Age determination of two South African <i>Acacia</i> species using ring counts and radiocarbon dating

February, Edmund C.; Mader, André; Bond, William J.

doi:10.1111/j.1365-2028.2006.00651.x

Cited by 9 publications

(9 citation statements)

References 13 publications

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“…Despite several dendrochronological studies have been conducted on acacia species (February et al, 2006;Gourlay, 1995a;Gourlay, 1995b;Gourlay and Kanowsky, 1991;Mariaux, 1975;Martin and Moss, 1997;Robbertse et al, 1980;Steenkamp et al, 2008) only few authors (Eshete and Stahl, 1999;Tarhule and Hughes, 2002) have studied (marginally) A. seyal, one of the most widely distributed tree in Sahelian arid environments. Also, most works are based on trees from natural stands, lacking the background information necessary to reconstruct the tree-life history (Gourlay, 1995a).…”

Section: Discussionmentioning

confidence: 97%

“…Even if recently some dendrochronological studies were carried out in different African countries (February et al, 2006;Fichtler et al, 2004;Gourlay, 1995a;Gourlay et al, 1996;Milton et al, 1997;Steenkamp et al, 2008;Trouet et al, 2001), an important gap of knowledge exists about semi-arid Sahel areas (Cherubini et al, 2003). Only few studies have focused on Western Sahel and its typical trees (Eshete and Stahl, 1999;Mariaux, 1975;Martin and Moss, 1997), because of several different reasons i.e.…”

Section: Introductionmentioning

confidence: 95%

“…These results enabled several authors to investigate more closely the relationships between wood formation and seasonal climatic trends, in particular, its climatic signal (Cook and Kairiukstis, 1990). Tree rings formed during the rainy season have been used to understand tree growth under different water availability in several species including some acacias (Eshete and Stahl, 1999;February et al, 2006;Martin and Moss, 1997;Steenkamp et al, 2008), yet the relationships are sometimes difficult to interpret, as growth limitations or changes in growth patterns are not well known.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Wood-growth zones in Acacia seyal Delile in the Keita Valley, Niger: Is there any climatic signal?

Nicolini

Tarchiani

Saurer

et al. 2010

Journal of Arid Environments

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Section: Discussionmentioning

confidence: 97%

Section: Introductionmentioning

confidence: 95%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Wood-growth zones in Acacia seyal Delile in the Keita Valley, Niger: Is there any climatic signal?

Nicolini

Tarchiani

Saurer

et al. 2010

Journal of Arid Environments

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“…Some tree species have lifespans of more than a thousand years [30,31]. High estimates (>1000 yr) have also been reported for savanna trees [6], but newer research based on 14 C dating estimates the age of some A. nigrescens and A. nilotica individuals to be less than 100 years [32]. Longevity estimates of greater than 100 years are cast in the form of general statements (150 y, Serengeti, [33]), based on mortality rates (>> 100 y, Mojave desert, [29]) and on repeat photography (> 100 y, Arizona, [34]).…”

Section: Discussionmentioning

confidence: 99%

Longevity and growth of Acacia tortilis; insights from 14C content and anatomy of wood

Andersen

Krzywinski

2007

BMC Ecol

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BackgroundAcacia tortilis is a keystone species across arid ecosystems in Africa and the Middle East. Yet, its life-history, longevity and growth are poorly known, and consequently ongoing changes in tree populations cannot be managed in an appropriate manner. In other arid areas parenchymatic bands marking growth zones in the wood have made dendrochronological studies possible. The possibilities for using pre- and post-bomb 14C content in wood samples along with the presence of narrow marginal parenchymatic bands in the wood is therefore tested to gain further insight into the age, growth and growth conditions of A. tortilis in the hyper-arid Eastern Desert of Egypt.ResultsBased on age scenarios and the Gompertz growth equation, the age of trees studied seems to be from 200 up to 650 years. Annual radial growth estimated from calibrated dates based on the post-bomb 14C content of samples is up to 2.4 mm, but varies both spatially and temporally. Parenchymatic bands are not formed regularly. The correlation in band pattern among trees is poor, both among and within sites.ConclusionThe post-bomb 14C content of A. tortilis wood gives valuable information on tree growth and is required to assess the age scenario approach applied here. This approach indicates high longevities and slow growth of trees. Special management measures should therefore be taken at sites where the trend in tree population size is negative. The possibilities for dendrochronological studies based on A. tortilis from the Eastern Desert are poor. However, marginal parenchymatic bands can give insight into fine scale variation in growth conditions and the past management of trees.

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“…These discs were then prepared for microscopy by polishing with a belt sander (4 00 Makita, Japan) using progressively finer sandpaper (February et al 2006). The polished discs were then scanned at 3600 dpi (HP ScanJet 3970 Series) and the images imported into Cybis CooRecorder (Larsson 2006).…”

Section: Sampling Methodsmentioning

confidence: 99%

History matters: tree establishment variability and species turnover in an African savanna

2011

Self Cite

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Abstract. Demographic variability in the tree component of savannas, arising from both spatial and temporal variability in fire, herbivory, and climate, is thought to be a key driver maintaining tree-grass coexistence in savannas. Modeling work has shown that this variability can be vital to the persistence of savanna as a biome and that variability in climate, herbivory and fire affect tree establishment. However, empirical evaluations of the idea that savanna tree establishment is variable have so far been limited to tests of the effects of major events (such as the East African rinderpest epidemic) on tree establishment. The degree to which tree establishment varies in savannas under less extreme variability in climate, herbivory and fire remains unknown.We tested whether establishment of adult trees was constant or episodic using tree ring counting of three Acacia species in Hluhluwe iMfolozi Park in South Africa. Patterns of establishment of adult trees were analyzed at three spatial scales for temporal and spatial patchiness. Establishment of adult trees was not constant for any of the three species of Acacia, and all three species showed significant spatial patchiness and larger-scale temporal variability in establishment patterns. Spatial patchiness highlights the importance of landscape processes like fire and herbivory, while larger-scale temporal variability indicates that climatic variability also structures tree demography.These results suggest that current tree cover in savannas is a product of ecological history and is not necessarily determined by current ecological processes. An historical perspective is essential for interpreting patterns of tree cover in savannas, in models of the effects of climate, fire and herbivory (especially elephants), in experimental work, and in analyses of continental patterns of tree cover alike.

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Age determination of two South African Acacia species using ring counts and radiocarbon dating

Cited by 9 publications

References 13 publications

Wood-growth zones in Acacia seyal Delile in the Keita Valley, Niger: Is there any climatic signal?

Wood-growth zones in Acacia seyal Delile in the Keita Valley, Niger: Is there any climatic signal?

Longevity and growth of Acacia tortilis; insights from 14C content and anatomy of wood

History matters: tree establishment variability and species turnover in an African savanna

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