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Investigation:

CD-08 (Trumbore / Camargo)

LBA Dataset ID:

CD08_RADIOCARBON_MANAUS

Originator(s):

1. CHAMBERS, J.Q.
2. HIGUCHI, N.
      3. SCHIMEL, J.P.

Point(s) of Contact:

ORNL DAAC User Services Office Oak Ridge National Laboratory Oak Ridge, Tennessee 37 (ornldaac@ornl.gov)

Dataset Abstract:

This data set reports the ages and growth rates of trees as determined by radiocarbon dating (14C), selected from a logging operation near the city of Itacoatiara, about 250 km east of Manaus, Brazil in 1997. Samples were collected from forty-four trees from 15 species with a basal diameter greater than 100 cm and prepared for radiocarbon dating by Accelerator Mass Spectrometry (AMS) at Lawrence Livermore National Laboratory. There is one comma-separated ASCII data file with this data set.

Beginning Date:

1997-01-01

Ending Date:

1997-12-31

Metadata Last Updated on:

2011-03-07

Data Status:

Archived

Access Constraints:

PUBLIC

Data Center URL:

http://daac.ornl.gov/

Distribution Contact(s):

ORNL DAAC User Services Office Oak Ridge National Laboratory Oak Ridge, Tennessee 37 (ornldaac@ornl.gov)

Access Instructions:

PUBLIC

Data Access:

IMPORTANT: The LBA-ECO Project website is no longer being supported. Links to external websites may be inactive. Final data products from the LBA project can be found at the ORNL DAAC. Please follow the fair use guidelines found in the dataset documentation when using or citing LBA data.
Datafile(s):

LBA-ECO CD-08 Radiocarbon Dates for Large Trees from a Forest near Manaus, Brazil:  http://daac.ornl.gov/cgi-bin/dsviewer.pl?ds_id=996

Documentation/Other Supporting Documents:

LBA-ECO CD-08 Radiocarbon Dates for Large Trees from a Forest near Manaus, Brazil:  http://daac.ornl.gov/LBA/guides/CD08_Radiocarbon_Dates_Manaus.html

Citation Information - Other Details:

Chambers, J.Q., N. Higuchi, and J.P. Schimel. 2011. LBA-ECO CD-08 Radiocarbon Dates for Large Trees from a Forest near Manaus, Brazil. Data set. Available on-line [http://daac.ornl.gov] from Oak Ridge National Laboratory Distributed Active Archive Center, Oak Ridge, Tennessee, U.S.A. doi:10.3334/ORNLDAAC/996

Keywords - Theme:

Parameter Topic Term Source Sensor
AGE DETERMINATIONS BIOSPHERE VEGETATION LABORATORY AMS (ACCELERATOR MASS SPECTROMETERS)

Uncontrolled Theme Keyword(s):  RADIOCARBON DATING, TREE AGE

Keywords - Place (with associated coordinates):

Region
(click to view profile)
Site
(click to view profile)
North South East West
Amazonas (Manaus) ZF3 Biological Dynamics of Forest Fragments Project (BDFFP) -2.33300 -2.33300 -60.06400 -60.06400

Related Publication(s):

Chambers, J.Q. The importance of tree age structure in Amazon rain forests. 2001. In: Lessons from Amazonia (R. Bierregaard, C. Gascon, A.A. dos Santos and T. Lovejoy, Eds.) Yale University Press, pp 68-78.

Chambers, J.Q., N. Higuchi, and J.P. Schimel. 1998. Ancient trees in Amazonia. Nature 391(6663):135-136.

Data Characteristics (Entity and Attribute Overview):

Data Characteristics:

Data are presented in one comma-delimited ASCII file: CD08_Manaus_forest_tree_age_data.cvs



Column Number Column Heading Units Description



1 species Species or genus (when species unknown) name of sampled tree

2 common_name Common name for this species/genus in the Central Amazon

3 family Biological family name

4 radiocarbon_date Age determined from radiocarbon dating given as calendar age with 1997 as the tree harvest date. Radiocarbon dating was performed at Lawrence Livermore National Laboratory using standard protocols

