Chapter 8.

The Evolution of Pine Plantation Silviculture in the Southern United States

Thomas R. Fox, Eric J. INTRODUCTION 1 Jokela, and H. Lee Allen ine (Pinus spp.) plantation silviculture in the Southern United States is one of the major P success stories for forestry in the world. In 1952, there were only 1.8 million acres of pine Abstract—In the 1950s, vast acreages of cutover plantations in the South (fig. 8.1), containing 658 63 forest land and degraded agricultural land existed million cubic feet of timber (U.S. Department in the South. Less than 2 million acres of southern of Agriculture, Forest Service 1988). At the turn pine plantations existed at that time. By the end of the 21st century, there are 32 million acres of of the 20th century, there were 32 million acres of pine plantations in the South that contain 23.9 southern pine plantations in the Southern United billion cubic feet of timber (Wear and Greis 2002). States, and this region is now the woodbasket Perhaps more remarkable is the significant of the world. The success story that is southern increase in productivity that occurred during pine forestry was facilitated by the application of this period (fig. 8.2). Mean annual increment of research results generated through cooperative pine plantations has more than doubled, and work of the U.S. Department of Agriculture Forest rotation lengths have been cut by > 50 percent. Service, southern forestry schools, State forestry The success of pine plantation silviculture has turned the South into the woodbasket of the agencies, and forest industry. This chapter reviews United States (Schultz 1997). the contributions of applied silvicultural research in land classification, tree improvement, nursery These remarkable changes in the last 60 years management, site preparation, weed control, and were the result of a variety of factors that came fertilization to plantation forestry in the South. together at the end of World War II. Economic These practices significantly increased productivity factors, including a declining agricultural economy coupled with a rapidly expanding pulp and paper of southern pine plantations. Plantations established industry based on southern pine, combined to in the 1950s and 1960s that produced < 90 cubic provide the impetus for the large increase in feet per acre per year have been replaced by southern pine plantations. The success of this plantations established in the 1990s that are effort was due in large part to the cooperative producing > 400 cubic feet per acre per year. research and technology transfer efforts of many Southern pine plantations are currently among organizations, including the U.S. Department of the most intensively managed forests in the world. Agriculture Forest Service (Forest Service), State Growth of plantations managed using modern, forestry agencies, forestry programs at southern integrated, site-specific silvicultural regimes rivals universities, and forest industry. that of plantations of fast-growing nonnative The objectives of this chapter are to describe species in the Southern Hemisphere. Additional the evolution of southern pine plantation gains in productivity are likely as clonal forestry silviculture over the last 50 years and to outline is implemented in the South. Advances in forest our view of the current state of the art of pine biotechnology will significantly increase growth plantation silviculture in the South. Rather than and quality of future plantations. It appears likely present an exhaustive review of the literature, that the South will remain one of the major wood-producing regions of the world. 1 Associate Professor of Forestry, Virginia Polytechnic Institute and State University, Department of Forestry, Blacksburg, VA 24061; Professor of Forestry, University of Florida, School of Forest Resources and Conservation, Gainesville, FL 32611; and C.A. Schenck Distinguished Professor of Forestry, North Carolina State University, Department of Forestry, Raleigh, NC 27695, respectively. Southern Forest Science: 64 Past, Present, and Future Productivity was aserious problem associatedwithproduction in theState,hadbeencleared by1860.Soilerosion million acres,or47percent ofthetotallandarea of theCivilWar (Williams 1989).InVirginia >25 C FORESTRY INTHESOUTH SETTING THESTAGE FORPLANTATION has madetothissuccessstory. contributions thatappliedcoop-erativeresearch part ofthis,wehopetodemonstratethesignificant duringthistime (fig.8.3).As have beenobserved their contributiontotheproductivitygainsthat advances duringthelast50yearsandillustrate we willhighlightwhatbelievearethemajor from 1940through 2010. Southern United States plantations inthe productivity inpine management practices to contributions of intensive Figure 8.3—Estimated from 1940through 2010. Southern United States plantations inthe rotation age inpine total yieldandpulpwood Figure 8.2—Estimated Wear andGreis 2002). Agriculture 1988, Department of 1999 (data from U.S. States from 1952to in theSouthernUnited acres of pineplantations Figure 8.1—Numberof from thecolonialperioduntil thebeginning throughout theCoastalPlain andPiedmont learing offorestsforcropproduction occurred

Volume at harvest Plantation area (tons per acre) Total yield (tons per acre) (million acres) 100 150 200 250 100 150 200 250 10 15 20 25 30 35 50 50 0 5 0 0 9015 9017 9019 002010 2000 1990 1980 1970 1960 1950 1940 9015 9017 9019 002010 2000 1990 1980 1970 1960 1950 1940 9216 9017 951999 1985 1977 1970 1962 1952 Fertilization Weed control Tree improvement Clonal andbiotech Total yield Establishment period virginiana Mill.) andshiptimbersfrom liveoak( were navalstoresfromlongleaf pine( forests the firstmajorproductsfrom southern (Williams 1989).Other thantimberforlocaluse, timber andforestproducts since colonialtimes Civil War andWorld War II. throughout theSouthbetweenendof amounts ofagriculturallandtobeabandoned ( crops andpestproblemssuchasthebollweevil due toerosion,accompaniedbylowpricesforcash South (Bennett1939).Decliningsoilproductivity important agriculturalcropsthroughoutthe of cottonandtobacco,whichwerethemost Anthonomus grandis The Southhasbeenanimportantsourceof Year Pulpwood rotationage Year Natural stand Planting Site preparation Miller)(Butler 1998,Williams 1989). ), causedlarge 0 10 20 30 40 50 60 Quercus P. palustris Rotation age (years) The production of lumber in the South increased Commenting on the situation in the 1950s, gradually following the Civil War and more Wahlenberg (1960) stated, “Much land suitable dramatically beginning in the 1880s and 1890s, for loblolly pine that has been made unproductive when available timber in the Lake States was through heavy cutting, wildfire, natural depleted. Between 1890 and 1920, the South was catastrophe, or abandonment of agriculture is in the major lumber-producing region in the country. need of planting.” Wakeley (1954) estimated that Production peaked at approximately 140 billion there were 13 million acres of land requiring board feet in 1909, when the South produced 46 planting in the South in 1950. percent of all timber cut in the United States Tree planting in the South, which had nearly (Williams 1989). After 1909, lumber production ceased during World War II, rapidly increased in declined gradually until the start of the Great the years immediately following the war (U.S. Depression in 1929, when production fell sharply. Department of Agriculture, Forest Service 1988). The discovery by Charles Herty that acceptable A large percentage of this planting occurred on pulp and paper could be made from southern farmland associated with the Soil Bank Program 65 pine had a dramatic impact on southern forestry of the 1950s. The successful reforestation of beginning in the 1930s (Reed 1995). A rapid abandoned and degraded agricultural land increase in the pulp production in the South illustrated the conservation value of trees and followed this discovery (Josephson and Hair 1956). their role in reducing soil erosion and improving Numerous pulp and paper mills were constructed water quality (Bennett 1939). The rapid expansion throughout the South during the 1930s, increasing of the pulp and paper industry in the South during 8. Chapter the demand for smaller diameter southern pine the 1930s increased the demand for pine pulpwood timber. Pulp and paper companies purchased large and stimulated planting on forest industry land. tracts of timberland during this period to provide By this time, the superior growth and yield of pulpwood for these new facilities (Williams 1989). pine plantations relative to naturally regenerated stands had become evident. For example, the At the start of the 20th century, almost no effort original plantations established by Great Southern was devoted to reforestation following timber Lumber Company clearly showed the potential Silviculture Pine Plantation harvest (Williams 1989). Destructive fires often value of fully stocked plantations compared to the followed logging, killing much of the natural poorly stocked naturally regenerated stands that regeneration that might otherwise have become were the norm at the time (Wakeley 1954). established on many cutover tracts. During the 1920s, the Forest Service recognized the need NURSERY PRACTICES AND for large-scale tree planting in the South and SEEDLING HANDLING began a research program to address reforestation issues. The first large-scale planting of southern rtificially regenerating the large pine occurred between 1920 and 1925 when the acreages found in the South required an Great Southern Lumber Company planted A abundant supply of high-quality seedlings. A approximately 7,000 acres near Bogalusa, LA concerted research effort of the Forest Service on (Wakeley 1954). During the 1920s, the Forest reforestation in the South began in the 1920s and Service also began its reforestation program in culminated with the publication of Agricultural the South with the planting of 10,000 acres in the Monograph 18 “Planting the Southern Pine” Sumter National Forest in South Carolina. During (Wakeley 1954). This classic publication provided the 1930s, the Civilian Conservation Corps planted foresters detailed information on seed collection > 1.5 million acres across the South. The success and processing, seedling production, and planting of these early efforts demonstrated the feasibility practices needed to successfully establish southern of establishing pine plantations. pine plantations. With its publication, the stage was set for the rapid expansion of southern THE ADVENT OF PLANTATION FORESTRY pine seedling production. In 1950, the Forest Service, the Soil Conservation Service, the t the end of World War II, the legacy of Tennessee Valley Authority, and all States in abusive agricultural practices that had the South operated forest nurseries to produce A degraded soil productivity to the point where pine seedlings for reforestation activities on crop production was no longer profitable, coupled public and private land (U.S. Department of with exploitative timber harvesting without Agriculture, Forest Service 1949). Many industrial provision for regeneration, left the South with a organizations also began to establish or expand substantial acreage of land requiring reforestation. nurseries to meet their seedling needs at this time. Southern Forest Science: 66 Past, Present, and Future Productivity high-quality seed fromdesirablesources (Squillace the 1950swas theabsenceofreliablesupplies of Tree ImprovementandGenetic Gain commonly >90percent. ratesforplantedseedlings tolevels survival transport, storage,andplanting,haveincreased proper careandhandlingofseedlingsduring practices,togetherwith improved nursery i.e., priortoDecember(South2000).Today, were planteddeeperandearlierintheseason; whenlargerseedlings and growthalsooccurred planting siteingoodcondition.Improvedsurvival atthe in makingcertainthatseedlingsarrive was probablythesinglemostimportantfactor transport, nowwidespreadthroughouttheSouth, use ofrefrigeratedvansforseedlingstorageand 1982, U.S.DepartmentofAgriculture1989).The andgrowthofseedlings(Dierauf initial survival were foundtobethecriticalfactorsensuring andtransporttotheplantingsite during lifting Cline 1991).Propercareandhandlingofseedlings better evaluateseedlingquality(Johnsonand as rootgrowthpotentialwerealsodevelopedto diameter (South2000),physiologicalcriteriasuch withroot-collar still probablybestcorrelated is and South1991).Althoughseedlingsurvival size andqualityoftheseedlingsproduced(Mexal seedling nurseries,substantiallyimprovingthe into standardoperatingproceduresatmostpine inoculation,wereincorporated and mycorrhizal increasingnitrogen(N)fertilization, root pruning, beddensity,groups, reducingnursery toppruning, as sowingseedbysizeclassandsinglefamily practices,such (Carlson 1986).Improvednursery important factorsaffectingseedlingperformance order lateralroots,weredemonstratedtobe including root:shootratioandthenumberoffirst- seedling quality. Rootcharacteristicsofseedlings, practicesand placed onimprovingnursery Cooperative in1970highlightstheimportance ForestSouthern Management Nursery oftheAuburn improved seed.Theformation relative scarcityandhighcostofgenetically received considerableattentionbecauseofthe were thoughttobedifficultcontrol,theproblem suchasweather,survival, insects,anddisease, Although manyofthefactorsaffectingseedling during the1950s,1960s,and1970s(Dierauf1982). was acontinuingproblemthroughouttheSouth However,with seedlingsurvival. seedlingsurvival and needlecharacteristicsthatwerecorrelated on seedlingheight,root-collardiameter, andstem pineseedlingsbased grading systemforsouthern A majorlimitationonseedling productionin Wakeley (1954)developedawidelyused Engelm. var. Program began establishingslashpine( Florida CooperativeForest Genetics Research 1953). Industrialmembers of theUniversity drought-hardy loblollypine ( by theTexas Forest in1952toproduce Service pineseedorchardwasestablished first southern pineseed(Zobelandothers1958).The southern methodofproducing and becamethepreferred Research Council1999). Industrial ForestUniversity in1956(Southern of Floridain1953andNorthCarolinaState cooperatives weresoonfoundedattheUniversity the South.Additional treeimprovementresearch cooperative programsatuniversitiesthroughout result oftheappliedresearchconductedthrough wasinlargepartadirect pine plantationforestry plantation forestry. Thefuturesuccessofsouthern pine cooperative wasamajoreventinsouthern appliedresearch university-Government Talbert ofthisindustry- 1984).Theformation improvement programintheSouth(Zobeland thefirsttree products companies,formed andincooperationwith14forest Service Zobel,onbehalfoftheTexasBruce Forest economically justified(Perry andWang 1958). costs associatedwithseedorchardscouldbe recognized whenitwasdemonstratedthatthe of geneticallyimprovedseedwasfinally (Lindquist 1948,Schreiner1950).Thevalue improvement inforesttreesstartedtoemerge as evidencesupportingthevalueofgenetic 1954). Thisviewbegantochangeinthe1950s pine(Wakeleygains inthegrowthofsouthern selection andbreedingwouldleadtosignificant widely acceptedthatgeneticimprovementthrough use (Perry andWang 1958),becauseitwasnot was initiallyamajorobstacletotheirwidespread cost ofestablishingandmanagingseedorchards genetically improvedseed(Bates1928).Thehigh early asthelate1920smeansofproducing phenotypes (Goddard1958). established innaturalstandscontaininggood supply ofcones,seedproductionareaswereoften 1954). Inordertoprovideamoreconsistent felled duringloggingofnaturalstands(Wakeley seed wasobtainedfromconescollectedtrees for reforestation(McCall1939).At thattime,most 100 milesoftheplantingsite,wasrecommended 1944). Therefore,useoflocalseed,collectedwithin sources outgrowingmoredistant(Wakeley pine,withlocal known toaffectgrowthofsouthern 1989). Geographicvariationinseedsourceswas The seedorchardconceptquicklygainedfavor The seedorchardconceptwasproposedas elliottii ) seedorchards in1953(Wang P. taeda L.) (Zobel P. elliottii and Perry 1957). By 1987, > 9,700 acres of seed Initially, little site preparation was done because orchards had been established in the South, and of the cost (Shoulders 1957). However, the need > 85 percent of the trees planted in the South for site preparation was highlighted by the failure originated from improved seed produced in seed of many plantations established on cutover sites, orchards (Squillace 1989). which was in stark contrast to the success of plantations established on old agricultural fields Tree improvement programs in the South and grassy savannas. The old-field effect on focused primarily on improving volume growth, improved survival and growth was attributed to tree form, disease resistance, and wood quality various factors, including low levels of competing (Dorman 1976, Zobel and Talbert 1984). Because of hardwood vegetation, improved soil physical the length of time required for tree breeding and properties, and improved soil fertility due to testing, the gains in wood production due to tree residual fertilizer and lime. Therefore, the aim improvement were not fully realized for several of site preparation was to re-create these old- decades (Todd and others 1995, Zobel and Talbert field conditions on cutover sites using various 1984). Seed from first-generation seed orchards 67 mechanical means such as anchor chaining, became available in large quantities in the 1960s chopping, burning, root raking, shearing, and and early 1970s. When these plantations matured disking. Mechanical site preparation practices in the 1980s, they produced 8 to 12 percent more often evolved more rapidly through trial and volume per acre at harvest than trees grown error by field foresters and equipment from wild seed (Squillace 1989). The increased

