Recent Research Indicates Plant Community Responses to Intensive Treatment Including Chemical Amendments

1989 ◽  
Vol 13 (3) ◽  
pp. 152-156 ◽  
Author(s):  
Benee F. Swindel ◽  
Joel E. Smith ◽  
Daniel G. Neary ◽  
Nicholas B. Comerford

Abstract Plant community responses to several factors (planted species, competition control, and nutrients) that influence stand development were tested in a factorial experiment on a flatwoods Spodosol. A moisture gradient across replications, augmented by irrigation, permitted testing of afourth factor (moisture regime). There were differences between slash pine (Pinus elliottii var. elliottii Engelm.) and loblolly pine (Pinus taeda L.) crown development, but no response to moisture gradient. Pines and other plants responded dramatically to continuing competition control andrepeated fertilization. Nonpine crown cover was reduced from 100% on plots without herbicides to less than 10% on treated plots. Pine crown cover at 5 years averaged 73% with both fertilization and competition control versus 11% on control plots. Both pine and nonpine cover changed significantlyacross bed, furrow, and interbed niches, and niche interacted with chemical (fertilizer and herbicide) treatment. Competition control dramatically reduced plant species richness; modal number of species observed on 5 m transects was reduced from 10 on plots without herbicides to 2 on plotsrepeatedly treated. South. J. Appl. For. 13(3):152-156.

1987 ◽  
Vol 11 (2) ◽  
pp. 91-95 ◽  
Author(s):  
Catherine G. Bacon ◽  
Shepard M. Zedaker

Abstract The growth response of young loblolly pine (Pinus taeda L.) to different amounts of competition control was studied in plantations of three ages in the Virginia Piedmont. Eight competition control treatments involved the removal of all, two-thirds, one-third, or none of the hardwoodstems either with or without herbaceous weed control. Results after three growing seasons showed a significant increase in pine diameter and volume growth with competition control. Treatments combining woody and herbaceous control resulted in better pine growth than the same treatments withoutherbaceous control, in the two youngest stands. The best response, obtained with the two-thirds woody plus herbaceous control treatment, resulted in: a 100% increase in volume growth over the check plots in seedlings treated at the beginning of their second growing season in the field; a 93% increase in one-year-old seedlings; and a 53% increase in the growth of seedlings treated before the third growing season. South. J. Appl. For. 11(2):91-95.


1988 ◽  
Vol 12 (4) ◽  
pp. 259-261 ◽  
Author(s):  
J. David Lenhart ◽  
W. Thomas McGrath ◽  
Terry L. Hackett

Abstract Five surveys of pine plantations in East Texas over an 18-year period (1969-1987) indicated that fusiform rust (Cronartium quercuum [Berk.] Miyabe ex Shirai f. sp. fusiforme Birdsall and Snow) infection rates have increased to current levels of about 50% on slash pine (Pinus elliottii Engelm.) and are continuing to increase on loblolly pine (Pinus taeda L.) to 10-15% levels. South. J. Appl. For. 12(4):259-261.


1993 ◽  
Vol 17 (3) ◽  
pp. 135-138 ◽  
Author(s):  
Eric J. Jokela ◽  
Stephen C. Stearns-Smith

Abstract Data from six fertilizer trials established in semimature southern pine stands (five slash pine, Pinus elliottii Engelm. var. elliottii; one loblolly pine, Pinus taeda L.) were analyzed to determine the efficacy of single vs. split fertilizer treatments. Both fertilizer treatments supplied an elemental equivalent of 200 lb nitrogen (N)/ac and 50 lb phosphorus (P)/ac; however, the first treatment was delivered as a single dose, and the second treatment was a split N application (i.e., 50 lb N and 50 lb P/ac (initial); 150 lb N/ac (2 yr later). Cumulative responses of fertilized plots were still significantly greater than the controls in five trials after 8 yr and averaged 43% (15.7 ft²/ac) and 39% (607 ft³/ac) for basal area and stand volume growth, respectively. In general, no significant differences in either the magnitude or duration of response were detected between the single and split N fertilizer treatments. This suggests that delaying a portion of the N application for 2 yr will not diminish the level of growth responses attained. Therefore, land managers have flexibility in using either application method when implementing midrotation fertilizer prescriptions. South. J. Appl. For. 17(3):135-138.


