Maroc - TIMBERBIZ.COM.AU - A La Une - 10/Jan 00:18

Three of the world’s most resilient trees

Trees provide myriad benefits, from being a source of food to absorbing carbon and even contributing to gender equity. But across the planet, tree and plant species face many threats, including from the climate crisis, disease and deforestation for urban development and agriculture. Source: Timberbiz More than 1 in 3 tree species worldwide are at risk of extinction, according to new research from the International Union for Conservation of Nature and Natural Resources (IUCN). Urgent action is needed to scale up local, national and international tree conservation efforts, says the report. And while this help will be vital, there are many examples of how trees themselves can be resilient or adapt to adverse conditions while providing multiple benefits to the ecosystems and people around them. These are three resilient trees. The baobabs For centuries, Africa’s baobabs have been an important source of food, fibre for ropes or clothing, and medicine; supporting rural communities across the continent. This includes creating a livelihood for many women who collect and sell the trees’ fruit. The tree is also important for carbon sequestration, soil health and biodiversity. Recent research suggests that adult populations of this iconic ‘upside-down tree’ are thriving and do not appear to be dying off any faster due to the climate crisis. They are vulnerable to animals, including livestock which are partial to their roots. But many baobabs live for a long time, with some of the oldest reaching 2,500 years of age. This means that they are used to surviving harsh conditions. Alongside having non-flammable bark that makes them resistant to wildfires, they store large amounts of water in their trunks to survive dry seasons. Experts have found they will likely have experienced extensive fluctuations in rainfall during the past 1,000 years. The baobab is among the trees identified for their environmental, social and market potential in Africa’s Sahel region by 1t.org, the World Economic Forum’s platform for the trillion trees community. The project works to mobilize the private sector to conserve, restore and grow a trillion trees by 2030. The Giant Sequoias The largest trees in the world by volume, giant sequoias are indigenous only to the US state of California. They can grow to heights of 90 metres and the oldest is more than 3,200 years old. Part of the secret to this long life is that sequoias are resistant to insects and disease and have thick bark and high canopies that protect them against fires. In fact, fire helps them reproduce by removing competitors for light, water and food and releasing the seeds from their fallen cones so they can reproduce. In recent years, however, the effects of drought on the land, as well as the taller trees around them, have made giant sequoias more vulnerable to fire. Giant sequoias also have an impressive ability to capture and store large amounts of carbon dioxide over their lengthy lifespans. Experts say one tree can pull about 85 kg of carbon out of the atmosphere per year. Scientists say the trees grow best in their home in the Sierra Nevada mountains. But a recent study in the United Kingdom has found that giant sequoias, introduced to the country 160 years ago, are well adapted to the milder climate and are growing at rates close to their native ranges. The researchers note, however, that long-term consideration should be given to how they will thrive in the UK’s changing climate in the coming years. Mangroves Mangroves are trees and shrubs that have adapted to live in intertidal zones – areas where the ocean meets the land between high and low tides. They can be found on tropical and subtropical shores everywhere from Florida to South America, Africa to South-East Asia, which is home to nearly a third of all mangroves. They have grown to survive in hot, muddy and salty conditions that would kill off most plants. And they bring many benefits. Mangrove forests are among the most biodiverse places on Earth, providing a home for many species, from fish and sharks to hummingbirds and even tigers. They have an important role in coastal communities too, acting as a barrier against waves and storm surges. In fact, they protect more than 15 million people globally and reduce property damage by $65 billion. And they are very effective at capturing and storing carbon, up to five times more carbon per acre than tropical rainforests. However, the world’s mangroves are under threat from human activity, with up to 35% estimated to have disappeared since 1980. Experts say large amounts of mangrove habitat loss is restorable and initiatives such as the Vida Manglar project in Colombia are working with communities to do so. This project is an example of how close cross-sector collaboration between non-profits, communities and governments can help restore thousands of acres of this invaluable species.