Erratum: Loblolly pine growth response to herbaceous vegetation control at different planting densities

2000 ◽  
Vol 30 (1) ◽  
pp. 178
Author(s):  
Harold Quicke ◽  
Glenn Glover ◽  
Ralph Meldahl
1999 ◽  
Vol 29 (7) ◽  
pp. 960-967 ◽  
Author(s):  
Harold Quicke ◽  
Glenn Glover ◽  
Ralph S Meldahl

Growth of Pinus taeda L., with and without control of competing herbaceous vegetation, was evaluated over 15 years at planting densities ranging from 747 to 2990 trees/ha. A height response to vegetation control of 0.9 m at age 5 decreased to 0.3 m at age 15. Convergence in the cumulative height between treated and untreated stands did not translate into converging basal area and volume yield. For 1500 and 2200 trees/ha, volume response to early vegetation control increased to age 15. For 800 trees/ha volume gains increased to age 12 and were stable between ages 12 and 15. Higher densities apparently captured more of the site resources made available through vegetation control. Age-15 volume gains for 2200, 1500, and 800 trees/ha were 71 (23%), 48 (17%), and 19 m3·ha-1 (8%), respectively. A separate adjustment term in height and basal-area models captured the short-term positive effect of vegetation control on height growth and longer term basal-area responses. Previously published height and basal-area models were modified to account for planting-density effects.


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.


1999 ◽  
Vol 14 (4) ◽  
pp. 208-213 ◽  
Author(s):  
V. J. Monleon ◽  
M. Newton ◽  
C. Hooper ◽  
J. C. Tappeiner

Abstract The effect of different densities of varnishleaf ceanothus (Ceanothus velutinus var. laevigatus) and herbaceous vegetation control on stem diameter, height, and volume of plantation Douglas-fir (Pseudotsuga menziesii vat. menziesii) seedlings was examined during the 10 yr following planting. Initial densities of ceanothus ranged between 0 and 15,000 seedlings/ha and were obtained by interplanting ceanothus germinants or chemical thinning after clearcutting and broadcast-burning. Herbaceous vegetation control was achieved by a single application of glyphosate following planting, with shrub seedlings covered. Ceanothus density in the range of 0 to 6,750 plants/ha did not have an effect on Douglas-fir diameter, height, or volume at age 10; however, Douglas-fir growth was significantly decreased when ceanothus densities reached 15,000 plants/ha. Ten years after planting, Douglas-fir volume in the treatments with 6,750 ceanothus/ha or less was 1.7 times greater than that in the 15,000 ceanothus/ha treatment. On the other hand, removal of herbaceous vegetation after planting significantly increased tree diameter, height, and volume, regardless of ceanothus density. Even 10 yr after the application of the treatment, trees without early herb competition grew faster and had mean dbh, height, and volume that were 1.02 cm, 0.55 m, and 12.98 dm³/tree greater respectively than those with herbs. Thus, a treatment at plantation establishment to control herbaceous vegetation and to reduce ceanothus density to less than 7,000 plants/ha will ensure an increase in growth and stocking for at least 10 yr. West. J. Appl. For. 14(4):208-213.


1984 ◽  
Vol 8 (4) ◽  
pp. 194-197 ◽  
Author(s):  
T. R. Clason

Abstract A single hardwood eradication treatment in a 7-year-old loblolly pine (Pinus taeda L.) stand along with pine stocking control increased growth and yield over a 10-year period. Herbaceous vegetation control had no detectable effect at ages 12 and 17. Treated plots had smaller stems, which could be controlled more readily by fire, although the number of understory stems was similar for all treatments. Mean annual radial and merchantable volume growth on treated plots surpassed controls by 30%. Future stand values were enhanced by removing hardwood competition. Residual stand sawtimber volumes on the treated plots were twice that of the control.


2021 ◽  
Author(s):  
Yanshu Li ◽  
E David Dickens ◽  
Matthew Sault ◽  
Jacek P Siry ◽  
Robert L Izlar ◽  
...  

Abstract The effects of midrotation competition control and fertilization were studied in two loblolly pine stands in the Coastal Plain of Georgia. The use of fertilizer or herbicide alone did not enhance wood yields above the control, which negates the cost spent to conduct these practices. The combined treatment of fertilization and herbicide promoted higher average pine annual increment and greater proportion of sawtimber. Site limiting factors, most likely both competing woody vegetation and low nutrient status, largely determined the effectiveness and priority of midrotation treatments. The economic returns of the combined treatment varied considerably depending on stumpage prices, treatment costs, and magnitude and duration of the growth response. Sawtimber prices (absolute value and relative to pulpwood and chip-n-saw) play a critical role in the marginal returns of midrotation treatments. Continued depressed sawtimber prices will discourage private landowners from investing in midrotation vegetation control and fertilization. Study Implications: Midrotation fertilization and vegetation control can be attractive silvicultural treatments to increase timber volume and economic returns. Assessment of site variables that limit growth, especially soil fertility and plant competition, must be conducted before prioritization of treatments. The economic returns of midrotation treatments vary greatly depending on treatment costs, stumpage prices, and magnitude and duration of pine growth response compared with controls. The pine growth response of particular concern is ingrowth of trees into the sawtimber size class and growth of sawtimber-sized trees. Sawtimber prices play a critical role in the marginal internal rate of return of the additional investment. Lackluster timber prices (especially sawtimber prices) may render investment in midrotation fertilization and vegetation control unattractive and have detrimental effects on timber supply and forest health of the region in the long term.


