Amazon Forest Forecasts

For decades, the Amazon forest has been considered an ecosystem on the brink of irreversible decline. However, long-term field observations reveal a picture that defies conventional degradation scenarios. Despite climate stress, the forest structure continues to shift toward denser growth.

Since the early 1970s, scientists have been systematically monitoring the condition of pristine areas of the Amazon. As part of a large-scale monitoring programme, 188 permanent sites were studied, some of which have been monitored for over 30 years. The primary indicator was tree crown area—a reliable indicator of biomass and overall forest health, reports Science & Vie.

The data obtained showed steady growth: the average canopy area increased by approximately 3.3 per cent per decade. Moreover, this trend was observed across all regions of the Amazon, not just in isolated local areas. The growth affected not only older, large trees but also younger ones, gradually changing the architecture of the entire forest. "This process has been ongoing for more than thirty years, despite ecosystem fragmentation and increasing climate stress," emphasizes study co-author Adriana Esquivel-Muelbert.

"Even a small but stable increase in biomass on such a scale signifies a serious shift in the global carbon balance, and it cannot be ignored when assessing climate scenarios," says ecologist and Pravda.ru columnist Denis Polyakov. The study was conducted by the RAINFOR network and published in the journal Nature Plants. More than 60 scientific institutions from South America, Europe, and the UK participated in the project. This length and geographic scope allowed for the identification of processes that are impossible to capture in short-term studies.

Scientists note that forest growth is systemic. It is not limited to individual tree species or age groups, but encompasses the entire ecosystem, creating a new equilibrium. The main factor explaining this is the changing composition of the atmosphere. Rising carbon dioxide concentrations enhance photosynthesis, providing plants with additional resources for growth. This effect is known as "CO fertilization."

According to a research team from the University of Birmingham, additional carbon stimulates both large dominant species and young pioneer trees equally. 

No previous model predicted such a uniform response. "The forest responds in a remarkably coordinated manner—all levels of vegetation benefit from this atmospheric excess," the study notes.

The scientists call the results encouraging, but emphasise that this applies exclusively to intact forests. As soon as the ecosystem is fragmented or deforested, the positive effect disappears. "Tall trees cannot be replaced in the short term, and planting saplings will not compensate for their loss," warns researcher Rebecca Banbury Morgan of the University of Bristol.

Large trees play a key role in carbon storage and maintaining biodiversity. Their disappearance dramatically reduces the ecosystem's resilience, even if new plantings look promising. Climate models continue to point to increased droughts, more frequent fires, and further temperature increases. These factors could gradually offset the benefits accumulated over decades.

"Large trees will only survive if ecosystem connectivity is maintained," emphasizes study co-author Oliver Phillips. Deforestation acts as a threat multiplier, capable of quickly interrupting the current positive dynamics.

–Pravda.ru