Why does Lord Shiva apply ash on His body?

Question

I have seen many photos and images of lord Shiva with his white body color. I listen that he was applying ashes on His body but don't know why.

I like to know the story about Lord Shiva applies ash on His body.

Answer 1

Chapter 18, Vidyeswara Samhita of Shiva Mahapurana explains the reason behind this. It says Shiva burned universe He created and applied on His body as ashes. He is showing "essence of World" symbolically (translated by JL Sastri)

यथा स्वविषये राजा सारं गृह्वाति यत्करम्।
यथा मनुष्याः सस्यादीन्दग्ध्वा सारं भजन्ति वै॥ ६७॥

67.A king takes the essence of wealth by way of tax, in his kingdom. The and with their Men burn plants and take the essence thereof.

यथा हि जाठराग्निश्च भक्ष्यादीन्विविधान्बहून्।
दग्ध्वा सारतरं सारात्स्वदेहं परिपुष्यति॥६८॥

68.The gastirc fire burns different kinds of foodstuffs and with their essence nourishes the body.

तथा प्रपञ्चकर्ताऽपि स शिवः परमेश्वरः।
स्वाधिष्ठेयप्रपञ्चस्य दग्ध्वा सारं गृहीतवान्॥६९॥

69.Similarly the great lord Siva, the creator of the universe, burns the universe presided over by Him and takes the essence of the same.

दग्ध्वा प्रपञ्चं तद्भस्म स्वात्मन्यारोपयेच्छिवः।
उद्धूलनस्य व्याजेन जगत्सारं गृहीतवान्॥७०॥

70.After burning the universe He applies the ashes over his body. Under the pretext of annihilation He has taken the essence out of the same.