Second leaf, four leaf... Whaaat?

[Hillfarm]

What does it mean when someone says, my fruit trees are in the second (could be the fourth, or whatever number) leaf? As an example, "This is a fourth leaf apple tree". What does this mean?
I'm sorry, but I cant find an explanation on the internet; and, I want to understand what people are referring to, when they say this phrase. I am not real experienced, at the fruit tree game, and I am looking for a little schooling.
Thanks looking, and for any responses in advance.

 

[buckvelvet]

The amount of 'leafs' refers to the number of times a tree has come awake at its final destination. You get a tree in the mail from a nursery and plant it, it wakes up, that's its 1st leaf, 4 years later is it's 4th leaf, etc...

 

[Hillfarm]

Thanks for the reply buckvelvet. I have pondered this question for almost two years now.