manufacturers than through formal research 8. Chapter financial value of plantations established with and development efforts. first-generation improved seed probably exceeded 20 percent when gains from other traits such as The most consistent thread in the stem straightness, disease resistance, and wood development of site preparation practices density were included (fig. 8.4) (Todd and others on upland cutover sites in the South was the 1995). Continued breeding and testing led to the need to control competing hardwood vegetation development of second-generation orchards in (Haines and others 1975). Roller-drum choppers

1980s. Second-generation seed orchards currently were introduced as a site preparation tool Silviculture Pine Plantation produce more than 50 percent of the seed in in the middle 1950s and quickly gained the South. It is estimated that volume growth popularity. Chopping, especially when followed in current plantations will be 14 to 23 percent by prescribed fire, reduced logging slash and greater than in plantations established using first- residual nonmerchantable stems and, thus, generation material (fig. 8.4) (Li and others 1997). improved access to the site for planting (Balmer and Little 1978). However, chopping did not MECHANICAL SITE PREPARATION effectively control competing hardwood efore the 1950s, planting was generally vegetation. Disk harrows were first employed limited to old fields and grassy savannas in the late 1950s to provide soil tillage similar to B that originated on cutover sites following that found in old fields and to control hardwood frequent wildfires. Most cutover pine sites in the sprouting. However, the level of hardwood South were regenerated after harvest by leaving control achieved following harrowing was often six to eight seed trees per acre (Duzan 1980). Unfortunately many of these stands failed to 60 regenerate pine adequately due to competition 50 from hardwoods. The inconsistent results obtained with natural regeneration led to trials 40 with clearcutting and planting. Foresters faced 30 considerable obstacles in their attempt to convert 20 these natural stands of mixed pine and hardwoods to plantations after harvest. Lack of markets for 10 low-grade hardwoods often led to poor utilization gain value volume Percent

compared to natural population compared to natural 0 that left large numbers of nonmerchantable stems NaturalFirst Second and heavy logging slash on the site. This inhibited generation generation Control planting and, coupled with the rapid regrowth of Open pollinated pollinated hardwoods, led to poor survival and growth of Figure 8.4—Growth increases in southern pine seedlings planted in the rough. plantations due to tree improvement practices in the Southern United States (adapted from Li and others 1997, Todd and others 1995). Southern Forest Science: 68 Past, Present, and Future Productivity (Terry andHughes1978). andgrowthofplantedseedlings improved survival and reduced soildisturbanceduring harvesting, removed excesswaterand, thus,improvedaccess, primary, secondary, andthird-stageditchesthat sophisticateddrainagesystemsincluding construct and early1970s.Largedraglineswereusedto Atlantic andGulfCoastal Plaininthelate1960s widespread drainageofforestedwetlandsinthe 1,300 percent(Terry andHughes1975), ledtothe of studies,rangingfrom80percenttoalmost pines followingdrainagereportedinanumber The phenomenalgrowthresponseofplanted (Maki 1960,MillerandMaki1957,Schlaudt1955). adjacent todrainagecanalswasclearlyevident improved growthofloblollyandslashpineplanted North Carolinainthelate1930s.By1950s intheHofmannForestSouth occurred ineastern inthe large-scale drainageprojectforforestry production (Wooten andJones1955).Thefirst of removingexcesswaterfromwetsitesforcrop intensive drainageclearlydemonstratedthevalue swamps intoproductiveagriculturallandsthrough planted seedlings.Thewidespreadconversionof andgrowthof tables greatlyaffectedsurvival of poorlydrainedsoilswithhighseasonalwater the controlofcompetingvegetation,presence with in thePiedmont.Inadditiontoconcerns different setofproblemsthantheircounterparts cutoversitesintooldfields. turning achieved theholygrailofsitepreparation— sprouting, suggestedthatforestershadfinally coupled withthegreatlyreducedhardwood planted ontheseintensivelypreparedsites, andearlygrowthofseedlings improved survival thedebrisdried.The after were thenburned harrow. Inmanycases,thewindrowsandpiles The areawasthenbroadcastdiskedwithalarge into thepilesandwindrowsalongwithslash. raked taken, theforestfloorandtopsoilwereoften into pilesandwindrows.Unlessgreatcarewas blade. Theslashandloggingdebriswereraked were firstshearednearthegroundlineusingaKG this three-passsystem.Residualstemsandstumps 1974).Largebulldozerswereused in Crutchfield Coastal Plain(Hainesandothers1975,Wells and throughout muchofthePiedmontandupper broadcast diskingasthestandardpractice widespread useofshearing,windrowing,and desired old-fieldconditions,culminatinginthe during the1960sand1970sinpursuitof mechanical sitepreparationcontinuedtoincrease disappointing (Duzan1980).Theintensityof Foresters inthelowerCoastalPlainfaceda MANAGED PLANTATIONS ENVIRONMENTAL IMPACTS OFINTENSIVELY CONCERN OVER SUSTAINABILITY AND andgrowthofplantedseedlings. survival achieve theconditionsneededtoensuresuperior two passesofthebeddingplow, was requiredto competition. Insomecasesdoublebedding,using soil tillageandaeration,reducedshrub Effective beddingtreatmentsimprovedsurface (Duzan1980). that qualitybedswereformed conducted onsitesrequiringbeddingtoensure KG shearingandwindrowing,wasusually involving of thebeds,intensivelandclearing,often with beddinganddecreasesthequalityheight 1974).Becauseslashinterferes and Crutchfield Shoulders 1974,Terry andHughes1975,Wells compared toflat-plantedsites(McKee and onbedded based onthesuperiorgrowthobserved preparation practiceonpoorlydrainedsoils, and beddingsoonbecamethestandardsite bedding plowswereintroducedinthe1960s, seedlings (Bethume1963,Smith1966).Specialized modified toproducearaisedplantingsitefor The firstbeddingwasdonewithfireplows development ofbeddingintheCoastalPlain. (McKee andShoulders1970)ledtothe microtopography withimprovedsoilaeration The improvedgrowthofseedlingsonelevated andgrowth(Burton1971). seedling survival were saturatedduringthewinter, whichdecreased plantations ledtoextendedperiodswhenthesoils reduced evapotranspirationratesinyoung clearing (Cain1978).Evenondrainedsites, wascombinedwithintensivedebris harrowing seedlings onpoorlydrainedsoils,evenwhen andgrowthofplanted flooding limitedthesurvival sites. However, seasonallyhighwatertablesand practices evolvedmuchastheyhadonupland KG shearing,windrowing,androot-raking soils intheCoastalPlain.Chopping,burning, were majorobjectivesofsitepreparationonwet and controllingcompetinghardwoodvegetation radiata pine in New Zealand confirmed that radiata pineinNewZealand confirmed interest intheSouth.Subsequent workwith caused byheavywindrowing, stimulatedgreat intensively preparedsitesin Australia, apparently declines inradiatapine( by Keeves (1966) onsecond-rotationproductivity siteproductivity. aboutlong-term concern A report T As onuplandsites,reducingloggingdebris simulate old-fieldconditionssoongenerated both thePiedmontandCoastalPlainto he intensityofsitepreparationconductedin P. radiata D. Don)on windrowing on sandy soils induced severe nutrient regimes (Burger and Kluender 1982). In the deficiencies that would degrade site quality Piedmont, the desire to minimize soil disturbance (Ballard 1978). Foresters throughout the South during site preparation, concerns over nutrient observed the wavy height growth pattern in losses and long-term site productivity, and windrowed plantations where trees adjacent to the availability of newly developed herbicides the windrows were considerably taller than trees that effectively controlled hardwood sprouts between the windrows. A large windrow effect combined to shift most of the site preparation on growth of loblolly pine was documented in the from mechanical to chemical treatments. In the North Carolina Piedmont (Fox and others 1989, Coastal Plain, mechanical treatments were Glass 1976). Windrowing decreased site index by modified so that sites could still be bedded with 11 feet in this loblolly pine plantation. As in New larger amounts of slash and logging debris left Zealand and Australia, it was demonstrated that on site. V-blades were developed that pushed declines in growth observed on windrowed sites aside logging debris and cleared a path for bedding plows without removing organic matter were caused by nutrient deficiencies due to 69 displacement of the forest floor and topsoil from and nutrients from the site. Also, larger bedding the interior of the stand to the windrows (Morris plows were developed that cut through thick root and others 1983, Vitousek and Matson 1985). mats and residual slash while still creating well- These observations led to the search for formed beds that elevate seedlings above high alternative, less intensive site preparation water tables, thus reducing the need for treatments that would maintain site quality windrowing on poorly drained sites. 8. Chapter (Burger and Kluender 1982, Tippin 1978). The impacts of intensive forest management Nutrient losses associated with intensive on water quality have long been an important whole-tree harvesting also generated much issue in the South. The large amount of bare soil concern during this period. Nutrient budget exposed following harvest and site preparation calculations seemed to suggest that whole- often led to increased erosion on steeply sloping tree harvesting would deplete soil nutrient land in the Piedmont (Nutter and Douglass reserves, particularly such elements as calcium, 1978). The work of Coile and Schumaker (1964) Silviculture Pine Plantation and consequently degrade site quality (Ballard demonstrated the correlation between topsoil and Gessel 1983, Mann and others 1988). depth and site quality in the Piedmont. Given Numerous studies comparing conventional bole- the degraded site quality in most of the Piedmont only harvests with whole-tree harvests were caused by the past agricultural practices, installed in response to this concern. Long- additional losses of topsoil by erosion following term analysis of these studies eventually revealed harvest and site preparation were a concern. that whole-tree harvesting had no detrimental There were also concerns about the offsite effects on soil nutrient levels or site productivity environmental impacts of intensive harvesting and on most sites if the slash and logging debris were site preparation. Increased erosion and movement left on site (Johnson and Todd 1998). Where of sediment that increased turbidity in streams excessive soil disturbance during harvest and site became a major issue with the amendment of the preparation did have negative effects, ameliorative Federal Water Pollution Control Act in 1972, which treatments such as soil tillage and fertilization for the first time regulated forestry activities as restored productivity in nearly all cases (Fox 2000, nonpoint sources of pollution. Best Management Nambiar 1996). Practices (BMP) were developed in all the Southern States in response to this legislation Because long-term site productivity was to minimize soil erosion and offsite movement closely tied with organic matter and N availability, of sediment from forestry activities (Cubbage harvesting and site preparation treatments were and others 1990). These BMPs have proven to modified during the 1980s to leave as much organic be very effective at reducing nonpoint sources of matter on site as possible. The goal was to obtain pollution from forestry activities when properly the amount of soil tillage required to achieve implemented (Aust and others 1996). Although acceptable seedling survival while leaving most voluntary in most States, compliance with BMPs is of the logging slash and forest floor on site (Morris uniformly high today in forestry operations across and Lowery 1988). The link between improved the South (Ellefson and others 2001). harvest utilization and site preparation led to more integrated harvesting and site preparation Southern Forest Science: 70 Past, Present, and Future Productivity

