@mkwadee Sorry, I understand it's a metaphor, but the fact is just false.
Beside the trees that grow slow but do not produce any fruit, such as gingko, in the fruit realm you have a lot of pretty nice fruit produced by fast growing trees such as papaya, pomegranate etc.
If you mean to say that in the same species, for example if you have 10 apple trees, the slow growing one will beat better fruit again, not true. If it's growing slow something is holding it down (bad genes, lack of water, lack of light...), and it will likely yield less.