Christmas: Frankincense and Myrrh
In the history of baffling Christmas presents, none may be stranger than the three gifts of the Magi: gold, frankincense and myrrh. The gold, in traditional interpretations, represented God’s splendor and power. The frankincense, burned for purification, suggested divinity. Myrrh, a funereal spice, prefigured the crucifixion and the anointing of the dead.
Thus the holiest plant of the Christmas season may be a raggedy shrub with peeling bark that seems to grow best in the most inhospitable of climates. Boswellia sacra is better known as the Frankincense Tree. The shrub’s gum resin is one of the biblical gifts that the wise men bestowed on the infant Jesus.
Until recently, Americans who wished to cultivate their own frankincense could only hope for another biblical house call. Marc Hachadourian, who manages the Nolen Greenhouses at the New York Botanical Garden, describes frankincense seed as hard to find and harder still to grow.
“In horticulture, there are a few plants that we joke about that have a miserable life,” he said. “Boswellia is only happy in its native environment. And even then, it’s not as happy as it could be.”
In the Frankincense family (Burseraceae) there are 19 species of the genus Boswellia Roxb. ex Colebr. Five or six of these species are endemic to the Island of Socotra, Yemen, a Unesco World Heritage site, near the mouth of the Gulf of Aden, which has a ban on botanical exports. The island is very isolated and through the process of speciation, a third of its plant life is found nowhere else on earth. Other Boswellia reside in the anarchic hinterlands of Yemen and Somalia.
Boswellia sacra is not much of a looker. The paired leaves appear small and crinkled. But the exfoliating bark is something else again: ocher and papery, like a sheet of baking parchment scorched in the oven.
Some appreciate the plant less for its beauty than its deeper botanical riddles. It is said one can predict rain from the swelling of the nodes along the branches. When the barometric pressure drops, Boswellia take every opportunity to grow, flower, and to set seed.
Harvesters slash the trunk with a hatchet and collect the dried beads of sap. Researchers in Eritrea, writing in the Journal of Applied Ecology, observed that frequent resin-tapping in another Boswellia species (B. papyrifera) lowered the number of seeds and lessened their viability.
Accounts from the ancient world make frankincense sound like a cross between aspirin, penicillin, Xanax and Viagra, with a touch of duct tape and magic.
When cut, a white bead of sap forms at the wound. Egyptians, according to “Plants of Dhofar,” believed this to be “the sweat of the gods, fallen to earth.”
The aroma hints at cypress and citrus and maybe witch hazel. But at the same time, it seems like nothing else in the American garden or forest.
Tips for Growers
If you want to grow Boswellia sacra at home it helps to have a desert in the backyard. Failing that, the best place to start might be Jason Eslamieh’s book, “Cultivation of Boswellia: Sacred Trees of Frankincense” (A Book’s Mind; $33).
Gardeners across the sunbelt — in Orlando, Houston, Phoenix, Los Angeles — may be able to keep Boswellia outdoors year round. When the temperature falls below 40° (4½° C.) for a day or two, Boswellia drops its leaves. In colder weather, the plant quickly dies. Given a choice, it doesn’t like to be confined to a pot.
Pumice is the preferred soil medium, if you can find it. Some gardeners have had luck substituting Turface MVP (a baseball diamond supplement) and Oil-Dri absorbent (a garage cleaner). Make sure to change the soil every year or two, lest a buildup of salts and minerals starts to poison the pot.
It is possible to grow Boswellia under lights. But it’s easier to shut the plants down for the winter on a shelf in the bedroom.
The other plant-gift of the Magi is a rangy assemblage of vicious thorns, called myrrh (Commiphora myrrha). Also a member of the Frankincense family, Myrrh is probably harder to cultivate outside its native range. Myrrh is native to Oman, Yemen and the Horn of Afrida (Djibouti, Ethiopia, Somalia, and Northeast Kenya). It only grows at an altitude of between 800-4,000 feet above sea level (250-1300 m), with a yearly mean rainfall of about 9-11 inches (230-300 mm) in thin limestone soils.
Technically, myrrh is the aromatic oleoresin of a number of small, thorny tree species of the genus Commiphora, which grow in dry, stony soil. An oleoresin is a natural blend of an essential oil and a resin. Myrrh resin is a natural gum.
