Young and mature rubber leaves were collected during cool season (January), hot season (May) and rainy season (August) by collecting three trees out of six trees a plot. So, that means in each plot, there were six samples a plot. To describe more about the rubber leaf sampling, the experimental plots were divided to 3 parts. First part was upper plot, second part was middle plot and third part was lower plot. In each part, one rubber tree was chosen then 3-5 of young rubber leave and mature rubber leave were separately collected by cutting at top of canopy and lower canopy as shown in Figure 4.