Growth of juvenile and sapling trees differs with both fire season and understorey type: Trade-offs and transitions out of the fire trap in an Australian savanna

dc.contributor.authorWerner, Patricia
dc.date.accessioned2015-12-10T23:08:07Z
dc.date.issued2011
dc.date.updated2022-05-29T08:17:39Z
dc.description.abstractCanopy tree populations in mesic savannas are often bimodal with few saplings but many smaller individuals of indeterminate age that repeatedly suffer topkill and regenerate from underground tissues. Little is known about growth rates or mechanisms that allow subadult trees to reach the canopy. The wooded savannas of northern Australia have high frequencies of dry-season fires. In a 32400-m 2 field experiment, 2405 juveniles (<150-cm height) and saplings (150-499cm) of the eucalypt canopy species were individually marked and measured the year prior to fires set in three different seasons and again at the end of the growing season (without fires) a year later. Trees in unburnt plots served as controls. All fire treatments were repeated in plots dominated by the most common understorey, a native annual grass (sorghum) and in plots dominated by perennial native species; these produce different fuels for fires and competitive regimes for young trees. After early dry-season fires, height growth of larger juveniles and all saplings was significantly enhanced, especially in sorghum. After late dry- or wet-season fires, juvenile trees grew well, but all of the small saplings (150- to 299-cm height) were reduced to 'juveniles' and did not recover pre-fire heights but, instead, produced many new basal (coppice) stems. Late, dry-season fires reduced more than 80% of large saplings (300-499cm) to juvenile size in sorghum, whereas in non-sorghum, 60% of the trees grew to poles (500-999cm). The results demonstrate that juvenile and sapling growth responses to fire and the probability of subadult trees reaching the canopy are related to fire-understorey interactions, and suggest that the mechanisms include morphological and carbohydrate storage dynamics which vary with tree size and life history stage. The key to successful management of a sustainable woody canopy lies in the understorey.
dc.identifier.issn1442-9985
dc.identifier.urihttp://hdl.handle.net/1885/63152
dc.publisherBlackwell Science Asia
dc.sourceAustral Ecology
dc.subjectKeywords: carbohydrate; coniferous forest; fire behavior; forest canopy; forest management; growth rate; growth response; juvenile; morphology; native species; population dynamics; sapling; savanna; sorghum; trade-off; understory; woodland; Australia; Eucalyptus Eucalyptus population dynamics; Fire-understorey interaction; Fire: effect of fire season; Savanna woodland: tree: height growth; Tree: canopy replacement
dc.titleGrowth of juvenile and sapling trees differs with both fire season and understorey type: Trade-offs and transitions out of the fire trap in an Australian savanna
dc.typeJournal article
local.bibliographicCitation.issue6
local.bibliographicCitation.lastpage657
local.bibliographicCitation.startpage644
local.contributor.affiliationWerner, Patricia, College of Medicine, Biology and Environment, ANU
local.contributor.authoremailrepository.admin@anu.edu.au
local.contributor.authoruidWerner, Patricia, a175809
local.description.embargo2037-12-31
local.description.notesImported from ARIES
local.identifier.absfor060207 - Population Ecology
local.identifier.absfor060208 - Terrestrial Ecology
local.identifier.absseo960806 - Forest and Woodlands Flora, Fauna and Biodiversity
local.identifier.ariespublicationu4279067xPUB775
local.identifier.citationvolumeOnline 9 DEC 2011
local.identifier.doi10.1111/j.1442-9993.2011.02333.x
local.identifier.scopusID2-s2.0-84865599483
local.identifier.thomsonID000309240400023
local.identifier.uidSubmittedByu4279067
local.type.statusPublished Version

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