"Reflection Pond" by U.S. National Park Service , public domain
![]() | Denali TrailsRock Creek Trail |
Brochure of Rock Creek Trail at Denali National Park & Preserve (NP&PRES) in Alaska. Published by the National Park Service (NPS).
featured in
![]() | National Parks Pocket Maps | ![]() |
![]() | Alaska Pocket Maps | ![]() |
covered parks
Denali Trails
National Park Service
U.S. Department of the Interior
Denali National Park and Preserve, Alaska
Rock Creek
TRAIL
An Environment of Competition
The boreal forest of Denali is a subarctic ecosystem consisting of a patchwork of
coniferous and deciduous trees stands interspersed with lakes, wetlands, and tundra.
Boreal forests support relatively few plant species, mainly white and black spruce and
a small number of deciduous trees and shrubs. Boreal forests in Denali are underlain
by discontinuous permafrost, inorganic soils that are frozen for all or most of the year.
Explore the boreal forest and discover the competitive strategies that plants use to
survive the short subarctic summer.
walk along the trail, pay attention to the
OPEN Asforestyoucanopy—the
layer of forest formed by
Closed
the tops of trees. Note if the canopy is open,
where sunlight streams through to hit the forest
floor; or closed, where the branches of the trees block the sunlight
casting the forest floor into shadow. The presence or absence of
sunlight determines what trees and plants can survive.
Fire
Fire in the boreal forest plays an integral role in the reproduction of black
spruce. The tree needs fire to open its
cones. The seeds then fall to the forest
floor. A wildfire occurred in this area
in 1924, and many of the black spruce
today are attributed to that event.
FAST
Compared to evergreen needles, the leaves of
deciduous plants have a large surface area to
gather energy from the sun. This creates an advantage of speed for growth during the warm,
sun-rich summer months or when a hole develops in the forest
canopy. However, the autumn light triggers these leaves to fall
to the forest floor where they are broken down by insects
and bacteria and their nutrients recycled into soil for the
next growing season. The advantage then goes to the
evergreen trees, which continue photosynthesizing
when temps allow.
Slow
Black Spuce
Picea mariana
Evergreen
Leafs: Short. 1-2 cm long, 4 sided
Bark: Scaly, dark brown to reddish.
Average Height: 20 -30 ft (7- 10 m).
Alder
Alnus glutinosa
Deciduous
Leafs: Oval to broad. Finely double toothed.
4-8 cm long.
Bark: Smooth reddish brown.
Average Height: 3.2 - 10 ft (1-3 m).
distinctive classes of organisms
YOURS Two
have adapted to low-light conditions in
Mine
the boreal forest understory by obtaining
their energy without directly harvesting
it from the sun—parasitic plants and saprophytic fungi. For
example, unlike green plants that photosynthesize groundcones obtain most of their nutrients from the roots of living
alder shrubs.
of the plants in the boreal
DEFENSE Many
forest produce alleleochemicals,
Offense
toxins that adversely affect
potential browsers. Willow
produces a chemical that snowshoe hare cannot process,
aspen leaves produce a chemical that deters porcupines, and
spruce bark and needles contain terpene, which is difficult for
most wildlife to digest.
DISPERSAL
Plants use a large amount of
energy to reproduce. An
effective seed dispersal agent can provide that extra advantage
to survival. Plants such as fireweed use wind to carry their
seeds, while other plants produce edible berries. Blueberries,
crowberries, soapberries and low-bush cranberries mature
when wildlife like bears are fattening up for winter and when
birds are migrating south. For these plants, this means widespread dispersal combined with a nutrient-rich scat that will
fertilize the seed as it grows.
Crowberry
Empetrum nigrum
Leafs: Needle-like, 3-8mm long.
Bark: Juicy berry-like drupes, edible.
Average Height: Up to 15cm tall.
Witches Broom
Spruce broom rust, a fungus, alternates
between two hosts to complete its life
cycle beginning on the leaves of
common bearberry. Once the spores
of the rust are released, they infect
developing spruce needles. A hormonal
response to the parasite causes the
formation of witch’s broom, a dense
mass of shoots with discolored needles
growing from a single point in the
branches of the spruce. Occasionally
witch’s broom causes reduced growth
or top-kill.
Denali Trails | Rock Creek Trail
Moderately strenuous
2.4 miles/3.8 km, 2 hrs one way
Please stay on trails.
Bebb Willow
Salix bebbiana
Deciduous
Leafs: Elliptic to narrowly egg shaped.
Smooth edged. 2-5 cm long.
Bark: Dull grayish to reddish brown.
Average Height: Up to 32 ft (10 m).
This trail guide was produced in
partnership by the National Park Service
and the Alaska Geographic Association.
NPS Photo/Tim Rains