As per Hindu mythology , starting today, the 16th day of the lunar period of mourning begins, which is also called "pitr paksh". The duration of pitr paksh is of 16 days, as per the Hindi lunar calendar, during which people pay homage to their dead ancestors. As per Hindu mythology, our traditions, individuality and behavior is a direct inherentence from our ancestors which continue to remain with us, till we die .There is a nice and humble way through which we can store into our memories what we have learnt from our ancestors, and that is through planting a tree. Through religion and mythology, we have learnt that giving our environment its due respect, mainly through looking after plants and trees gives us utmost blessings of our forefathers. As per Hindu mythology, there are over 84 lakh different types of births one can have out of which an important one is, being birthed as a tree. Therefore, through this medium, one can use the period of 'shraad' to plant trees in memory of their ancestors. This is important as it will not only help us retrieve the falling ecological balance, but also enable us in keeping the memories of our forefathers alive.
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(Source: Translated from bhaskarhindi.com)