van der Sleen et al. 2015 - Supplementary information

Trees, 2011

Knowledge on juvenile tree growth is crucial to understand how trees reach the canopy in tropical forests. However, long-term data on juvenile tree growth are usually unavailable. Annual tree rings provide growth information for the entire life of trees and their analysis has become more popular in tropical forest regions over the past decades. Nonetheless, tree ring studies mainly deal with adult rings as the annual character of juvenile rings has been questioned. We evaluated whether juvenile tree rings can be used for three Bolivian rainforest species. First, we characterized the rings of juvenile and adult trees anatomically. We then evaluated the annual nature of tree rings by a combination of three indirect methods: evaluation of synchronous growth patterns in the tree-ring series, 14 C bomb peak dating and correlations with rainfall. Our results indicate that rings of juvenile and adult trees are defined by similar ring-boundary elements. We built juvenile tree-ring chronologies and verified the ring age of several samples using 14 C bomb peak dating. We found that ring width was correlated with rainfall in all species, but in different ways. In all, the chronology, rainfall correlations and 14 C dating suggest that rings in our study species are formed annually. Cedrelinga Months S N J M M J S N J M M J S N J M M J

Dendrochronologia, 2002

Tree-ring analysis in the tropics exists since more than one hundred years. In more than 20 tropical countries and numerous tree species the existence of annual tree-rings is doubtless proven. Rhythmic growth is induced by short drought periods or long lasting inundation, the influence of the photoperiod is questionable. Climatological analyses of tree-ring chronologies show the influence of El Nin Ä o on tree growth. Tree-ring based age determinations give maximum ages of not more than 600 years for broad leaf trees in tropical lowlands. Increment estimations by ring-width measurements give reliable results for sustainable management systems in tropical forests.

Australian Journal of Botany, 2018

The presence of distinct growth rings in a large number of tropical tree species has allowed a range of studies involving the growth history during the life span of the tree. This work aimed to examine the presence of tree rings and study growth patterns of tree species from five seasonally dry tropical forest fragments. Wood cores were extracted using 5-mm increment borer. The macroscopic structure of growth rings from 24 deciduous tree species was observed under stereomicroscope and classified according to anatomical features and visibility of the ring boundary. Distinct growth rings were detected for 19 species (79%). Seven species were submitted to tree-ring analyses, including cross-dating and dating quality control using the COFECHA program. Dated ring-series were analysed by comparing increment rates and accumulated diameter at breast height fitted curves to detect growth patterns. The variations among growth curves indicated different strategies of establishment and developm...

Journal of Ecology, 2006

1 Growth patterns and ages of tropical forest trees are strongly governed by temporal variation in light availability. Periods of high growth after canopy disturbances (releases) are necessary for successful canopy regeneration, but their importance cannot be studied without lifetime data. The recent detection of annual rings in tropical forest trees enables such analyses. 2 We used tree ring analysis to study lifetime growth patterns and age variation in six Bolivian rain forest species. Our aims were to evaluate the magnitude and sources of age variation of canopy trees, to analyse the frequency of suppression and release events, and to analyse the relation between temporal growth changes and tree age. 3 The average age of trees of 60 cm diameter differed threefold between species and by two-to threefold even within species. This variation was mainly explained by variation in passage time through the juvenile categories. 4 We used strong relative growth changes to detect release and suppression events. On average, canopy trees experienced 0.8-1.4 releases, with a maximum of 4. 5 We distinguished four canopy accession patterns by which trees have attained the canopy (growth without major growth changes, one release event, one suppression event, or several release and suppression events), with increasing time required to attain the canopy. The distribution of trees over categories of canopy accession is therefore closely related to the average age of canopy trees and its variation. 6 There were clear differences among species in how trees attained the canopy and in the length of slow-growth periods they experienced, suggesting differences in shade tolerance and growth responses to gaps, which are indicative of life-history differences among non-pioneer tree species. 7 Canopy attainment of tropical rain forest trees does not occur by steady growth, but rather by irregular patterns of growth spurts and stand-stills, probably mostly caused by temporal variation in light. Differences in these patterns may largely explain differences in the ages of large tropical rain forest trees.

PloS one, 2015

It is still unclear whether the exponential rise of atmospheric CO2 concentration has produced a fertilization effect on tropical forests, thus incrementing their growth rate, in the last two centuries. As many factors affect tree growth patterns, short -term studies might be influenced by the confounding effect of several interacting environmental variables on plant growth. Long-term analyses of tree growth can elucidate long-term trends of plant growth response to dominant drivers. The study of annual rings, applied to long tree-ring chronologies in tropical forest trees enables such analysis. Long-term tree-ring chronologies of three widespread African species were measured in Central Africa to analyze the growth of trees over the last two centuries. Growth trends were correlated to changes in global atmospheric CO2 concentration and local variations in the main climatic drivers, temperature and rainfall. Our results provided no evidence for a fertilization effect of CO2 on tree ...

