Environmental and allometric drivers of tree growth rates in a north Australian savanna

Prior, Lynda D.; Brook, Barry W.; Williams, Richard J.; Werner, Patricia A.; Bradshaw, Corey J. A.; Bowman, David M. J. S.

doi:10.1016/j.foreco.2006.06.034

Cited by 59 publications

(130 citation statements)

References 46 publications

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“…Our study raises the question of how the fast growing (height-response) individuals with thinner bark, mainly eucalypts (Prior et al 2006), had higher rates of survival after fire than thicker-barked diameter-response individuals? Furthermore, an explanation for the cooccurrence of both height-and diameter-responses is required, especially considering that growing tall appears to have significant advantages over growing wide and thus would be expected to become the dominant response.…”

Section: Discussionmentioning

confidence: 90%

“…Fire is an important driver of tree dynamics in savannas worldwide because it can limit seedling recruitment and prevent the transition of juvenile trees to the canopy (Prior et al 2006, Bond 2008, Midgley et al 2010, Murphy et al 2010. Juvenile trees most strongly experience the impact of fire because their entire above ground biomass is within the flame zone.…”

Section: Introductionmentioning

confidence: 99%

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How do small savanna trees avoid stem mortality by fire? The roles of stem diameter, height and bark thickness

et al. 2011

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Abstract. To recruit to reproductive size in fire-prone savannas, juvenile trees must avoid stem mortality (topkill) by fire. Theory suggests they either grow tall, raising apical buds above the flames, or wide, buffering the stem from fire. However, growing tall or wide is of no advantage without stem protection from fire. In Litchfield National Park, northern Australia, we explored the importance of bark thickness to stem survival following fire in a eucalypt-dominated tropical savanna. We measured bark thickness, prefire height, stem diameter and resprouting responses of small stems under conditions of low to moderate fire intensity. Fire induced mortality was low (,10%), topkill was uncommon (,11% of 5 m to 37% of 1 m tall stems) and epicormic resprouting was common. Topkill was correlated only with absolute bark thickness and not with stem height or width. Thus, observed height and diameter growth responses of small stems are likely different pathways to achieving bark thick enough to protect buds and the vascular cambium. Juvenile height was traded off against the cost of thick bark, so that wide stems were short with thicker bark for a given height. The fire resilience threshold for bark thickness differed between tall (4-5 mm) and wide individuals (8-9 mm), yet tall stems had lower P Topkill for a given bark thickness. Trends in P Topkill reflected eucalypt versus non-eucalypt differences. Eucalypts had thinner bark than non-eucalypts but lower P Topkill . With deeply embedded epicormic buds eucalypts do not need thick bark to protect buds and can allocate resources to height growth. Our data suggest the only 'strategy' for avoiding topkill in fireprone systems is to optimise bark thickness to maximise stem bud and cambium protection. Thus, escape height is the height at which bark protects the stem and a wide stem per se is insufficient protection from fire without thick bark. Consequently, absolute bark thickness is crucial to explanations of species differences in topkill, resprouting response and tree community composition in fire-prone savannas. Bark thickness and the associated mechanism of bud protection offer a proximate explanation for the dominance of eucalypts in Australian tropical savannas.

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Section: Discussionmentioning

confidence: 90%

Section: Introductionmentioning

confidence: 99%

How do small savanna trees avoid stem mortality by fire? The roles of stem diameter, height and bark thickness

et al. 2011

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“…Frequent burning has been observed to reduce tree growth rates in Australian savannahs [23,24] and tall open forests [25], though contrary results have been observed in some eucalypt forests e.g., [26]. Decreased nutrient availability due to the combustion of leaf litter and humic material as well as inhibited growth associated with fire damage to roots and stems are potential drivers of reduced growth rates in regularly burnt forests [25].…”

Section: Impacts Of Frequent Burning On Carbon and Stand Structurementioning

confidence: 99%

“…Such key demographic processes influence stand structure and biomass. The shortening of intervals between fires (i.e., increasing fire frequency) has been observed in some cases to lead to reductions in growth rate [23][24][25] and recruitment [22,26], increases in tree mortality [22,[25][26][27] and reductions in tree basal area and carbon storage [22,25,27,28].…”

