Split plot in time, with six blocks (sites 1-6), four species of log as the main plot treatment, top and side cylinders as subplot treatments. The same log is repeatedly sampled on a monthly basis.
PVC Cylinders, 25 cm diameter and 25 cm tall, are mounted on logs in top and side positions. Drain holes have been installed on the top mounted cylinders to prevent waterlogging of the log. Periodically the cylinders are capped and CO2 evolved is trapped in 0.1 N NaOH solution. Because of the variation in respiration rate, the amount of solution has varied from 20 to 80 ml. Exposed solutions are then processed by first adding excess BaCl solution, filtering the precipitate and then titrating with 0.1 N HCl. Solutions vary in the degree they absorb CO2. The final calculated value has been adjusted to reflect the changes in trap efficiency brought about by CO2-absorption.
A new method of CO2 capture was begun in 1992. Approximately 30 g of oven dry 6-12 mesh Sodalime was exposed within the closed chambers for the same 24 hour period. After this period the sodalime was oven dried at 100 degrees for eight hours and the weight gain was used to calculate the amount of CO2 evolved. During the period of use there was no change in absorption efficiency.