Can Olive Trees Protect From Forest Fires?

Recent News

The sum­mer of 2017 was a long and hot one across much of the Mediterranean. Low rain­fall and high tem­per­a­tures resulted in wide­spread drought but also destruc­tive for­est fires in sev­eral coun­tries, includ­ing Portugal, France, Italy, Croatia, Greece and Turkey.

Portugal was the worst hit, with 141,000 hectares dec­i­mated by fire and 64 lives lost. In Greece, 15,000 hectares of land were lost to fires, while in France an area of 12,000 hectares was dev­as­tated.

After tak­ing stock of the extent of the dam­age, the causes of the fires were traced to a vari­ety of causes: light­ning strikes, arson, human neg­li­gence and inad­e­quate for­est man­age­ment.

In Portugal, the fact that euca­lyp­tus trees make up over a quar­ter of the coun­try’s for­est cover was con­sid­ered a sig­nif­i­cant cause for the rapid prop­a­ga­tion of the deadly fires. The bark and sap of the fast-grow­ing euca­lyp­tus are highly flam­ma­ble and added fuel to the already rag­ing fires. Eucalyptus trees were also to blame for California’s sec­ond dead­liest fire in his­tory – the 1991 fire in Oakland.

Today euca­lyp­tus pulp is one of Portugal’s biggest exports. In recent years, for­mer agri­cul­tural lands left to aban­don were trans­formed into groves of euca­lyp­tus to be sold as a cash crop to the pulp and paper indus­try.

In light of this sum­mer’s deadly fires, local envi­ron­men­tal groups are now lob­by­ing to have these groves replanted with native cork and holm oaks which are less flam­ma­ble and more resis­tant to fire than the highly com­bustible euca­lyp­tus.

Meanwhile, in the depart­ment of Var in the Provence-Alpes-Côte d’Azur region of south­east­ern France, local farm­ers and polit­i­cal lead­ers are dis­cussing the pos­si­bil­ity of plant­ing more olive groves and vine­yards to pro­tect agri­cul­tural land from drought and for­est fires. This year alone, the depart­ment has expe­ri­enced 398 for­est fires with a loss of 3,562 hectares.

The risk of fire is a con­stant worry for farm­ers across the Mediterranean. Former agri­cul­tural land left to aban­don quickly becomes cov­ered in under­growth and even­tu­ally wood­land which presents a fire haz­ard.

Creating swathes of cleared land between for­est and agri­cul­tural land is one way to pre­vent fires from eas­ily spread­ing. When land is reg­u­larly plowed or grazed by ani­mals, the main­tained fields lack the under­growth that can catch fire eas­ily. Other pre­ven­tive mea­sures can be taken like clear­ing wild veg­e­ta­tion from the edges of road­ways and pri­vate prop­er­ties, and plant­ing vine­yards or olive groves to cre­ate pro­tec­tive bar­ri­ers.

Olive trees and grapevines can cre­ate a nat­ural bar­rier to fire because they are leafy plants that retain humid­ity and need lit­tle water. In the south of France, some for­est roads are lined with vine­yards to act as fire bar­ri­ers.

A recent arti­cle in the French news­pa­per Le Figaro high­lighted the exam­ple of the island of Porquerolles in the depart­ment of Var. Following a fire in 1897 that com­pletely dec­i­mated the island’s veg­e­ta­tion, three large vine­yards were planted to pre­vent the spread of fire between five demar­cated for­est areas that divide the island. But the direc­tor of the fire and res­cue ser­vices of Var, General Martin, made the point in the arti­cle that vine­yards are ​“a pos­si­ble solu­tion as long as they’re cleared of under­growth” includ­ing dry grass that can cause a fire to spread.

The olive tree is a hardy plant that’s con­sid­ered to have fire retar­dant qual­i­ties and can offer pro­tec­tion against fire and wind. Olive trees can live for cen­turies and even if its branches and trunk are destroyed, the tree can regen­er­ate itself thanks to its robust root sys­tem.

A brochure pub­lished by the state of Victoria, Australia included the olive tree in its list of sug­gested fire-resis­tant plants to be planted in areas prone to bush­fires.

Another tree found to be remark­ably fire-resis­tant is the Mediterranean cypress tree. A 2015 study con­cluded that thanks to the high water con­tent of its leaves, the cypress is fire-resis­tant and can help pro­tect from wild­fires.

• Le Figaro


• LA Times