Total volume (tons per acre) response ofpinesfollowingherbicideapplication. herbicide efficacyanddocumentthegrowth Numerous trialswereestablishedtoevaluate test herbicidessuitableforuseinforestry. in1980toidentifyand Cooperative wasformed The Auburn UniversitySilviculturalHerbicide that couldreplace2,4,5-T (Fitzgerald 1982). prepared sites,fosteredthesearchforherbicides about hardwoodsproutingonlessintensively intensively preparedmechanically, andconcerns productivityofsitesthatwere of thelong-term South. However, aboutsustainability concerns essentially ceasedforanumberofyearsinthe release treatmentsandchemicalsitepreparation was cancelledin1979.At thattime,bothhardwood andGjerstad1991). to theherbicide(Lowry species ofhardwoods,andpineswereresistant it wasinexpensivetoapplyandeffectiveonmany plantations fromcompetinghardwoods,because 2,4,5-T waswidelyusedtoreleaseyoungpine (Duzan 1980).Duringthe1960sand1970s, stands withscattered,poorlygrowingpines intolow-qualityhardwood plantations turned absence offollow-upreleasetreatments,many effectively controlhardwoodsprouting.Inthe sites, mechanicalsitepreparationalonedidnot Gjerstad 1991).Unfortunatelyonmostcutover and acceptable accesstothesite(Lowery required mechanicalmethodstoprovide because thepoorutilizationduringharvest was notwidelyusedduringthisperiod,generally was absent.However, chemicalsitepreparation field conditionswherehardwoodcompetition objectives ofsitepreparationwastocreateold- 1980, Clason1978,Duzan1980).Oneofthemain (CainandMann days ofplantationforestry T CONTROLLING COMPETING VEGETATION pine at age 8(adapted from Miller andothers1995). Figure 8.5—Effect of competition control ongrowth of loblolly 10 15 20 25 30 35 40 45 0 5 The registrationof2,4,5-T uses forforestry pines wererecognizedfromtheearliest competition ongrowthandyieldofsouthern he detrimentaleffectsofhardwood hc od ebTotal Herb Woody Check Competition control(herbicides) (Oust and others1991). in pineplantations throughouttheSouth (Minogue growing seasonwassoona widespread practice Control ofherbaceousweeds duringthefirst and others1989,Smethurst andNambiar1989). impactonpinegrowth(fig.8.5) (Glover long-term was clearthatherbaceousweed controlhada Nelson andothers1981).Bythelate1980s,it (Fitzgerald 1976,Holtandothers1973, observed following herbicideapplicationswerewidely seedlings, largeandconsistentgrowthresponses herbaceous weedswithoutdamagingyoungpine hexazinone inthe1970sthateffectivelycontrolled With theadventofnewerherbicidessuchas herbaceous vegetation(Terry andHughes1975). significantly followingcontrolofgrassand showed thatheightgrowthofseedlingsincreased weeding experimentsinyoungpineplantations seedlings werenotavailable.However, mechanical herbaceous vegetationwithoutdamagingpine effectively controlledgrassesandother known inthe1960s,becauseherbicidesthat vegetation inyoungpinestandswasnotwell Mann 1980,Clason1978),theeffectofherbaceous on pinegrowthwaswelldocumented(Cainand upper CoastalPlain. ofsitepreparationinthePiedmontand form thedominant Gjerstad 1991)andiscurrently and preparation onmostuplandsites(Lowery preparation hadreplacedmechanicalsite and others1992).Bythe1990s,chemicalsite compared tomechanicallypreparedsites(Knowe at alowercostonchemicallypreparedsites discovered thatsimilarorbettergrowthoccurred site preparationexpandedrapidlywhenitwas thus, increasedpinegrowth(fig.8.5).Chemical (Fitzgerald 1982,Millerandothers 1995)and, effectively controlledhardwoodsprouting newer herbicidesrevealedthatthesecompounds began toincreaseasresultsfromstudiesofthe (Minogue andothers1991). treatments withherbicidessuchas2,4,5-T was generallymoresuccessfulthanprevious in pineplantationsusingthesenewerherbicides andothers1993).Hardwoodcontrol (Neary degradation, andminimaloffsitemovement with lowmammalianandfishtoxicity, rapid compounds weremoreenvironmentallybenign, uses.Thenewer registered forforestry (Roundup herbicidessuchasglyphosate Several alternative imazapyr (Arsenal Although theeffectofhardwoodcompetition The useofherbicidesforsitepreparation ® ), andtriclopyr(Garlon ® , Accord ® ® ), sulfometuronmethyl ), hexazinone(Velpar ® ) weresoon ® ), ACCELERATING GROWTH BY FERTILIZATION 1980). Critical foliar concentrations for N and P ven though a considerable body of research on were identified for slash and loblolly pine that forest soil fertility, tree nutrition, and response were well correlated with growth response E to fertilizers existed showing that growth following fertilization (Comerford and Fisher increases following fertilization were possible 1984, Wells and others 1973). (Walker 1960), forest fertilization did not develop Field trials conducted by both the North as an operational silvicultural practice until the Carolina State Forest Fertilization Cooperative 1960s. Operational deployment was hampered by and the CRIFF Program, initiated in the 1970s an inability to accurately identify sites and stands and 1980s, revealed that growth of most of the that consistently responded to fertilization. A slash and loblolly pine plantations in the South major breakthrough occurred with the discovery were limited by the availability of both N and of spectacular growth responses in slash pine P (Allen 1987, Fisher and Garbett 1980, Gent following phosphorus (P) additions on poorly and others 1986, Jokela and Stearns-Smith drained clay soils, locally called gumbo clay, in 1993, North Carolina State Forest Nutrition 71 the flatwoods of Florida (Laird 1972, Pritchett Cooperative 1997). This work confirmed that a and others 1961). Volume gains of up to 5 tons per large and consistent growth response following acre per year over 15 to 20 years were observed midrotation fertilization with N (150 to 200 on similar soils throughout the Coastal Plain pounds per acre) and P (25 to 50 pounds per acre) (Jokela and others 1991a). The long-term growth occurred on the majority of soil types (fig. 8.6). response following P fertilization on these gumbo Growth response following N plus P fertilization 8. Chapter clays translated into 5- to 15-foot increases in site averaged 75 cubic feet per acre per year on poorly index. When foresters learned to identify these drained soils and 69 cubic feet per acre per year P-deficient sites and prescribe appropriate on well-drained soils, which represents a growth fertilizer applications, fertilization emerged as increase of approximately 25 percent (North an operational treatment (Beers and Johnstono Carolina State Forest Nutrition Cooperative 1974, Terry and Hughes 1975). Typically, optimal 1997). These responses have typically lasted for growth responses were achieved on these sites at least 6 to 10 years, depending on soil type, Silviculture Pine Plantation when approximately 50 pounds per acre of fertilizer rates, and stand conditions. Based elemental P was added at the time of planting on these results, the number of acres of southern (Jokela and others 1991a). pine plantations receiving midrotation fertilization Results from fertilizer trials on other soil with N and P increased from 15,000 acres annually types in the Coastal Plain and Piedmont were in 1988 to approximately 975,000 acres in encouraging, but they remained somewhat 2000 (North Carolina State Forest Nutrition inconsistent (Pritchett and Smith 1975). This Cooperative 2001). By the end of 2000, > 11.1 inconsistency limited further expansion of forest million acres of southern pine plantations had fertilization programs. The Cooperative Research been fertilized in the United States since 1969. in Forest Fertilization (CRIFF) Program at the University of Florida and the North Carolina State Loblolly (+ 50 pounds per acre P) Forest Fertilization Cooperative were formed Slash (+ 50 pounds per acre P) in 1967 and 1970, respectively, to address this Loblolly (no phosphorus) Slash (no phosphorus) problem. Researchers in these two programs 18 and the Forest Service worked to identify reliable 16 diagnostic techniques to identify sites and stands 14 that responded to fertilization. Diagnostic 12 techniques including soil classification, soil and 10 foliage testing, visual symptoms, and greenhouse 8 and field trials were developed to help foresters 6 (tons per acre) decide whether or not to fertilize (Comerford response Volume 4 Slash and Fisher 1984; Wells and others 1973, 1986). 2 0 The soil classification system developed by the 0 100 200 300 CRIFF Program proved to be an effective tool N rate (pounds per acre) for determining the likelihood of obtaining an economic growth response following fertilization Figure 8.6—Growth response of loblolly and slash pine and was adopted widely (Fisher and Garbett on a variety of soil types following midrotation application of nitrogen (N) and phosphorus (P) fertilizer (adapted from North Carolina State Forest Nutrition Cooperative 1997). Southern Forest Science: 72 Past, Present, and Future Productivity properties (Fisher andGarbett 1980).Many be nutrientdeficient basedonsoilmorphological system wascreatedtoidentify soilsmostlikelyto in intensivelymanagedplantations. TheCRIFF neededtomakesilvicultural decisions information were developedtoprovidemanagers withthe andCampbell1991). type (Morris and sitepreparationwerealsoaffectedbysoil erosion, compaction,andpuddlingduringharvest Equipment limitationsandthepotentialfor andGjerstad1991). prescriptions (Lowery taken intoaccounttodevelopappropriate herbicides, suchashexazinone,andhadtobe influence theefficacyandoffsitemovementof 1983). Soilpropertieswerealsofoundtostrongly and others in thesamelandscape(Comerford was smallandinconsistentonsandySpodosols drained UltisolsinthelowerCoastalPlain,but fertilization waslargeandsustainedonpoorly (Fox 1991).For example,growthresponsetoP found tobestronglyaffectedbysoilproperties fertilization, thinning,andweedcontrolwere treatments suchasdrainage,sitepreparation, (Stone 1975).Growthresponsestosilvicultural as managementpracticesbecomemoreintensive 1960). (Coile 1960,Thornton identify andprioritizesitessuitableforplanting industrial landownersthroughouttheSouthto system oflandclassificationwaswidelyusedby 1955, CoileandSchumaker1964).The andRalston and slashpinesiteindex(Barnes withloblolly topsoil andsubsoilwerecorrelated class, depthtothesubsoil,andtextureof 1975).Soilpropertiessuchasdrainage (Carmean geology, withforestsitequality andlandform vegetationcharacteristics, properties, understory soil effort inthe1950sand1960stocorrelate and poorlystocked(Coile1960).Thisledtoalarge scheduled forplantingbecausetheywerecutover difficult toassessthequalityofmanysites intheSouth,itwasoften of plantationforestry quality sites.Unfortunatelyintheearlyyears wereinsufficientonpoor- plantation forestry fromtheinvestmentin the financialreturns fromnaturalstandstoplantationsbecause shifted important intheearly1950sasmanagement increases. Thisrelationshipbecamemore increase inanexponentialfashionassitequality S SITE CLASSIFICATION DEVELOPMENT OFFOREST Specialized soilclassification programs increases The needfordetailedsoilinformation of plantations.Merchantableyieldtendsto important factoraffectinggrowthandyield ite qualityisperhapsthesinglemost OF SOUTHERNPINE REALIZING THEGROWTH POTENTIAL previously used. improvement overthegeneralrecommendations These site-specificprescriptionsareagreat silvicultural prescriptionsonasite-by-sitebasis. foresters arenowabletomakedetailed withthesetools, their exactlocation.Armed accuratelydetermine allowed foresterstovery specific basis.UseofGlobalPositioning Systems detailed silviculturalrecommendationsonasite- on differentsoiltypesenablesforesterstomake of thegrowthresponsestosilviculturalpractices of intensivesilviculturalregimes.Spatialanalysis tooltoassistwiththeimplementation a powerful Systemsduringthe1990sprovided Information and Campbell1991). (Morris Service Natural ResourcesConservation than themultipurposesoilmapsproducedby purposes andhavegenerallyprovenmoreuseful weredevelopedspecificallyforforestry surveys 1960).Thesesoil (Campbell 1978,Thornton important forintensiveforestmanagement onsoilpropertiesconsidered information programs toprovideforesterswithsite-specific organizations initiateddetailedsoilmapping to theoperational silviculturalpracticesused in throughout the rotation.Thiswasincontrast nutrientdeficiencies were usedtocorrect the rotation,wasastandard practice.Fertilizers of weeds,especiallyduring the firstfewyearsof United States(Evans1992). Completeremoval usually moreintensivethan thoseintheSouthern Hemispherewere practices intheSouthern Hemisphere. not foundintheSouthern Snow] andthosecausedbyrootpathogens,were f. sp. [ rust UnitedStates,suchasfusiform the Southern others 1994).Inaddition,diseasesendemicto and explanations forthedifferences(Harms proposedas respiration rates,wereoften nighttime temperaturesleadingtolower example, climaticdifferences,especiallylower growth potentialbetweenthetworegions.For differencesin toexplaintheobserved forward over theyearsnumerousexplanationswereput South werepuzzledbythisphenomenon,and range (SedjoandBotkin1997).Foresters inthe W Cronartium quercuum The developmentofsophisticatedGeographic It wasalsonotedthatplantationmanagement fusiforme hen planted in the Southern Hemisphere, hen plantedintheSouthern significantly fasterthanintheirnatural slash andloblollypinewerefoundtogrow (Hedge.&N.Hunt)BurdsallG. (Berk.)MiyabeexShirai the Southern United States through the 1980s Empirical results from these studies demonstrated that focused on reducing costs per acre. Early spectacular growth responses of both slash and herbicide applications, whether for chemical loblolly pine following complete and sustained site preparation, herbaceous weed control, or weed control in combination with repeated hardwood release, usually did not completely fertilization (Borders and Bailey 2001, Colbert and control competing vegetation. Even though others 1990, Neary and others 1990, Pienaar and growth response was found to be proportional Shiver 1993). These results demonstrated that the to the amount of competing vegetation controlled growth potential of southern pines was not being (Burkhart and Sprinz 1984, Liu and Burkhart achieved in most operational plantations in the 1994), operational herbicide treatments were South, and that growth rates rivaling those in the usually based on application rates that achieved Southern Hemisphere could be achieved in the a threshold level of control at the lowest cost. South through intensive management (table 8.1). Similarly, fertilization treatments were generally limited to a single application during the rotation PREDICTING GROWTH AND YIELD IN 73 to minimize costs (Allen 1987). Perhaps more SOUTHERN PINE PLANTATIONS importantly, silvicultural treatments were hroughout the 1950s and early 1960s, generally applied as individual, isolated treatments forest managers were forced to rely on rather than as part of an integrated system. T yield predictions developed for natural stands. Notable in this respect for many organizations Miscellaneous Publication 50 (U.S. Department was the debate over the relative value of genetic of Agriculture, Forest Service 1929) was the 8. Chapter improvement and silvicultural treatments for most widely used source of southern pine volume increasing stand productivity. In the Southern predictions at that time. However, it was soon Hemisphere, it was recognized early on that to apparent that stand growth and yield in achieve high levels of productivity in southern plantations differed fundamentally from that pine plantations, genetics and silvicultural factors in natural stands. Growth-and-yield models for must be considered as equal components of an southern pine plantations began to appear in integrated management system.

