegetation control (2,546). There were no apparent trends in percent fusiform infection levels across site preparation treatment intensity levels. South. J. Appl. For. 26(1):32–36.


2002 ◽  
Vol 32 (8) ◽  
pp. 1451-1459 ◽  
Author(s):  
Mahadev Sharma ◽  
Harold E Burkhart ◽  
Ralph L Amateis

The effect of spacing rectangularity on tree growth and stand development was evaluated using tree data obtained annually from a loblolly pine (Pinus taeda L.) spacing trial monitored through age 16 years. In this trial, plots with an initial planting density of 2240 trees/ha occur at slightly and highly rectangular spacings. Spacings with rectangularities 3:4 and 1:3 were used to evaluate the rectangularity effect. Survival and the development of height, diameter, volume per hectare, and basal area per hectare of loblolly pine trees were not affected by rectangularity. Diameter and height distributions were found to be a function of age but not a function of the rectangularity of initial spacing. Crown width, however, was affected by rectangularity. The crown width was larger at larger row or column distance than at smaller row or column distance, but the ratio of crown widths between and within rows was not equal to the rectangularity of the original planting spacing.


1997 ◽  
Vol 27 (2) ◽  
pp. 265-271 ◽  
Author(s):  
H Hasenauer ◽  
H E Burkhart ◽  
R L Amateis

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.


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