BOTANICAL AND ECOLOGICAL CHARACTERISTICS
SPECIES: Gymnocarpium dryopteris | Oak Fern 



GENERAL BOTANICAL CHARACTERISTICS : 
The deciduous oak fern is delicate in appearance and grows up to 11.8
inches (30 cm) tall [17].  Its petioles are 4 to 12 inches (10-30 cm)
long and parallel to the ground [21].  The blade is divided into three
triangular leaflets [17].  Each petiole arises from a single node on the
creeping rhizome [21].  Spore covers are absent [16].


RAUNKIAER LIFE FORM : 
   Chamaephyte
   Geophyte


REGENERATION PROCESSES : 
Oak fern reproduces by spores and sprouts from rhizomes. The spores are
adapted for high wind dispersal [18].  There is much outcrossing in this
species, and no intragametophytic fertilization [18].  Spores have been
found in soil seedbanks where adult plants are absent [23].  Spores have
sprouted in a greenhouse from soil samples taken from beneath canopy
gaps in northern hardwood forests [24].


SITE CHARACTERISTICS : 
Oak fern occurs on mesic to wet sites in mixed conifer and northern
hardwood stands [20].  Soils are moist to well-drained, with pH ranging
from 4.5 to 6.4 [7,10,36].  Soil textures are gravelly or sandy to silty
clay loams [4,7].  Oak fern grows at elevations from 21 to 1,700 feet
(7-518 m) in the Adirondacks [20].  In Alberta it occurs from 1,960 to
4,300 feet (600-1,300 m), and in Idaho oak fern occurs at elevations
between 2,500 and 4,500 feet (760-1,370 m) [7,10].  Oak fern occurs on
moderately steep slopes and northeast to north and west aspects [7,10].

Some plant species associated with oak fern include Alaska-cedar
(Chamaecyparis nootkatensis), devil's club (Oplopanax horridus), alder
(Alnus spp.), mountain maple (Acer spicatum), red-osier dogwood (Cornus
sericea), twinberry honeysuckle (Lonicera involucrata), thimbleberry
(Rubus parviflorus), prickly rose (Rosa acicularis), highbush cranberry
(Viburnum edule), twinflower (Linnaea borealis), heartleaf arnica
(Arnica cordifolia), starry Solomon's-seal (Smilacina stellata), and
bluejoint reedgrass (Calamagrostis canadensis) [7,10,12,14,17,30].


SUCCESSIONAL STATUS : 
Facultative Seral Species

Oak fern is an indicator of cool, moist sites and mid- to late-seral
forests [4,21,22,30]. Oak fern will grow on disturbed sites before
canopy cover is established in the subboreal spruce (Picea) zone of
British Columbia [14].  It is present in that zone in both mesic seral
communities and climax forests.  Similarly, in spruce-hemlock (Tsuga)
forests of southeast Alaska oak fern will begin establishing in 25- to
35-year-old stands following disturbance by logging or fire [1].  They
will then dominate the understory for the following century.  Oak fern
has been used as a site-quality indicator species on lodgepole pine
(Pinus contorta) and white spruce (Picea alba) stands in west-central
Alberta [34].  It is also used as a secondary indicator of slope
instability in grand fir (Abies grandis)/pachistima (Pachistima
myrsinites) habitat types on the Clearwater National Forest, Idaho [27].


SEASONAL DEVELOPMENT : 
Oak fern unfolds its fronds in early spring [6] and senesces in autumn
[16].

Related categories for Species: Gymnocarpium dryopteris | Oak Fern