Revision of Alwyn H. Gentry Forest Transect Dataset from Tue, 2011-02-15 09:12

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Over 22 years, Alwyn H. Gentry collected data from 226 sites on six continents. Gentry and his collaborators collected all plants with stem diameters equal to or exceeding 2.5 cm diameter at breast height (dbh) along ten 2 x 50 m transects, totaling 0.1 hectare at each site.

Ecological Level: Community

Biome: Temperate & tropical forests

Location: Temperate North America; Mexico, Central America, West Indies;  South America; Europe; Africa; Tropical Asia and Australasia - coordinates available

Spatial Scale of data: 0.1 hectare

Frequency: once

Observational/Experimental: Observational

Dataset Location:

Data collection summary: All plants with stem diameters equal to or exceeding 2.5 cm diameter at breast height (dbh) were surveyed and measured along ten 2 x 50 m transects. Further information is contained in the Monograph in Systematic Botany from the Missouri Botanical Garden entitled "Global Patterns of Plant Diversity: Alwyn H. Gentry's Forest Transect Data Set" authored by Oliver Phillips and James S. Miller.

Data Collected: Species abundances and diameters at breast height (dbh).

Issues: Given the incredible diversity at many of the sites and the state of taxonomy, many of the individuals are identified to morphospecies only. Cross-site taxonomic comparisons are unreliable.

Acquiring & Using data: The Missouri Botanical Garden is committed to making Al Gentry's transect data available to all researchers but does make several requests to help us track usage and insure that Gentry's work is properly acknowledged. In order to track how often the data is used and where requests are coming from, it is required that an access form be filled out each time that the Web files are consulted.

Researchers who make use of the data in publications are requested to acknowledge Alwyn H. Gentry, the Missouri Botanical Garden, and collectors who assisted Gentry or contributed data for specific sites. It is also requested that a reprint of any publication making use of the Gentry Forest Transect Data be sent to:

Bruce E. Ponman
Missouri Botanical Garden
P.O. Box 299
St. Louis, MO 63166-0299

Last modified: 
Taxonomic Group: 


I noticed that using the version of Gentry that the retriever downloads that the counts table has a total of 74237 individuals but the stems table has a total of 82131 individuals with a DBH greater than zero. My guess for why these are different is that if a single individual tree branched below breast height then that tree would have had more than one dbh recorded for it thus adding more records to the stems table than the counts table.

One other issue I would like to point out is that one of the sites has count data in a different format then all the other sites (each stem is on its own row) - see discussion here:

Dan - yes, you're right about the difference that's the distinction. This would definitely be useful information to add to the description here. Likewise I think adding a note to the main document about the differently formatted dataset would be a nice contribution as well.