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[填空题]To Save Trees, Fighting One Alien Insect with Others
Rusty Rhea sighs wistfully as he talks about the beauty and peace of standing amid a grove (小树林) of deep green hemlocks in Appalachia, some of them up to 160 feet (50 meters) tall and more than 500 years old.
"This is a very special tree," said Rhea, an entomologist for the U.S. Forest Service’s Forest Health Protection program in Asheville, North Carolina. "I was brought up here, and I don’t want to see another species go by the wayside."
The evergreen trees, a hallmark of southern Appalachia’s national parks, are under attack by an invasive insect barely visible to the eye but potent enough to fell the giants of the eastern United States’ old-growth forests.
Already the tiny bug from Japan, known as the hemlock woolly adelgid (HWA), has killed upward of 95 percent of the hemlocks in Virginia’s Shenandoah National Park. Now they are making their way through the half-million-plus-acre (200,000-plus-
[填空题]
{{B}}To Save Trees, Fighting One Alien Insect with Others{{/B}}
Rusty Rhea sighs wistfully as he talks about the beauty and peace of
standing amid a grove (小树林) of deep green hemlocks in Appalachia, some of them
up to 160 feet ( 50 meters ) tall and more than 500 years old.
"This is a very special tree," said Rhea, an entomologist for the U.S.
Forest Service’s Forest Health Protection program in Asheville, North Carolina.
"I was brought up here, and I don’t want to see another species go by the
wayside."
The evergreen trees, a hallmark of southern
Appalachia’s national parks, are Under attack by an invasive insect barely
visible to the eye but potent enough to fell the giants of the eastern United
States’ old-growth forests.
Already the tiny bug from Japan,
known as the hemlock woolly adelgid (HWA), has killed upward of 95 percent of
the hemlocks in Virginia