the 1960s in response to the need for improved Silviculture Pine Plantation Several forward-looking research projects growth-and-yield information (Bennett 1970, established during the 1980s provided direct Bennett and others 1959, Burkhart 1971, Clutter evidence of the growth potential of intensively 1963, Coile and Schumaker 1964). Initially, managed southern pine within its native plantation growth-and-yield models were whole- range. Most notable among these were studies stand models that simply predicted current stand established by the Plantation Management yield (Bennett 1970, Bennett and others 1959). Research Cooperative at the University of However, more sophisticated models were soon Georgia and the Intensive Management Practices developed that were able to predict total yield Assessment Center at the University of Florida. as well as the diameter distribution of the stand (Bennett and Clutter 1968, Burkhart and Strub 1974, Smalley and Bailey 1974). These diameter Table 8.1—Growth rates of pines throughout distribution models, although more complicated the Worlda and data intensive, proved to be substantially more useful tools for forest managers, because Location Species Age MAI volume of specific products could be estimated which provided a more accurate estimate of years ft3/ac/yr stand value. In the 1970s, distance-dependent individual-tree growth models were developed Costa Rica Pinus caribaea 8 449 that incorporated the effects of neighboring New Zealand P. radiata 25 457 competing trees on growth (Daniels and Burkhart Brazil P. taeda 15 429 1975). Distance-dependent tree growth models South Africa P. taeda 22 412 should provide better estimates of the impact of Australia P. taeda 20 302 United States silvicultural practices such as thinning. However, Florida P. elliottii 20 207 it has generally been found that diameter Georgia P. taeda 14 374 distribution models give results very similar to those of individual-tree growth models in MAI = mean annual increment. most cases with less effort and lower cost a Data from Arnold (1995), Evans (1992), Borders and Bailey (Clutter and others 1983). (2001), Yin and others (1998). Southern Forest Science: 74 Past, Present, and Future Productivity widespread implementation ofintensive This realizationwasthedriving factorinthe fromforestmanagement. the financialreturns density managementcould significantly increase site preparation,weedcontrol, fertilization,and of plantationsresultingfrom improvedgenetics, andgrowth recognized thatincreasedsurvival improved plantationgrowth.Itwassoonwidely silviculturalregimesthat from alternative planning toolstopredictthefinancialreturns managers werealsoabletousetheseharvest present valueoffuturecashflows.Forest and quantitativemannerthatoptimizedthe technique tomanagetimberlandinanorganized first timeorganizationswereabletousethis management throughouttheSouth.For the fundamentally changedpineplantation schedulingprogram(Clutter 1968) harvest the MAX-MILLION linearprogramming-based (Clutter andothers1983).Thedevelopmentof schedulingproblemsforthe firsttime harvest techniques tosolverealisticallysizedforest made itpossibletouselinearprogramming 1964). Improvementsincomputersthe1960s in thiseffort(Chappelle1966,Curtis1962,Leak planning toolinthe1960swasamajoradvance introduction oflinearprogrammingasaforest land baseundermanagement(Davis1966).The fromtheoverall that optimizedfinancialreturns foresters strovetocreateafullyregulatedforest Rheney 1995). remarkable degreeofprecision(Pienaarand in intensivelymanagedpineplantationswitha accurately predictstand-leveltimberproduction models ordiameterdistributionmodels,can yield models,whetherindividualtreegrowth growth-and- Liu andBurkhart1994).Modern andyield(BurkhartSprinz1984, structure and theimpactofhardwoodcompetitiononstand (Amateis andothers2000,Bailey1989), others 1989,Caoand1982),fertilization Clutter andothers1984),thinning(Amateis as sitepreparation(Baileyandothers1982, predict theimpactofsilviculturalpracticessuch Models havebeendevelopedthataccurately pineplantations. of growthandyieldinsouthern accuratemodels produced sophisticatedandvery in 1979.Thesetwoprogramshave formed University GrowthandYield Cooperativethat and theVirginia Polytechnic InstituteandState attheUniversityofGeorgiain1976 that formed Plantation ManagementResearchCooperative was enhancedtremendouslybytheworkof As plantationsreplacednaturalstands, Growth-and-yield researchintheSouth Dalla-Tea andJokela1991). and others1998,Colbert others1990, productivity onmostsitesin theSouth(Albaugh area developmentand,consequently, controls of lightorwater, moststronglyaffectsleaf nutrient availability, ratherthanavailability others 1994).Recentresearch hasshownthat and Jokela1998,Vose andAllen1991,Vose and availability oflight,water, andnutrients(McCrady by thegeneticpotentialoftreesand to standleafarea(fig.8.7),whichiscontrolled pineplantations isrelated Productivity ofsouthern convert ittostemwoodbiomass(Cannell1989). forest tocaptureincomingsolarradiationand bytheabilityof productivity isdetermined but alsobyoperationalforesters,thatforest recognized, notonlybyresearchscientists controlling forestproductivity. Itisnowwidely understanding ofthephysiologicalprocesses now basedonbothempiricalresultsandan the-art silviculturalregimesisthattheyare state-of-trials. Animportantfeatureofcurrent based primarilyontheresultsofempiricalfield can beimprovedgreatlybypropermanagement. this approach,sitequalityisnolongerfixed,but andothers1990).Withand others1990,Neary nutrient availabilitythroughouttherotation(Allen are integratedtomaintainoptimalwaterand site preparation,weedcontrol,andfertilization, soil types,andsilviculturaltreatments,including which improvedgenotypesarematchedtospecific moving towardamorefullyintegratedapproachin interactions andsynergies.Today, managementis in isolationwithlittleunderstandingoftheir property, andindividualtreatmentswereapplied Heretofore, sitequalitywasviewedasastatic in concerttooptimizestandproductivity. which geneticandsiteresourcesaremanipulated treatments toamuchmoreintensivesystemin planting coupledwithisolatedindividual M SITE-SPECIFIC SILVICULTURE CURRENT STATE-OF-THE-ART: INTEGRATED, plantations intheSouth(Van Deusen1999). block sizerestrictionsnowimposedonindustrial problems presentedbytheadjacencyandharvest scheduling solve theextremelycomplexharvest improved tothepointwheretheyarenowable scheduling modelshavebeenrevisedand 1990s. Thedescendantsoftheseoriginalharvest inthe1980sand silviculture thatoccurred In thepast,mostsilviculturaldecisionswere anagement of southern pineplantations anagement ofsouthern from arelativelyextensivesystemof in theUnitedStatesisbeingtransformed In intensively managed plantations, interactions Current growth rates in intensively managed among silvicultural treatments and genetics are plantations in the South may exceed 350 cubic now recognized. There are also large differences feet per acre per year (Borders and Bailey 2001), in growth efficiency among families of both loblolly which puts them on par with fast-growing and slash pine, and these differences can now be plantations in other parts of the World (table 8.1). exploited to improve stand productivity (Li and These intensively managed plantations offer others 1991, McCrady and Jokela 1998, Samuelson landowners attractive financial returns (Yin and 2000). The combined effect on growth potential Sedjo 2001, Yin and others 1998). Although the that results from the use of improved genotypes costs associated with intensive management are and intensive silviculture appears to be at least higher, financial returns from such plantations additive (McKeand and others 1997). Recent are higher because the growth rates are much results from progeny tests demonstrated that greater and the rotation lengths shorter. General the growth of some better families increased realization of this fact is causing a paradigm shift more than the growth of poorer families as site in the philosophy of forest landowners in the 75 quality or silvicultural inputs, or both, increased South. Current management of pine plantations (fig. 8.8). Foresters are now using this information is moving away from the traditional focus on to deploy better genotypes to higher quality sites minimizing cost per acre to a new emphasis on that will be managed more intensively. decreasing cost per ton of wood produced. Because wood costs are usually the single largest cost in Foresters now modify silvicultural practices to

