Autumn olive berries an unwanted species
LAKE COUNTY — What was seen as a beneficial move by conservation officials decades ago to plant autumn olive berries in the hopes of sustaining wildlife is now seen as an ecological nightmare — with the stubborn, thriving species taking over the landscape and competing with native species.
The autumn olive berry, a large shrub with delightful, fragrant flowers in the spring and bountiful, edible red berries in the fall, can seem inviting, but the plant — which can grow by the hundreds in areas not regularly maintained — are invasive.
The plant was introduced to the U.S. from Asia in 1830, but really became popular from the 1940s to 1970s, according to research by Michigan State University Extension. Soil conservation districts introduced the plant in their spring sales, seeing it as a wildlife cover and food, wind breaks, highway barriers and soil stabilizers. This plant was drought- disease- and insect- resistant, and could grow in poor soils in full sun or partial shade. The only places it wouldn’t grow was in wet areas or deep shade.
Animals devoured the berries, but the seeds would pass through their digestive tracts and hit the ground to grow rapidly into a 15-foot-tall berry-producing bush within a span of two to three years.
Once the plant is mature, by August, clusters of bright red berries with faint, silvery speckles are visible, and by September and October, the sweet, slightly tart fruit is ripe.
“In terms of wildlife nutritional value, berries from native shrubs have more fat content for wildlife. Autumn olives have high sugar, but don’t give the caloric value other plants have,” said Mark Shermak, forester at the Baldwin/White Cloud Ranger District.
Shermak noted other issues with the autumn olive berry.
“Another problem is the plant is seen more and more in the local landscape, and this can be problematic with regenerating forests, such as aspen clear cuts. They compete with the trees. The seeds pass through the birds, and more autumn olives are regenerating. They also are a nitrogen fixer, adding nitrogen to the soil,” he said, adding the disturbance in the soil could encourage other non-native species to grow.
Shermak said the plant was seen as a good species to plant for wildlife when they were first introduced into conservation districts.
“What wasn’t known at the time was all the effects the plant would have. Now we are seeing ramifications, such as competition with native vegetation, and shade competition for other plants. If we cut down trees, the sun reaches the forest floor, and the autumn olive responds to sunlight, growing faster than other trees.
“They are fairly tough to kill. If you don’t get the entire root system removed, the root will regenerate. Herbicide methods are used, but these can be very expensive. The larger the shrub, the more expensive and difficult to treat. They flourish in fallowed fields that haven’t been mowed, and when farmers want to reclaim the fields, it is a lot of work to get the plant removed. If there is such an issue now with the plant, where will the problem be 50 years in the future?”
Even though the berry is invasive and are not encouraged to be planted, they are not without benefits. The berries contain 10 to 14 times more lycopene than tomatoes. They also are rich in Vitamin C and other vitamins. In Asia, autumn olives are used to treat and prevent myocardial and pulmonary infections and are used on various forms of cancer.
The berries can be made into jams, wine, fruit leather and marinades.
Wolf Lake resident Nancy Wetherell has been picking autumn olive berries after she learned about their nutritional attributes.
“I think the berries are really delicious when they are ripe,” she said. “I use them in smoothies or make jam with them. They have good health attributes and are high in antioxidants. I would be disappointed if they were gotten rid of.”