The deforestation of the tropical rainforests is progressing unstoppably. According to scientists at the Helmholtz Centre for Environmental Research (UFZ), these forests are becoming fragmented at a higher rate than expected.
The deforestation of the tropical rainforests is progressing unstoppably. According to scientists at the Helmholtz Centre for Environmental Research (UFZ), these forests are becoming fragmented at a higher rate than expected. By analysing high-resolution satellite data, they were able to measure even the smallest piece of tropical forest and, for the first time, study the changes in tropical fragmentation. In a paper for Science Advances, they discuss how this previously unnoticed and underestimated increase in fragmentation to almost one third of the forest area has consequences for the global carbon cycle. Because of increased tree mortality, large amounts of carbon are released at the forest edges. Model simulations also show that these emissions could increase in the future. Only through less deforestation can the process be slowed down.
The UFZ modelling team used satellite data from 2000 and 2010 with a very high resolution of 30 metres. They were able to compare where in Central and South America, Africa, and South-east Asia connected tropical forests still exist or where they have disappeared. With the help of a complex cluster algorithm and high-performance computers, they found that the number of isolated forest areas increased by more than 20 million to 152 million between 2000 and 2010. This increase in forest fragments is particularly serious because it has also increased the proportion of forest edges in the total forest area. The forest edge is defined as the area of forest that extends 100 metres into the forest from open land. This edge area increased from 27 to 31% (i.e. from 517 to 589 million hectares) between 2000 and 2010. "This situation has deteriorated so much that now almost one third of the world’s tropical forest areas are in edge areas. If deforestation is not stopped, this trend will continue", says lead author and UFZ modeller Dr Rico Fischer. The effect of accelerated fragmentation occurred mainly in the tropics of Africa. There, the number of forest fragments increased from 45 million to 64 million within only 10 years. The proportion of the forest edge in the total forest increased from 30 to 37% (2000: 172 million hectares; 2010: 212 million hectares). In contrast, the proportion of forest edges in Central and South America rose by only 2% to 25% (2000: 215 million hectares; 2010: 232 million hectares).
Read more at: Helmholtz Center for Environmental Research
