Interaction Between Weed Control and Loblolly Pine,Pinus taeda, Seedling Quality

1988 ◽  
Vol 2 (2) ◽  
pp. 191-195 ◽  
Author(s):  
Robert J. Mitchell ◽  
Bruce R. Zutter ◽  
David B. South

Third-year heights, third-year root-collar diameters, and 3 yr volume growth of loblolly pine seedlings were examined in relation to a) root-collar diameter class at time of planting and b) herbaceous weed control. Treatments were a) no weed control and b) complete control for 2 yr. For both weed control treatments, means for third-year heights, groundline diameters, and volume growth were related positively to initial seedling diameter. The influence of initial seedling diameter on third-year diameters and heights did not differ among weed control treatments. However, the influence of initial diameter on volume growth did differ among weed control treatments. Thus, when using herbaceous weed control, additional gains in early volume growth can be realized by planting seedlings with large root-collar diameters.

1982 ◽  
Vol 6 (1) ◽  
pp. 30-33 ◽  
Author(s):  
John L. Ruehle

Abstract Container-grown loblolly pine seedlings (Pinus taeda L.) with Pisolithus tinctorius, Thelephora terrestris, or no ectomycorrhizae (control) were outplanted on a South Carolina reforestation site. Two years after planting, seedlings initially colonized with Pisolithus or Thelephora had greater survival, height, and root collar diameter than control seedlings. Growth data were integrated into seedling volume indices (D²H). Seedlings with ectomycorrhizae at planting had nearly a three-fold greater D²H than seedlings initially without ectomycorrhizae. These results provided additional field validation for the hypothesis regarding benefits of ectomycorrhizae on this type of planting stock.


Weed Science ◽  
1979 ◽  
Vol 27 (6) ◽  
pp. 583-588 ◽  
Author(s):  
C. H. Fitzgerald ◽  
J. C. Fortson

Hexazinone [3-cyclohexyl-6-(dimethylamino)-1-methyl-1,3,5-triazine-2,4 (1H, 3H)-dione] effectively controlled herbaceous weeds in a loblolly pine (Pinus taeda L.) plantation in 1975. Pine seedling height increased as a result of weed control following 1 to 3 kg/ha applications but phytotoxic symptoms were evident. A 1976 field study indicated activated charcoal root coatings may reduce phytotoxic action. Hexazinone at 3 and 4 kg/ha applied to either the foliage or the soil was toxic to potted pine seedlings in 1976. The addition of surfactant to hexazinone treatments at 2, 3, and 4 kg/ha increased pine phytotoxicity to unacceptable levels. When hexazinone was applied to soil at 2, 3, and 4 kg/ha, activated charcoal root coatings reduced pine mortality to acceptable levels on Norfolk sandy loam. Charcoal was less effective on Madison clay loam. Pine tolerance on both soils was acceptable at 2 kg/ha.


1988 ◽  
Vol 2 (4) ◽  
pp. 490-494 ◽  
Author(s):  
James D. Haywood

Herbaceous weed control was studied on a loblolly pine planting site in central Louisiana. Pine growth was enhanced without eradicating weeds; reducing weed biomass about 50% increased the mean inside bark volume of loblolly pine saplings 53% on the weeded treatments compared to the untreated control after five growing seasons in the field. Pines receiving both preplant weed control with glyphosate or disking and postplant weed control with a series of yearly treatments (1982, atrazine plus simazine; 1983, atrazine plus oxyfluorfen; 1984, hexazinone; and 1985, hexazinone) had 62% greater volume than pines on the preplant-only treatments. So, the best gains in loblolly pine volume required postplant weed control.


