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Clematis vitalba (vine, climber) |
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General Impact
Hill et al. (2001) report that, "Vines can climb the tallest forest trees, forming a dense, light-absorbing canopy that suppresses all vegetation beneath it. C. vitalba can be so vigorous that the weight of foliage and stems breaks the supporting trees, reducing once-healthy forest to a low, long-lived thicket of vines scrambling over stumps and logs". However Ogle et al. (2000) observe that the vines ascend to the canopy of forest but are unable to climb large diameter emergent trees unless shrubs and smaller trees provide a series of ‘stepping stones’ to the crown of tall trees. Their study findings (study area Taihape reserve, New Zealand) indicate that the numbers and variety of understorey trees and shrubs that have been severely reduced following the infestation of C. vitalba correlates with observations of the growth habit of C. vitalba. Ogle et al. showed e.g. that not a single canopy tree species had been lost from the Taihape Reserves though 25% or so of the understorey trees and shrubs species had been lost.
Location Specific Impacts:New Zealand Habitat alteration: Hill et al (2001) report that, "Vines can climb the tallest forest trees, forming a dense, light-absorbing canopy that suppresses all vegetation beneath it. C. vitalba can be so vigorous that the weight of foliage and stems breaks the supporting trees, reducing once-healthy forest to a low, long-lived thicket of vines scrambling over stumps and logs". However Ogle et al (2000) observe that the vines ascend to the canopy of forest but are unable to climb large diameter emergent trees unless shrubs and smaller trees provide a series of ‘stepping stones’ to the crown of tall trees. Their study findings (study area Taihape reserve , New Zealand) indicate that the numbers and variety of understorey trees and shrubs that have been severely reduced following the infestation of C. vitalba correlates with observations of the growth habit of C. vitalba. Ogle et al showed e.g. that not a single canopy tree species had been lost from the Taihape Reserves though 25% or so of the understorey trees and shrubs species had been lost. Poland Competition: Several species that do not tolerate shade are reportedly affected. The scale of impact of this species is moderate Washington (United States (USA)) Habitat alteration: The Washington State Noxious Weed Control Board (2003) states that, "On Orcas Island in San Juan County, the impacts of C. vitalba are visible and spreading as this species climbs over the forested areas."
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