Pengaruh Waktu Tebang terhadap Keawetan Alami Bambu Andong (Gigantochloa psedoarundinace)

Abstract

Gigantochloa pseduarundinaceae, also known as Andong bamboo, used in this study. Samples were taken from bamboos which were harvested once each month in a year starting from February 2013 to January 2014. Bamboos culms were cut into strips. The strips were put in a safe, dry place, and free from wood destroying organisms. After all of the bamboos were collected, the laboratory testing is conducted based on SNI 01.7207-2006 methods. Field testing were also conducted based on ASTM D 1758-06 methods. According to the laboratory test, the bamboos were categorized as durability class III (medium durability) and durability class IV (bad durability). According to laboratory testing, the least loss of bamboo mass occurred on Maret and the highest number of termite mortality occurred on November. While, the results of the field test show that the value of the highest durability grade and the weight lowest loss rate was occurred on bamboo which is harvested in March to May. Best subset regression were used to determine the environmental factors during harvesting process which was dominantly affecting the bamboos' durability. The observed environmental factors were rain levels, humidity, and temperature. According to best subset regression analysis, the rain level and humidity during the harvesting period were two main factors affecting the bamboos' natural durability. The best subset regression resulted that rainfall and humidity during the harvest were the two main factors that affect the durability of bamboo at observed daily rainfall intervals (1-20 mm). Rain levels and humidity give fluctuating effects on the loss of mass. The maximum loss was happened on 74% humidity. If the humidity is bellow 74%, or above 74%, the mass loss tend to decrease. The rain level also affect the mass loss. Low rainfall level 1 to 4 mm showed the decrease in mass loss, and became stabilized when the rain level reach above 4 mm. According to the data, it is recommended to harvest the bamboos on March to Mei, when the durability are the highest and the mass loss are the lowest.