Woody Invasive: Glossy Buckthorn (GB)

Glossy buckthorn (Frangula alnus) reproduces primarily from seed, relying on dispersal by birds, small mammals, and gravity. Importantly, medium to fullsize glossy buckthorn trees potentially produce 430-1,560 offspring per year, making seed propagation its primary mode of reproduction.

When glossy buckthorn invades a woodlands it changes the growing conditions in the following ways:
• Decreases soil pH; the soil becomes more acidic
• Lowers the water table, making it less accessible to plants with shorter root systems
• Decreases light reaching the understory and shades out native species
• May produce compounds that prevent germination of other plants (allelopathic effects), similar to common buckthorn

( https://www.michigan.gov/-/media/Project/Websites/invasives/Documents/Response/Status/egle-ais-frangula-alnus.pdf?rev=6d5550e9d1bc4c538ef72a11564e0f7f )

These changes impact vegetation and animal life of a woodlands.
• Decreases presence of native grasses and even shade tolerant sedges
• Reduces the total plant cover, especially of native saplings
• Lowers survival of native saplings because increased shade starves them of life-giving light
• Alters both the number and diversity of pollinators
• GB monocultures harm habitats that songbirds call home; nesting here exposes them to greater predation
• Creates environments in which exotic earthworms thrive

REMOVAL & CONTROL: The method chosen for removal is critical! Cutting glossy buckthorn without removing the roots not only stimulates vigorous growth of stump sprouts, but these sprouts can produce fruit even within the same season. Uprooting is far better.

One source of optimism. Glossy buckthorn is extremely shade intolerant. So if upper canopy native trees are allowed to progress naturally toward more mature successional stages, glossy buckthorn might be choked out. On the other hand, opening up the light in the woodlands by removing trees or pruning limbs will give any glossy buckthorn present an unfortunate population boost. After maintenance that adds light to the woodland, follow up the following few years to remove buckthorn seedlings that may have sprouted.

MORE INFORMATION:
• "What We Know About Glossy Buckthorn" by UNH Extension Forestry Information Specialist Karren Bennett
• GLOSSY BUCKTHORN (Frangula alnus) - PEI Invasive Species Council - https://peiinvasives.com/glossy-buckthorn/

And a similarly invasive related shrubby tree - COMMON BUCKTHORN

• COMMON BUCKTHORN -- NEW YORK INVASIVE SPECIES (IS) INFORMATION
New York State's gateway to science-based invasive species information
https://nyis.info/invasive_species/commonbuckthorn/

Posted on 07 de novembro de 2023, 06:42 PM by ecrow