Why is it not good to sleep under a Peepal Tree at night?

In India, Mostly People ignores sleeping under Peepal Tree. But most of these people in India and around the world do not know the actual reason behind it. So, I decided to do some research and find out the truth behind it and found out some really knowledgeable and must share stuff.

Why is it not good to sleep under a tree at night?

Well there are two type of belief behind this. One is traditional belief i.e. what people believe and other is scientific belief . We will talk about both traditional and scientific (or ancient) belief with some of its history one by one:

◾Traditional Belief (what people think):

People believes that Ghost lives on Peepal Tree and will haunt you if you go near to Peepal Tree at night because Ghosts are believed to be active in form at night. That's why People ignores to go near and sleep under Peepal Tree at night. This believe still carry on in this modern era.

◾Scientific (Ancient) Belief:

During the day, in presence of sunlight, the plants use up the CO2 and release O2 in the process of photosynthesis. But during night, plants won’t perform photosynthesis so they are unable to use the CO2 and this further leads to increase in the proportion of CO2 in the air. During night the trees breathe in oxygen and release CO2. If one sleeps under the trees, the amount of increased CO2 in the air around will certainly affect the health. So it is inadvisable to sleep under trees during night. He suffers from suffocation. He feels excess weight on his chest. For this reason, some rural people imagine and fear that ghosts would come and sit on their chests if they sleep under Peepal or Banyan trees.

Jan van Helmont found out the recipe of plant-food in mid-17th century. Before that the world was clueless about the relation between sunlight, carbon dioxide that magically produces glucose for plants. Our ancestors probably knew about photosynthesis and the effects of inhaling carbon dioxide in the night. Hence people were discouraged from venturing near a peepal tree at night and stories of ghosts were woven around these trees.

So, whatever our ancestors told us to do there was a reason behind all that. But, unfortunately it lost its true meaning by the time because of not knowing the reason behind it but taking it as a universal fact.

There are 3 photosynthesis pathways adapted by plants for carbon fixation namely C3 pathway (Calvin cycle), C4 pathway and CAM pathway (Crassulacean Acid Metabolism). C3 and C4 are common among land plants and among these two, C3 is the most common.
CAM pathway can be seen in desert plants and epiphytes (i.e. plants that live on other plants). Unlike C3 and C4 plants, these plants keep their stomata closed during day and open it during night for fix CO2 in the form of malate and releases O2. They do it so, to prevent loss of water due to sunlight. During the day, they breakdown the malate and use the released CO2 through Kalvin cycle to produce sugars, similar to C3 plants. So, CAM plants releases oxygen during night.
Peepal tree is a hemi-epiphyte in its native habitat i.e. the seeds germinate and grow as an epiphyte on other trees and then when the host-tree dies, they establish themselves in the soil. When they live as an epiphyte, they use CAM pathway to produce carbohydrates and when they live on soil, they switch to C3 type photosynthesis. So, a Peepal tree can also release oxygen during the night depending on whether it is an epiphyte or not. Refernence: https://www.quora.com/How-is-it-possible-that-the-Peepal-tree-releases-oxygen-all-the-time