Why do rubber workers have to tap rubber at night?

Natural rubber is the liquid rubber collected from rubber trees. The rubber tree is native to Brazil in South America. It is called the Brazilian Hevea brasiliensis and grows in tropical and subtropical areas. It must be exposed to sunlight all day long and photosynthesize through chlorophyll to make the various elements in the tubes in the tree stems react chemically to produce rubber liquid (referred to as liquid rubber) composed of rubber hydrocarbons as the main component. Therefore, there is almost no liquid rubber in the rubber tree during the day, so it cannot be said to be tapped. The content of rubber hydrocarbons in the rubber liquid is as high as 90%, and as low as 35%. There are also proteins, resins, moisture, ash, etc., so the liquid rubber is white and sticky to the touch. At two or three o'clock in the morning of the next day, the liquid rubber slowly generated in the tube will be full, so the liquid rubber is squeezed out drop by drop along the spiral cut under the tree by "internal pressure" and flows into the rubber bowl below. When the bowl is almost full of liquid rubber, the rubber worker takes out the rubber bucket to collect it. It was not until the east was a dark blue that the glue inside the tree slowly flowed out. When the sun came out, the glue also flowed out.