Luquillo LTER

Thirty two 50m by 20m permanent plots were established in the Luquillo Experimental Forest. Twenty-four plots were located by one of three rivers, the Sonadora, Icacos, and Mamayes. Plots were located at 50m intervals along the rivers. To locate a plot, the elevation of a site was determined using a GPS receiver while standing in the river, and the plot was established by moving into the forest from the river, and staking out a corner at that elevation, as soon as we were out of the immediate riparian zone. The long axis of each plot runs parallel to the contours of the slope. Using a field tape, each plot was divided into ten 10mx10m quadrats (in two rows of five), and then each quadrat was further subdivided into four 5mx5m subquadrats. Every free-standing woody stem greater than 1 cm dbh was marked, using a individually numbered metal tag tied to the plant using green horticulture tape. The diameter of the stem was measured at 130cm above the ground, and the stem was identified to species. The numbers for each plot were independent, starting over at 1. At the conclusion of each plot four corner posts were left in the ground, with a metal tag tied to its top, to help with re-location.