5 standard_error Radiocarbon date standard error

6 calibrated_date Radiocarbon age adjusted for atmospheric variability

7 1997_age Measured age of tree at harvest date, uncalibrated

8 base_diameter cm The diameter of the tree stump where sample was taken

9 average_growth_rate cm/yr Base diameter (from column 8) divided by age (from column 7) = average growth rate



Example data records



species,common_name,family,radiocarbon_date,standard_error,calibrated_date,1997_age,base_diameter,average_growth_rate

Bagassa guiananensis,Tatajuba,Moraceae,300,50,310,350,110,0.31

Brosimum parinarioides,Amap ,Moraceae,280,50,310,350,100,0.29

Cariniana micrantha,Tauari vermelha,Lecythidaceae,1440,50,1330,1370,180,0.13

Cariniana micrantha,Tauari vermelha,Lecythidaceae,780,50,680,720,140,0.19

Cariniana micrantha,Tauari vermelha,Lecythidaceae,650,50,615,660,140,0.21

Cariniana micrantha,Tauari vermelha,Lecythidaceae,470,50,520,560,150,0.27

Cariniana micrantha,Tauari vermelha,Lecythidaceae,440,50,510,550,150,0.27

Cariniana micrantha,Tauari vermelha,Lecythidaceae,360,50,413,460,180,0.39



There are no missing values.

Data Application and Derivation:

The ages of tropical rain forest trees provide critical information for understanding the dynamics of tree populations, determining historical patterns of disturbance, developing sustainable forestry practices and calculating carbon cycling rates (Chambers et al., 1998). These data provide an estimate of the age of these trees when they were harvested in a logging operation.

Quality Assessment (Data Quality Attribute Accuracy Report):

Quality Assessment:

The main source of error is for trees less than about 350 years old, where errors can be as large as plus/minus 150 years. For trees older than 350 years, error in calendar age estimates are about 50 years.

Process Description:

Data Acquisition Materials and Methods:

Forty- four trees from 15 species were selected for radiocarbon dating from a logging operation (Mil Madeireira) near the city of Itacoatiara, about 250 km east of Manaus, Brazil. The logging operation is on 80,000 hectares of primary forest where they have identified sixty- five species as commercially valuable. Our samples were either selected at the log yard where boles were stacked prior to processing or through use of a geographic information system that precisely located stumps from all harvested trees in 2.000 ha blocks. Trees were chosen according to size with approximately 100 cm the minimum base diameter. The centermost wood (first ring) from the base of the tree provides a date commensurate with the sapling stage of a tree. In all species samples, a ring structure was evident. Data were collected from the center-most region of the stumps. However, if a bole was hollow, samples were taken from either the upper end of the base section or if the hollow was continuous along the stem, from the periphery of the hollow at the base.



The samples were radiocarbon dated (14C) by Accelerator Mass Spectrometry (AMS) at Lawrence Livermore National Laboratory (for a review of AMS techniques, see Taylor et al, 1992). Age determined from radiocarbon dating is given as calendar age with 1997 as the tree harvest date. The accuracy of radiocarbon dating varies with the age of the organic material because atmospheric 14C concentrations respond to production rate changes caused by natural variation in cosmic radiation. There are fluctuations in the calibration curve of radiocarbon age versus true (calendar) age (Stuiver and Becker 1986). Because of these fluctuations, radiocarbon analysis can only unambiguously date organic material that is more than 350 years old. Radiocarbon dates on younger material typically correspond to several possible calibrated age ranges between 1650 and 1950 A.D., unless other evidence allows discrimination between these possibilities.

References:

Chambers, J. Q., N. Higuchi, and J. P. Schimel. 1998. Ancient trees in Amazonia. Nature 391:135-136. doi:10.1038/34325



Chambers, J. Q., T. Van Eldik, J. Southon, and N. Higuchi. 2001. Tree age structure in tropical forests of Central Amazonia. Pages 68-78 in R. O. J. Bierregaard, C. Gascon, T. E. Lovejoy, and R. C. G. Mesquita, editors. Lessons from Amazonia. Yale University Press, New Haven.



Stuiver, M.,Becker,B.,1986. High-Precision decadal calibration of the radiocarbon timescale, AD1950�2500BC. Radiocarbon 28(2B): 863�910.



Taylor, R.E., A. Long and R.S. Kra (eds.), Radiocarbon After Four Decades An Interdisciplinary Perspective (New York: Springer Verlag, 1992).

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