Trees-structure and Function, 2011

Annual rings are generally not anatomically distinct in trees growing in the humid tropics. The possibility to use radial variation in stable isotopes (δ18O and δ13C) for the identification of annual rings in these trees was investigated in two species growing in the tropical rainforest of Central Guyana, Carapa guianensis and Goupia glabra. The climate is characterised by an annual precipitation of 2,700 mm that is distributed over two rainy and two dry seasons. Cores were taken from trees of measured diameter increment rates. High-resolution tangential sections in radial direction were dissected from these cores and isotopic ratios were measured on whole wood. Variation in δ13C was about 1‰ at an annual scale, whereas δ18O showed two to four times larger annual excursions. The minima in δ18O were selected as primary indicators of annual boundaries at the main wet season when also δ18O of precipitation water has its minimum. The minima in δ13C coincided often with these. The simultaneous occurrence is consistent with increased discrimination against 13C at high water availability. They were used as secondary criteria. Annual rings could thus be identified with reasonable certainty in both species from radial variation in isotopic ratios as verified with measured diameter increment rates. The short sequence covered in the analysis did not show clear correlation with the available precipitation data for the area. The method supplemented with other dating methods may prove to be practically useful for identifying annual rings and applying classical dendrochronology when more cost effective automatic sampling devices become available.

Ecology and Evolution, 2017

In temperate climates, tree growth dormancy usually ensures the annual nature of tree rings, but in tropical environments, determination of annual periodicity can be more complex. The purposes of the work are as follows: (1) to generate a reliable tree-ring width chronology for Prioria copaifera Griseb. (Leguminoceae), a tropical tree species dwelling in the Atrato River floodplains, Colombia; (2) to assess the climate signal re- corded by the tree-ring records; and (3) to validate the annual periodicity of the tree rings using independent methods. We used standard dendrochronological procedures to generate the P. copaifera tree-ring chronology. We used Pearson correlations to eval- uate the relationship of the chronology with the meteorological records, climate regional indices, and gridded precipitation/sea surface temperature products. We also evaluated 24 high-precision 14C measurements spread over a range of preselected tree rings, with assigned calendar years by dendrochronological techniques, before and after the bomb spike in order to validate the annual nature of the tree rings. The tree-ring width chro- nology was statistically reliable, and it correlated significantly with local records of an- nual and October–December (OND) streamflow and precipitation across the upper river watershed (positive), and OND temperature (negative). It was also significantly related to the Oceanic Niño Index, Pacific Decadal Oscillation, and the Southern Oscillation Index, as well as sea surface temperatures over the Caribbean and the Pacific region. However, 14C high-precision measurements over the tree rings demonstrated offsets of up to 40 years that indicate that P. copaifera can produce more than one ring in certain years. Results derived from the strongest climate–growth relationship during the most recent years of the record suggest that the climatic signal reported may be due to the presence of annual rings in some of those trees in recent years. Our study alerts about the risk of applying dendrochronology in species with challenging anatomical features defining tree rings, commonly found in the tropics, without an independent validation of annual periodicity of tree rings. High-precision 14C measurements in multiple trees are a useful method to validate the identification of annual tree rings.

Forest Systems, 2012

To determine the annual periodicity of growth rings in seven tree species from a tropical moist forest in Santa Cruz, Bolivia, a fire scar was used as a marker point to verify the annual nature of tree rings. The number of tree rings formed between the 1995 fire scar and the collection of the cross sections in 2002 was visually identified. The seven species showed annual growth rings. In most cases, boundaries between rings were marked by the presence of marginal parenchyma and wall-thicked fibers formed at the end of the growing season. Growth lenses and false rings were recorded in some species. Tree rings can be carefully used in Santa Cruz forests to determine rates of growth. This information is crucial for defining forest management practices in tropical regions.

Forest Ecology and Management, 2014

Implementing sustainable forest management requires basic information on growth, ages, reproduction and survival of exploited tree species. This information is generally derived from permanent sample plots where individual trees are monitored. Accurately estimating growth rates and especially tree ages from plots is however challenging, as plots often contain only few individuals of the exploited species and monitoring periods cover only a fraction of the life-span of most trees.