Are palm trees fire resistant?

Syagrus romanzoffiana Picture courtesy K M from flickrSyagrus romanzoffiana Picture courtesy K M from flickrOne of the questions most often asked is: “Are palm trees fire resistant?” In my research, this subject seems to be contentious, with fire officials stating that they are not, and some growers saying that what makes palms so flammable is the way the dead leaves cling to the trees, and if palms are well maintained and watered regularly, they are fire resistant. Read more below.

Following the deadly Woolsey Fire in Malibu, California, on November 8, 2018, that burned in Los Angeles and Ventura Counties, destroying 96,949 acres of land and 1,643 structures, killing three people, and forcing the evacuation of more than 295,000 people, the City Council of Malibu voted to approve a fire-resistant landscape ordinance that bans palm trees, restricts the use of other highly flammable trees, and seeks to create a five-foot wide non-flammable buffer zone around structures.

Among the thousands of trees that dot Southern California’s landscape, perhaps none symbolizes the region more than the towering Fan, King, and Queen Palm trees. But when not maintained properly, palm trees can create a deadly fire hazard--literally exploding into flames in a matter of minutes. According to fire officials it took 45 minutes to extinguish Queen Palms planted just feet away from homes. Fire fighters claimed that palm trees are like little rockets, and even a three-foot palm tree by a front door is the worst thing you can have in a fire.

The Woolsey fire damaged or destroyed more than 480 homes in the city of Malibu, and officials concluded that Palm fronds, Ficus hedges, and garden infrastructures like wooden decks and fences, likely contributed to the spread of fire in some residential areas that might otherwise not have burned.

It is obvious that a lot of research still has to be done on this subject, but we do know that the absence of a vascular cambium in palm trees, which instead have a scattering of vascular bundles throughout the cross section of the stem, and the location of the terminal bud under many layers of leaf bases, makes palms among the most fire resistant of trees. However, this does not make them less hazardous in the garden.

For example, the Desert Fan Palms (Washingtonia filifera) which grow In Los Angeles are a fire hazard because of their drying fronds which can catch fire in the open. These palms are also particularly prone to burning in the low, hot dessert oases of southern California, but although they may be damaged by fires, a mature tree is rarely killed by fire due to the scattering of these vascular bundles, which also provide insulation from the heat. In fact, Desert Fan Palms actually increase their seed production immediately after fires. So it seems that although many species of palms can survive wildfires, this does not necessarily make them safe to plant close to homes.

Click here to see Google images of the Desert Fan Palm

In South Africa, the Mexican Fan Palm (Washingtonia robusta) is widely planted in gardens, and because it also does not naturally drop its dead fronds but rather folds them down around the stem, forming a dense 'petticoat', it is a fire hazard. Unmaintained trees spread fires when this dead thatch catches fire and the dried fronds break free and spread the blaze to neighbouring structures, often with disastrous consequences, so in urban gardens it is necessary to remove these dead fronds.

Click here to see Google images of the Mexican Fan Palm

Other palms like the  King Palm (Archontophoenix cunninghamiana) and the Cocos or Queen Palm (Syagrus romanzoffiana) are palm species that actively shed their old leaves, and if they are well maintained, their smooth trunks and clean crown shafts provide no tinder for a blaze, making them more fire-resistant. Others recommended by palm growers in California as being fire resistant are the Kentia Palm (Howea forsteriana), and the Dwarf Date Palm (Phoenix roebelenii).  

Click here to see Google images of the King Palm

Members can click here to read more about the Cocos or Queen Palm

Click here to see Google images of the Kentia Palm

Members can click here to read more about the Dwarf Date Palm

Other Palms grown in South African gardens include the Mediterranean or European Fan Palm (Chamaerops humilis) which is very resilient to recurrent fires and re-sprouts very quickly from basal suckers from an underground rhizome. The re-sprouting of this species does not necessary come from new dormant buds (as in most typical re-sprouters) but from the normal apical buds which are protected from the fire by the leaf bases in the stem. The first re-sprouting leaves often show a typical burned-brown-green pattern, and this is because is because in palms, as in all Monocotyledons, the meristem is at the base of the leaves and therefore more protected, so even burned leaves can still grow from the base, but the upper part of the leaf will be partly burnt. This palm also often flowers very quickly after fire.

Members can click here to read more about the Mediterranean or European Fan Palm

The Canary Island Palm (Phoenix Canariensis) will burn in a fire but can survive, and often grows even stronger after having been blackened by fire. In October of 2013, after more than 1,200 Canary Island Date Palms  were damaged by a devastating fire on La Gomera Island in the Canary Islands, a cleanup was carried out which involved climbing up the sooty trunks to reach the sad-looking crowns and remove the dead fronds with saws and special knives. This is dangerous work because of the great height these palms can attain, and also because of the hard needle-sharp spikes at the ends of the fronds. The clean-up was part of fire prevention measures all over the island of La Gomera, and included the removal of thousands of tons of dead and partially burnt vegetation, as well as any other material that could easily catch alight.

Members can click here to read more about the Canary Island Palm

The Bismarck Palm (Bismarckia nobilis) is endemic to Madagascar, and regenerates quickly on land which has been cleared for agriculture by burning, it is one of the most conspicuous features of this arid region.

Members can click here to read more about the Bismark Palm

The Windmill Palm, Chinese Windmill Palm, Chusan Palm (Trachycarpus fortunei) is listed as a high fire hazard because it develops a rather slender single stem covered with a loose mat of coarse brown, flammable fibre, and if the tree is not correctly maintained, the dead leaves hang down from the top, forming a brown skirt that will catch flying embers and quickly ignite.

Members can click here to read more about the Windmill Palm

In conclusion, while palm trees are fire resistant, it is important to note that they are not fireproof. If you already have palm trees in the garden and do not want to remove them, it is important to prune the trees regularly and to keep them well-watered during periods of drought to help prevent them from becoming dried out and more susceptible to fire.