how old does a tree have to be to be considered an "old growth tree"?

Answer 1

More than 150 years old.

Answer 2

Old growth forests typically contain large live trees, large dead trees (sometimes called "snags"), and large logs. Old growth forests usually have multiple vertical layers of vegetation representing a variety of tree species and a variety of different age classes.

By contrast, in the U.S., old growth is often used to imply a forest has experienced little or no direct disruption by Euro-Americans and looks about as it would had Europeans not come to America. However, this criterion is difficult to apply, since it is often impossible to determine the history of human management

Forest regenerated after severe disruptions, such as clear-cut or fire is often referred to as second-growth or regeneration until a long enough period has passed that the effects of the disturbance are no longer evident. Depending on the forest, this may take anywhere from a century to several millennia. Hardwood forests of the eastern United States can develop old-growth characteristics in one or two generations of trees, or 150-500 years.

So an old growth tree would come from an old growth forest.

Answer 3

150+

Answer 4

after cutting a branch then they count circles inside the branch-many circles means old Tree.save trees.I adore Trees.

Answer 5

Really Old!