You can also do this if you want to play around with pandas. However, I like punchagan's way.
# replicating your dataframe
lake = pd.DataFrame({'co tp': ['DE Lake', 'Forest', 'FR Lake', 'Forest'],
'area': [10, 20, 30, 40],
'count': [7, 5, 2, 3]})
lake.set_index('co tp', inplace=True)
# to get key value using pandas
area_dict = lake.set_index('area').T.to_dict('records')[0]
print(area_dict)
output: {10: 7, 20: 5, 30: 2, 40: 3}