On Egypt's Red Sea coast, fish swim among thousands of newly planted mangroves, part of a programme to boost biodiversity, protect coastlines and fight climate change and its effects.
After decades of destruction during which the mangroves were cleared, all that remained were fragmented patches totalling about 500 hectares, the size of only a few hundred football pitches.
Sayed Khalifa, the head of Egypt's agriculture syndicate who is leading efforts to replant the mangroves, calls the unique plants a treasure because of their ability to grow in salt water where they face no problems of drought.
"It's an entire ecosystem," Mr Khalifa said, knee-deep in the water. "When you plant mangroves, marine life, crustaceans and birds all flock in."
Between the tentacle-like roots of months-old saplings, small fish and tiny crab larvae dart through the shallows — making the trees key nurseries of marine life.
Mr Khalifa's team are growing tens of thousands of seedlings in a nursery, which are then used to rehabilitate six key areas on the Red Sea and Sinai coast, with the aim of replanting about 210 hectares.
But he dreams of extending the mangroves as far as possible, pointing past a yacht marina about six kilometres to the south.
The government-backed programme, costing about $50,000 a year, was launched five years ago.
Mangroves have a powerful impact in combating climate change.
The resilient trees "punch above their weight", absorbing five times more carbon than forests on land, according to the UN Environment Programme (Unep).
The stands of trees also help to filter out water pollution and act as a natural barrier against rising seas and extreme weather, shielding coastal communities from destructive storms.
Unep calculates that protecting mangroves is 1,000 times cheaper than building seawalls over the same distance.
Despite their value, mangroves have been annihilated worldwide at rapid speed.
More than a third of mangroves globally have been lost, researchers estimate, with losses up to 80 per cent on some Indian Ocean coastlines.
Mangrove expert Niko Howai, from Britain's University of Reading, said in the past many governments had not appreciated "the importance of mangroves", eyeing instead lucrative "opportunities to earn revenue" including through coastal development.
In Egypt's case, "mass tourism activities and resorts that cause pollution", as well as boat activity and oil drilling wreaked havoc on mangroves, said Kamal Shaltout, a botany professor at Egypt's Tanta University.
Mr Shaltout said mangrove restoration efforts "will go to waste" if these threats are not addressed.
"The problem is that the mangroves we have are so limited in number that any damage causes total disruption," he said.
There is little reliable information to indicate how much has been lost, but Mr Shaltout said "there are areas that have been completely destroyed", particularly around the major resort town of Hurghada.
Red Sea destinations account for 65 per cent of Egypt's tourism industry.
The scale of damage, according to a 2018 study by Mr Shaltout and other researchers, "probably far exceeds what could be replaced by any replanting programme for years to come".
Efforts to link up replanted areas will be potentially blocked by barriers of marinas, resorts and coastal settlements.
"Mangroves are hardy, but they are also sensitive, especially as saplings," Mr Howai said.
"Intermingling mangrove reforestation with existing development projects is not impossible, but it is going to be more challenging."
To be successful, Mr Shaltout said that tourist operators must be involved, including by making resorts responsible for replanting areas themselves.
"It could even come with certain tax benefits, to tell them that just like they have turned a profit, they should also play a role in protecting nature," the botanist said.
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