This is the 2995th most frequent Arabic word.
أصحابها
"Her/its owners" or "her/its companions."
أصحابها refers to the individuals who own the objects being talked about (the trees in this case).
الأشجار في الحديقة تتجمل عندما يعتني بها أصحابها.
The trees in the garden become beautiful when their owners care for them.
أصحابها is used to denote the relation of possession, referring to the pens' rightful owners.
الأقلام على الطاولة هي ملك أصحابها.
The pens on the table belong to their owners.
Here, أصحابها references the individuals who take responsibility or ownership of the cars.