pulp, lumber, and engineered wood production, 8. Chapter take advantage of interactions among treatments minimizing wood cost through intensive based on a better understanding of their impacts management may be the best way for forest on site resource availability (Allen and others industry in the South to remain competitive in 1999). As an example, both chemical site global markets. preparation and disking treatments are used to control competing hardwoods. Although disking Genotype also improves soil physical properties, it is likely Nutrients that the combined growth response following Silviculture Pine Plantation disking coupled with herbicide treatment would be less than additive. Therefore, chemical treatments are now substituted for mechanical treatments on sites where hardwood competition is a severe Water problem. In contrast, the growth response following fertilization coupled with herbicide growth volume Annual control of competing hardwoods might be more Leaf area index than additive since hardwoods responding to fertilizer compete more vigorously with the pine Figure 8.7—Relationship between leaf area index crop tree for light and water (Borders and Bailey and growth rate in southern pine plantations. 2001, Swindel and others 1988). Weed control plus fertilization is the most widespread treatment used to accelerate growth in pine plantations in 50 the South (Albaugh and others 1998, Colbert and 45 A others 1990, Jokela and others 2000). Fertilization 40 regimes have been developed that enable foresters 35 B to match nutrient supply with the demand of the 30 25 stand. Depending on the soil type, various types C 20 and amounts of fertilizer may be added four or

(tons per acre) 15 more times during a 20-year rotation to augment

Family mean volume Family 10 native soil fertility and maintain high nutrient 5 availability. These fertilizer applications are 0 coordinated with site preparation treatments 0 10203040 and weed control as needed during the rotation to Site mean volume (tons per acre) ameliorate soil physical limitations and eliminate Increasing site quality competition for soil water and nutrients, thus insuring optimal growing conditions for the Figure 8.8—Performance of loblolly pine families [identifications are (A) 07–56, (B) 08–59, and designated crop trees throughout the rotation. (C) 01–64] as site quality increases (adapted from McKeand and others 1997). Southern Forest Science: 76 Past, Present, and Future Productivity are large.At ofthe21 theturn pine through geneticmanipulation ofsouthern of nutrientavailability. from thismoresophisticated management increases inthefuturearelikely tooccur soil typesacrosstheregion.Significantgrowth fertilizer regimescanbeoptimizedforspecific pinessothat are beingdevelopedforsouthern of soilnutrientsupply, treedemand,anduptake stand throughouttherotation.Mechanisticmodels manner thatmatchesnutrientdemandofthe both macronutrientsandmicronutrientsina in theSouthwillhavetobemodifiedsupply and others1991b,Will 1985).Fertilization regimes (Evans 1992,GonçalvesandBenedetti2000,Jokela South astheyhaveinotherpartsoftheWorld nutrients otherthanNandPwilldevelopinthe and nutrientdemandincrease,deficienciesof N andPsupply. Itislikelythatasgrowth rates fertilizationregimes focusonmaintaining Current not highenoughtomeettheseincreaseddemands. increase. Thenutrientsupplyinmostforestsoilsis stands increase,thedemandfornutrientswillalso somewhat different.Asgrowthratesofforest However, thefuture offertilizationmaybe in someplantations(Yin andothers1998). approaching thislevelofcompetitioncontrol management regimesare grow back.Current additional herbicideapplicationuntiltheweeds no additionalgrowthgainsarelikelyfrom will probablyleveloff. Onceasiteisweed-free, growth responsetosomesilviculturaltreatments inthefuture.However,forestry atsomepointthe rotation willremaintheparadigmofplantation water andnutrientavailabilitythroughoutthe silvicultural managementregimesthatoptimize uses(SedjoandBotkin1997). and preservation large areasofnativeforestsforconservation demand forwoodandfiberstillreserve increase inthefuturetomeetincreasing plantations fortimberproductionwillhaveto restricted. Theuseofintensivelymanaged native forestsinmanypartsoftheworldisbeing in Nations 1997).Inaddition,timberharvesting (Food andAgricultureOrganizationoftheUnited urbanization (Wear andGreis2002)ordegraded land arebeinglosttootherusessuchas B THE PROMISE OFBIOTECHNOLOGY THE FUTURE:CLONAL FORESTRY AND plantations were stillplantedwithopen-pollinated, The potentialgainsinfuture plantations Implementing integratedsite-specific ecause ofthecontinuedincreaseinworld’s increasing, whilelargeamountsofforest populations, demandforforestproductsis st century, most pine clones(fig.8.9).Basedonresultsfromclonal way toproduceadequatenumbersofsouthern will provetobethemosteconomicalandefficient androoted cuttings of somaticembryogenesis itislikelythatsomecombination In thenearterm, use ofrootedcuttingsandsomaticembryogenesis. pine isstillunderdevelopmentandincludesthe technology tomassproduceclonesofsouthern developed tooptimizepulpproduction.The clones withspecificwoodpropertieshavebeen plantations inBrazil(Evans1992).Inaddition, year havebeendocumentedinclonaleucalyptus rates exceeding600cubicfeetperacre 1995).Growth improved productivity(Arnold Hemisphereandhavedramatically the Southern eucalyptus plantationsarewidelyplantedin potential (Gleedandothers1995).Clonal individual treesthatpossessexcellentgenetic to massproduceidenticalcopiesofselected relies onvegetativepropagationprocedures Clonalforestry plantations inthenearterm. pine for increasingtheproductivityofsouthern States. pineintheUnited operational withsouthern and eucalyptus( parts oftheworldwithspeciessuchasradiatapine 2000). Thistechnologyiswidelyusedinother from controlledpollination(Foster andothers multiply thelimitednumberofseedlingsavailable this obstacle,rootedcuttingsarebeingusedto large-scale reforestationneeds.To overcome seed nowavailableisnotsufficienttomeet Consequently, thequantityofcontrol-pollinated expense andtimerequiredtoproducethisseed. drawback ofcontrolledpollinationistheadditional increase growthsignificantly(fig.8.4).One pollination ofeliteparents,becausethiscan toward theuseofseedproducedbycontrolled half-sib families.Manyorganizationsaremoving pines intheUnited States. embryogenesis into aclonalforestry program for southern Figure 8.9—Integration of rooted cuttings andsomatic Cryopreservation Clonal forestry holdsthegreatestpromise Clonal forestry Embryogenic tissue plantlets Tissue culture Eucalyptus Clones selected spp hedges Clonal cuttings Rooted . ) andwillsoonbe outplantings Clonal plantations in other parts of the world, it will managed forests in the world (Schultz 1997). likely be possible to increase productivity of Site-specific, integrated management regimes southern pine plantations by at least 50 percent that incorporate the genetic gains available from by deploying appropriate clones to specific soil tree improvement along with silvicultural practices types and then implementing integrated, intensive that optimize resource availability throughout the silvicultural regimes. Mean annual increments rotation are now the norm. Growth rates in many > 500 cubic feet per acre per year may soon be pine plantations in the South are now approaching within our reach on selected sites in the South. those in the Southern Hemisphere. Additional gains in productivity are likely as management In the longer term, prospects for new regimes are refined further. In the near term, developments in forest biotechnology are implementation of clonal forestry holds the bright. Research is revealing the genetic basis greatest promise to dramatically increase of disease resistance, wood formation, and growth productivity in southern pine plantations. in southern pine. Molecular markers are being As a result, the South is likely to remain developed that will substantially increase the 77 the woodbasket of the United States for the efficiency of conventional tree breeding programs foreseeable future. because they will no longer have to rely on phenotypic expression of desired traits in long- LITERATURE CITED term field trials (Williams and Byram 2001). The use of molecular markers is particularly valuable Albaugh, T.J.; Allen, H.L.; Dougherty, P.M. [and others]. 1998.

