Young, vigorous Myrica faya trees aggressively colonizing a
field near Hawai‘i Volcanoes National Park.Myrica faya, referred to as fayatree, was brought to Hawai‘i by Portuguese immigrants from the islands of the Azores and Madeira in the late 1800s. Whereas this small to medium tree is not considered a problem species in its native habitats, it is an aggressive invader of native mid to upper elevation habitats in Hawai‘i, where it is displacing native species. It produces fruit prolifically and also has the ability to fix atmospheric nitrogen through association with the actinomycete Frankia. This allows it to rapidly colonize nitrogen poor volcanic soils, overtopping and shading out native vegetation. The unnaturally rich supply of nitrogen further encourages colonization by other nonnative plants and invertebrates (e.g., earthworms), permanently altering the soil environment in favor of introduced organisms.
Other than M. faya, the only representative of the genus Myrica, or of the family Myricaceae in Hawai‘i, is M. cerifera, introduced from eastern North America where it is native. Like M. faya, M. cerifera is without value in Hawai‘i and no effort is made to protect this species. The family Myricaceae is the only member of the order Myricales, thus M. faya is phylogenetically isolated from near relatives in Hawai‘i, which makes it an ideal candidate for biocontrol from this standpoint.
Young, vigorous Myrica faya trees aggressively colonizing a
field near Hawai‘i Volcanoes National Park.
A young Myrica faya tree colonizing recent cinder substrate
in a native ‘ohi‘a forest (left). The invading trees (light green foliage,
right photo) grow much more rapidly than the native species, soon encroaching into, and
overtopping the canopy, where they may shade out the native species and form a monotypic
stand.
On the island of Hawai‘i, M. faya is able to colonize recent
lava flows, typically becoming established at the base (arrow) of a larger tree or shrub,
such as the endemic ‘ohi‘a lehua (Metrosideros polymorpha) shown here.
This establishment is probably the result of seeds being deposited under the parent
tree by a roosting bird. The parent tree also furnishes a favorable microclimate
(i.e., shade and moisture) for the M. faya seedling to become established.
Myrica faya invading a native ‘ohi‘a
forest at the edge of Kilauea Caldera in Hawai‘i Volcanoes National Park. The
upright, light green new growing shoots of M. faya (arrows) are visible
throughout the stand of the darker, gray-green ‘ohi‘a.
Members of the genus Myrica, including M. faya, are
capable of fixing atmospheric nitrogen through root nodulation (shown here) and
association with the actinomycete Frankia. Such N fixation has been shown
to provide a significant growth advantage to this species, as compared to native Hawaiian
species, in colonizing new, N-poor substrates, such as new lava deposits. Addition
of unnatural nitrogen amounts to the substrate further encourages colonization by other
nonnative flora and fauna.
A fruiting branch of M. faya.
Prolific fruit set contributes to the invasive ability of this species.
Myrica faya in its native habitats
Diseases and insects of Myrica faya