Our planet is alive because of forests. They absorb carbon, maintain ecosystems, and sculpt landscapes. However, rates of tree death are increasing on all continents. Scientists caution that this development has profound social repercussions that are yet little understood, going beyond environmental concerns.

Earth: Samuli Junttila, associate professor of laser scanning at the University of Helsinki said, “We don’t currently know whether climate change will lead to the death of 10 percent or 50 percent of all trees worldwide.”

Over 100 scholars from around the world collaborated with Junttila. Collectively, they examined almost half a million forest monitoring surveys from five continents and 89 nations. The findings indicated that the primary cause was human-induced climate change. Tree loss is being caused by a number of factors, including disease, insect infestations, forest fires, storms, and rising temperatures.

Carbon loss and the balance between forests and climate

The foundation of Finland’s climate policy is its woods. As strong carbon sinks, trees help achieve the Paris Agreement‘s target of keeping global warming to less than 2 °C (35.6 °F) by balancing emissions. Ensuring that forests continue to absorb carbon despite rising global temperatures is essential to their protection. For this endeavor, accurate tree health knowledge is essential.

Approximately 20% of the carbon dioxide emitted by human activities is absorbed by forests worldwide. It is now very difficult to anticipate whether this sink will stay stable due to mortality rates. The speed at which forests may transition from storing carbon to releasing it has previously been demonstrated by significant droughts, such the 2010 Amazon drought.

Keeping an eye on woods from above

Junttila and associates established the Global Ecosystem Health Observatory to monitor forest health. To identify tree fatalities, they employ computer vision tools in conjunction with satellite and aerial imagery.

Earth: “We need monitoring periods of at least five years to determine whether a particular tree is dead or alive. In addition to this basic knowledge, it’s essential to understand the characteristics of local habitats and to have data on the age, size, and species of trees,” said Junttila. “Only then can we begin to infer how tree mortality is progressing as the climate continues to warm. The good news is that modern technology already makes much of this possible.”

Enhanced forest monitoring

Scientists emphasize that frequent assessments of the size, condition, and status of trees are necessary for monitoring. Only with regular observations can mortality drivers like drought, fire, insects, and storms be reliably linked. Crucial hints can be found in information about whether trees died standing, uprooted, broken, or harvested. It is feasible to assess losses in carbon and biomass, not only tree counts, by combining remote sensing and ground verification.

A lack of forest data

The study identifies deficiencies in the monitoring of forest mortality and was published in New Phytologist. Africa, Central America, and some regions of Russia have the worst coverage. Plots frequently exist but are not regularly remeasured.

Long-term investment, common standards, and international cooperation are needed to improve this. Forecasts are weakened when scientists are unable to link local mortality patterns to global climate factors due to a lack of consistent data.

Both wealthier countries and those with large tropical forests would be able to make significant contributions if monitoring networks were strengthened while providing equal access to technology and training.

How well humans can predict forest resilience in a warming world ultimately depends on filling in these data gaps.

Only the surface is visible to satellites

Using remote sensing tools like satellites and LiDAR, canopy declines may be seen globally. However, understory mortality is masked because satellites primarily monitor top-layer trees. While still difficult, integrating satellite signals with field data is crucial. Although they are expensive and not always readily available, emerging technologies like UAV surveys and high-resolution photography offer finer detail.

Fairness in worldwide carbon monitoring

Scholars also demand more equitable international cooperation. Despite having enormous variety, many tropical forests are difficult to manage because of their expense, remote location, and even potential safety hazards.

All too frequently, investigations are led by scientists from more developed nations, while local researchers supply data without acknowledgment.

A more equitable methodology would enable scientists in areas with limited data to take the lead in studies and policymaking.

Local forests are necessary for climate solutions

Tree mortality is a social and scientific problem. In addition to providing resources and storing carbon, forests also support biodiversity. In addition to technology, strategies informed by reliable data are needed to address the increasing number of tree deaths.

Dispersed research could be turned into reliable forecasts by a worldwide monitoring system based on equitable cooperation. Because the health of societies is inextricably linked to the health of forests, this research is vital and urgent.

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Teaser image, a brown squirrel on green leafed tree – copyright transly.eu