Natural vs artificial Christmas tree. And presepe?
Enrico Canuto, Former Faculty, Politecnico di Torino, Torino, Italy
An environmental dilemma
The environmental dilemma between natural and artificial Christmas tree is only one of tens, hundreds of dilemmas of modern welfare societies facing everything permeating pollution and growing global warming.
Let us first briefly recall two possible origins of the Christmas tree. (i) Some authors  associate Christmas trees with Protestant Christian reformer Martin Luther, who is said to have added lighted candles to an evergreen tree. (ii) An earlier association  is with the tree of paradise of medieval mysteries which were played on 24 December. In such plays, a tree decorated with apples was used as a setting for the play.
The environmental impact of natural (Fraser firs, left figure, about 2 m height, 15 kg weight) and made-in-China artificial trees (about 2 m height, 5 kg weight) has been analytically studied in  with the life cycle assessment method  on behalf of the American Christmas Tree Association.
Among the indicators accounted for in , we restrict to (i) the primary energy demand from non-renewable resources and (ii) the global warming potential (GWP) or carbon footprint. Although the study results strictly depend on US way of living, they can provide useful indications to other countries.
The primary energy demand from non-renewable resources (NR) is a measure in MJ (megaJoule) of the ‘feedstock energy’, i.e. of the energy that would be released upon combustion plus all other energies used during the product life cycle. Restriction to energy from limited non-renewable resources is such to penalize the choice of artificial trees, since cultivation of natural trees uses a lot of unlimited solar energy, but, as we will see, not in a drastic way. Artificial trees require their greater part of NR energy during the production process; the same demand by natural trees concerns cultivation and transport from farm to retail.
GWP is a measure in kg of artificial greenhouse gas emissions, such as CO2 and methane. It is widely accepted that these artificial emissions are causing an increase in the absorption of the radiation emitted by the Earth, magnifying the natural greenhouse effect. The production process of artificial trees is the major contributor to greenhouse gas emission. Natural trees do not emit but absorb carbon dioxide during cultivation; their major emission occurs at the end of life and depends on the way the waste is treated.
Table 1 shows rounded values of the above indicators taken from . Values have been rounded to account for uncertainty, not mentioned in . In the table, distinction is made between appropriate disposal of the wasted natural trees (landfill, see Remark 1) and incineration. Appropriate landfill process results in carbon sequestration, which is indicated by negative emissions. An alternative end-of-life disposal is composting, which is not reported in Table 1 since emissions are only slightly smaller than incineration. To conclude, document  first remark is that the overall environmental impact of both natural and artificial trees is extremely small when compared to other daily activities such as driving a car. Second, conserving an artificial tree for more than three years looks better than buying a natural tree every year for what concerns energy demand. Natural trees have zero greenhouse gas emissions if and only if their waste is appropriately disposed, without incineration/composting.
The last row of Table 1 provides a rough estimate of the natural tree rental for five years (the case is absent in ). Energy demand is estimated to be larger than the case of buying a new natural tree each of five years (row 4), because of the back delivery to the farm. The significant impact reduction comes from GWP, whichever be the end-of-life disposal.
|Table 1 -Natural versus artificial Christmas tree impact|
|No||Case||NR energy demand [MJ]||Landfill GWP: CO2 equivalent [kg]||Incineration GWP: CO2 equivalent [kg]|
|1||Artificial tree (+)||310||NA||19|
|2||Natural tree (once)||95||-3||5|
|3||Natural tree (thrice)||285||-10||16|
|4||Natural tree (five times)||470||-16||26|
|5||Natural tree rental (five years, estimate)||≈500||-16||5|
|NA Not appropriate, (+) average lifespan 6 years |
Assuming that both artificial and natural Christmas trees do not look environment friendly, which decoration may be an alternative?
Christmas Presepe (Nativity Scene): environment and art friendly
Saint Francis of Assisi is credited with creating the first Nativity Scene in 1223 at Greccio, central Italy. The scene takes its inspiration from the accounts of the birth of Jesus in the Gospels of Matthew and Luke.
The Gospel of Luke, 2,7-9. Et peperit filium suum primogenitum, et pannis eum involvit, et reclinavit eum in praesepio: quia non erat eis locus in diversorio. Et pastores erant in regione eadem vigilantes, et custodientes vigilias noctis super gregem suum. Et ecce angelus Domini stetit juxta illos, et claritas Dei circumfulsit illos, et timuerunt timore magno.
The Italian word ‘presepe’ derives from the Latin ‘præ-sæpes’, where ‘præ’ means ‘before’ and ‘sæpes’ means ‘fence’, hence ‘fenced place’ and by extension ‘manger, crib’.
Domestic Nativity Scene with moss covered landscape. http://www.parrocchiafonte.it /lafonte/mesi_pubblicazioni/2011-02 /Premiazioni%20Concorso%20Presepi.htm
Domestic Nativity Scenes usually consist of miniature landscapes including a grotto or stable with a crib where the infant Jesus is deposed between the Virgin Mary and Joseph. Angels may be placed on the grotto. The surroundings may be just rural with shepherds and domestic animals, in which case landscape is covered by moss. Villages can be added with artisans and housewives. The choice of landscape and figurines is left to adult and children sense of religion, feeling, creativity, tradition in a chorale of colors, lights, views and also sounds. Every people, family, community can design, shape, built and decorate their own presepe.
Recently Pope Francis published on the topic the Apostolic Letter 'Admirabile signum': "With this Letter, I wish to encourage the beautiful family tradition of preparing the nativity scene in the days before Christmas, but also the custom of setting it up in the workplace, in schools, hospitals, prisons and town squares. Great imagination and creativity is always shown in employing the most diverse materials to create small masterpieces of beauty. As children, we learn from our parents and grandparents to carry on this joyful tradition, which encapsulates a wealth of popular piety. It is my hope that this custom will never be lost and that, wherever it has fallen into disuse, it can be rediscovered and revived."
