Hans Jansen operates a Christmas tree stand in the Hillbrow
neighborhood, the most densely populated neighborhood in
the city.
He purchases yellowwood tree from a supplier
located in the countryside.
The supplier has a limited amount
of capacity and several customers in other large cities.
Because of this, those selling the tree must commit in spring
(October) to a number of trees to purchase from the supplier.
In December, the trees are sold.
In January, any unsold
trees can be collected by the supplier and liquidated