Idea of aspirin came from ancient use of willow bark extract against headaches, both contain salicylic acid. It's well known that salicylic acid helps with rooting. We used to put aspirins in flower vases also to maintaiin cut flowers longer. As to getting fruit trees to fruit faster---i suppose it's possible if they also are rooting faster. But how many aspirins or bottles of aspirins would you have to use on a full grown tree? Seems like the cost of the aspirin might be higher than the cost of the fruit produced?