Pine is related to the planet Saturn, and is the incense of Capricorn (December 22nd to January 19th).
"The pine is the tree of Aquarius and possesses great magical powers..." - Samael Aun Weor
This dried and bundled pine is ignited on the end, then the flames are blown out, allowing the tips to smolder and release plumes of smoke. The smoke is then distributed over the area to be cleaned, in accompaniment with prayer. You can then dip the hot end in water, saving it for later use. In this way, a bundle will last a long time.
"In their operations of elemental magic, ancient magicians used smudging with laurel branches, mugwort (artemisia), rue, sage, pine, rosemary, etc. Such plants were burned on burning coals. This observance is magnificent. The air is filled with the smoke of plants, the exorcised fire will reflect the will of the operator, and the subtle forces of nature will listen and respond to him." - Samael Aun Weor, Secret Doctrine of Anahuac