data_tree_biologyclassification

Lists are not usually considered trees because of their linear structure, whereas a tree can have a branching structure. However, they posses the feature of hierarchy and vertical order that is essential in all kind of trees. A list always has an element followed by exactly one smaller list, meanwhile a tree has an element followed by some number of smaller trees. In this way, a list is a tree in which non -leaf nodes always have exactly one subtree. The lists, are in this way, lianas; long-stemmed woody plants, not constrained in size, they can range from small, indiscrete size, to giant lianas thick as trees that seemingly hang in the middle of the forest.

Comparable to botany species, there exist many different kinds of tree graphs, with different branching structures and node contents. For example, in a binary tree the non -leaf nodes always have exactly two subtrees and in a ternary tree they have exactly three subtrees. Each kind of tree has its own class of algorithms to construct trees, traverse trees, and look up information; its own use and own behaviour.

In a context where trees are supposed to have a root, a tree without any designated root is called a free tree. A free tree is an unrooted tree, defined to be a connected graph having no cycles and no size restrictions, the only constraint is to maintain the no loop nature of trees. If any edge of a free tree is deleted, the free tree ceases to exist, as it is no longer connected. In biology, unroot a tree has two possible scenarios: dead or rerooting. there are two ways to reroot plants: in water, and in a rooting medium such as soil. Depending on the plant it requires specific temperature or external chemical components to stimulate root growth.

*Used for example to analyzing networks or showing the structure of hydrocarbons, a graph with no loop & no root. http://pipelines.local/images/Hydrocarbons_800.gif