2001 ◽  
Vol 25 (2) ◽  
pp. 75-83 ◽  
Author(s):  
Dwight K. Lauer ◽  
Bruce R. Zutter

Abstract Site preparation treatments of early single bed (EB), late single bed (LB), double bed (DB), EB + banded pre-plant herbicide (PP), and EB + broadcast pre-plant herbicide (BPP) were applied to four locations in Florida. Three of the four locations included these treatments crossed with a first-year post-plant herbicide application to control herbaceous vegetation(HC). Second-year pine heights evaluated at two slash pine (P. elliottii Engelm.) locations and one loblolly pine (P. taeda L.) location averaged taller (4.6 vs. 3.5 ft) following double-pass (DB, PP, BPP) than single-pass (EB, LB) treatments, taller (4.9 vs. 4.0 ft) for pre-plant herbicide (PP, BPP) than DB, but did not differ between PP and BPP. There were no significant interactions between site preparation and HC with HC, increasing second-year pine height by 0.5 ft. Pine height was greater for pre-plant herbicide treatments than for DB treatments because pre-plant herbicide treatments provided better control of competing vegetation. Vegetation control differed among treatments. DB improved control of woody shrubs over single bedding alone, but increased herbaceous cover in the first growing season. The increase in herbaceous cover following DB accounts for the relatively small gain in second-year pine height (0.2 ft) for DB compared to LB. Pre-plant herbicide treatments following early bedding improved control of both woody shrubs and first-year herbaceous vegetation. Pre-plant herbicide treatments also shifted the composition of herbaceous vegetation towards less competitive species. HC improved control of herbaceous plants, and lowest first-year herbaceous cover was achieved with the combination of HC with pre-plant herbicide treatments. South. J. Appl. For. 25(2):75–83.


1996 ◽  
Vol 20 (1) ◽  
pp. 53-57 ◽  
Author(s):  
Jimmie L. Yeiser ◽  
Richard A. Williams

Abstract Plots in 13 loblolly pine (Pinus taeda L.) plantations established on sandy or sandy-loam soils in SE Oklahoma and SW Arkansas received herbaceous vegetation control using hexazinone and sulfometuron methyl. Treatments consisted of a one-time herbicide application over-the-top of loblolly pine seedlings by one of three methods: spot, band, or broadcast. At the end of 1 and 5 growing seasons, data were collected for survival, height, and diameter growth and compared for seedlings in areas untreated and treated for herbaceous vegetation control. Only data corresponding to herbicide rates and application methods labeled for use today are included in data analysis. When compared with untreated checks, seedlings treated for herbaceous vegetation control exhibited significant increases in first-year survival at 11 sites and in height and groundline diameter (GLD) at 12 of the 13 test sites. At the end of 1 growing season, herbaceous vegetation control provided mean seedling increases of 16.7%, 0.4 ft, and 0.1 in. for survival, height, and GLD, respectively. After 5 growing seasons, advantages from herbaceous vegetation control had increased with significant differences existing in survival, height, and diameter at breast height (dbh) on 10 of 11 test sites, as 2 sites were lost to wildfire. Numerically, treatment differences had increased to 18.4%, 2.4 ft, and 0.6 in. for survival, height, and dbh, respectively. South. J. Appl. For. 20(1):53-57.


1991 ◽  
Vol 15 (4) ◽  
pp. 193-199 ◽  
Author(s):  
Phillip M. Dougherty ◽  
Robert F. Lowery

Abstract Two studies were installed at diverse locations to evaluate the seedling-centered area of herbaceous vegetation control needed to optimize seedling survival and growth. Study site I, established in 1986, was located on an upland Piedmont site in northeast Georgia. Study site II, established in 1985, was located on an alluvial site in southeastern Oklahoma. Treatments applied on both sites were: a no vegetation control check, and competition control in seedling-centered spots 2, 4, 6, and 8 ft in diameter. After 3 years in the field at the Georgia site, trees in the 6 and 8 ft diameter spot treatments averaged 13% to 15% better survival, 49% to 64% larger diameters at breast height (dbh), and 19% to 24% greater height than trees in the check treatments. On the Oklahoma site, after 3 years in the field, survival in treatments receiving vegetation control ranged from 41% to 56% greater survival than in the check treatment. Height in the 4, 6, and 8 ft diameter spot treatments averaged 32% to 47% taller, and dbh was 238 to 425% larger than those in the check. Most of the gain in survival was obtained with only a 2 ft diameter spot size at the Oklahoma location. At the Georgia installation, a 6 to 8 ft diameter spot size treatment was required to obtain a significant increase in survival. Diameter and height responses at both locations increased in proportion to the area treated with herbicide. South. J. Appl. For. 15(4):193-199.


1999 ◽  
Vol 29 (7) ◽  
pp. 968-978 ◽  
Author(s):  
Glenn Glover ◽  
Harold Quicke

A study was established with loblolly pine (Pinus taeda L.) planted at 1683 trees/ha competing with sweetgum (Liquidambar styraciflua L.), water oak (Quercus nigra L.), or loblolly pine at densities of 0, 1794, 2692, and 5382 trees/ha. The study is a split-split plot with three blocks. Main plots are the three competitor species; subplots are with or without 2 years of herbaceous vegetation control (HVC); and sub-subplots are competitor densities. The study was measured at 6 years after establishment. Pines in pure plots responded to HVC with a mean basal area gain of 1.8 m2/ha (13%). With HVC, basal area increased 2.7 m2/ha (70%) for sweetgum and 2.3 m2/ha (58%) for water oak. Pines in mixed plots did not respond, or responded negatively, to HVC. Pine height, basal area, volume index, and canopy projection were only slightly affected by sweetgum density above zero. Pine characteristics decreased as water oak density increased. Adding sweetgum or water oak to pine reduced total (pine + hardwood) volume index and basal area.


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