A 50-Year Retrospective of the Forest Productivity Cooperative in the Southeastern United States: Regionwide Trials

2020 ◽  
Author(s):  
David R Carter ◽  
H Lee Allen ◽  
Thomas R Fox ◽  
Timothy J Albaugh ◽  
Rafael A Rubilar ◽  
...  

Abstract In 2019, the Forest Productivity Cooperative (FPC) celebrated its 50th anniversary. The mission of the FPC is and has been creating innovative solutions to enhance forest productivity and value through the sustainable management of site resources. This industry-government-university partnership has generated seminal research with sweeping implications for increasing productivity throughout the southeastern United States and Latin America. To commemorate this semicentennial, we highlighted some of the pivotal findings in the southeastern United States from the past 50 years derived from our large, regional experiments: regionwide trials. Study Implications: Fifty years of research have yielded substantial management implications for intensively managed loblolly pine in the southeastern United States. Some of our most impactful findings are the following: our generalized fertilization rate of 200 lb ac−1 elemental N and 25 lb ac−1 elemental P has been found to increase growth on most plantations in the region when applied at or before midrotation, whereas the addition of K and micronutrients was found to be important on the Pleistocene Terraces. Stands with a leaf area index (LAI) less than 3.5 will respond to fertilization, increasingly, so the lower the initial LAI. Our long-term site preparation studies demonstrated the importance of pairing optimal site preparation with fertilization and that subsoiling and tillage typically yielded lesser gains than fertilization and vegetation control at establishment. Fertilization tends to be more important to growth responses at midrotation than onetime vegetation control treatments, but an additive response when the two treatments are applied together is generally experienced. When fertilization is paired with thinning, the rate of postthinning diameter growth is accelerated.

2007 ◽  
Vol 242 (2-3) ◽  
pp. 558-568 ◽  
Author(s):  
M. Chad Lincoln ◽  
Rodney E. Will ◽  
Lawrence A. Morris ◽  
Emily A. Carter ◽  
Daniel Markewitz ◽  
...  

2008 ◽  
Vol 32 (3) ◽  
pp. 101-110 ◽  
Author(s):  
John S. Iiames ◽  
Russell Congalton ◽  
Andrew Pilant ◽  
Timothy Lewis

Abstract Quality assessment of satellite-derived leaf area index (LAI) products requires appropriate ground measurements for validation. Since the National Aeronautics and Space Administration launch of Terra (1999) and Aqua (2001), 1-km, 8-day composited retrievals of LAI have been produced for six biome classes worldwide. The evergreen needle leaf biome has been examined at numerous validation sites, but the dominant commercial species in the southeastern United States, loblolly pine (Pinus taeda), has not been investigated. The objective of this research was to evaluate an in situ optical LAI estimation technique combining measurements from the Tracing Radiation and Architecture of Canopies (TRAC) optical sensor and digital hemispherical photography (DHP) in the southeastern US P.taeda forests. Stand-level LAI estimated from allometric regression equations developed from whole-tree harvest data were compared to TRAC–DHP optical LAI estimates at a study site located in the North Carolina Sandhills Region. Within-shoot clumping, (i.e., the needle-to-shoot area ratio [γE]) was estimated at 1.21 and fell within the range of previously reported values for coniferous species (1.2–2.1). The woody-to-total area ratio (α = 0.31) was within the range of other published results (0.11–0.34). Overall, the indirect optical TRAC–DHP method of determining LAI was similar to LAI estimates that had been derived from allometric equations from whole-tree harvests. The TRAC–DHP yielded a value 0.14 LAI units below that retrieved from stand-level whole-tree harvest allometric equations. DHP alone yielded the best LAI estimate, a 0.04 LAI unit differential compared with the same allometrically derived LAI.


2020 ◽  
Vol 12 (9) ◽  
pp. 1406 ◽  
Author(s):  
Chris W. Cohrs ◽  
Rachel L. Cook ◽  
Josh M. Gray ◽  
Timothy J. Albaugh

Leaf area index (LAI) is an important biophysical indicator of forest health that is linearly related to productivity, serving as a key criterion for potential nutrient management. A single equation was produced to model surface reflectance values captured from the Sentinel-2 Multispectral Instrument (MSI) with a robust dataset of field observations of loblolly pine (Pinus taeda L.) LAI collected with a LAI-2200C plant canopy analyzer. Support vector machine (SVM)-supervised classification was used to improve the model fit by removing plots saturated with aberrant radiometric signatures that would not be captured in the association between Sentinel-2 and LAI-2200C. The resulting equation, LAI = 0.310SR − 0.098 (where SR = the simple ratio between near-infrared (NIR) and red bands), displayed good performance ( R 2 = 0.81, RMSE = 0.36) at estimating the LAI for loblolly pine within the analyzed region at a 10 m spatial resolution. Our model incorporated a high number of validation plots (n = 292) spanning from southern Virginia to northern Florida across a range of soil textures (sandy to clayey), drainage classes (well drained to very poorly drained), and site characteristics common to pine forest plantations in the southeastern United States. The training dataset included plot-level treatment metrics—silviculture intensity, genetics, and density—on which sensitivity analysis was performed to inform model fit behavior. Plot density, particularly when there were ≤618 trees per hectare, was shown to impact model performance, causing LAI estimates to be overpredicted (to a maximum of X i + 0.16). Silviculture intensity (competition control and fertilization rates) and genetics did not markedly impact the relationship between SR and LAI. Results indicate that Sentinel-2’s improved spatial resolution and temporal revisit interval provide new opportunities for managers to detect within-stand variance and improve accuracy for LAI estimation over current industry standard models.


