Below is an instruction that describes a task. Write a response that appropriately completes the request.

### Instruction:
When 312 is  of which currently forests, km² what is the land formation?

### Inputs:
table_name: table, columns: ['land formation', 'area, km²', 'of which currently forests, km²', '% forests', 'habitat type']

### Response:
SELECT land formation FROM table WHERE of which currently forests, km² = 312