Leaf area and above- and belowground growth responses of 8. Chapter with complex traits that have low heritability, loblolly pine to nutrient and water additions. Forest Science. which is usually the case in southern pine. 44: 1–12. Genetic engineering accomplished by directly Allen, H.L. 1987. Fertilizers: adding nutrients for enhanced introducing foreign DNA into trees has been forest productivity. Journal of Forestry. 85: 37–46. reported in a number of species, including radiata Allen, H.L.; Dougherty, P.M.; Campbell, R.G. 1990. pine and hybrid poplar (Bauer 1997). The potential Manipulation of water and nutrients–practices and opportunities in Southern U.S. pine forests. Forest for this technology to dramatically improve wood

Ecology and Management. 30: 437–453. Silviculture Pine Plantation properties, disease resistance, and growth rates Allen, H.L.; Weir, R.J.; Goldfarb, B. 1999. Investing in wood of forest trees has been reported widely in both production in southern pine plantation. In: Opportunities the technical and popular press. Unfortunately, for increasing fiber supply for the paper industry in the although the first successful transgenic trees were Southern United States: a university perspective. Raleigh, produced in the 1980s (Fillatti and others 1987), NC: North Carolina State University: 31–38. it remains difficult to produce transgenic trees, Amateis, R.L.; Burkhart, H.E.; Walsh, T.A. 1989. Diameter especially the southern pines. Numerous hurdles increment and survival equations for loblolly pine trees remain to be overcome before the promise of growing in thinned and unthinned plantations on cutover, site prepared lands. Southern Journal of Applied Forestry. genetic engineering in trees is fulfilled (Sederoff 13: 170–174. 1999). Even with the concerted research efforts Amateis, R.L.; Liu, J.; Ducey, M.J.; Allen, H.L. 2000. currently underway in this area, it seems likely Modeling response to midrotation nitrogen and phosphorus that several decades will elapse before transgenic fertilization in loblolly pine plantations. Southern Journal trees are a feature of operational southern of Applied Forestry. 24: 207–212. pine plantations. Arnold, R.B. 1995. Investment in fast-growing trees offers future wood procurement advantages. Pulp and Paper: CONCLUSIONS 135–137. anagement practices in southern pine Aust, W.M.; Shaffer, R.M.; Burger, J.A. 1996. Benefits and plantations have undergone a dramatic costs of forestry best management practices in Virginia. Southern Journal of Applied Forestry. 20: 23–29. M evolution over the last 50 years. By applying research results to operational plantations, Bailey, R.L.; Burgan, T.M.; Jokela, E.J. 1989. Fertilized midrotation-aged slash pine plantations–stand structure foresters have more than doubled the productivity and yield projection models. Southern Journal of Applied of operational southern pine plantations over this Forestry. 13: 76–80. period (fig. 8.3). For example, older management Bailey, R.L.; Pienaar, L.V.; Shiver, B.D.; Rheney, J.W. 1982. practices that produced plantations with growth Stand structure and yield of site-prepared slash pine rates of < 90 cubic feet per acre per year have plantations. Res. Bull. 291. Athens, GA: University of been replaced by new practices that create stands Georgia, College of Agriculture Experiment Station. 83 p. that are currently producing 400 cubic feet per acre per year on some sites. Pine plantations in the South are among the most intensively Southern Forest Science: 78 Past, Present, and Future Productivity Burkhart, H.E.;Sprinz,P Burkhart, H.E.1971.Slashpineplantationyieldestimates Burger, J.A.;Kluender, R.A.1982.Sitepreparation–Piedmont. Borders, B.E.;Bailey, R.L.2001.Loblollypine–pushingthe Bethume, J.E.1963.Ridging:low-costtechniquesfor NewYork:Bennett, H.H.1939.Soilconservation. McGraw-Hill Bennett, F.A.; McGee,C.E.;Clutter, J.L.1959.Yields ofold- Bennett, F.A.; Clutter, J.L.1968.Multiple-productyield Bennett, F.A. forold- 1970.Yields patterns andstandstructural Beers, W.L., Jr.; Johnstono,H.E.1974.Intensivecultureof Bauer, L.S.1997.Fiber withinsecticidaltree.Journal farming Bates, G.G.1928.Tree ofForestry. Journal “seedfarms”. R.L.;Ralston,C.W.Barnes, 1955.Soilfactorsrelatedtogrowth Balmer, W.E.; Little,N.G.1978.Sitepreparationmethods. Ballard, R.;Gessel,S.P Ballard, R.1978.Effectsofslashandsoilremovalonthe pages unknown]. of Forestry andWildlife Resources.[Numberof Polytechnic InstituteandState University, School plantations. FWS–3–84.Blacksburg, VA: Virginia hardwood competitioneffectsonyields ofloblollypine Science. 17:452–453. based ondiameterdistributions:anevaluation.Forest Raleigh, NC:NorthCarolinaStateUniversity:58–74. In: Symposiumontheloblollypineecosystem(eastregion). 25: 69–74. ofAppliedForestry. Journal limits ofgrowth.Southern 23(3): 6–8,18. increasing growthonwetflatwoodssites.Forest Farmer. Book Co.,Inc.993p. ForestSoutheastern ExperimentStation.19p. U.S. DepartmentofAgriculture,Forest Service, field slashpineplantations.Stn.Pap. 107.Asheville,NC: Forest ExperimentStation.21p. Department ofAgriculture,Forest Southeastern Service, sawtimber, gum.Res.Pap. SE–35.Asheville,NC:U.S. estimates forunthinnedslashpineplantations–pulpwood, ForestSoutheastern ExperimentStation.81p. NC: U.S.DepartmentofAgriculture,Forest Service, field plantationsofslashpine.Res.Pap. SE–60.Asheville, 201–211. Atlanta: U.S.DepartmentofAgriculture,Forest Service: Proceedings ofasymposiumonmanagementyoungpines. slash pine.In:Williston, H.L.;Balmer, W.E., eds. of Forestry. 95:20–23. 26: 969–977. [Publisher unknown].23p. Exp. Tech. Bull.559.[Placeofpublicationunknown]: and yieldofslashpineplantationsinFlorida.FloridaAgric. AreaStateandPrivateForestry:Southeastern 60–64. U.S. DepartmentofAgriculture,Forest Service, of maintainingproductivityonpreparedsites.Atlanta: In: Tippin,T., ed.Proceedings:asymposiumonprinciples [Number ofpagesunknown]. Forest Pacific Service, NorthwestResearchStation. PNW–163. Portland, OR:U.S.DepartmentofAgriculture, forest siteandcontinuousproductivity. Gen.Tech. Rep. ofForestNew ZealandJournal Science.8:248–258. productivity ofsecondrotationradiatapineonapumicesoil. ., eds.1983.I.U.F.R.O. symposiumon .T. 1984.Amodelforassessing Clutter, J.L.;Harms,W.R.; Brister, G.H.;Rheney, J.W. 1984. Clutter, J.L.; Fortson, J.C.;Pienaar, L.V. [andothers].1983. Clutter, J.L. 1968.MAX-MILLION–a computerized forest Clutter, J.L. 1963.Compatiblegrowthandyieldmodels Clason, T.R. 1978.Removalofhardwoodvegetationincreases Chappelle, D.E.1966.Acomputerprogramforscheduling W.H.Carmean, 1975.Forest sitequalityevaluationinthe Carlson, W.C. 1986.Rootsystemconsiderations inthequality Cao, Q.V.; Burkhart,H.E.;Lemin,R.C.,Jr. 1982.Diameter Cannell, M.G.R.1989.Physiologicalbasisofwoodproduction: Campbell, R.G.1978.TheWeyerhaeuser landclassification Cain, M.D.;Mann,W.F., Jr. control 1980.Annualbrush Cain, M.D.1978.Plantedloblollyandslashpineresponseto Butler, C.B.1998.Treasures ofthelongleafpinesnavalstores. Burton, J.D.1971.Prolongedfloodinginhibitsgrowthof M.R. 1974.Amodelforsimulationof Burkhart, H.E.;Strub, Service, Southeastern Forest Southeastern Service, ExperimentStation.173p. Asheville, NC:U.S.Departmentof Agriculture,Forest Georgia, andnorthFlorida.Gen.Tech. Rep.SE–27. plantations intheLowerCoastalPlain oftheCarolinas, andyields ofsitepreparedloblollypine Stand structure John Wiley. 333p. Timber management:aquantitativeapproach.NewYork: of Georgia,SchoolForest Resources.[Notpaged]. management planningsystem.Athens, GA:University for loblollypine.Forest Science.9:354–371. ofAppliedForestry.Journal 2:96–97. growth andyieldofayoungloblollypinestand.Southern of pagesunknown]. Pacific NorthwestForest ExperimentStation.[Number OR: U.S.DepartmentofAgriculture,Forest Service, sequential planningperiods.Res.Pap. PNW–33.Portland, allowable cutusingeitherareaorvolumeregulationduring United States.Advances inAgronomy. 27:209–269. Forestry. 10:87–92. ofApplied Journal of loblollypineseedlings.Southern Resources. 62p. and StateUniversity, SchoolofForestry andWildlife FWS–1–82. Blacksburg,VA: Virginia Polytechnic Institute distributions andyieldsofthinnedloblollypineplantations. 4: 459–490. a review. ofForest ScandanavianJournal Research. Area, StateandPrivateForestry: 74–82. Department ofAgriculture,Forest Southeastern Service, moisture-site productivitysymposium.Atlanta: U.S. system. In:Balmer, W.E., ed.Proceedingsofthesoil of AppliedForestry. 4:67–70. Journal increases earlygrowthofloblollypine.Southern Station. 6p. Agriculture, Forest Forest Southern Service, Experiment Res. NoteSO–237.NewOrleans:U.S.Departmentof bedding andflatdiskingonapoorlydrainedsite–anupdate. Shalimar, FL:Tarkel Press.269p. Forest Experiment Station.4p. U.S. DepartmentofAgriculture,Forest Southern Service, loblolly pineseedlings.Res.NoteSO–124.NewOrleans: College ofForestry: 128–135. for treeandstandsimulation.Stockholm,Sweden:Royal planted loblollypinestands.

In: Fries, J.,ed.Growthmodels Coile, T.S. 1960. Summary of soil-site evaluation. In: Burns, Fitzgerald, C.H. 1976. Post-emergence effects of Velpar P.D., ed. Southern forest soils. Baton Rouge, LA: Louisiana in a Piedmont pine plantation. Proceedings of the Southern State University: 77–85. Weed and Science Society of America. 29: 299. Coile, T.S.; Schumaker, F.X. 1964. Soil-site relations, stand Fitzgerald, C.H. 1982. Chemical site preparation and release structure, and yields of slash and loblolly pine plantations in loblolly pine stands. In: Symposium on the loblolly pine in the Southern United States. Durham, NC: T.S. Coile, Inc. ecosystem (east region). Raleigh, NC: North Carolina State 296 p. University: 75–85. Colbert, S.R.; Jokela, E.J.; Neary, D.G. 1990. Effects of annual Food and Agriculture Organization of the United Nations. fertilization and sustained weed control on dry matter 1997. State of the world’s forests–1997. Rome. 465 p. partitioning, leaf area, and growth efficiency of juvenile loblolly and slash pine. Forest Science. 36: 995–1014. Foster, G.S.; Stelzer, H.E.; McRae, J.B. 2000. Loblolly pine cutting morphological traits: effects on rooting and field Comerford, N.B.; Fisher, R.F. 1984. Using foliar analysis to performance. New Forests. 19: 291–306. classify nitrogen-responsive sites. Soil Science Society of America Journal. 48: 910–913. Fox, T.R. 1991. The role of ecological land classification systems in the silvicultural decision process. In: Mengel, D.L.; Tew, Comerford, N.B.; Fisher, R.F.; Pritchett, W.L. 1983. Advances D.T., eds. Ecological land classification: applications to 79 in forest fertilization on the Southeastern Coastal Plain. In: identify the productive potential of southern forests. Gen. Ballard, R.; Gessel, S.P., eds. I.U.F.R.O. symposium on forest Tech. Rep SE–68. Asheville, NC: U.S. Department of site and continuous productivity. Gen. Tech. Rep. PNW–163. Agriculture, Forest Service, Southeastern Forest Portland, OR: U.S. Department of Agriculture, Forest Experiment Station: 96–101. Service, Pacific Northwest Forest Experiment Station: 370–378. Fox, T.R. 2000. Sustained productivity in intensively managed forest plantations. Forest Ecology and Management. 138: Cubbage, F.W.; Kirkman, L.K.; Boring, L.R. [and others]. 187–202. 8. Chapter 1990. Federal legislation and wetland protection in Georgia: legal foundations, classification schemes, and industry Fox, T.R.; Morris, L.A.; Maimone, R.A. 1989. The impact of implications. Forest Ecology and Management. 33/34: windrowing on the productivity of a rotation age loblolly 271–286. pine plantation. In: Miller, J.H., ed. Proceedings of the fifth biennial southern silvicultural research conference. Gen. Curtis, F.H. 1962. Linear programming the management Tech. Rep. SO–74. New Orleans: U.S. Department of of a forest property. Journal of Forestry. 60: 611–616. Agriculture, Forest Service, Southern Forest Experiment Station: 133–140. Dalla-Tea, F.; Jokela, E.J. 1991. Needlefall, canopy light

