Trunk Growth in Tropical Trees Decreases During Increased Heat and Drought: New Study

Trunk growth of trees in the tropical ecosystem is also affected by elevated dry conditions, according to a new study.

Researchers from the University of Arizona (UA) conducted ecological research to further understand tropical trees, as well as predict their future amid a worsening climate change.

Trunk growth, also known as a growth ring or tree ring, is crucial for the development of a tree.

In recent decades, the emergence of growth rings was discovered in hundreds of tropical tree species. It was found that this part of the tree is sensitive to drought and the absence of rainfall.

The UA researchers acknowledged that ecologists in the past have assumed tree rings to be absent in tropical trees due to the lack of rain and temperature in the environment surrounding the trees.

In light of the new study, ecologists can create a map of which trees in the tropics can survive or not.

Trunk Growth

In the new study published in the journal Nature Geoscience on Thursday, March 31, the team of ecologist researchers found that if the dry season is drier or warmer than usual, there is a reduced trunk growth in tropical ecosystems, as well as the subtropics.

The study highlighted the need for scientists to better understand how tropical trees respond to severe or extremely dry conditions, so they can predict how these trees will be affected by future climate change.

Climate Change and Ecology

The scientists were surprised when it was found that the effects of increased drier and warmer years have a more severe effect in the tropics in arid or warm regions.

This has led to the linkage of climate change once again in the field of ecology.

In particular, climate change apparently increases the sensitivity of tropical trees to climate fluctuations.

Based on the findings of the research, slower tree growth speeds up the death risks of tropical trees.

The researchers found tree growth is more affected by climate during the dry season compared to the wet season, affecting the land carbon sink.

This is evident in the tropical and subtropical regions of Earth where there is a frequent occurrence of both hot and cold temperatures.

Growing Database

The tropical tree rings apparently contain rich data on tree growth history, according to Pieter Zuidema from the Wageningen University & Research in the Netherlands and the lead author of the study, as cited by the Eurek Alert portal of the American Association for the Advancement of Science.

In acquiring the data, UA researchers and their collaborators created a new global network containing more than 14,000 tree-ring data from 350 locations in 30 tropical and subtropical countries worldwide.

The said data has been uploaded to the International Tree-ring Databank.

Heat and Drought

Scientists reiterated that increased heat and drought is the primary factor that hampers tropical tree growth. With the continuance of climate change, both tropic and subtropic regions are expected to witness of warmer temperatures.

Over recent decades, human-induced climate change has been pointed out to be the cause of drastic natural phenomena that have not been seen prior to the Industrial Revolution of the 18th century.

These phenomena include extreme droughts and abnormal heat index signatures, as per the Center for Climate and Energy Solutions.