Sapflow measurements from atoll vegetation: 40-60 trees including Pisonia grandis, Heliotropium foerthianum, Pandanus spp., and Cocos nucifera will have small (1 cm by 10 cm) sections of bark carefully removed from about chest height. Three narrow (<1 mm) holes will be drilled 10 cm into the tree trunk within these stripped sections, and metal probes will be inserted into these three holes. Drills and probes will be sterilized prior to installation. Water-resistant, non-toxic grease will be applied around the bases of the probes to help prevent foreign objects or substances from entering the holes. The probes will be connected to ruggedized plastic cases (approx. 25 by 10 by 10 cm) housing data loggers and batteries, which will be strapped or nailed to the tree trunks. These sapflow probes are frequently used in studies of forest hydrology without causing detectable harm to the sampled trees. Additionally, a 15 cm long tree core (~2 mm wide) will be sampled from each tree trunk to measure wood density and moisture content. Trees will be tagged with steel tags and nails if not already permanently marked. We will also install a weather station in a location determined in coordination with Ecostation staff.

Approved