Growth Assessment of Native Tree Species from the Southwestern Brazilian Amazonia by Post-AD 1950 14C Analysis: Implications for Tropical Dendroclimatology Studies and Atmospheric 14C Reconstructions
, Nathan de Oliveira Barreto 2, Gabriel Assis-Pereira 2, Ana Carolina Barbosa 3, Fidel A. Roig 4,5 and Mário Tomazello-Filho 2
Round 1
Reviewer 1 Report
This is a very interesting and timely contribution to the developing field of tropical dendrochronology. The comparison between tree-ring dates and the radiocarbon spike is not new for tropical dendrochronology, and in fact an additional reference is needed to show that it has already been done for more than 20 years (1999a Biondi, F. and J.E. Fessenden. Radiocarbon analysis of Pinus lagunae tree rings: Implications for tropical dendrochronology. Radiocarbon 41: 241–2490). However, this article shows additional results for the Amazonian rainforest, and in particular it demonstrates how even species that apparently can be crossdated are in fact characterized by growth rings with non-datable features. This is a very important finding.
In reading the article, I found some minor editorial issues that can be resolved easily upon careful re-reading by the authors themselves or by the journal staff (for example, line 129).
Author Response
We appreciate the reviewer's positive feedback and are happy to comply with his/her suggestions. The pioneering work of “Biondi, F. and J.E. Fessenden. Radiocarbon analysis of Pinus lagunae tree rings: Implications for tropical dendrochronology. Radiocarbon 41: 241–2490 (1999)” was added to our list of references and main text.
We also revised the editorial issues and corrected all typos.
Reviewer 2 Report
Review of Santos et al., ‘Growth assessment of native tree species from the southwestern Brazilian Amazonia by post-AD 1950 14C analysis: Implications for tropical dendroclimatology studies and atmospheric 14C reconstructions’
The paper combines dendrochronology, dendroclimatology and annual radiocarbon measurements to test true annual tree growth of three tropical tree chronologies, and to provide tropical 14C data sets. The paper is the latest in a series of publications of these research topics, with G.M. Santos first author of two publications, and co-author of another eight papers.
The statistical ring-width parameters of all three series provide consistent annual growth pattern; however, high precision 14C data in the bomb test interval clearly demonstrate missing annual rings for one of the three series, and true annual growth of the other two.
The paper demonstrates the perfect match of highest precision 14C and tree-ring methodology to develop and evaluate dendrochronology and dendroclimatology in tropical regions, which is still much less advanced compared to the extra-tropics. The detailed presentation of the dendro research (wood anatomy, tree-ring statistics and x-ray densitometry) and the extensive 14C technique (cellulose extraction, duplicate high precision 14C measurements, 14C reference samples) appears rather unique, and it will serve as template for future work.
I consider this paper an excellent example of the successful collaboration of two quite different fields, wood anatomy and isotope physics.
A few glitches:
Ref. 50 = ref. 29
Line 46, 167 : [ ] missing
Line 162 : inch-2
Author Response
We are glad to learn the reviewer appreciates our contribution.
We thank this reviewer for pointing out our glitches in the main text.
Besides Ref. 50 = ref. 29, another 4 citations were found in duplication at the reference list. They were removed, and their respective numbers reordered in the main text.
All missing brackets were reviewed, and “inch-2” was replaced by “grit”, which is a better unit to address the size of abrasive materials on the sandpaper we used.
