BEIRUT: The stone pine, a steady feature of Lebanon’s landscape for generations, has recently come under renewed threat from invasive insects that are affecting a staple of Lebanese cuisine: the pine nut. While some ailing pines exhibit symptoms of dying branches, others have succumbed to “Dry Cone Syndrome,” leaving pine cones empty of their lucrative seed.
According to Nabil Nemer, head of the Agricultural Engineering Department at the Holy Spirit University of Kaslik, the first signs of this wave of pine distress were recorded in 2001.
Dry Cone Syndrome was officially confirmed in 2013, according to Nemer who has researched insects and diseases in Lebanese forests since 1999. While both branch-death and DCS were found in mountainous regions of Lebanon, the capital’s Horsh Beirut park has also been affected. Tree dieback was recorded in the park in 2016 and it is now, according to officials temporarily, closed.
“The big losses were registered in Horsh Beirut because the trees are young ... compared to trees in the Metn and other regions,” Nemer told The Daily Star, explaining why dieback in Horsh – the last remaining section of the city’s pine forest – seemed particularly dramatic.
“Until now, the causes [of the issues] are attributed to insects,” Nemer said. “However, we should know that the insect problems is directly related to stressed trees, which is due to climate change or low rainfall ... that may render the trees more stressed and thus prone to insect attacks.”
One invasive insect species, Leptoglossus occidentalis or Western conifer seed bug, started appearing in Lebanon between 2012 and 2013, Nemer said, causing low pine-nut yields. Additionally, wood borers are causing tree dieback.
Lebanon’s rampant bird hunting has allowed numerous insect species to flourish in the absence of natural predators. The decline of Lebanon’s stone pines has consequences beyond the environmental, Jad Abou Arrage, an environmental economist at the Lebanese University, told The Daily Star.
After citing “indirect effects” on ecotourism, Abou Arrage stressed that impacts have already been experienced first-hand in rural areas that financially depend on the trees.
“Of course there will be consequences, especially on the livelihood of people living in rural areas,” he said. “There are many who rely on timber and non-timber products ... pine nuts from these trees are a source of secondary income for many.”
Anwar Choucair, a Metn resident, has long harvested pine nuts on his family’s properties in Baabda’s Arsoun, Salima Deir al-Haf and Ras al-Metn, as a secondary source of income. “My family ... has owned large areas of land that have been inherited from previous generations,” he said. Since the early onset of DCS, the Choucairs have noticed a significant decline in yields.
“It started almost five years ago and up until last year, it has been getting worse. We used to harvest around 3 tons of pine cones yearly, but recently we’ve been making less than 20 percent of that, with harvests reaching only 250 kilograms.”
Choucair added that harvesting 250 kg was only possible with the intervention of the American University of Beirut and NGOs, which worked with the Agriculture Ministry to protect areas of trees.
Choucair said traps he set up for insects have seen their population decreased around 50 percent in the past year, adding that the ministry plans to employ mass applications of insecticide. “Overall, we are feeling optimistic.”
But Nemer noted that the rate of pine forest loss has yet to slow, with 2016 figures marking peak dieback.
Nemer recommends that pine growers and municipalities remove dead trees from forests to stop the spread of insects, an intervention supported by the Agriculture Ministry.
The U.N. Food and Agriculture Organization implemented a project between July 2014 and July 2016 to provide guidelines for sustainable management of Lebanon’s stone pines. But with the fairly recent arrival of DCS in the Mediterranean, FAO program assistant Marie-Louise Hayek urged caution. “DCS is a problem not confined to Lebanon alone, but affecting the whole Mediterranean region. ... Research on dealing with DCS has started recently and it may take time before giving accurate conclusions.”