Longitudinal data on native tree growth (e.g., change in diameter) provides important information on the performance and productivity of these long-lived organisms over discrete environmental periods (e.g., seasons, years).  The data in this file may prove useful to many users including, but not limited to ecological or forestry modelers ground truthing regional models estimating tree productivity, forestry students learning to estimate how individual tree basal area changes over seasons or year, or instructors and students looking for real world data sets that depict annual patterns of logistic growth. 

Data Type and Collection:  In May 2018, I installed fourteen (14) D1 Permanent Tree Girth bands (UMS GmbH, München, Gmunderstr. 37; supplied by METER USA/Decagon Devices [Pullman, WA, USA]) on mature (>25 cm Diameter at Breast Height [DBH]) White Pines (Pinus strobus) located on the Fish Lake Environmental Education Center property (Lapeer County, Michigan).  Each band was secure at 1.5 to 1.6 m above the soil surface (depending on branch position) and bands were installed according to manufacturer’s instructions.  Data values report the estimates of tree diameter (cm) reported from visual inspection of the band’s scale at taken approximate between 9:00AM and 12:00PM on the data collection date specified.  Data collection will be ongoing and I will post new diameter data annually.

Data Usage Notes:  Sampling interval varies by year. For example, in 2018 measurements of tree diameter were made every 1-2 weeks from May to August, but in 2019 sampling intervals occurred roughly once every month.  In 2020, due to property restrictions in the COVID-19 pandemic I was only able to get diameter estiamtes in February and November.  Below is a list of the column headers description:

Column Headers:

1. “Tree_ID”:  Column with a unique identified for each tree with band
2. “Measurement_Number”: Column indicated the number, in sequence, of measurement on each unique tree
3. “Northing”:  The latitude location of the tree estimated to the nearest 3 m
4. “Easting”:  The longitude location of the tree estimated to the nearest 3 m
5. “Measurement_date”:  The calendar date on which measurements of diameter were taken
6. “Diameter_ cm” columns:   The diameter of each tree on that sample date reported in centimeter