interception, and productivity of young, intensively managed Gent, J.A., Jr.; Allen, H.L.; Campbell, R.G.; Wells, C.G. Silviculture Pine Plantation slash and loblolly pine stands. Forest Science. 37: 1298–1313. 1986. Magnitude, duration, and economic analysis of loblolly pine growth response following bedding and phosphorus Daniels, R.F.; Burkhart, H.E. 1975. Simulation of individual fertilization. Southern Journal of Applied Forestry. 10: tree growth and stand development in managed loblolly 124–128. pine plantations. FWS–5–75. Blacksburg, VA: Virginia Polytechnic Institute and State University, Division Glass, G.R. 1976. The effects from rootraking on an upland of Forestry and Wildlife Resources. [Number of Piedmont loblolly pine (Pinus taeda L.) site. Tech. Rep. 56. pages unknown]. Raleigh, NC: North Carolina State Forest Fertilization Cooperative. 44 p. Davis, K.P. 1966. Forest management: regulation and valuation. 2d ed. New York: McGraw Hill Book Co. 519 p. Gleed, J.A.; Darling, D.; Muschamp, B.A.; Nairn, B.J. 1995. Commercial production of tissue cultured Pinus radiata. Dierauf, T.A. 1982. Planting loblolly pine. In: Proceedings of Tappi Journal. 78(9):147–150. the symposium on the loblolly pine ecosystem (east region). Raleigh, NC: North Carolina State University: 24–135. Glover, G.R.; Creighton, J.; Gjerstad, D.H. 1989. Herbaceous weed control increases loblolly pine growth. Journal of Dorman, K.W. 1976. The genetics of breeding southern pines. Forestry. 87: 47–50. Agric. Handb. 471. Washington, DC: U.S. Department of Agriculture, Forest Service. [Number of pages unknown]. Goddard, R.E. 1958. Additional data on the cost of collecting cones from a seed production areas. Journal of Forestry. Duzan, H.W., Sr. 1980. Site preparation techniques for artificial 56: 846–848. regeneration. In: Mann, J.W., ed. Proceedings of a seminar on site preparation and regeneration management. Clemson, Gonçalves, J.L.; Benedetti, V., eds. 2000. Nutriçaoe fertilizaçao SC: Clemson University: 54–63. florestal. Piracicaba, SP, Brazil: Instituto de Pesquisas e Estudos Florestais. 427 p. In Portuguese. Ellefson, P.V.; Kilgore, M.A.; Phillips, M.J. 2001. Monitoring compliance with BMPs. The experience of State forestry Haines, L.H.; Maki, T.E.; Sandeford, S.G. 1975. The effect of agencies. Journal of Forestry. 98: 11–17. mechanical site preparation treatments on soil productivity and tree (Pinus taeda L. and P. elliottii Engelm. var. Evans, J. 1992. Plantation forestry in the tropics. 2d ed. Oxford: elliottii) growth. In: Bernier, B.; Winget, C.H., eds. Forest Clarendon Press. 403 p. soils and forest land management. Quebec: Les Presses de Fillatti, J.J.; Sellmer, J.; McCown, B. [and others]. 1987. L’Universite Laval: 379–396. Agrobacterium mediated transformation and regeneration Harms, W.R.; DeBell, D.S.; Whitesell, C.D. 1994. Stand of Populus. Molecular and General Genetics. 206: 192–199. and tree characteristics and stockability in Pinus taeda Fisher, R.F.; Garbett, W.S. 1980. Response of semimature slash plantations in Hawaii and South Carolina. Canadian and loblolly pine plantations to fertilization with nitrogen and Journal of Forest Research. 24: 511–521. phosphorus. Soil Science Society of America Journal. 44: 850–854. Southern Forest Science: 80 Past, Present, and Future Productivity Li, B.;McKeand, S.E.;Hatcher, A.V.; Weir, R.J.1997.Genetic Li, B.;McKeand, S.E.;Allen,H.L.1991.Geneticvariation Leak, W.B. 1964.Estimatingmaximumallowabletimber Laird, C.R.1972.Fertilization ofslashpineonpoorlydrained Knowe, S.A.;Shiver, B.D.;Kline,W.N. 1992.Fourth-year Keeves, A.1966.Someevidenceoflossproductivitywith Josephson, H.R.;Hair, D.1956.TheUnitedStates.In: Jokela, E.J.;Wilson, D.S.;Allen,J.E.2000.Earlygrowth S.C.1993.FertilizationJokela, E.J.;Stearns-Smith, of Jokela, E.J.;McFee, W.W.; Stone,E.L.1991b.Micronutrient Jokela, E.J.;Allen,H.L.;McFee, W.W. 1991a.Fertilization of Johnson, J.D.;Cline,M.L.1991.Seedlingqualityofsouthern Johnson, D.W.; Todd, D.E.,Jr. effectsonlong- 1998.Harvesting Holt, H.A.;Voeller, J.E.;Young, J.F. 1973.Vegetation control Lindquist, B.1948.Forstgenetik inderSchwedischen Improvement Program.In:Proceedingsofthe24 Cooperative TreeCarolina StateUniversity-Industry gains ofsecondgenerationselectionsfromtheNorth Science. 37:613–626. in nitrogenuseefficiencyofloblollypineseedlings.Forest of pagesunknown]. ForestNortheastern ExperimentStation.[Number PA: U.S.DepartmentofAgriculture,Forest Service, yields bylinearprogramming.Res.Pap. NE–17.Broomall, [Numberofpagesunknown]. Service. University ofFlorida,FloridaCooperativeExtension soils innorthwestFlorida.Circ.378.Gainesville,FL: of AppliedForestry. 16:99–105. Journal site preparationintheGeorgiaPiedmont.Southern response ofloblollypinefollowingchemicalandmechanical South Australia. Australian Forests. 30:51–63. successive rotationsof Co.: 149–200. geography offorestresources.NewYork: TheRonald Press Haden-Guest, S.;Wright, J.K.;Teclaff, E.M.,eds.Aworld ofAppliedForestry. Journal Southern 24:23–30. and herbaceousweedcontroltreatmentsatestablishment. responses ofslashandloblollypinesfollowingfertilization 17: 135–138. of AppliedForestry. Journal nitrogen treatments.Southern pinestands:effectsofsingleandsplit established southern 492–496. 55: manganese. SoilScienceSocietyofAmericaJournal. deficiency inslashpine:responseandpersistenceofadded 263-277. Dordrecht, TheNetherlands:KluwerAcademic Publishers: Dougherty, P southern pinesatestablishment.In: southern Academic Publishers:143–159. regeneration manual.Dordrecht,TheNetherlands:Kluwer M.L.;Dougherty,pines. In:Duryea, P 62:1725–1735. Science SocietyofAmericaJournal. changesinnutrientpoolsofmixedoakforests.Soil term WeedSouthern ScienceSocietyofAmerica.26:294. in newlyestablishedpineplantations.Proceedingsofthe Berlin: NeumanVerlag Radebeul.[Notpaged]. Walbaupraxis practice). (forestgenetics inSwedishforestry unknown]: [Publisher234–238. tree improvementconference.[Place ofpublication .M., eds.Forest regenerationmanual. Pinus radiata

Duryea, M.L.; Duryea, inthesouth-eastof .M, eds.Forest th southern Nambiar, E.K.S.1996. Sustainedproductivityofforests L.A.; Pritchett,W.L.;Morris, Swindel, B.F. 1983.Displacement L.A.;Lowery,Morris, R.F. 1988.Influenceofsitepreparation L.A.;Campbell,R.G.1991.Soilandsitepotential. Morris, Minogue, P Miller, W.D.; Maki,T.E. 1957.Plantingpineinpocosins. Miller, J.H.;Zutter, B.R.;Zedaker, S.M.[andothers].1995. Mexal, J.G.;South,D.B.1991.Barerootseedlingculture.In: McKee, W.H., Jr.; Shoulders,E.1974.Slashpine biomass McKee, W.H., Jr.; Shoulders,E.1970.Depthofwatertable McKeand, S.E.;Crook,R.;Allen,H.L.1997.Geneticstability McCrady, R.L.;Jokela,E.J.1998.Canopydynamics,light McCall, M.A.1939.Forest seedpolicyoftheU.S.Department Mann, L.K.;Johnson,D.W.; West, D.C.[andothers].1988. Maki, T.E. 1960.Improvingsitequalitybywet-landdrainage. Lowery, R.F.; Gjerstad,D.H.1991.Chemicalandmechanical Liu, J.;Burkhart,H.E.1994.Modellinginter-andintra-specific Society of America Journal. 60:1629–1642. Society ofAmerica Journal. is acontinuingchallenge tosoilscience.SoilScience 47:951–954. Journal. flatwoods forestsoil.SoilScience Society ofAmerica of nutrientsintowindrowsduring sitepreparationofa ofAppliedForestry. Journal growth. Southern 12:170–178. on soilconditionsaffectingstandestablishmentandtree Publishers: 183–206. manual. Dordrecht,TheNetherlands:KluwerAcademic M.L.;Dougherty,In: Duryea, P 335–358. Dordrecht ,TheNetherlands:KluwerAcademic Publishers: M.L.; Dougherty, P plantationestablishment.In: management after ofForestry.Journal 55:659–663. ForestSouthern ExperimentStation.48p. Orleans: U.S.DepartmentofAgriculture,Forest Service, control: theCOMProject.Gen.Tech. Rep.SO–117.New pine relativetoherbaceous,woody, andcompletecompetition A regionalframeworkofearlygrowthresponseforloblolly Publishers: 89–115. manual. Dordrecht,TheNetherlands:KluwerAcademic M.L.;Dougherty,Duryea, P Science SocietyofAmericaProceedings.38:144–148. response tositepreparationandsoilproperties.Soil Science. 16:399–402. and redoxpotentialofsoilaffectslashpinegrowth.Forest 84–89. ofAppliedForestry. Journal loblolly pine.Southern 21: on predictedfamilyresponsestosilviculturaltreatmentsin pine families.Forest Science.44:64–72. interception, andradiationuseefficiencyofselectedloblolly ofForestry.of Agriculture.Journal 37:820–821. Forest Science.34:412–428. hydrologiclosses,nutrientcapitalandregrowth. postharvest Effects ofwhole-treeandstem-onlyclearcuttingon University Press:106–114. forestsoils.BatonRouge,LA:LouisianaState southern P In: Burns, Kluwer Academic Publishers:251–261. Forest regeneration manual.Dordrecht,TheNetherlands: M.L.;Dougherty,site preparation.In:Duryea, P cutover, site-preparedlands.AnnalsofBotany. 73:429–435. competition inloblollypine( .J.; Cantrell,R.L.;Griswold,H.C.1991.Vegetation .Y., symposium: ed.Eighthannualforestry .M., eds.Forest regenerationmanual. .M., eds.Forest regeneration Pinus taeda .M., eds.Forest regeneration L.)plantationson