1986 ◽  
Vol 10 (2) ◽  
pp. 109-112 ◽  
Author(s):  
J. David Lenhart ◽  
Ellis V. Hunt ◽  
Jock A. Blackard

Abstract Equations to estimate site index (index age 25 years) for plantations of loblolly pine (Pinus taeda L.) and slash pine (Pinus elliottii Engelm.) on non-old-fields in East Texas have been developed. The height-prediction curves were based on the Richards' growth function and track well within the range of the data (1-17 years). South. J. Appl. For. 10:109-112, May 1986.


2003 ◽  
Vol 33 (6) ◽  
pp. 1076-1083 ◽  
Author(s):  
Gregory T Munger ◽  
Rodney E Will ◽  
Bruce E Borders

To determine the importance of competition control and annual fertilization on leaf gas exchange, light-saturated net photosynthesis (Asat), stomatal conductance (gs), and internal CO2 concentration (Ci) were measured multiple times in different-aged loblolly pine (Pinus taeda L.) stands growing at a Piedmont (BF Grant) and Coastal Plain (Waycross) location in Georgia, U.S.A. At both locations, competition control decreased Asat and gs (Asat from 4.53 to 4.12 µmol·m–2·s–1, gs from 0.058 to 0.050 mol·m–2·s–1 at BF Grant; Asat from 4.22 to 4.01 µmol·m–2·s–1, gs from 0.054 to 0.049 mol·m–2·s–1 at Waycross). Overall, fertilization did not have a positive impact on Asat, even though fertilization significantly increased foliar nitrogen concentration. At BF Grant, fertilization significantly decreased gs from 0.057 to 0.051 mol·m–2·s–1 and Ci from 217 to 205 µmol·mol–1. In addition, the decrease in Ci associated with fertilization became larger with stand age. At Waycross, fertilization decreased Ci from 211 to 203 µmol·mol–1 and the interaction between fertilization and stand age was significant for gs and Ci. These results indicate that silivcultural practices that increase resource availability and stand growth did not enhance leaf gas exchange.


1989 ◽  
Vol 13 (4) ◽  
pp. 204-207 ◽  
Author(s):  
Bruce E. Borders ◽  
William M. Harrison

Abstract Age 8 measurements and analysis are reported and discussed for a large side-by-side loblolly pine (Pinus taeda L.)/slash pine (Pinus elliottii Engelm.) species comparison study. It is shown that loblolly pine performed better than slash pine in CRIFF soil groups A, D, F, and G whileslash pine and loblolly pine performed similarly in CRIFF soil groups B and C. South. J. Appl. For. 13(4):204-207.


1989 ◽  
Vol 13 (1) ◽  
pp. 5-8 ◽  
Author(s):  
Robert S. Hansen ◽  
M. Victor Bilan

Abstract Age accounted for over 70% of the variation in tree height of 10- to 44-year-old loblolly pine (Pinus taeda L.) and slash (Pinus elliottii Engelm.) plantations established on deep sands, moderate sands, and nonsandy soils in the Northern Post-Oak Belt of Texas. Climatic and edaphicfactors, relating either directly or indirectly to the amount of moisture available for tree use, explained up to 17% of height growth variation. Height growth of the plantations was comparable to that of plantations growing in the pine-mixed hardwood forest cover type of East Texas. The NorthernPost-Oak Belt of Texas is an area approximately 50 to 100 miles wide located between the pine-mixed hard-wood forest type to the east and the black-land prairie to the west. Soils within the belt belong primarily to the Alfisol or Ultisol soil orders. The western-most areas of the belt receiveup to 20% less annual rain fall than the pine-mixed hardwood type of East Texas (U.S. Environmental Data and Information Service 1949-1982). The present forest of this area is dominated by post oak (Quercus stellata Wang.), black-jack oak (Quercus Marilandica Muench.), bluejack oak (Quercusincana Bartr.), and black hickory (Carya texana Buckl.) (Ward 1984). Loblolly pine (Pinus taeda L.) and shortleaf pine (Pinus echinata Mill.) occur naturally only in scattered locations (Wilson and Hacker 1986). South. j. Appl. For. 13(1):5-8.


