For example, one segment of North American forests has been assigned an annual value of 250 billion dollars; as another example, honey-bee pollination is estimated to provide between 10 and 18 billion dollars of value yearly.
舉例來說，北美森林的其中一段已被分配了2500億美元的年度價值，另一例子中，蜜蜂的授粉行為估計每年給予了100至180億美元。