Section: Introductionmentioning

confidence: 99%

Impacts of Frequent Burning on Live Tree Carbon Biomass and Demography in Post-Harvest Regrowth Forest

Collins

Penman

Ximenes

et al. 2014

Forests

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Abstract:The management of forest ecosystems to increase carbon storage is a global concern. Fire frequency has the potential to shift considerably in the future. These shifts may alter demographic processes and growth of tree species, and consequently carbon storage in forests. Examination of the sensitivity of forest carbon to the potential upper and lower extremes of fire frequency will provide crucial insight into the magnitude of possible change in carbon stocks associated with shifts in fire frequency. This study examines how tree biomass and demography of a eucalypt forest regenerating after harvest is affected by two experimentally manipulated extremes in fire frequency (i.e., ~3 year fire intervals vs. unburnt) sustained over a 23 year period. The rate of post-harvest biomass recovery of overstorey tree species, which constituted ~90% of total living tree biomass, was lower within frequently burnt plots than unburnt plots, resulting in approximately 20% lower OPEN ACCESSForests 2014, 5 803 biomass in frequently burnt plots by the end of the study. Significant differences in carbon biomass between the two extremes in frequency were only evident after >15-20 years of sustained treatment. Reduced growth rates and survivorship of smaller trees on the frequently burnt plots compared to unburnt plots appeared to be driving these patterns. The biomass of understorey trees, which constituted ~10% of total living tree biomass, was not affected by frequent burning. These findings suggest that future shifts toward more frequent fire will potentially result in considerable reductions in carbon sequestration across temperate forest ecosystems in Australia.

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“…One of the limitations in implementing management plans is the lack of reliable data about mean annual increments (MAI) of woody species in natural and managed conditions (PRIOR et al, 2006).…”

Section: Introductionmentioning

confidence: 99%

CLIMATE-TREE GROWTH RELATIONSHIPS OF Mimosa tenuiflora IN SEASONALLY DRY TROPICAL FOREST, BRAZIL

Mattos

Braz

Domene

et al. 2015

CERNE

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Mimosa tenuiflora is a native pioneer tree from the Caatinga used commercially as firewood due to its high calorific value. It is deciduous, its trunk does not reach large diameters and it has good regrowth capacity. This study intended to determine the annual increment in diameter of M. tenuiflora and its correlation with rainfall, as basis for fuel wood management. Disks from the stem base of M. tenuiflora trees were collected in 2008 in Sertânia and Serra Talhada, Pernambuco State, from regrowth of trees coppiced in 2003 and in Limoeiro do Norte, Ceará State, from a plantation established in 2002. The trees have well-defined annual growth rings, highly correlated with annual precipitation and are well-suited for dendrochronological investigations. Forest managers must consider the influence of previous drier years in the wood production when predicting fuel wood harvesting. The high growth correlation with the previous year's rainfall in regions where the rains start after photoperiodic stimulation indicate the necessity of understanding the growth dynamics of the species under dry forest conditions through additional ecophysiology studies. RELAÇÃO CLIMA-CRESCIMENTO DE ÁRVORES DE Mimosa tenuiflora EM FLORESTA TROPICAL SECA SAZONAL, BRAZILRESuMO: Mimosa tenuiflora é uma árvore pioneira e nativa da Caatinga usada, comercialmente, para lenha, em razão do seu elevado poder calorífico. É decídua, com perda de folhas no final da estação chuvosa, seu tronco não atinge grandes diâmetros e tem boa capacidade de rebrota. Este estudo tem por objetivo determinar o incremento anual em diâmetro de M. tenuiflora e sua correlação com a precipitação, visando a subsidiar o manejo florestal de madeira para energia. Discos da base do tronco de árvores de M. tenuiflora foram coletados em 2008, em

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Environmental and allometric drivers of tree growth rates in a north Australian savanna

Cited by 59 publications

References 46 publications

How do small savanna trees avoid stem mortality by fire? The roles of stem diameter, height and bark thickness

How do small savanna trees avoid stem mortality by fire? The roles of stem diameter, height and bark thickness

Impacts of Frequent Burning on Live Tree Carbon Biomass and Demography in Post-Harvest Regrowth Forest

CLIMATE-TREE GROWTH RELATIONSHIPS OF Mimosa tenuiflora IN SEASONALLY DRY TROPICAL FOREST, BRAZIL

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