2002 ◽  
Vol 26 (4) ◽  
pp. 173-180 ◽  
Author(s):  
Michael D. Cain ◽  
James P. Barnett

Abstract Genetically improved, container loblolly pine (Pinus taeda L.) seedlings were compared to naturally established loblolly seedlings on a cutover pine site. Crop pines on 6 of 12 plots were released from woody and herbaceous competition within a 2 ft radius of each stem. On release plots, woody competition was controlled by hand-cutting for 5 consecutive yr and herbaceous competition was controlled with herbicides for 4 consecutive yr after pine establishment. Competition control increased 12 yr survival by 68 percentage points for natural pines and by 47 percentage points for planted pines. Twelve years after field establishment, mean-tree volume of planted pines was no different than that of naturally established pines. Nevertheless, volume gains of 150% to 200% were achieved within regeneration techniques as a result of release. South. J. Appl. For. 26(4):173–180.


1999 ◽  
Vol 29 (7) ◽  
pp. 1065-1072 ◽  
Author(s):  
Lisa E Schabenberger ◽  
Shepard M Zedaker

This study was established to determine the effects of competition control on loblolly pine (Pinus taeda L.) yield and woody plant diversity in Virginia Piedmont plantations 12-14 years of age. In a factorial experiment, loblolly pine and competing woody vegetation were analyzed at eight levels of competition control: total, two-thirds, one-third, or no woody stem control in combination with either total or no herbaceous vegetation control. Pine yield increased linearly with increasing levels of woody control intensity. As woody control increased, noncrop woody plant basal area and woody plant diversity (Shannon index (H')) in the canopy decreased. Woody plant species richness in the canopy was reduced by herbaceous control and by total woody control. Percent woody cover, H', and species richness in the understory were not affected at any level of competition control. Regression analysis was used to examine relationships between loblolly pine yield, noncrop woody dominance and canopy plant diversity (H'). Pine yield was negatively correlated (R2 = 0.74) with the percentage of noncrop woody basal area (PNCW BA) in the canopy, while canopy diversity was proportional to PNCW BA (R2 = 0.97). Canopy diversity was inversely related to pine yield (R2 = 0.77), with a high trade-off in diversity at low yield levels, but with decreasing sensitivity as pine yield increased.


2019 ◽  
Author(s):  
Jesse Miller ◽  
Hugh Safford

Ecological disturbance is a major driver of ecosystem structure and evolutionary selection, and theory predicts that disturbance frequency and / or intensity should determine its effects on communities. However, adaptations of species pools to different historical disturbance regimes are rarely considered in the search for generalizable community responses to disturbance. To explore how disturbance severity affects plant diversity patterns, we review studies of understory plant community responses to wildfire in conifer forests of western North America across a gradient of departure from historical fire regimes. We find that post-fire plant species richness may generally be maximized at disturbance severities that match the predominant historical disturbance regime in a given ecosystem. Studies that examined multiple spatial scales indicate that plant community responses to fire are likely to be scale-dependent, suggesting that post-disturbance monitoring should consider community responses at multiple scales. Our review highlights that considering adaptations to historical disturbance regimes may improve the ability to predict disturbance effects on communities. We discuss future research needs; quantitative studies that compare community responses to fire at multiple scales across different historical fire regimes would be particularly useful. Ultimately, considering disturbance as a multivariate problem is likely to lead to greater inference than traditional bivariate approaches.


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