Hello,
In class we were discussing having a program with "70,000" tree
objects in it.
The design pattern that makes your program efficient is the Flyweight
pattern.
Here's a URL to an explanation and some code:
http://dofactory.com/Patterns/PatternFlyweight.aspx
If you don't want to go through the hassle, make your Tree class as
bare as possible (unique features only, like age, size, etc) and put
all of the methods in a separate class.
Eric