Pine nuts, furniture, paper, Christmas decor, the buildings we inhabit, and the lovely smell of the mountain air - what do these things all have in common? They all exist thanks to our old friend, the pine tree.

Many of these items are present in our everyday lives, but now there's another big one to add to this list: potable drinking water.

A recent study published in PLOS (Boutilier et al.) showed that the xylem tissue from pine trees was successful in removing at least 99.9% of bacteria from water when used as a filter.

UNICEF reports that 748 million people in the world do not have access to safe, clean drinking water and that approximately 1,400 children die per day from disease caused by unsafe water or inadequate sanitation. Current methods for water disinfection are expensive or impractical for small towns and villages in developing countries, making a new method of water disinfection that could be used in such places a huge breakthrough in the prevention of water borne disease.

So how does this work? The researchers used 1 inch long sections of pine branches that were about 1 cm in diameter. The bark was removed, and this piece of branch was then inserted into the end of tubing and sealed. Water was filtered through this tubing and traveled through the xylem tissue of the branch with a small amount of pressure to help it through. This method is not only suitable for pine trees, but all coniferous trees are good candidates based on the pattern of flow through the pit membranes in the xylem tissue. The research showed that these pit membranes are responsible for the trapping of bacteria, just like they trap tiny air bubbles that can kill the tree.

A color enhanced electron microscope image from MIT showing the round xylem pit membranes (red and blue) with E. coli bacteria (green) trapped inside.

Organisms and particles down to approximately 100nm in size could be filtered using this method and filtering in this way can provide the amount of drinking water required for one person each day, which is about four liters.

There are clear issues associated with this new method of filtration that will need to be addressed prior to becoming a viable technology - such as the presence of coniferous trees in areas of the world that need clean water, the limit of water that can be filtered in this way, and still the 0.01% of bacteria that can get through as well as smaller viruses that might evade filtration - but if you're ever stuck in the mountains surrounded by pines and happen to have some tubing in your pocket, you just might not get sick from drinking the water.

~Alyssa Conly