What about the toxicology of burning bay leaf wood as a source of fuel

On the 18th of January 2015, a blog visitor known as TheRegulator posted a real interesting question in the most famous blog entry Ive written so far, the one on the toxicity of Bay Leaf. His/Her question was:

"I would like to pose a question of a different focus regarding bay leaf. Your article, questions and comments all focus on the leaf. But what about the toxicology of burning bay leaf wood as a source of fuel? The burning of certain tree woods are more toxic than others. One specie of tree, for example, is so toxic that the inhalation, ingestion or touch poses a health risk."

Incredibly juicy this question!!! Had I some more free time and Id be researching this topic like a mole on steroids, but my work has forced me to look very briefly into it. TheRegulator could have helped by stating exactly the name of the species that is known to release extremely toxic fumes when burned. But I did not quit and I found it.

I investigated, during the very limited free time I have in between the final year of my PhD, nappies and my own business, and I found some nice literature on the topic:

Polyciclic aromatic hydrocarbons (PAHs) - molecules present in Laurus Nobilis leaves that have been utilised as indicators of air pollution in Tuscany (for example). The mean PAH foliar levels in laurel leaves are well correlated with PAH air concentration [1], thus providing a good estimate of the PAHs respiratory burden. But this did not provide me with the necessary information. I was inclined to believe that any toxicity derived from burning bay leaf wood would have to do with the combustion of the oils/volatile compounds found in its composition. But apart from L. Nobilis antibacterial and fungicidal properties [2] I could not find any information pointing to toxicity of combustion fumes. In fact, Laurus Nobilis is my favourite bronchopulmonary disinfectant.

But then suddenly my research offered me some interesting and scary results. Camphor Laurel!!!! Camphor Laurel, scientifically known as Cinnamomum camphora, when burned produces significant amounts of many chemicals believed to be toxic and even carcinogenic [3]. There are studies that report this plants combustion smokes as responsible for many animal deaths, especially in Australia [3]:

A less lethal species, the Cherry Laurel - Prunus laurocerasus can also be seen as incredibly dangerous if combusted as it contain cyanolipids that release cyanide and benzaldehyde (toxic agents).

There are anecdotal reports all over the internet of common people burning laurel prunings without any issues. But what laurel prunings??? That is the RIGHT question! Most of us are worried about the hydrogen cyanide that is released during the combustion, due to cyanogenic glycosides present in the leaves of the Cherry Laurel. During its combustion/maceration, the cyanogenic glycosides will become hydrogen cyanide, glucose and benzaldehyde [4]. Cyanide kills by starving the central nervous system of oxygen and has been used by entomologists to kill insects without inflicting physical pain. Benzaldehyde...

In summary:

Combustion fumes from Camphor laurel wood = Extremely dangerous, especially if youre in Australia!

Combustion fumes from Prunus laurocerasus wood = Very dangerous. Avoid whenever possible;

Combustion fumes from Laurus Nobilis wood = Unlikely to cause any harm if handled properly, but it is better to avoid exaggeration.

[1] Lodovici, M., Akpan, V., Casalini, C., Zappa, C., Dolara, P. (1998). "Polyciclic aromatic hydrocarbons  in Laurus Nobilis leaves as a measure of air pollution in urban and rural sites of Tuscany". Chemosphere, 36(8), pp.1703-1712.

[2] Bay Laurel, Laurus Nobilis, leaves, [http://quickbooker.org/kunden/wildherbsofcrete_com/pages/portraits-of-our-essential-oils-from-wild-herbs-of-crete/laurus-nobilis.php], last visited on the 21st of January 2015, last update unknown.

[3] Camphor Laurel - NSW Scientific Committee - final determination, [http://www.environment.nsw.gov.au/determinations/camphorlaurelktp.htm], last visited on the 21st of January 2015, last update on the 28th of February 2011.

[4] The MAK collection for Occupational Health and Safety, Benzaldehyde, [http://onlinelibrary.wiley.com/doi/10.1002/3527600418.mb10052e0017/pdf], last visited on the 21st of January 2015, last updated on the 15th of october 1998.

1st image kindly taken from frametoframe, [http://frametoframe.ca/2013/10/poison-garden-blarney-castle-ireland/].

2md image taken from Camphor Laurel Menace, [http://www.camphorlaurel.com.au/].

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Bamboo Alternative Source of Livestock Feed

For about a year now we have been getting nice big bundles of bamboo trimmings from a friend who grows lots of this wonderful plant in his permaculture garden.  He frequently harvests the poles for building, cutting off the leafy bits and baling them up for us to feed to our livestock.  Bamboo is after all a grass, which is quite high in protein, up to four times as high as other fodder grasses.  The species we have been using are mainly clumping timber (Bambusa oldhamii) and golden bamboo (Phyllostachys aurea).  In Asia, farmers have been feeding their livestock bamboo for hundreds of years.  For us, this is a free and nutritious supplement for our animals.  As the price of alfalfa (and feed in general) is steadily rising, feeding bamboo is one more way we can cut our feed costs.  We have planted several types of clumping bamboo in the hopes that we can produce a small quantity on our own property.  As our knowledge of permaculture design grows we are also planning on planting part of our hillside with quantities of forage trees.  The ultimate goal is to grow as much feed as we can on our small holding. 

The real question about the bamboo is...do they like it.  YES!  The goats and cow strip the poles clean, leaving us with thin branches to use in the garden as stakes or in our hugelkultur mounds. We have even used the leftover branches for mulch. 

Bamboo is versatile with many uses and quite easy to grow.  Just be sure you research how to grow it (or better yet, contain it) before you begin!

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