Skandapurana 2.2.9.48

2.2.9.48

pṛthvīpradakṣiṇaphalaṃ śatadhā bhajaṃte paryaṃti ye sakalakalmaṣadāryaraṇyam ..

Those who walk around the forest that destroys all sins attain a hundredfold the fruit of circumambulating the earth;