1988 ◽  
Vol 12 (4) ◽  
pp. 234-239
Author(s):  
David B. South ◽  
R. J. Mitchell ◽  
R. K. Dixon ◽  
Mark Vedder

Abstract In July 1986, stunted loblolly pine (Pinus taeda L.) seedlings were studied at a nursery in Union Springs, Alabama. Stunted seedlings were found only in seedbeds formed on new ground (soil having no history of producing a nursery crop of ectomycorrhizal tree seedlings). The stunted seedlings were either nonmycorrhizal or had extremely low levels of ectomycorrhizae, whereas nonstunted seedlings had a greater degree of ectomycorrhizal development. Stunted seedlings were deficient in phosphorus (0.07%), whereas nonstunted seedlings had sufficient phosphorus (0.15%). An application of phosphoric acid (H3PO4) to stunted seedlings increased shoot phosphorus and resulted in substantial growth improvement. The phosphorus application reduced the percentage of cull seedlings (root-collar diameter <3.2 mm) from 62% to 8%. This study also demonstrates that when a seedbed is formed on new ground, ectomycorrhizal deficiencies can occur even when ectomycorrhizal tree hosts are present in the immediate vicinity. The ectomycorrhizal deficiency in the seedlings observed in this study may have been related to restricted spore dispersal caused by insufficient rainfall that had occurred after spring fumigation. South J. App. For. 12(4):234-239.


1993 ◽  
Vol 23 (10) ◽  
pp. 2116-2125 ◽  
Author(s):  
Dwight K. Lauer ◽  
Glenn R. Glover ◽  
Dean H. Gjerstad

Herbaceous weed control studies installed by the Auburn University Silvicultural Herbicide Cooperative to examine response to methods and duration of herbaceous weed control in eight loblolly pine (Pinustaeda L.) plantations were analyzed to determine stand response through age 9. Studies were designed to compare weed control treatments with an untreated check, weed control methods (band vs. broadcast), and weed control duration (first year vs. first 2 years). Pine growth was increased by weed control on all sites. Growth was increased by an additional year of weed control (duration) on about one-half of the sites, but did not differ between band and broadcast treatments (method). Age 9 volume response above the check averaged 27.3 m3/ha for first-year weed control and 42.9 m3/ha for the first 2 years of weed control. Individual-tree height growth between ages 7 and 9 did not differ by treatment at most sites, but stand volume growth was higher with weed control at six of the eight sites. Uniformity of individual tree size, as represented by the standard deviation of DBH adjusted for dominant height, was more dependent on survival, hardwood encroachment, and level of fusiform rust stem infection, which varied by treatment and site, than on the result of herbaceous weed control per se. Growth projections made with the least intensive weed control treatment at each site indicated that on average, merchantable volume at age 22 with weed control will equal that of an age 25 stand without weed control. Largest gains were on sites where weed control increased survival.


1992 ◽  
Vol 16 (1) ◽  
pp. 40-47 ◽  
Author(s):  
Rodney L. Busby

Abstract Herbaceous weed control using Oust (sulfometuron methyl²) is economically efficient in loblolly pine (Pinus taeda L.) plantations given reasonable expectations about the long-term effect of the treatment on stand growth. Increases in the sizes of the growth increments following treatment that have been reported in the literature, and the economic returns this analysis shows are possible, indicate that investment in herbaceous weed control can be a prudent silvicultural option. South. J. Appl. For. 16(1):40-47.


1994 ◽  
Vol 18 (3) ◽  
pp. 105-109 ◽  
Author(s):  
James D. Haywood

Abstract Herbaceous weed control influenced the growth of planted loblolly pine (Pinus taeda L.) over a 10-yr-period. Five treatments were examined: (1) Untreated control: seedlings were planted in the established herbaceous vegetation; (2) Glyphosate: glyphosate was broadcast in September 1981 before planting; (3) Disked: plots were cross-disked in September 1981 before planting; (4) Glyphosate-PPWC: glyphosate was broadcast before planting as in Treatment 2, and postplant weed control (PPWC) herbicides were broadcast yearly for 4 yr (1982, atrazine plus simazine ; 1983, atrazine plus oxyfluorfen; 1984 and 1985, hexazinone ); and (5) Disked-PPWC: plots were disked before planting as in Treatment 3, and the PPWC herbicides were broadcast as in Treatment 4. Four years of PPWC did not affect survival and resulted in greater height, dbh, and volume per loblolly pine through 10 growing seasons. The disked-PPWC plots were the most productive through 8 growing seasons, but higher than average mortality after 8 yr on the disked-PPWC treatment resulted in the glyphosate-PPWC plots producing more volume per acre after 10 growing seasons. Total volume production was 253 inside bark ft³/ac greater on the two PPWC treatments than on the untreated controls. South. J. Appl. For. 18(3): 105-109.