.M., eds. Duryea, Neary, D.G.; Bush, P.B.; Michael, J.L. 1993. Fate, dissipation Sederoff, R. 1999. The promise of biotechnology. In: and environmental effects of pesticides in southern forests: Opportunities for increasing fiber supply for the paper a review of a decade of research progress. Environmental industry in the Southern United States: a university Toxicology and Chemistry. 12: 411–428. perspective. Raleigh, NC: North Carolina State University: 59–68. Neary, D.G.; Rockwood, D.L.; Comerford, N.B. [and others]. 1990. Importance of weed control, fertilization, irrigation, Sedjo, R.A.; Botkin, D. 1997. Using plantations to spare and genetics in slash and loblolly pine early growth on poorly natural forests. Environment. 39: 14–20. drained Spodosols. Forest Ecology and Management. 30: 271–281. Shoulders, E. 1957. Site preparation–does it pay? Forests and People. 7(3): 20–21, 23. Nelson, L.R.; Pedersen, R.C.; Autry, L.L. [and others]. 1981. Impact of herbaceous weeds in young loblolly Smalley, G.W.; Bailey, R.L. 1974. Yield tables and stand pine plantations. Southern Journal of Applied Forestry. structures for shortleaf pine plantations in Tennessee, 5: 153–158. Alabama, and Georgia highlands. Res. Pap. SO–97. New Orleans: U.S. Department of Agriculture, Forest Service, North Carolina State Forest Nutrition Cooperative. 1997. Southern Forest Experiment Station. 57 p. Ten-year growth and foliar responses of midrotation loblolly pine plantations to nitrogen and phosphorus fertilization. Smethurst, P.J.; Nambiar, E.K.S. 1989. Role of weeds 81 NCSFNC Rep. 39. Raleigh, NC. [Number of pages in the management of nitrogen in a young Pinus radiata unknown]. plantation. New Forests. 3: 203–224. North Carolina State Forest Nutrition Cooperative. 2001. Smith, L.F. 1966. Site preparation and cultivation improve North Carolina State Forest Nutrition Cooperative. 30th survival and growth of planted slash pine. Tree Planters’ annual report. Raleigh, NC: North Carolina State University, Notes. 64: 12–15. Department of Forestry. 16 p. South, D.B. 2000. Planting morphologically improved pine Chapter 8. Chapter Nutter, W.L.; Douglass, J.E. 1978. Consequences of harvesting seedlings to increase survival and growth. For. Wildl. Res. and site preparation in the Piedmont. In: Tippin, T., ed. Ser. 1. Auburn, AL: Auburn University. 12 p. Proceedings: a symposium on principles of maintaining Southern Industrial Forest Research Council. 1999. A review productivity on prepared sites. Atlanta: U.S. Department of of cooperative forestry research in the South. South. Indust. Agriculture, Forest Service, Southeastern Area State and For. Res. Counc. Rep. 7. Washington, DC: American Forest Private Forestry: 65–72. and Paper Association. 82 p. Perry, T.O.; Wang, C.W. 1958. The value of genetically superior Squillace, A.E. 1989. Tree improvement accomplishments seed. Journal of Forestry. 56: 843–845. in the South. In: Proceedings of the 20th southern forest Pine Plantation Silviculture Pine Plantation Pienaar, L.V.; Rheney, J.W. 1995. Modeling stand-level growth- tree improvement conference. Clemson, SC: Clemson and-yield response to silvicultural treatments. Forest University: 9–20. Science. 41(3): 629–638. Stone, E.L. 1975. Soil and man’s use of forest land. In: Winget, Pienaar, L.V.; Shiver, B.D. 1993. Early results from an old-field C.H., ed. Forest soils and forest land management. Quebec: loblolly pine spacing study in the Georgia Piedmont with Les Presses de L’Universite Laval: 1–9. competition control. Southern Journal of Applied Forestry. Swindel, B.F.; Neary, D.G.; Comerford, N.B. [and others]. 17: 193–196. 1988. Fertilization and competition control accelerate early Pritchett, W.L.; Llewellyn, W.R.; Swinford, K.R. 1961. Response southern pine growth on flatwoods. Southern Journal of of slash pine to colloidal phosphate fertilization. Soil Science Applied Forestry. 12: 116–121. Society of America Proceedings. 25: 397–400. Terry, T.A.; Hughes, J.H. 1975. The effects of intensive Pritchett, W.L.; Smith, W.H. 1975. Forest fertilization in the management on planted loblolly pine (Pinus taeda L.) U.S. Southeast. In: Bernier, B.; Winget, C.H., eds. Forest growth on poorly drained soils of the Atlantic Coastal Plain. soils and forest land management. Quebec: Les Presses de In: Bernier, B.; Winget, C.H., eds. Forest soils and forest L’Universite Laval: 467–476. land management. Quebec: Les Presses de L’Universite Laval: 351–377. Reed, G.M. 1995. Realization of a dream: Charles H. Herty and the South’s first newsprint mill. Forest and Conservation Terry, T.A.; Hughes, J.H. 1978. Drainage of excess water why History. 39: 4–16. and how? In: Balmer, W.E., ed. Proceedings: Soil moisture site productivity symposium. Atlanta: U.S. Department of Samuelson, L.J. 2000. Effects of nitrogen on leaf physiology Agriculture, Forest Service:148–166. and growth of different families of loblolly and slash pine. New Forests. 19: 95–107. Thornton, E.S. 1960. Applications of site evaluation to a large industrial forest. In: Burns, P.D., ed. Southern forest soils. Schlaudt, E.A. 1955. Drainage in forestry management Baton Rouge, LA: Louisiana State University: 73–76. in the South. In: Water, the yearbook of agriculture 1955. Washington, DC: U.S. Department of Agriculture: 564–568. Tippin, T., ed. 1978. Proceedings: a symposium on principles of maintaining productivity on prepared sites. Atlanta: Schreiner, E.J. 1950. Genetics in relation to forestry. Journal U.S. Department of Agriculture, Forest Service, of Forestry. 48: 33–38. Southeastern Area State and Private Forestry. [Number of pages unknown]. Schultz, R.P. 1997. Loblolly pine. The ecology and culture of lobolly pine (Pinus taeda L.). Agric. Handb. 713. Todd, D.; Pait, J.; Hodges, J. 1995. The impact and value of tree Washington, DC: U.S. Department of Agriculture, improvement in the South. In: Proceedings: 23rd southern Forest Service. [Number of pages unknown]. forest tree improvement conference. Asheville, NC: [Publisher unknown]: 7–15. Southern Forest Science: 82 Past, Present, and Future Productivity Walker, L.C.1960.Fertilizing pine:aroundupof southern Wakeley, P Wakeley, P Wahlenberg, W.G. 1960.Loblollypine:itsuse,ecology, Vose, J.M.;Allen,H.L.1991.Quantityandtimingofneedlefall Vose, J.J.;Dougherty, P Vitousek, P Van Deusen,P U.S. DepartmentofAgriculture.1989.Aguidetothecareand U.S. DepartmentofAgriculture.1988.TheSouth’sfourth U.S. DepartmentofAgriculture.1949.Trees, theyearbook U.S. DepartmentofAgriculture.1929.Volume, yield,andstand Wear, forest DavidN.;Gries,JohnG., eds. 2002.Southern Wang, C.W.; Perry, T.O. seedorchardsin 1957.Grafted observations andconcepts.In: observations 233p. Service. 18. Washington, DC:U.S.DepartmentofAgriculture,Forest of Forestry. 42:23–32. NC: DukeUniversity. 603p. regeneration, protection,growthandmanagement.Durham, and Management.41:205–219. in NandPfertilizedloblollypinestands.Forest, Ecology, area ofpinestands.EcologyBulletin.43:102–114. Factors influencingtheamountanddistributionofleaf 120–125. ofAppliedForestry. Joiurnal plantations. Southern 9: preparation decreasesoilnitrogenavailabilityinyoung Silva Fennica. 33:207–216. R8–MB39. [Placeofpublicationunknown].44p. pineseedlings.Serv.planting ofsouthern Manage.Bull. Washington, DC.512p. forthefuture.For.forest: alternatives Resour. Rep.24. of agriculture.Washington, DC.944p. Washington, DC.202p. pines.Misc.Publ.50. tables forsecondgrowthsouthern Southern ResearchStation.635p. Southern NC: U.S.DepartmentofAgriculture,Forest Service, resource assessment.Gen.Tech. Rep.SRS–53.Asheville, Georgia: 93–101. improvement conference.Athens, GA:Universityof the South.In:Proceedings:Fourth foresttree southern 86–95. forest soils.BatonRouge,LA:LouisianaStateUniversity: . 1954. Planting the southern pines.Agric.Monogr.. 1954.Plantingthesouthern . 1944.Geographicsourcesofloblollypine.Journal .M.; Matson,P .C. 1999. Multiple solution harvest scheduling. .C. 1999.Multiplesolutionharvest .M.; Long,J.N.[andothers].1994. .A. 1985. Intensive harvesting andsite .A. 1985.Intensiveharvesting

Burns, P Burns, .D., ed.Southern Zobel, B.J.;Talbert, J.1984.Appliedforesttree Zobel, B.J.;Barber, J.;Brown,C.L.;Perry, T.O. 1958.Seed Zobel, B.J.1953.Seedorchardsforsuperiortrees.Forest Yin, R.;Sedjo,R.2001.Isthistheageofintensive Yin, R.;Pienaar, L.V.; Aronow, M.E.1998.Theproductivityand Wooten, ofourdrainage H.H.;Jones,L.A.1955.Thehistory Williams, M.1989.Americansandtheirforests:ahistorical Williams, C.G.;Byram,T.D. 2001.Forestry’s thirdrevolution: Will, G.1985.NutrientdeficienciesandfertilizeruseinNew Wells, D.M.;Berenyi,N.M.;Davey, C.G.;Crutchfield, C.B. Wells, D.M.1974.Intensivecultureof C.G.;Crutchfield, Wells, C.G.;Craig, J.R.;Kane,M.B.;Allen,H.L.1986.Foliar improvement. NewYork: JohnWiley. 505p. Forestry. 56:815–825. of orchards–their conceptandmanagement.Journal Farmer. 13(2):10–12,20. ofForestry.Piedmont. Journal 99:10–17. management: astudyofloblollypineonGeorgia’s ofForestry. Journal profitability offiberfarming. 96:13–18. Washington, DC:U.S.DepartmentofAgriculture:478–491. enterprise. In:Water, theyearbookofagriculture1955. geography. Cambridge:CambridgeUniversityPress.599p. 116–121. ofAppliedForestry. Journal programs. Southern 25: integrating biotechnologyinto Forest ResearchInstitute. 53p. NewZealand: Zealand exoticforests.FRIBull.97.Rotorua, Forest Experiment Station.15p. Department ofAgriculture,Forest Southeastern Service, of loblollypine.Res.Pap. SE–110.Asheville, NC:U.S. fertilization 1973. Soilandfoliarguidelinesforphosphorus 212–228. Atlanta: U.S.DepartmentofAgriculture,Forest Service: Proceedings: asymposiumonmanagementofyoungpines. young loblollypine.In:Balmer, W.E.; Williston, H.L.,eds. 50: 1330–1335. in loblollypine.SoilScienceSocietyofAmericaJournal. response and soiltestsforthepredictionofphophorus Pinus taeda L.breeding