The young and small trees that make up most of the forests in eastern North America increased seed production under climate change, while the old and large trees that dominate most of the forests in western North America are slow to respond, Duke said. A new university-led study has been discovered.
The decline in seed production or fertility of these trees has given the ability of western forests to regenerate following the massive dieback associated with rising temperatures and intensifying droughts currently occurring in many states. May limit.
The continental divide, first reported in a new study, “may dramatically change the composition and structure of forests in North America in the 21st century,” said James S., professor of environmental science at Duke, who led the study. Clark said.
Knowing that contrasting reactions occur and understanding why they occur will help scientists develop conservation and management strategies to more accurately predict and mitigate future changes in North American forests. Useful for.
Researchers from 48 institutions collaborated with Clark in a peer-reviewed study published on February 23. Nature Communications..
Fecundity is a measure of a tree’s ability to regenerate after dieback or other major damage by distributing seeds to habitats that are more likely to survive in the future. This is an important factor in determining future forest response to climate change, but like many ecological processes, it is noisy, volatile and very difficult to estimate.
Fertility changes over time based on changes in tree size, growth rate, or access to light, water, and other resources, with two indirect effects: climate-dependent growth effects and climate-dependent climate effects. About the size of the tree caused by the effects of different climates — currently not taken into account in the models used to predict future changes.
“This was the only major demographic process that facilitated forest response to climate change and lacked field-based estimates,” Clark said.
To address this issue, he can synthesize decades of raw data on size, growth, canopy spread, and access to resources of approximately 100,000 trees in long-term research sites and experimental forests throughout North America. Invented new statistical software. Raw unfiltered data revealed that previous meta-analyses based on averaged measurements were overlooked. On a continental scale, fertility increases as trees grow larger. And it begins to decline.
“This explains the east-west division. Most trees in the east are in the size class, which is young, fast-growing, and fertile, so indirect effects from the climate that promotes growth also increase seed production. “I will,” Clark said. “The opposite happens with old, large trees in the west. Of course, there are small and large trees in both areas, but the areas are quite different in size structure and react in different ways.
“Once we have a collective understanding of how this all works, the next step is to apply it to individual species or stands and incorporate it into the model we use to predict future forest changes.” He said.
The data used in this study came from trees in the Mastiff Inference and Prediction (MASTIF) monitoring network. The network includes more than 500 long-term field research sites nationwide, including plots that are also part of the National Ecological Observation Network (NEON).
Increased drought threatens almost all US forests
“Continent-wide tree fertility caused by indirect climate effects” Nature Communications (2021). DOI: 10.1038 / s41467-020-20836-3
Courtesy of Duke University School of Nursing
Quote: Climate effects, forest seed production acquired on February 23, 2021 from https: //phys.org/news/2021-02-climate-impacts-east-west-forest-seed.html (2021) Promotes the east-west division (February 23)
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Climate effects promote east-west division of forest seed production
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