Research in a moorland region of England shows that reforestation is insufficient to address the climate pressures facing forests. However, informed livestock management and strategic tree planting could limit losses, the study suggests.
The United Kingdom, as well as China, Saudi Arabia, Japan and South Korea, have set themselves the goal of becoming carbon-neutralin the coming decades. In other words, these countries aim to store as much carbon as they emit. This is an ambitious goal, which often relies on financing large-scale projects to create carbon sinks, such as planting trees.
Indispensable in the fight against climate change, forests represent (along with oceans) one of the most powerful carbon sinks in the world. The solution therefore seems simple and within reach. But it is actually much more complicated, as several environmental specialists have already pointed out.
A recent study by researchers from the UK's University of Plymouth demonstrates this through a concrete example. The study focused on the moorland region of Dartmoor, located in southwest England. The researchers studied the expansion and connection of upland oak woodland, also known as "temperate rainforests."
Published in the journal Ecological Solutions and Evidence, the findings reveal that the presence of livestock grazing on the surrounding vegetation hinders the growth of young oaks. Those that remain are less tall and with a life expectancy generally not exceeding eight years, if left unprotected.
Not so straightforward
Overall, the study estimates that the natural regeneration of oak saplings on several Dartmoor sites is confined to within 20 meters from the nearest mature tree. According to the researchers, this level of natural expansion is insufficient to adequately contribute to carbon storage, as well as flood mitigation and biodiversity, at the pace or scale needed in these upland landscapes.
"The planting of trees and an end to deforestation are increasingly being highlighted as low cost and environmentally sensitive mechanisms to combat climate change. These measures have been factored into the net-zero agendas of UK and other governments, with world leaders also pledging to address the issue during COP26 in Glasgow last year," explains Dr Thomas Murphy, who led the research.
"Our findings however suggest the expansion of oak woodland into UK upland pasture systems is not a simple process. They may have a critical role to play, but these important temperate rainforests have been historically degraded and are now highly fragmented," he continues.
The study does, however, propose some ways to manage these temperate rainforests in a more sustainable manner. Among the solutions mentioned are planting four-to-seven-year-old oaks directly in areas of dense vegetation to protect the saplings from livestock. Or excluding livestock from sites where young oaks (one-to-three years old) are developing, to maximize their growth and survival.
