Tall trees in the Central Amazon are affected by periods of high peak temperatures, which can cause them to drop their leaves and branches – ScienceDaily
The forests of the Amazon are becoming increasingly fragmented due to deforestation and fires. A study published in Nature Communications, led by researchers at the University of Helsinki and led by researchers from around the world, measures the effects of fragmentation on plant phenology in a new way. The study shows the annual life cycle events of plants from bud burst and leaf expansion to leaf and branch fall. Detailed measurements of LiDAR’s surface scan allowed researchers to monitor how changing environmental conditions caused by climate and fragmentation affect different layers of the forest.
Warming effects on Amazon forests
If greenhouse gases (GHG) and CO2 According to the IPCC’s Sixth Assessment Report, emissions will double from current levels by 2050, with Amazon’s maximum temperatures likely to exceed 35 degrees Celsius at least 150 days a year by the end of the century. The study was published in Nature communication explains why this is bad news for the Amazon rainforest. The study shows that the tall trees in the Central Amazon are affected by substrate temperatures above 35 degrees.
In August and September, very high temperatures of over 35 degrees are usually measured in many parts of the Amazon. The tops of old, untouched forests usually protect to some extent from the high temperatures observed in the undergrowth. However, when the temperature in these layers below reaches 35 degrees, tall trees drop their leaves and branches.
“If the number of days these very high temperatures are recorded in the forests also increases, we may see that tall trees suffer significantly,” says postdoctoral researcher Matheus Nunes, lead author of the study.
The “breathing” of the earth is changing
In tropical forests, there is still a great deal of uncertainty about the timing and causes of seasonal events such as leaf shedding and eruption. Understanding these patterns is crucial to understanding how tropical ecosystems are responding to climate change.
“We designed the experiment with a modern laser scanner with repeated measurements to study the seasonal dynamics of the Amazon forests,” says Eduardo Maeda, project coordinator funded by the Academy of Finland.
In recent decades, there has been debate as to whether Amazon plants restrict more light or water. This study shows that the problem is more complex because it showed large variation in the vertical layer of the forest. In other words, the trees in the lower layers, or strata, were more luminous, while the tall trees in the upper layers were mostly affected by climatic variations.
Forest fragmentation
Complicating matters further is the fact that research shows that deforestation in the area is exacerbated by negative warming effects.
“Small, fragmented remaining forests tend to have hotter temperatures in the substrate because more light penetrates the forest,” says José Luís Camargo, co-author of the study and director of the Biological Dynamics of the Forest Fragments Project. the world’s longest study of habitat fragmentation in the central Amazon.
The hotter temperatures in these remaining forest pieces increase the pressure on the tall trees, causing the trees to drop their leaves and branches for a long time. It is currently estimated that 176,555 km2 The Amazon forests are subject to marginal effects. If deforestation continues and forests fragment, we are likely to see serious consequences and a large-scale change in the way tropical ecosystems breathe.
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