Lebanon's forests: Lebanese cedar biology

Part of the conifer family
The Lebanese cedar belongs to the order of plant species called Coniferae, or conifers. Commonly (but not always correctly) known as evergreens, conifers are found around the world and include the tallest and longest-lived organisms ever to have lived on land.

Conifer trees are characterised by needle-like leaves and have reproductive structures called cones. Other conifer species include larch, pine, juniper, spruce, and cyprus.

Three true cedars
Although many trees around the world are popularly known as cedars, there are only three recognized species of "true cedars":

• the deodar (Cedrus deodara), characterized by drooping branches and silvery needles and found in the Himalayas and Hindu Kush.
  
• the Lebanese cedar (C. libani), characterized by horizontal branches and blue-green needles, historically found from Turkey through the Middle East to North Africa, with a small-leaved variety on the island of Cyprus.
  
• the Mount Atlas cedar (C. atlantica), characterized by ascending branches and yellow-green needles, and found in the mountains of Morocco.

However, these three are so closely related that some biologists regard the them as different geographical subtypes of the same species.

Wide-spread branches and a flattened top
In addition to the blue-green foliage, the most striking characteristics of full-grown wild Lebanese cedar are the large, wide-spreading horizontal branches and the broad, flattened top. They can reach heights of 20m, and spread out to 9-15m. The trees live for a long time - the oldest tree is more than 1,000 years old. Lebanese cedars generally form open forests with an undergrowth of grasses and shrubs.

Prefers an ocean view
All cedar species are only found at high elevations. Lebanese cedars grow at 1300–2100m, and prefer deep soil on slopes facing the sea. The trees require a lot of light and around 1000mm of rain a year. The natural range of the Lebanese cedar extends from Turkey's Taurus mountains in the north-west, through Syria, Lebanon, Israel, and Jordan to North Africa.

However, from being a once-abundant species, human activities over the past 4,500 years have resulted in Lebanese cedar only remaining as fragmented and degraded populations throughout much of its range. In Lebanon, the species once completely covered Mount Lebanon, but now only survives in 12 isolated patches.

Slow to mature
As a conifer, Lebanese cedar trees have cones for reproduction. The species is slow to mature, with trees only producing cones after 25-30 years of age. And even when the cones appear, they take 2-3 years to mature. Individual trees have both male cones, which produce pollen, and larger female cones, which are fertilized by the pollen to produce seeds. After they are mature, the female cones open to release the seeds, which fall to the ground to grow into a new cedar tree.