Australia’s forests are facing a serious issue: they’re losing trees faster as the climate warms. A recent study looked at data from 2,700 sites across the country, examining different forest types, from lush woodlands to dry savannas. This research focused on what’s called “background tree mortality,” meaning tree deaths not caused by logging, clearance, or fires.
Belinda Medlyn, a professor at Western Sydney University’s Hawkesbury Institute for the Environment, led the research. She pointed out that the rate of tree deaths has been increasing consistently over the years in all types of forests. “This increase is very likely due to rising temperatures,” she explained.
Since the pre-industrial era, the world has warmed by an average of nearly 1.2 degrees Celsius, with most warming happening in the last 50 years. Trees, like all living things, react to their environment. Factors such as drought or competition for resources can impact how many trees die off. However, this study ruled out areas impacted by fires or logging, focusing instead on how tree mortality has changed over time.
Interestingly, the increase in tree deaths varied across different biomes. The most significant rise was found in tropical savannas, where tree mortality jumped by 3.2 percent a year from about 15 per 1,000 trees in 1996 to nearly double that by 2017. This trend is concerning because deaths aren’t being balanced out by new tree growth, which means that overall forest stock is shrinking.
This decline impacts the forests’ ability to store carbon. Medlyn stated that it is very likely that these forests are losing their capacity to capture carbon dioxide over time. The research underscores a troubling situation: while forests currently absorb about one-third of human-made carbon dioxide emissions, this ability may lessen as temperatures rise.
Recent studies indicate that some of Australia’s tropical rainforests are already emitting more carbon than they absorb. This might not just be an Australian issue; the trend could be widespread globally. Trees across different ecosystems are at risk, raising questions about the future health of forests everywhere.
In summary, tree mortality in Australia is increasing due to climate change, and this phenomenon may foreshadow broader issues for forests worldwide. Understanding these dynamics is crucial as we think about our reliance on forests to manage carbon emissions. For more details on global carbon processing by forests, you can check out data from the [Food and Agriculture Organization (FAO)](http://www.fao.org).
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