o's Yucatán peninsula.
She found that mahogany trees there were sparsely dispersed among other
species at an average density of one tree per hectare (about 2.5 acres),
though occasionally in clumps of up to 20 mahoganies per acre. Mahogany
trees grow so big and wide that they must be spaced far apart to "keep
from crowding each other out," she said.
What Snook couldn't find was equally important. There were no mahogany seedlings
successfully growing under the forest canopy. Any seedlings she found were
instead "on roadsides and abandoned agricultural fields," she
Back in the forest, Snook also found young mahogany trees growing where
she detected signs of old hurricane or fire damage.
Snook then began a systematic search for more sites of past disturbances
by conducting "oral history" interviews with local residents.
"I had to be careful not to lead people into answers," recalled
Snook, who speaks fluent Spanish. "I asked them things like, 'Is there
any part of the forest where you know something happened in the past? Can
you take me there?'" She also used local people's memories to date
the ages of post-disturbance trees.
Like Sherlock Holmes, the fictional detective about whom Snook read avidly
while at Grinnell, she collected multiple clues to unravel the mystery.
Hurricanes periodically blow through Yucatán forests, she said. "They
knock down some trees and branches, but most of the trees survive."
However, the fallen debris provides ample fuel "that ignites in the
next dry season," she added. "And only 15 percent of the trees
survive the subsequent fire."
But the odds are especially good that mature mahoganies will be left standing.
"They're very good survivors," with large buttresses, aerodynamically
shaped crowns and stout branches that resist wind damage, plus thick bark
to protect against flames, she said.
Those older trees can then provide sources of seed t
Contact: Monte Basgall
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