Management implications of annual growth rings in Pterocarpus angolensis from Zimbabwe

1999 ◽  
Vol 124 (2-3) ◽  
pp. 217-229 ◽  
Author(s):  
D.W Stahle ◽  
P.T Mushove ◽  
M.K Cleaveland ◽  
F Roig ◽  
G.A Haynes
2008 ◽  
Vol 6 (2) ◽  
Author(s):  
Iriwi Louisa S. Sinon

<p><em>Study dendrochronology or tree-ring dating is defined as the study of chronological sequence of annual growth rings in trees. Teak (Tectona grandis) is one of various tree species that has been identified for the use of tree-ring studies in tropical regions. Teak is found to be suitable for dendrochronology as it is long-lived and develops defined annual growth rings. In Java, teak cans growth naturally or intensively in plantation. The two silviculture conditions will give different sensitivity on climate effect. Therefore, the effect of silviculturer will on natural teak and plantation teak in Saradan, Madiun, and East Java. As a part of the study, ten core samples from natural- growth teak were measured. The samples of growth rings is spanned from 1832 – 2004. Using the COFECHA program, the correlation of the samples (r) was found to be 0.44 point, which is satisfactory to the standard used in dendrochronology. Thus, from this study it can be concluded that natural teak could still be used in dendrochronology, although the sensitivity are not as high as plantation teak. </em></p>


1986 ◽  
Vol 16 (2) ◽  
pp. 423-426 ◽  
Author(s):  
Laurance D. Hall ◽  
Vasanthan Rajanayagam ◽  
Wendy A. Stewart ◽  
Paul R. Steiner

A magnetic resonance scanner has been used to obtain images at 0.14 T, based on the water in aspen (Populustremuloides Michx.). In addition to visualization of the expected structural features such as annual growth-rings and knots, several additional features appear that require further study. Kiln-dried wood does not contain sufficient water to give an image, but can do so after impregnation with water.


Trees ◽  
2008 ◽  
Vol 22 (5) ◽  
pp. 663-670 ◽  
Author(s):  
Gustavo Calderucio Duque Estrada ◽  
Cátia Henriques Callado ◽  
Mário Luiz Gomes Soares ◽  
Cláudio Sérgio Lisi

Radiocarbon ◽  
2013 ◽  
Vol 55 (2) ◽  
pp. 833-840 ◽  
Author(s):  
Laura E Beramendi-Orosco ◽  
Sergio Hernandez-Morales ◽  
Galia Gonzalez-Hernandez ◽  
Vicenta Constante-Garcia ◽  
Jose Villanueva-Diaz

Dendrochronological studies are limited in tropical regions because not many tree species form annual growth rings. This work reports an evaluation of the dendrochronological potential of tropical ash (Fraxinus uhdei) and its use as a bioindicator of fossil CO2 concentration in urban areas by means of radiocarbon analysis on growth rings. We analyzed a cross-section of a tree that grew during the period 1932–2007 in San Luis Potosí, one of the most industrialized cities in Mexico. The Δ14C values obtained follow the same variation pattern as the calibration curve of the Northern Hemisphere (NH) zone 2 (Hua and Barbetti 2004), with the peak centered in 1964, but they are lower by up to 124′. The high correlation coefficient (r = 0.990, p < 0.001) between the variation patterns indicates that this species does form annual growth rings, and the lower values can be attributed to the 14C dilution caused by fossil CO2 emissions. The magnitude of the Suess effect varied between −6.9% and −0.5%, equivalent to fossil CO2 concentrations ranging between 21.9 and 1.5 ppmv. The Suess effect and fossil CO2 values have significant variations with no apparent monotone increasing trend, suggesting that the CO2 emissions during the studied period have diverse sources. It is concluded that F. uhdei has potential for dendrochronological studies in tropical areas because its growth rings are formed annually and, furthermore, it can be used as a bioindicator of atmospheric 14C variations and fossil CO2 concentration in urban areas.


Author(s):  
Anthony Bassutti

Large scale land disturbances are occurring in sensitive Arctic regions as a result of climate change. These disturbances which are caused by permafrost melting and can damage fragile tundra ecosystems and have important impacts on downstream water quality. Determining the timeline of these disturbances will aid in the understanding of the effect of climate change in the Arctic. This can be performed through the analysis of environmental proxy records such as those found in the annual growth rings of trees, which express environmental stresses, such as those experienced during a land disturbance. Dendrochronology of the most northern occurring woody plant, Salix arctica (arctic willow) has been explored only a few times in the past, and its potential for paleoenvironmental studies in the Arctic have been largely over‐looked. We examined the thickness of annual growth rings from S. arctica from two areas of land disturbance on southern Melville Island, Nunavut. Common growth trends were found in both dead (snag) and living samples from the sites. Preliminary data show that a substantial disturbance in the growth of the samples is evident approximately 40 years ago and was likely due to land disturbance. These initial findings demonstrate the successful use of S. arctica as a paleoenvironmental indicator and provide useful tools to determine the timing of past permafrost disturbances and climate change in the Arctic. We are continuing to investigate additional samples from other sites to determine if the method can be used as a novel tool for understanding permafrost landscape dynamics.


2016 ◽  
Vol 88 (suppl 1) ◽  
pp. 517-525 ◽  
Author(s):  
BRUNNA T. SOUZA ◽  
GUSTAVO C.D. ESTRADA ◽  
MÁRIO L.G. SOARES ◽  
CÁTIA H. CALLADO

ABSTRACT The formation of annual growth rings has been confirmed for several mangrove species in the last decade, among which is the Rhizophora mangle. However, the record of annual rings for this species was made in a region with high hydric seasonality, a widely recognized induction factor of annual rings in tropical species. In this sense, the present study aimed to verify the occurrence of annual growth rings in R. mangle in the mangroves of Guaratiba (Rio de Janeiro, Southeastern Brazil), a region with low hydric seasonality. For this purpose, the crossdating technique was applied in ten trees collected with known age (seven years). The growth rings are characterized by alternating layers of low vessel density (earlywood) and high vessel density (latewood). Multiple regression analysis indicated that growth rings width variation is driven by precipitation, water surplus, water deficit and water storage. Crossdating analysis confirmed the existence of annual growth rings in the R. mangle in Guaratiba. This discovery in a region with low hydric seasonality increases the dendrocronological potential of this species and suggests the importance of biological factors (eg. phenological behavior) as complementary inductors for the formation of growth rings in this species.


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