Does Mistletoe Kill Oak Trees?

Mistletoe, with its distinctive white berries, is a parasitic plant.

The species of mistletoe commonly used for holiday decorations come from several genera within the Loranthaceae plant family. The plants are parasitic, taking nutrients and water from host trees, including oaks. Mistletoe does not always kill an oak or other tree, but it may damage it or stunt its growth.

Types

According to Liberty Hyde Bailey in "Hortus Third," American commercial mistletoe is generally Phoradendron serotinum, sometimes known as "false mistletoe," which is parasitic on oaks and other deciduous trees in the eastern part of North America. Another native, Arceuthobium pusillum, known as "dwarf mistletoe," is parasitic on conifers.

Effects

MIstletoe is sometimes called a "hemi-parasite," as its green leaves contain chlorophyll, which produces a certain amount of energy for the plant. However, the plants cannot survive apart from the host trees. Mature trees are weakened by the parasites' consumption of nutrients. Saplings can be killed by it.

Considerations

Conservation may actually encourage the spread of mistletoe. When older trees are not felled by humans or killed by forest fires, mistletoe lodging in those trees has more years to complete annual reproduction cycles. More mistletoe berries means more plants, which in turn damage more trees.

References

• "Hortus Third"; Liberty Hyde Bailey, Zoe Esther Bailey, et al.; 1976
• National Geographic News: When Mistletoe Attacks. Investigating a Forest Parasite.