According to a recent study the forest does not regenerate after wildfires because of recent climate changes. The study published in the journal Proceedings of the National Academy of Sciences suggests that the recent changes in the climate have made it difficult for the tree seedlings to regrow after the wildfires in low-elevation forests, which contributes to forest loss.
Kimberley Davis, the study's lead author said, "the ability of forests to recover following a wildfire depends on annual climate conditions because tree seedlings are particularly vulnerable to hot and dry weather. We wanted to identify the specific conditions necessary for post-fire tree regeneration to better understand how climate change has been affecting forests through time."
The researchers used tree rings to determine establishment dates of more than 2,800 trees that regenerated after fires in Arizona, California, Colorado, Idaho, Montana and New Mexico between 1988 and 2015. Annual tree regeneration rates were much lower when seasonal climate conditions, including temperature, humidity and soil moisture, crossed specific threshold values.
Adult trees can survive in warmer and drier conditions than seedlings, and the study found that some low-elevation areas that are currently forested no longer have climate conditions that are suitable for tree regeneration and in those areas, high-severity fire may lead to ecosystem transitions from forests to grasslands or shrublands.
Forests contain high levels of biodiversity and provide a variety of ecosystem services, such as carbon sequestration and water regulation and supply and it is important to understand how climate change and wildfires will affect tree regeneration because forests are important economically, ecologically and culturally.