We can't explain all data structures to you or we would be here for years. Data structures is a generic term for the way data is "structured". A tree is one way data can be structured. Think of a family tree. Where parents have kids and those kids have kids and those kids have kids. You start with 2 people and suddenly you have 20 great grand children which forms a hierarchy.
I cover one type of tree known as a binary tree in my blog which I have linked to below...
Martyr2's Programming Underground - Nodes in a Linked List and Binary TreesPay special attention to my neat little graphic to get an idea of what the tree looks like conceptually. Now this is only one type of a tree but trees can essentially have as many sub nodes as you want. The node that starts it all off is known as the "root" node, nodes that have subnodes of their own are known as "branches" and the nodes which end a branch are known as "leaf" nodes. See the similarity to a tree?
As mentioned before this is just one type of way to structure data. Nodes themselves can be called data structures. Other structures include linked lists, arrays, objects, lists, tables etc.
I hope you get the basic idea. Wikipedia has a great list of other types of structures as well as links that explain them all. You can find this page at the link below...
Wikipedia for data structuresThat should give you plenty of information to start you off. Enjoy!
"At DIC we be data structuring code ninjas... when we are at the annual DIC football varsity games we sometimes get in a pascal's triangle format, but it often collapses because we are nerds"