aggregate retention造句

Either few trees or many trees can be retained under the variable retention system, and trees can be retained in patches ( aggregated retention ) or left uniformly throughout a stand ( dispersed retention ); hence the name " variable retention . " It is a technique for retaining trees as key structural elements of a harvested stand for at least until next harvest rotation in an effort to maintain species, habitat diversity and forest-related processes.
It's difficult to find aggregate retention in a sentence. 用aggregate retention造句挺难的