Interference interactions in experimental pine-hardwood stands

dc.contributor.authorFredericksen, Todd Simonen
dc.contributor.committeechairZedaker, Shepard M.en
dc.contributor.committeememberKreh, Richard E.en
dc.contributor.committeememberNilsen, Erik T.en
dc.contributor.committeememberSeiler, John R.en
dc.contributor.committeememberSmith, David Williamen
dc.contributor.departmentForestryen
dc.date.accessioned2014-03-14T21:16:30Zen
dc.date.adate2008-07-28en
dc.date.available2014-03-14T21:16:30Zen
dc.date.issued1991-12-15en
dc.date.rdate2008-07-28en
dc.date.sdate2008-07-28en
dc.description.abstractCompetition for resources and other interference from non-crop vegetation often limits the productivity of pine and pine-hardwood forest stands in the southern United States. However, forest researchers have yet to fully quantify the effect of this interference on forest tree yield and there is an incomplete understanding of the biological mechanisms of interference. To better quantify the effects of interference interactions and elucidate their mechanisms, a field replacement series experiment and two supporting greenhouse experiments were carried out using loblolly pine (Pinus taeda L.), red maple (Acer rubrum L.), black locust (Robinia pseudoacacia L.), and herbaceous vegetation. Interference between pine. hardwood species, and herbaceous vegetation significantly impacted the growth and yield of young experimental pine-hardwood stands. While herbaceous vegetation significantly affected all stands. it reduced the yield of hardwood species more than loblolly pine. Loblolly pine appeared to ameliorate the effect of herbaceous vegetation on hardwoods in some stands. Interference outcomes were site- and scale-dependent. In field stands, synergistic adjustment in total yield due to pine-hardwood interference was not observed, except for loblolly pine-black locust mixtures on lower site quality replicates. Hardwood species suppressed the growth of pine in seedling stands planted at very close spacing in greenhouse boxes, while the yield at age three of less densely-planted field stands was positively related to the proportion of pine in the stand. Close spacing increased the ability of wide-spreading hardwood crowns to overtop and restrict light availability to conically-shaped pine crowns. Interference outcomes were related to the interactive effect of light, soil moisture, and soil nitrogen resources on tree growth and competitive ability. If not overtopped by hardwoods, loblolly pine had high yields in mixtures with hardwoods and competed effectively for soil moisture and nitrogen through efficient use of these resources. Changes in allometric relationships were observed for tree species in response to interference including root-shoot ratios, crown dimensions, and specific leaf areas. Tall fescue (Festuca arundinacea Schreb.), the principal herbaceous species in the field study, appeared to affect the physiology and yield of all species through allelopathy in a greenhouse experiment. suggesting that reduced yield in herbaceous plots may be due to direct chemical effects in addition to resource competition.en
dc.description.degreePh. D.en
dc.format.extentvi, 167 leavesen
dc.format.mediumBTDen
dc.format.mimetypeapplication/pdfen
dc.identifier.otheretd-07282008-134718en
dc.identifier.sourceurlhttp://scholar.lib.vt.edu/theses/available/etd-07282008-134718/en
dc.identifier.urihttp://hdl.handle.net/10919/38901en
dc.language.isoenen
dc.publisherVirginia Techen
dc.relation.haspartLD5655.V856_1991.F745.pdfen
dc.relation.isformatofOCLC# 25611887en
dc.rightsIn Copyrighten
dc.rights.urihttp://rightsstatements.org/vocab/InC/1.0/en
dc.subject.lccLD5655.V856 1991.F745en
dc.subject.lcshForest management -- Southern Statesen
dc.subject.lcshHabitat partitioning (Ecology)en
dc.subject.lcshHardwoodsen
dc.subject.lcshPineen
dc.subject.lcshPlant competitionen
dc.titleInterference interactions in experimental pine-hardwood standsen
dc.typeDissertationen
dc.type.dcmitypeTexten
thesis.degree.disciplineForestryen
thesis.degree.grantorVirginia Polytechnic Institute and State Universityen
thesis.degree.leveldoctoralen
thesis.degree.namePh. D.en

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