Pacific Southwest Research Station

Native Forests

Native Hawaiian forests, such as the one pictured here, are seriously threatened by invasive plants, like strawberry guava. Invasives threaten not only the forests and the species that inhabit them, but the range of services they provide as well. Photo by Jack Jeffrey, US Fish and Wildlife Service

Native animal species depend on native plants for food. Strawberry guava serves as food for non-natives, like pigs, themselves damaging to native forests. Photo by Jack Jeffrey, US Fish and Wildlife Service

Native tree species, like the koa pictured here, are crowded out when strawberry guava invades native forests.

Strawberry Guava

Strawberry guava fruit comes in several colors and shapes, depending on the subspecies. The fruit, which are edible and can be used to make juice and other food products, contain dozens of seeds that are easily spread.

Once established, strawberry guava quickly invades -- and eventually dominates -- native Hawaiian forests. Shown here, is an aerial view of a strawberry guava invasion in Wao Kele o Puna, on the island of Hawaii. Photo courtesy of Carnegie Airborne Observatory.

Strawberry guava forms nearly impenetrable thickets, like the one shown here, that crowd out native species and break up landscapes. The thickets also serve as refuge for fruit fly pests of agriculture. Photo by Jack Jeffrey, US Fish and Wildlife Service

Over time strawberry guava displaces native Hawaiian rainforest. These photos show a typical sequence from upper elevations that have not yet been overrun by strawberry guava to lower elevations where the native species have been severely impacted and, in the end, replaced completely. The sequence is along a trail in the Hawaii Experimental Tropical Forest, Laupahoehoe unit (Laupahoehoe Natural Area Reserve) on Hawaii Island. Photos by Christian Giardina, US Forest Service

3200' Hawaiian forest with few invasive species.

2900' Invasion by strawberry guava & clidemia

2700' Native overstory, young guava beneath.