Question: Do chill hours increase in dwarf fruit trees over what they are for the same variety in standard size tree?  Maureen - Lakeland, Florida

Answer: Maureen, good question.  To the best of my knowledge dwarfing rootstock or semi-dwarfing rootstocks do not change the chill requirements on the fruit trees.  On the other hand, dwarfing and semi-dwarfing rootstocks often cause the tree to fruit earlier in its life (often called making it precocious) so I would not absolutely rule out minor changes.

I did an Internet search and have found no information on the subject.

We have seen high chill varieties put wrongly in low chill areas (example might be putting an Elberta Peach in Lakeland, FL.) and the top eventually dies since it will not leaf out and the rootstock will continue to thrive.  In these instance the rootstock is not imparting it's characteristics to the budded top.

I wish I could say it did so changing a rootstock would allow more deciduous fruit trees to thrive in Lakeland Florida.  You may have highly desirable weather, but it limits the fruit choices for the fruit trees requiring more chilling hours.

Ron Ludekens