Environmental and Ecological Benefits
1. Carbon sequestration
Ancient trees act as important carbon sinks by accumulating and storing large amounts under their trunks. Ancient trees store carbon at greater rates than younger trees
2. Fixing nitrogen
Nitrogen fixation process converts the atmospheric N2 into more suitable compounds (nitrates, nitrites, or ammonia) that are essential for plants growth. Biological nitrogen fixation is done by certain bacteria, which are found in abundance in old forests.
3. Serve as 'Mother Trees'
Ancient trees contain the most stress-resistant specimens of trees. Losing them would mean that future generations of trees would be deprived of their genes, becoming more vulnerable to extreme climates. In addition, ancient trees’ mycorrhizal network supply carbon and other nutrients to smaller trees, with limited access to sunlight; which explains why trees surrounding ancient trees tend to have lower mortality rates and faster growth rates.
A meta-analysis, of 519 areas of temperate and boreal forests aged between 15 and 800 years old, found that old-growth forests and these ecosystems account for ~10% of the world’s carbon sequestration capability.
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4. Habitat for endangered species
Ancient trees provide habitat for various plant and animal species among which species of conservation concern. Some examples of animal species that are dependent on old-growth forests include the spotted owl in Canada, the Olympic salamander, the Del Norte salamander, the tailed frog in the US, orangutan in southeast Asia, and the lead-beaters possum in south-east Australia.
5. Create microclimates to protect species against global warming
Due to their denser, more complex biomass and higher canopies, old-growth forests provide cooler microclimates. This makes these trees refuge sites for various species, plants, animals, and humans alike.
Social Benefits
1. Forest Bathing
Old-growth forests are suitable for carrying out forest bathing, an ancient practice involving spending time around trees inhaling the aerosols and organic volatile compounds that have many proven therapeutic properties.
2. MEdicinal Benefits
Besides the medicines provided directly from old trees, some ancient trees also host certain fungi with high therapeutic potentials: antibacterial, anticancer, antiviral, and anti-inflammatory properties.
Impact of climate change on ancient trees
Globally, it is difficult to assess the causes of tree mortality. However, based on the visible causes of death, ~12% of tree mortality in terms of biomass loss across the world is caused by large disturbances, which include some of the climate change related events such as fires, wide-scale uprooting of trees by wind, and pest outbreaks.
Each climate event can impact ancient trees in multiple ways:
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Heavy winds / Storms
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Changes in rainfall pattern
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Temperature changes / Drought
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Uprooting of trees
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Changes in rainfall pattern impacting lifecycle of trees, with water not being available at the required time and even leading them to death
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Extreme heat and an extended period of drought have been causing death of ancient trees or reducing their ability to absorb soil nutrients making them more susceptible to diseases.
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Swaying of trees reducing root strength, resulting in less anchorage for future events
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Waterlogging could impact the mycorrhizal fungi of the trees which reduces their ability to absorb nutrients and their resistance to diseases
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Diseases and pests thriving in warmer temperatures
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Tearing of branches (also caused due to heavy snow) creates exposed wounds
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Shifting of ranges where these trees could grow
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According to a 2014 estimate, the ancient trees are projected to decline by 87% over the next 300 years under the current management strategies.
Case Examples in the Middle East Region
1. Impact of rising temperatures on Cedars
Rising temperatures and a corresponding decrease in rain and snow are impacting Cedars. These climate events have caused disruption in the lifecycle of a bug that feeds on cedar trees.
Future warming in the Mediterranean region is expected to exceed the global rates by 25%.
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Historically, Cedar sawflies mated in springtime, hatched bugs on tree trunks, and fed on Cedar needles. These bugs would then hibernate underground for up to four years, before emerging back as adult sawflies. However due to the warming up of earth, ground has become less cold and humid in winter, which has caused the sawflies to emerge every year and in larger numbers. These sawflies attack cedars aged 20-100 years.
Over the past 30 years, temperatures in Tannourine (North of Lebanon) have risen by two degrees Celsius along with lesser snow and drought. This has resulted in dead tree skeletons in the Tannourine Cedars Forest Nature Reserve, at 1,800 metres altitude. During 2006-2018, the insects killed 7.5% of the Tannourine forest’s trees, majority being the young ones. In 2017, 170 trees dried up completely and became dead wood.
To curb the growing population of sawflies, authorities have been injecting a fungus into the ground to kill the bugs, but it is a huge task and needs further funding and resources.
