All measurement protocols are based on standard methods for Center for Forest Science Forest Dynamics Plots (http://www.ctfs.si.edu/) as published in Condit (1998).
All live, native, free-standing, woody stems ≥1.3 m tall and ≥1.0 cm DBH (1.3 m) are included. Epiphytes are included if they can be safely reached. Tree ferns are included if they are ≥ 50 cm tall. Stem diameters of woody vines (lianas) and Rubus hawaiiensis are not measured, but the percent cover of selected species is estimated in understory composition data (see Cover section).
The standard point of measurement (POM) for trees is 130 cm and 50 cm for tree ferns. POM is measured from the base of the tree on the south side for trees standing on level ground, or on the uphill side of trees on a slope, or on the underside of leaning trees. When a tree is leaning on a slope, we measure from the uphill side. POM is measured following contours along the trunk. Where there are irregularities, we measure at the closest point either above or below standard POM where the trunk is relatively cylindrical and representative of the size of the tree. If a tree fern cannot be measured with a diameter tape because it is completely prone or appressed to a tree, big tree calipers are used to measure it as close to 50 cm as possible.
The diameter of trees at breast height (130 cm) is measured in centimeters to the nearest millimeter. Calipers are used for trees <5-cm DBH, and a fabric or metal diameter tape is used for larger trees. For trees measured with calipers, the widest measurement at the recorded POM is taken as the DBH. DBH is measured perpendicular to the trunk, even for leaning trees. Care is taken not to damage bark when using metal calipers.
MEASURING MULTIPLE-STEMMED INDIVIDUALS
All stems ≥1 cm that arise at or below 130-cm above the ground are measured. Trees with horizontal branches that arise at or below 130-cm and are ≥1 cm are treated as multiple stemmed individuals. The largest stem of multiple stemmed individuals is designated as the “main” stem and tagged. Stems of the same species that are connected are treated as a multiple stems unless it is very clear that they are not from the same individual. In all cases, the POM is recorded for each stem.
MEASURING BIG TREES
Many large trees at Laupahoehoe have trunks covered with epiphytes. We do not measure around epiphytes. Instead we climb to where the trunk is free of lianas, epiphytes, and debris using a ladder or climbing gear.
Condit, R. 1998. Tropical Forest Census Plots: Methods and Results from Barro Colorado Island, Panama and a Comparison with Other Plots. Springer-Verlag and R. G. Landes Company. Berlin, Germany, and Georgetown, Texas.
Trees are mapped within each 5 x 5-m subquadrat using ArcPad (http://www.esri.com/software/arcgis/arcpad/index.html) mapping program on handheld field computers (Juniper Systems: http://www.junipersys.com/products/products.cfm?id=135). We work in teams of two with the data recorder holding the field computer and recording the data while the measurer locates, measures, and identifies each tree. As each tree is mapped, a custom data entry form appears on the screen and the tree data is entered into the form.