Answer to Question 1
Maintain clones that cannot be propagated by other sexual methods
Gain the benefits of certain rootstocks
Speed up the time to maturity
Repair damaged parts of trees
Answer to Question 2
The scion and the understock must be compatible.
The diameter of the understock must be equal or larger in size than the scion's
diameter; typically the scion is much smaller than the understock.
The cambium of the scion must be in close contact with the cambium of the
understock to ensure success of the graft union.
Grafting must be done at the proper time of the year.
Immediately after grafting, all cut surfaces must be thoroughly covered with
grafting wax to prevent desiccation.
The individual doing the grafting is critical to the success of the grafting operation.