Historically, Lebanon received 105 days of rain/snow annually, in the mountains, the ground had snow cover for three to four months. There has been a major decline, with only 40 days of rain and only a month of snow cover in 2018 winter.
With continued warming up of the temperature, a 2°C increase in temperature is expected to reduce snow cover in Lebanon by 40%, reaching 70% decrease in case of a 4°C increase.
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Due to the rising temperatures, the cedars’ reproduction sites are also shifting to higher altitudes to provide the cold conditions required by cedars to reproduce. However, in certain locations such as south of Beirut, there is no scope for such elevation. If the temperature continues to rise at the current rate, cedars will be able to thrive only at the northern tip of the country, at higher mountains by the end of the century.
2. Climate change threatening olive trees
Olive trees require fertile soil and a warm (not excessively hot) climate to grow. The warming up of sea temperatures and heat in the Sahara Desert is expected to reduce rainfall in the MENA region over the coming years along with growing desertification. This is increasingly impacting the growth and sustainability of olive trees in in the MENA region and across the Mediterranean region.
Other climate change events impacting olive harvests in countries across the Mediterranean include changing rainfall patterns, early spring frosts, increasing droughts and floods, fierce winds, insect infestations (olive fly), and the spread of harmful bacteria in olive trees.
The destructive impact of climate change on olive trees is visible from Tunisia to Palestine, and Turkey to Italy.
Due to extreme weather events such as unusually hot and dry summers, heavy rainfalls and shifting in seasons; olive oil output in Turkey recorded a 37% decline, between 2018 and 2019. One of the key elements of success in managing climate change is the Taskforce on Climate-Related Financial Disclosures (TCFD), that requires companies to disclose their climate impacts and manage their risks.
Other impact on the Mediterranean region:
- Extreme heat reduced the harvest of olives and olive oil production in Palestine in 2017.
- Tunisia’s 3,000-year of olive production is expected to get halved by 2030. Up to 80% of the country’s olive trees rely purely on rainfall.
- Italy, one of the major producers of olive oil globally, has suffered the most significant impact of climate change on olive trees over the past several years. It recorded a ~60% decline in olive harvests in 2018. Climate change continue to impact the olive sector in Italy, with aggressive droughts in 2022 expected to reduce the year’s olive oil production by 50-60% in Tuscany.
One of the various manifestations of extreme weather is the spread of a bacteria called Xylella fastidiosa, which have caused millions of olive trees diseased or dead in Italy. The bacteria, which originated from Central America, also reduces the drought resistance of the trees and it is anticipated to spread to the Middle East. From a solutions perspective, artificial irrigation is considered only as a partial solution since natural rainfall is more suitable for olive trees.
Ghaf trees, a solution to climate change?
The Ghaf tree has a vital cultural significance in the UAE and is linked to the country’s culture and heritage. It has significant economic value as a prominent source of food, fuel, fibers, fodder, timber, medicine and gum. Different parts of the Ghaf tree has been used in curing common cold, rheumatism, cough, dysentery, bronchitis, leprosy, asthma, leukoderma and scorpion stings.
Although it is native to Asia, it is currently planted worldwide, particularly in the Middle East, Africa, Asia, Central, and the Americas. The Ghaf tree is a resilient plant, well adapted to survive harsh desert environments by having deep root systems, allowing them to tap into underground water sources; therefore, providing habitat and food for a wide variety of desert-dwelling animals, including birds, insects, and mammals. This can help support local biodiversity and ecosystem health. Furthermore, Ghaf trees improve the agricultural productivity and support the growth of other plant species by making the soil around it more fertile by their symbiotic relationship with certain bacteria that allows them to convert atmospheric nitrogen into a form that plants can use.
In recent years, the Ghaf tree has gained recognition as an important species for ecosystem restoration and climate change mitigation. Like all trees, Ghaf trees absorb carbon dioxide from the atmosphere and store it in their biomass. This makes them an important tool for mitigating the effects of climate change, as increased tree cover can help reduce greenhouse gas concentrations in the atmosphere. Its ability to sequester carbon, enhance soil fertility, and provide habitat for wildlife makes it a valuable asset for sustainable development in arid regions.
Overall, Ghaf trees have many positive effects on the environment and human societies and are an important component of desert ecosystems that can be utilized to mitigate the impact of climate change.