When a tree wound penetrates through the bark and into the sapwood, the tree bleeds a resin. Myrrh gum, like frankincense, is such a resin. When myrrh is harvested the gum becomes hard and glossy. The gum is yellowish, and may be either clear or opaque. It darkens deeply as it ages, and white streaks emerge.
Myrrh was so valuable in acient times that it was equal in weight value to gold. During times of scarcity, its value rose even higher.
Frankincense tree facing uncertain Future
Ecologists have warned that the production of the fragrant resin could decline by half over the next 15 years.
The festive fragrance is produced by tapping the gum of trees in the Boswellia genus.
The findings, based on a study carried out in Ethiopia, have been published in the Journal of Applied Ecology.
"There are several reasons why [the tree species Boswellia papyifera] it is under threat," explained co-author Frans Bongers, an ecologist at Wageningen University in the Netherlands.
"The forests that remain are declining because the old individuals are dying continuously, and there there no new individuals coming into the system. That means that the forests are running out of trees."
"In places like Oman and Yemen, it is being cut down systematically. Now, in Ethiopia, it is being cut down as land is being turned over to agriculture."
The small trees, which generally reach a height of no more than five metres (16ft), grows in steepy, rocky habitats, providing cover for other plant species.
Each year, up to about 3kg of resin can be tapped from an individual tree. After about five years of tapping, management techniques suggest that the tree should be rested for a similar period in order to maximise future yields.
The genus Boswellia, overall, is generally classified as Vulnerable as a result of habitat fragmentation and poor levels of rejuvenation, explained Prof Bongers.
"If the tree germinates, then there is a small plant coming out of the ground, but then in the next dry season it goes down again because it is too dry," he told BBC News.
"Then in the wet season it comes up again. Yet in the next dry season it goes down again. That happens for a number of years, and we don't know how many years this happens - we know that it is at least six years.
"But it may be 10 years and we do not know what triggers what makes it come up above ground forever - maybe it is some sort of reserve, some sort of starch in the soil or root system.
"We are measuring this but we do not have real data, so it is complicated to manage the seedlings."
Prof Bongers added that the encroachment of more opportunistic tree species was also affecting the long-term survival of the frankincense forests.
"In the landscape, these tree has been the dominant species. That is why we can call it a frankincense forest, just like we can refer to beech woodlands in the UK," he said.
"In these woodlands, 80% of the individuals are frankincense trees. Yet some areas at the verges of the distribution of the species, there are other species coming in.
"What we are seeing at the verges of the populations we are following is that that the frankincense trees are phasing out and other species are coming in.
"All the young individuals in the forests are from other species, such asAcacia. We just see the forests running out of frankincense - other species are taking over."
The study examined 13 two-hectare plots, which involve monitoring more than 6,000 trees and collecting more than 20,000 measurements.
Using this data, the team modelled the fate of the species, and found the current levels of frankincense production is set to halve in the next 15 years.
"Current management of Boswellia populations is clearly unsustainable," Prof Bongers warned.
"Our models show that within 50 years, populations of Boswellia will be decimated, and the declining populations mean frankincense production is doomed. This is a rather alarming message for the incense industry and conservation organisations."
He added that tapping the trees for the valued resin was unlikely to be the main cause of the decline. Instead, there were a number of other things affecting the long-term future of the trees.
"Frankincense extraction is unlikely to be the main cause of population decline, which is likely to be caused by burning, grazing and attack by the long-horn beetle, which lays its eggs under the bark of the tree.
In the areas they studied, the team found that older trees in the population were not being replaced because few Boswellia seedlings survived to become saplings.
"The number of fires and intensity of grazing in our study area has increased over recent decades as a result of a large increase in the number of cattle, and this could be why seedlings fail to grow into saplings. At the same time, a large proportion of trees we studied died after being attacked by the long-horn beetle," Prof Bongers observed.
In order to ensure future rejuvination, he suggested that areas should be set aside for up to a decade so young Boswellia trees can become established.
09 FEBRUARY 2010, MIDDLE EAST
19 DECEMBER 1997
12 DECEMBER 2011
The world may still have gold and myrrh, but it's quite possible that frankincense could become a thing of the past, given ecological pressures on the arid lands where it grows in Ethiopia.
It's Summer in Australia
Forecast for Christmas Day in Sydney is Mid-80°s (29°C) and sunny. Of course it might be hotter in Florida this year. Current forecast for Orlando area on December 25? Low 80°s (28°C).