Cedrus libani: What does future hold for Lebanon's cedar trees?

AS its scientific label indicates, Cedrus libani is native to Lebanon, the eastern coast of the Mediterranean and elsewhere in Asia Minor, notably in Turkey. It is particularly well adapted to life in mountainous climates where it receives winter precipitation, intercept mist drifting in from the sea and often snow. 

Its natural habitat is characterised by warm, dry summers and cool, moist winters with an annual precipitation of 1,000–1,500 mm (39–59 in). 

For readers whose geographic knowhow is sketchy, Lebanon is a Middle Eastern country with over six million people. Located on the eastern coast of the Mediterranean Sea, its southern border is shared with Israel, with Syria to the east and north.

One of the smallest nations on the Asian mainland, it covers 10,400 km² or half the size of Wales. Much of the interior of the country is mountainous, often limestone.

THE IMMEDIATE FAMILY

A Lebanese cedar. (Image: Getty)

After a bit of wrangling amongst taxonomists, there are generally four species of cedar recognised – the Atlas (Cedrus atlantica), the Cyprus (C. brevifolia), the deodar (C. deodara), and the Lebanon cedar (C. libani).

Cedrus atlantica is native to the Rif and Middle and High Atlas Mountains in Morocco and to the Tell Atlas in Algeria. 

Most modern sources treat this western Mediterranean cedar as a true species, although some consider it a subspecies of the Lebanon cedar (C. libani subsp. atlantica). 

It is classed as ‘endangered’ in international conservation circles.

A distant relative is Cedrus deodara, the Himalayan cedar, or simply deodar, that is native to those high mountains.

IN THE BRITISH ISLES

Well known to dendrophiles, a detailed description of the stately, aromatic, gigantic cedar of Lebanon seems unnecessary. 

With its characteristic layers of branches and grey-green foliage, it is one of the most majestic of all landscape trees and is part of the enduring panorama of many of our grandest estates.

Exactly when the first specimen was introduced into Britain is debatable, but it dates from at least 1664, when it is mentioned in that classic Sylva, or A Discourse of Forest-Trees and the Propagation of Timber.

In these isles, this cedar was planted in the grounds of nearly every stately home and mansion from the mid 1700s onwards. 

However, it is not so commonly established today and has rather fallen out of fashion.

The slow-growing young trees may not bear cones until 40–50 years old, when they start to show the classic spreading branches with the cones perched on them.

Cedars here can suffer from Sirococcus blight. It’s a serious disease caused by the fungus Sirococcus tsugae, and its Latin name suggests it also affects hemlocks. 

First detected in England in 2013, this has since been confirmed in both Wales and Scotland.

The commonest symptoms are that the needles of impacted trees turn pink and drop off, their shoots die, they ooze a gumlike fluid and the bark can turn from green to dark red or purple. 

There are currently no effective control measures for this blight in the UK, but good working practices and better biosecurity can assist in limiting the spread from one specimen tree to the neighbours. 

C. libani is also susceptible to honey fungus and prone to aphid attack.

USES PAST AND PRESENT

Over the centuries, mankind has profited from the large and durable timber from this tree in the Levant or western Middle East. Most of the native stands have been felled, but scant old-growth remains. 

In antiquity, in the Middle East, cedar wood was used to construct major buildings such as temples, due to the tree’s exceptional size and durability. The timber has been harvested for boat building and trees were felled extensively during the Ottoman Empire for railroad sleepers.The wood is a source of an essential oil similar to turpentine and was used to make cough medicines, ointments and antiseptic.

Ancient Egypt even imported the oil from Lebanon for embalming the dead.

STATUS

Two of these cedars – the Atlas and the Lebanon – run the risk of extinction in the wild. Centuries of over-harvesting, over-grazing of regenerating saplings and wild fires have taken their toll on stocks in their native mountainous terrain. 

Of the vast cedar forests that once clothed most of Lebanon’s highlands, only roughly 17 km² of untouched climax stands remain, in scattered groves.

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Much of the woodland left no longer contains magnificent, mature or old-growth giants living up to a thousand years of age. 

A small number of spares and fragmented populations are protected though and some replanting is happening. But a new player in the equation is climate change.

CONSERVATION EFFORTS

This tree has enjoyed its human champions in Lebanon down the years. Indeed, the most famous grove there is nicknamed ‘The Cedars of God’ and has been fenced off for preservation from way back in 1876. It is a UNESCO World Heritage Site.

But now, after centuries of human depredation, the cedars of Lebanon face perhaps their most dangerous threat. Some experts fear climate change could wipe out most of the country’s remaining fragmented cedars by the end of the present century.

There are two main protected areas. The first, located south of the capital Beirut, is the Barouk Forest, at a relatively low altitude. The best ecological comfort zone for these charismatic, flagship cedars has historically been between 1,400 and 1,800 metres with ecotypes or genetic variants found both higher and lower on the limestone rocky slopes.

Yet as temperatures climb, this ideal growing stratum is shifting up the mountains to higher altitudes, chasing the winters the cedars need to reproduce. 

Experts prophesy that the only way is up, so the cedars there may disappear by the end of this century. As any new trees spread and reach the top, then they have nowhere left with a sustainable climate to colonise. 

Further north, the second remaining stronghold is the higher Tannourine Cedars Forest Nature Reserve, which has also lost many of its trees in under two decades. There though, the challenges are different but still directly linked to the warming, drying climate – this time from an insect pest.

The green cones of the Lebanese cedar tree. (Image: Getty)

Cephalcia tannourinensis is commonly known as the cedar web-spinning sawfly, whose larvae feast on the cedar trees’ young needles. This insect was unremarkable or overlooked by scientists until 1998, when a Lebanese entomologist identified it as the causal agent of a mysterious problem that started killing swaths of that protected cedar forest. 

The culprit was tracked down as this sawfly, which buries itself in the frozen ground in winter. It had never been a problem before as the timing of its life cycle did not really clash with that of the cedars. But with less winter snow and premature thawing the overwintering adults emerged ahead of normal – and just in time to lay their eggs on the still fresh flushing cedar shoots for the grubs to gorge themselves.

To strive to protect the cedars from total destruction, various Lebanese conservation groups are trying to diversify the locations and expand the tree populations.

Efforts to conserve this iconic tree are not unique to Lebanon. In Turkey, the forest service commenced an extensive replanting programme where the best endemic stands are in the high western Taurus mountain range in the south of the country overlooking the Mediterranean.

One ancient tree there in Turkey – estimated as 2,000 years old – is registered as a national monument. Its name is ‘Koca Katran Lüban sediri’ or ‘the big old cedar of Lebanon’.

THE FUTURE

Lebanon has witnessed turbulent times in the last few decades. And its ancient cedars have outlived empires and survived wars. Will these iconic trees survive in their natural environments for much longer in the face of this latest threat – humaninduced climate change? Watch this space.