2001 ◽  
Vol 25 (2) ◽  
pp. 69-74 ◽  
Author(s):  
Bruce E. Borders ◽  
Robert L. Bailey

Abstract With mean annual increments up to 5.4 cords/ac/yr, six loblolly pine (Pinus taeda L.) research sites in Georgia produced yields on par with other results from intensively managed loblolly plantations around the world. Cultural treatments in the Georgia study include complete control of vegetation other than the planted pines with multiple applications of herbicide, annual fertilization, the combination of complete vegetation control and annual fertilization, and an intensive mechanical site preparation treatment. Complete vegetation control resulted in higher yield production at ages 10 to 12 yr than the intensive mechanical treatment at all locations. This regime also resulted in higher yield production than the annual fertilization treatment at four of six locations. Volume mean annual increment for 10- to 12-yr-old plantations with the combination treatment of complete vegetation control and annual fertilization ranged from 325 to 490 ft3/ac, growth rates comparable to those obtained at other high biomass production areas throughout the world. Our economic evaluation based on these results shows that 8 to 12% real rates of return are feasible from investments in intensive loblolly pine plantations in the southeastern United States. South. J. Appl. For. 25(2):69–74.


2012 ◽  
Vol 86 (2) ◽  
pp. 287-298 ◽  
Author(s):  
Andres Susaeta ◽  
Pankaj Lal ◽  
Janaki Alavalapati ◽  
Evan Mercer ◽  
Douglas Carter

1992 ◽  
Vol 22 (6) ◽  
pp. 785-789 ◽  
Author(s):  
Thomas H. Green ◽  
Patrick J. Minogue ◽  
Charles H. Brewer ◽  
Glenn R. Glover ◽  
Dean H. Gjerstad

Absorption and translocation patterns of radio-labelled glyphosate (N-(phosphonomethyl)glycine) were examined in four species of woody plants to determine mechanisms of herbicide tolerance in species common to the southeastern United States. Loblolly pine (Pinustaeda L.) and yaupon (Ilexvomitoria (L.) Ait.), both tolerant to the herbicide, absorbed significantly less glyphosate than did red maple (Acerrubrum L.) or white oak (Quercusalba L.), indicating the importance of foliar absorption as a barrier to glyphosate entry. Although herbicide absorption was similar between the sensitive white oak and the tolerant red maple, white oak accumulated more glyphosate in the roots than did red maple, indicating that translocation patterns also contribute significantly to glyphosate tolerance in some woody species.


Weed Science ◽  
1990 ◽  
Vol 38 (6) ◽  
pp. 497-503 ◽  
Author(s):  
John R. Britt ◽  
Bruce R. Zutter ◽  
Robert J. Mitchell ◽  
Dean H. Gjerstad ◽  
John F. Dickson

Three herbaceous regimes were established, using herbicides, to examine the effects of interference on growth and biomass partitioning in loblolly pine (Pinus taedaL.). Trees were sampled near Auburn and Tallassee, AL. Trees at the Auburn site grown with low weed interference (LWI) had 4, 10, 10, 8, and 4 times greater total aboveground biomass than did trees with high weed interference (HWI) for ages one through five, respectively. Medium weed interference (MWI, Auburn site only) resulted in three times greater biomass the first 4 yr and two times greater total biomass by the fifth year compared to trees grown with HWI. Trees growing with LWI were 5, 8, 10, and 6 times larger than those with HWI for ages one through four, respectively, at the Tallassee site. At all levels of interference, the percentage of total biomass in foliage decreased, and stem and branch components increased, with increasing tree size at both sites. Trees growing with HWI had a lower percentage of total biomass in foliage and a greater percentage of total biomass in stem than those growing with LWI when compared over a common size. Growth efficiency per tree, expressed as annual increase in stem biomass per unit leaf area (g m−2), was slightly greater for trees growing with LWI compared to HWI when leaf area index (LAI3, total surface) was less than 0.2. For LAI values greater than 0.2 the relationship was reversed. The latter contradicts the idea that growth efficiency can be used as a measure of vigor for young loblolly pine. Changes in carbon partitioning to the development of leaf area are suggested to be driving the accelerated growth responses associated with a reduction of weed interference.


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