Alternative method for plots that overlap boundaries

[Jason.Henning]

An alternative method for dealing with plots that overlap study area or stratum borders.
Currently when a plot overlaps the boundary of the area of interest or the boundary between plots it is possible for users to account for these conditions by reducing the “percent measured” to reflect only the area of the plot within the boundary or stratum (see page 30 of the i-Tree Eco manual, v. 5.0).

An alternative to this approach is use a method that folds that part of the plot that overhangs the boundary back into the plot and recording twice any trees that fall in the folded part of the plot. The dark blue area in the figure below represents the folded area of the plot where tree would be recorded twice.

One easy way to do this is in the field is to use the “walkthrough” method described in this Forest Service document (goo.gl/qEwyu) . To use the walkthrough method follow these steps.

1. Measure all trees that are within the plot and also within the study area boundary.
2. Determine if there are any trees that are closer to the study area boundary than to plot center along the azimuth from plot center to tree center.
a.) Measure distance X from plot center tree center.
b.) Measure distance Y from tree center to boundary.

3. If Y is less than X (i.e. the tree is closer to the boundary than plot center) record that tree a second time. In the image all data for the indicated tree would be recorded twice since this tree is closer to the boundary than plot center.
For more details or rules for dealing with more convoluted boundaries refer to the original forest service document (http://www.fs.fed.us/ne/durham/4104/pap ... nt2004.pdf).

See Attachment for images