The sparse is used to modify already defined branch structures on a tree. The directives used are bound and are meant to be applied to a specific hierarchy level of the tree; for example, level 0 means the children branches of the root branch (es) are going to receive the modifications.
Levels List
Holds the directives listed per hierarchy level to be applied to. The list allows up to 5 hierarchy levels to be defined; if the hierarchy level is not present on the tree structure then that directive is simply not processed.

List of sparse properties per hierarchy level.
Reorder Mode
Switch the positions of the existing children branches on their parent, where the parent should match the hierarchy level specified on the list.
Reverse
Reverses the position of the children branches. Does not modify length or direction of the affected branches, but girth might get a new value as this property is position dependent.
Random
Randomizes the position of the children branches. This randomization could be fixed using a custom seed on this element.
Heavier at Top
Reorders the children branches of a hierarchy level putting the ones with more offspring levels at the top of their parent branch. The “heavier” term means only the levels beyond the affected branch.
Heavier at Bottom
Reorders the children branches of a hierarchy level putting the ones with more offspring levels at the base of their parent branch.
Length Sparsing Mode
Spreads all the children branches of a hierarchy level branch along their parent using a reference value. When length = 1 it uses the whole parent branch, 0 positions all the children branches at top of their parent branch.
Twirl Sparsing Mode
Adds a twirl to the children branches of a level branch around it.