Date: 24 October, 2019

Date set title: Michigan Big Woods research plot data

Date set creators: D. Allen, J. Vandermeer, C.W. Dick, I. Perfecto, and R.J. Burnham

Data set contact: dallen@middlebury.edu

Research overview:
This is a forest dynamics plot was established to better understand succession in a rapidly changing oak-hickory forest. 

Methods:
See related publication for full methods. Briefly, these data come from three censuses of a 23 ha forest research plots. All free-standing vegetation greater than 1 cm diameter at 1.3 m height (diameter at breast height; DBH) were tagged, identified, spatially mapped and had their DBH measured. The original census took place in 2008 and covered only 12 ha. A second census took place from 2008-2010 and expanded the plot to its current 23 ha. Finally a third census took place in 2014. In the second and third censuses the original trees were found, recorded for survival, remeasured, and new individuals were tagged. This plot is part of the Smithsonian Institution's Forest Global Earth Observatory (ForestGEO) global network of forest research sites.  https://forestgeo.si.edu/

Use and access:
Collecting and maintaining the data for this project requires an enormous effort. The PIs on this project would appreciate being considered collaborators on projects using these data and inclusion as co-authors on any articles. This is not required, but appreciated. Please contact David Allen (dallen@middlebury.edu). Use of these data is covered by the Creative Commons Attribution-NonCommerical 4.0 license (CC BY-NC 4.0).  

Citation for data set:
D. Allen, J. Vandermeer, C.W. Dick, I. Perfecto, and R.J. Burnham. 2019. Michigan Big Woods research plot data [Data set]. University of Michigan Deep Blue Data Repository.

Related publication:
D. Allen, C.W. Dick, R.J. Burnham, I. Perfecto, and J. Vandermeer. The Michigan Big Woods plot as the Edwin S. George Reserve, Pinckney, MI, USA. (Forthcoming in the Occasional Papers of the University of Michigan Museum of Zoology).


Files inventory:
-- 2003census.txt
-- 2008census.txt
-- 2014census.txt
-- codes.txt
-- personnel.txt
-- species.txt


Description of files:
2003census.txt: Has information about all individual trees included in the 2003 Big Woods plot census. This census was of the original 12 ha and only included stems greater than 3.2 cm DBH. Each row represents one stem.
-- tag: This is the number on the actual tag on the tree. Unfortunately we used four digit tags and have greater than 10,000 individuals, so these tags are not unique. Based on location and species it is clear which individual is which when in the field, but this column does not uniquely identify an individual. For that use treeid.
-- treeid: This number uniquely identifies the individual tree. Trees can have multiple stems so some tags are in multiple rows.
-- stemtag: This identifies stems within in an individual.
-- spcode: This gives the species code of the individual. Use species.txt to get the scientific name and family for the species code.
-- quadrat: This gives the 1 ha quadrat that the individual is in.
-- gx: This gives the x coordinate location of the individual in meters relative to the bottom left corner of the plot. The coordinate system is local to the plot.
-- gy: As above but for the y coordinate of the individual. Also in meters (m).
-- dbh: This is the diameter of the stem at its height of measurement (hom, see below). This is measured in centimeters (cm). Values of NA means the stem has died between the preceding and current census.
-- codes: This gives qualitative information about the stem. See codes.txt for a description of each code.
-- hom: This gives the height above the ground at which the diameter of the stem was measured. This height is measured in meters (m).
-- date: This gives the date on which the diameter of the stem was measured.

2008census.txt: Has information about all individual trees included in the 2008-2010 Big Woods plot census. This census was of the whole 23 ha plot and included stems larger than 3.2 cm DBH. It has the same columns as 2003census.txt.

2014census.txt: Has information about all individual trees included in the 2014 Big Woods plot census. This census was of the whole 23 ha plot and included stems larger than 1 cm DBH. It has the same columns as 2003census.txt.

codes.txt: Each row is a code explaining different statuses of stems.
-- code: Letter which links the code to stem in 2003census.txt, 2008census.txt, and 2014census.txt
-- status: Whether this code is for a dead or alive stem.
-- description: Description of what this code means for a stem.

personnel.txt: Each row is a person involved with the project.
-- firstname: First name of person involved with the project
-- lastname: Last name of person involved with the project
-- role: Role of that person involved with the project

species.txt: Each row is a taxon found in the plot.
-- species: The species epithet for that taxon.
-- genus: The genus for that taxon.
-- family: The family for that taxon.
-- idlevel: The taxonomic level at which the taxon is identified.
-- spcode: The species code which links this table to the census tables.