Ah, incense!  It all goes back to our primitive origins, with the discovery of fire.  When wood was burned, people discovered the amazing aromas that came from the wood, and the effects that these fragrances had on our emotions.  Then we started experimenting burning different materials, leaves, herbs, fruits.  As the smoke carried the aroma towards the sky, toward heaven, we saw that as a spiritual experience.  Burning fragrances became a part of religious and spiritual rituals, seen as both a gift from the gods, and an offering to the gods.
 
In both the Buddhist and Hindu traditions, incense is offered as a devotion.  It is also used to accompany meditation and is often burned daily on home altars.  

According to Ayurveda, there are five elements – and the different types of incense fall into these five categories and are burned to help balance energy.  Here is an example of each:
Air: (leaves) – Patchouli
Space: (fruit) – Anise
Fire: (flower) – Clove
Water: (stems and branches) – Sandalwood
Earth: (roots) – Ginger

The practice of burning incense can be an art – you can burn one fragrance at a time, or a blend, depending on what effect you want to have.  

Incense was the beginning of aromatherapy.  Aromatherapy is the science of using the fragrance of essential plant oils in healing treatments.  Aromatherapy is an energetic healing technique that uses the vibratory energy of various aromas to shift energy and bring relief from physical symptoms.  The aromas used are distilled directly from plants and placed in an oil base, forming what is called essential oils.

We connect to the physical world through our five senses. Aromatherapy has many benefits – it can be calming, relaxing, energizing, or soothing. It can help us to get to sleep, or help us to wake up! Here are the fragrances which help to balance each the doshas:
Vata- vanilla, orange, lavender, pine
Pitta- rose, jasmine, sandalwood, peppermint
Kapha- cinnamon, basil, eucalyptus, musk

Here’s my video about Aromatherapy on youtube: http://www.youtube.com/watch?v=CQLtHn-sWOU