Belem/New Delhi, Nov. 17 -- How can deforestation be stopped, is a central theme at the ongoing UN Climate Conference (COP30), which is being held in the Amazon, to drive home the importance of rainforests in arresting climate change, according to Brazilian President, Lula da Silva. But, it is important to ask where are these most critical ecosystems? A few satellite images can tell us how high and how dense rainforest ecosystems are. The Global Forest Canopy Height tool, with 10-m spatial resolution, tells us where the world's densest and tallest (and often oldest) growth rainforests are located. They are in Brazil's Amazon rainforests; in Africa's Congo basin, in parts of Indonesia and Malaysia but also parts of India's northeast, the Western Ghats and also islands like the Great Nicobar among others. The Andaman and Nicobar region has dense forests of canopy height of over 25 to 30 m in many regions, similar to the Amazon. What does a 30m canopy height mean? According to a paper published by Nature Ecology and Evolution in Nature journal in 2023: "A high-resolution canopy height model of the Earth" only 5% of the global landmass is covered by trees taller than 30 m and only 34% of these tall canopies are located within protected areas. But, satellite data has its own limitations. It gives a sense of what is at stake but tends to underrate canopy height and density of rainforests. The Nature study said that canopy height estimation with existing standard tools tends to struggle with the underestimation of tall canopies, as the height estimates saturate around 25 to 30 m. This is a fairly severe limitation in regions dominated by tall canopies, such as tropical forests, and deteriorates downstream carbon stock estimation, because tall trees have especially high biomass. According to Joice Nunes Ferreira, researcher at Embrapa Eastern Amazon, old-growth Amazonian forests are highly species-rich, with a great diversity of large trees and significant environmental and structural heterogeneity. The height of trees in the Amazon can reach up to 60-80 meters and tree density is more than 500 stems per hectare. In lowland rainforests, the canopy height can be 40-50 m range and 30-40m in lower montane rainforest. HT had reported on October 6 that the density of trees in Great Nicobar may be far higher than understood. It is between 500 to 800 trees per ha of land, of at least 30cm girth size or larger. Rainforests are so dense that at times it's difficult to see the open sky through the canopy, an ecologist had said, who preferred to remain anonymous. "Rainforests in general are almost identical/similar functionally: We have big trees, they have big leaves, most trees belong to a few species there and here, the total number of species is similar. There are also a lot of parallels despite their differences: They have lots of forest palms, we have fewer palms but compensate with climbing canes or/rattan; a lot of the amazon floods for some time of the year; our rainforests don't flood as much but a lot of SE Asian rainforests sit on perpetually boggy peat swamps," said Akshay Surendra, an ecologist and wildlife biologist studying tropical forests in the Andaman Islands. Both the Amazon and Great Nicobar face similar threats. In the Brazilian Amazon, in the most intact areas (western part of the basin), the main threat is climate change, followed by planned road paving projects. Mining also poses a localized threat in certain regions, according to Ferreira. In the Great Nicobar, the government has planned four projects in the region - International Container Transshipment Terminal (ICTT), Greenfield International Airport, Gas and Solar based Power Plant and Township; Area Development Projects - for which an area of 166.10sqkm is required. Of this, forest area is about 130.75sqkm. Of the forest area under the project, tree felling is envisaged in 64.76 sq km according to Andaman and Nicobar Islands Integrated Development Corporation Limited (ANIIDCO) call for EOI for tree enumeration and felling. The government has said the project is critical from the strategic, national and defence point of view. Some of this tree felling may affect tall trees, whose loss may take decades to replace....