Why and how this treasure has been partly forgotten and replaced by the aniconic Christmas tree, also in catholic families and communities? Are we facing the longstanding struggle of iconoclasm, pretending to be a pure and enlightened form of religion and culture, with the popular veneration of images?
In modern times, iconoclasm flourished in Europe during Protestant reformation, thrust by reformed leaders (Calvinists) such as A. Bodestein von Karlstadt (1486-1541), H. Zwingli (1484-1531) and J. Calvin (1509-1564), who invoked Bible’s prohibition of idolatry. Destruction of images in England was encouraged during Anglican reformation by reformers such as T. Cranmer (1489-1556) and by a Parliamentary ordinance in 1550 against superstition and idolatry.
Destruction of religious images by the Reformed in Zurich, 1524 (from https://commons.wikimedia.org/w/index.php?curid=45078911).
Reformation iconoclasm was soon followed by the XVIII century subtler and permeating Enlightenment. Destruction of images and churches, during French revolution, was supported by members of the government as well as the citizenry.
From . On 23 October 1793 radicals in the Commune managed to pass this measure, decreeing that "all religious effigies that exist in the various places in Paris are to be removed". On 7 November, the Commune extended its ruling to include signs of religion inside buildings.
At the end, Enlightenment invented a subtle iconoclasm, still alive, flourishing and commonly practiced, mostly aiming to neutralize the enthrallment of Catholic images .
From . The scientific Enlightenment exercised a philosophical iconoclasm by describing ideology as an idol that enthralls the naive and that must be broken; the sentimental Enlightenment neutralized the image by placing it in the museum and by calling it Art; and thirdly, Enlightenment taste commodified the image under the market’s hammer.
Iconoclasm of Catholic Churches is endless: see pictures below from Chile and Iraq.
Chilean masked vandals looting La Asuncion Catholic Church during protests against the government in Santiago, November 8, 2019. Left picture from newcastleherald.com.au Right picture from /www.lifesitenews.com/news/chiles-bishops-plead-for-calm-after-leftists-pillage-historic-catholic-church.
A Catholic church destroyed by Islamic State militants in Karamdes, Iraq, is examined by a priest following the 2016 liberation of the predominantly Christian town. From http://cbcpnews.net/cbcpnews/inside-a-church-destroyed-by-isis-in-iraq/
Let us now briefly and roughly try to assess the environment impact. Due to extreme variety of materials, layout and size, we assume a family nativity scene 1.5 m2 wide, where 3 m2 of 5 mm softwood (6 kg weight 6 kg) and 3 kg of figurines made by ABS resin (TBV) have been employed. Other materials are neglected and their impact included in a 20% contingency (TBV), except 1.5 m2 of dried moss. The lifespan of wood and figurines is assumed to be equal to human generation lifespan of about 35 years . The plaster presepe figurines modeled and colored by my father in the fifties of the past century are still in use. Dried moss may last more than five years, but glycerin preserved moss lasts for tens of years. Table 2 compares the rough impact estimation of a family presepe from previous data with the natural Christmas tree rental values in Table 1. The annual impact of a family presepe appears much smaller than natural tree rental, mainly due to a much longer lifespan.
|Table 2 – Impact of family nativity Scene (TBV)|
|No||Material||NR energy demand [MJ]||GWP – CO2 equivalent [kg]||Lifespan|
|2||Resin figurines ||≈300||≈10|
|5||Total (per year)||≈400 (<12)||≈15 (<0.5)||35 year|
|6||Natural tree rental||≈500 (≈100)||≈5 (≈1)||5 year|
|TBV = to be verified|
The results of Table 1 and Table 2 point out a well known critical property of (and critical attitude toward) modern goods: short lifespan (consumerism). Modern welfare life is deeply permeated and poisoned by that.
Christmas presepe is a cure of both subtle iconoclasm and permeating consumerism.
 PE Americas, Comparative Life Cycle Assessment of an Artificial Christmas Tree and a Natural Christmas Tree, Final report, Boston, November 2010.
 H. Haidle (2002). Christmas Legends to Remember, 2002, Thomas Nelson Inc.
 S. Karas, The Solstice Evergreen: history, folklore, and origins of the Christmas tree, Aslan, 1998.
 The Southern Christmas Tree Association, Keeping it REAL! It’s the natural choice, from www.southernchristmastrees.org/KeepItReal.html.
 D.F. Ciambrone, Environmental Life Cycle Analysis, CRC Press, Boca Raton, 1997.
 D. Devine, How long is a generation? Science provides an answer, from https://isogg.org/wiki/ How_long_is_a_generation? …
 S. Joshi, L.T. Drzal, A. Mohanty and S. Arora, Are natural fiber composites environmentally superior to glass fiber reinforced composites?, Composites, Part A, applied science and manufacturing, Vol 35, 2004, pp. 371-376.
 Anonymous, Timber and the environment, from http://www.greenspec.co.uk/building-design/timber-and-the-environment/
 J. Simpson, Iconoclasm and the Enlightenment Museum, from http://scholar.harvard.edu/files/jamessimpson/files/iconoclasm_and_the_enlightenment_museum.pdf.
 R. S. Clay, Sign of power: iconoclasm in Paris 1789-1795, University College London, 1999.
Remark 1 
“US landfills release only 33% of the carbon input; the rest remains sequestered in the landfill for more than 100 years (the time horizon of GWP for this study).”