pierre laszlo

Prunus dulcis (L). (Rosaceae)

Plant of the month (©Pierre Laszlo, all rights reserved)
Prunus dulcis (L). (Rosaceae) 

Writing about almond trees and almonds is challenging. It is not only difficult to avoid
the commonplace, in addition the sheer diversity of the topic is yet another hurdle. Mankind has enjoyed not only a long, but a caring relationship with almond trees. 
Humans named some of their own body parts after the fruit, almond-shaped eyes or fingernails. Wild almonds have been found in Greek archeological sites dating to 8000 BC. While the species originated in arid regions (Persia and Afghanistan), by 4,000 BC almond trees were cultivated all around the Mediterranean. The Bible often refers to almonds as objects of value and symbols of hope. King Tut carried several handfuls to his grave in 1352 BC, to accompany him on his journey into the afterlife. In Pre-Modern times, Arab traders brought almonds to Western Europe. The main area of production was then Mesopotamia, present-day Iraq. Almonds were grown also in Persia (Iran).
To stay within the circum-Mediterranean area, where almond trees continue to be grown, their early flowering, antedating spring, also makes for their attractiveness. In Provence, the white flowers may appear as early as the beginning of February — potential victims to the return of an episode of frost. They became allegorical of virginity and young love. 
The almond tree was brought to California in the 1700s by Spanish priests who settled the Mission at Santa Barbara. The industry started in California at about the turn of the twentieth century, due to development of superior cultivars in the late 1800s. Nowadays, California accounts for more than half the world production. Almond cultivation in California uses peachtree seedlings for the rootstock. Belonging to the same Prunus genus, peachtrees are cousins of almond trees. Later on, in California, almond tree branches are grafted onto the developing Prunus tree. In other parts of the world, such as Spain, the number 2 producer, almondtree seedlings are used. 
Almondtrees require cross pollination. Pollinators (honey bees) are absolutely essential, especially since, as just mentioned, cool, wet weather can occur during the relatively early blooming period. 
Nut-bearing plants co-evolved with nut-dispersing rodents and birds that originated as early as the Paleocene, about 60 million years ago. While most nuts originated with ancestors that thrived on wind dispersal of the seeds, in the case of the wild almond trees dispersal depended on frugivorous animals who ate the seeds, birds and food-hoarding rodents. 
Which helps to explain the high nutritional value of almonds. Not to belabor the point and to mention briefly health benefits, athletes increase their endurance performance from almonds in their diet, as compared e.g. to cookies. Likewise, almonds enhance memory and decrease the risk of cardiovascular disease. 
Wild almonds contain amygdalin, a source of cyanide. Domestication occurred, somehere in the Fertile Crescent, during the first half of the Holocene. The P. dulcis species was already cultivated 11,000 years ago to produce only sweet almonds. 
While wild almond species are toxic, domesticated almonds are not. Professor Jared Diamond of UCLA argues that a common genetic mutation causes an absence of amygdalin, and this mutant was grown by early farmers, "at first unintentionally in the garbage heaps, and later intentionally in their orchards ". Almonds were one of the earliest domesticated fruit trees due to "the ability of the grower to raise attractive almonds from seed. Thus, in spite of the fact that this plant does not lend itself to propagation from suckers or from cuttings, it could have been domesticated even before the introduction of grafting." (Zohary & Hopf). 
Finally, and relevant to current concerns about water shortages, growing a single almond demands a gallon of water. With the present drought in California, one wonders if its global leadership in the crop might be threatened.