https://www.futurity.org/saplings-forests-climate-change-2997242-2/
"As climate scientist Don Falk was hiking through a forest, the old, green
pines stretched overhead. But he had the feeling that something was missing.
Then his eyes found it: a seedling, brittle and brown, overlooked because of
its lifelessness. Once Falk’s eyes found one, the others quickly came into his
awareness. An entire generation of young trees had died.
Falk—a professor in the University of Arizona’s School of Natural Resources and
the Environment, with joint appointments in the Laboratory of Tree-Ring
Research and the Arizona Institute for Resilience—refers to this large-scale
die-off of the younger generation of trees as a recruitment failure. This is
particularly devastating for a population of trees because the youngest are
essential for forest recovery following massive die-off events, such as severe
wildfires and insect outbreaks, both of which will become more frequent as the
climate continues to change, he says.
To better understand how extreme climate conditions might trigger recruitment
failure, Falk and his coauthors examined how five species of four-year-old
trees respond to extended drought and heat.
They found that different species had different levels of drought tolerance and
that all species were more tolerant of the heat wave than expected. Their
findings appear in the journal
Frontiers in Forests and Global Change.
In general, older trees are more tolerant of tougher conditions, Falk says. But
when there are massive die-off events—which can be caused by drought and heat,
sometimes with associated insects, pathogens, or wildfire—tree populations
become dependent on their ability to regenerate."
Via Rixty Dixet.
Cheers,
*** Xanni ***
--
mailto:xanni@xanadu.net Andrew Pam
http://xanadu.com.au/ Chief Scientist, Xanadu
https://glasswings.com.au/ Partner, Glass Wings
https://sericyb.com.au/ Manager, Serious Cybernetics