2000 ◽  
Vol 17 (3) ◽  
pp. 95-99 ◽  
Author(s):  
J.L. Torbert ◽  
J.A. Burger ◽  
S.H. Schoenholtz ◽  
R.E. Kreh

Abstract A reforestation experiment was established to test the growth of three pine species on two different surface-mined sites in the Appalachian coalfields of southwest Virginia. One site was mined just prior to enactment of the 1977 Surface Mining Control and Reclamation Act (SMCRA), and one site was mined and reclaimed to its approximate original contour in accordance with post-SMCRA regulations. Three pine species (Pinus taeda, P. virginiana, and P. strobus) were planted on each site in 1981. A fertilization and an herbaceous weed control treatment were tested. Half the plots were fertilized with a 21 g fertilizer tablet at time of planting and a broadcast application of 50 kg/ha N as ammonium nitrate prior to the fourth growing season. Each plot was split to accommodate an herbaceous weed control treatment during the first 3 yr. After 11 yr, all three tree species grew very well on the prelaw bench site, but were less productive on the postlaw AOC site. The fastest growing species was loblolly pine, which averaged 22 ft tall. Aggressive herbaceous ground covers commonly established on surface-mined land to reduce erosion were successfully controlled by herbicides, resulting in a significant improvement in survival and growth for all tree species. Fertilization as used in this study had little effect on growth and was not as beneficial for tree establishment as the herbicide treatment. The performance of these commercial tree species in this study demonstrates that good forest management opportunities exist for the owners of surface-mined land. North. J. Appl. For. 17(3):95–99.


1990 ◽  
Vol 14 (3) ◽  
pp. 109-114 ◽  
Author(s):  
Barry D. Shiver ◽  
Bruce E. Borders ◽  
Henry H. Page ◽  
Steven M. Raper

Abstract A seedling survival study for site-prepared loblolly pine (Pinus taeda L.) plantations, consisting of 43 locations, was established during two planting seasons in 1986-87 in the Georgia Piedmont. Seedlings with top lengths less than 15 cm and with root collar diameters less than 2.5 mm survived significantly worse than larger seedlings, but such small seedlings comprised less than 2% of seedlings bagged and planted in the study. Culling in the field to eliminate such a small percentage of seedlings in addition to culling already done at the nursery is probably not worth the expense from a survival standpoint. Terminal bud condition was not related to survival. Seedlings planted deeper than root collar diameter survived the same as seedlings planted at root collar depth, but shallow planted seedlings had significantly poorer survival. Very loosely planted seedlings were more likely to die than firmly planted seedlings, but slightly loose seedlings survived as well as tightly planted seedlings. Differences between operationally planted and experimentally planted plots indicated that an average 10% increase in survival was possible from close planting crew supervision. Over 90% of first-year mortality occurred on both operationally and experimentally planted plots by the end of July. South. J. Appl. For. 14(3):109-114.


2005 ◽  
Vol 29 (3) ◽  
pp. 117-122
Author(s):  
Stephen W. Fraedrich ◽  
L. David Dwinell

Abstract Dazomet, metam sodium, and oxamyl were evaluated for nematode control and production of loblolly pine seedlings in a field infested by a Longidorus sp. Fumigation with dazomet or metam sodium reduced population densities of Longidorus to nondetectable levels early in the growing season but population densities subsequently increased to levels found in untreated control plots by the end of the growing season. Oxamyl had no effect on Longidorus population densities. Seedlings in dazomet-treated plots had significantly greater root and shoot weights than seedlings in control and oxamyl-treated plots within 6 weeks of seed sowing. At the end of the growing season, seedlings in the control and oxamyl plots were very stunted with poorly developed root systems. Seedling shoot length and root collar diameter in dazomet-treated plots averaged 27.4 cm and 4.0 mm, respectively, but in nonfumigated control plots these variables averaged 10.5 and 2.5 mm, respectively. Although dazomet and metam sodium were effective in reducing Longidorus populations for the first seedling crop after fumigation, production of a second crop without additional treatment would be inadvisable based on the increased population of Longidorus by the end of the first growing season. South. J. Appl. For. 29(3):117–122.


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