"A root ingrowth bag (purple mesh bag) helps estimate the annual root production of baldcypress swamps as part of a carbon storage study. After the bag has been set in the ground, it will be removed the following year... Bags are divided into three 10-cm sections, representing depths from 0 to 30 cm. Root bags are transported to the lab, washed by section, sorted, and weighed." - North American Baldcypress Swamp Volunteer Network (https://www.nwrc.usgs.gov/special/bald-cypress/methods.htm)