Indiana University - Indiana - Hemlocks - 2005-2013

Study Extent

The study area was the entire state of Indiana, initially performed by referencing aerial imagery from 2005. The study included ground truthing visits and collecting samples from random plots through 2013.

Sampling

Some localities include a name of a DNR reference coordinate, collected by Hank Huffmann around 2007 (Consists of the county followed by a unique name for the site. Ex: "Lawrence-GuthieCreek"). All sites with "basis_of_record" as "specimen" will have a herbarium sample collected by F. Collin Hobbs associated with it. The majority of Charles Deam's historic herbarium samples are housed at Indiana University. Records that could be matched up with a degree of certainty to present day stands are referenced with the corresponding catalog number. R. R. Van Stockum's 1979 dissertation includes a record of his visits to eight sites in Indiana where Tsuga canadensis was found, and are referenced where applicable.

Quality Control

The analysis of the aerial imagery for presence/absence of eastern hemlock was followed by physical visits to sites where hemlocks were expected.

Method steps

1. visual analysis of shp files from 2005 aerial imagery determined the distribution of eastern hemlock in the state of Indiana. Field trips were taken to verify predicted presence of the trees in randomly selected areas throughout the state. Where polygons were less than 1000m2, a centroid was calculated and is represented in this dataset. A sister dataset of grids for hemlock tree distribution for polygons greater than 1000m2 is included separately.

Tsuga canadensis (L.) Carrière -- eastern hemlock

1. Tsuga canadensis
   common name: eastern hemlock rank: species

The distribution of all smaller plots of hemlock within the state of Indiana in the United States.