Trees and Shrubs
Trees and Shrubs
The trees and shrubs, which make up the forest in the montane and subalpine environments of Beaver Ponds EEC, provide the framework for the ecosystems and habitats here. They provide important watershed services, such as recharge and storage for soil moisture and water purification. The importance of our forests reaches well beyond Beaver Ponds EEC, since Colorado's mountains serve as a watershed to 18 states.
There are about 145 species of amphibians, reptiles, birds, and mammals that utilize subalpine and montane forests, so the forests are important for the habitats and ecological webs of these creatures, as well.
Trees are the most visible plant at Beaver Ponds EEC. The majority of the trees are coniferous or conifers, meaning they produce cones. They have needles for leaves and keep them all year round. The conifers at Beaver Ponds EEC include Lodgepole pine, Douglas fir, Colorado blue spruce, Englemann spruce, Subalpine fir, Bristlecone pine, and Limber pine. The trees and shrubs at Beaver Ponds EEC can be classified into four ecosystems: mixed conifer, aspen, sagebrush, and riparian willow.
Mixed Conifer Ecosystem
The mixed conifer ecosystem provides calving areas for elk in the spring and cover for them in the summer. Elk tend to migrate to more open areas of Park County in the winter, possibly to avoid the deeper snow in the forests. The mixed conifer ecosystem provides a summer home to many neotropical, migratory song birds. These birds migrate from North America to what are considered the neotropical or new world regions of Mexico, Central America, and larger Caribbean islands.
Fire is very important for montane coniferous forests. Small, cool fires are part of nature's way to keep forests healthy. Some of the more serious fires in Colorado in recent years have been severe due, in part, to the policy of fire suppression. Regular, small fires were not allowed to burn, so the forest became a tinder box of dead timber and thick, dry understory vegetation. This dry vegetation, combined with drought conditions, cause firestorms to get so hot, they kill the next generation of seeds of all plant species. Succession cover takes a long time to return to the barren landscape, leaving it open to erosion and mudslides and reducing or eliminating many species that once thrived there. Beaver Ponds EEC uses prescriptions to manage our forests and to mitigate fire hazards. See our web section on Forestry.
Deciduous trees are those that lose their leaves seasonally. The willows, alders, and Rocky Mountain maples that grow on the Beaver Ponds EEC property are deciduous but are small in the high elevation environment and are considered shrubs or scrub.
Quaking aspen (Populus tremuloides) account for most of the deciduous trees in this forest. Aspen are a clonal species, meaning most trees in a stand are one organism. Some stands are considered by many scientists to be the largest, oldest, single-living organisms in the world. Aspen serves as an important successional tree after serious soil disturbances, such as fire or flood. They revegetate soil relatively quickly by sending out many root sprouts or suckers. They produce abundant litter that contains more nitrogen, phosphorus, potash, and calcium than leaf litter of most other hardwoods and conifers. The litter decays rapidly, forming a nutrient-rich humus that reduces runoff and aids in percolation and recharge of ground water. If you visit Beaver Ponds EEC in the spring, you will notice that soil under quaking aspen thaws faster, allowing the water to infiltrate faster than soil under conifers.
Aspen ecosystems are rich in biodiversity. The buds, catkins (seeds), leaves, twigs, and bark of the trees provide an important food source for many animals all year round. A few of these animals include moose, mule deer, elk, beavers, porcupines, rabbits, hares, rodents, and shrews. Additionally, aspen stands create a rich understory filled with forbs and berries favored by bear, and the trees themselves provide important feeding and nesting sites for many birds.
Beaver Ponds EEC has a south-facing hillside area where a sagebrush ecosystem thrives. The evergreen leaves, numerous seeds, and high levels of nutrients and proteins of the big sagebrush (Artemesia tridentata) provide a winter food source for mule deer, elk, and rabbits. Many bird and animal species depend on the habitat for cover, nesting sites and food.
Studies from the Rocky Mountain Research Station have found that over 240 insects and 70 spiders and other arachnids are associated with sagebrush, as well as 133 plant and 24 species of lichen. Sagebrush creates cool, micro-climates under its branches, allowing forbs, such as Indian paintbrush, other wild flowers and lichen, to grow in a habitat that might otherwise be too hot and dry.
Riparian Willow Ecosystem
Riparian willow ecosystems are diverse communities that may occur in response to disturbances like mining, flooding, and road building. Also, as in the case of these communities on Sacramento Creek at Beaver Ponds EEC, they may be considered climax communities, meaning they are stable and in the final stage of succession.
The upper end of the Beaver Ponds EEC property is a willow riparian ecosystem. The Latin genus name for willow species is Salicacea or Salix (abbreviated “S.”) Willow species at Beaver Ponds include: S. myrtillifolia, S.drummondiana, S.geyeriana, S.wolfii, S.planifolia, S.monicola, S. candida, S.bebbiana, S. brachycarpa and S. glauca.
The willow and other riparian plant species' roots need close contact with water and are able to withstand periodic flooding. They can replace roots quickly. In the spring, you will see the white puffs of the willow seeds that get lifted by the wind to fall and germinate on moist soil.
Willows, like aspens, create new sprouts by using suckers. The strong root system keeps willows from being washed away by the annual spring high water, which gushes down Sacramento Creek. Birds and deer use the plant for nesting sites and browsing.
Below are descriptions of predominant trees at Beaver Ponds EEC, from Colorado State Forest Service.
Bristlecone pine (Pinus aristata)
Bark: Light gray and smooth when young; red-brown with irregular, scaly ridges when mature.
Leaves: Evergreen needles are dark with white lines. They have white pitch dots on both surfaces; to 1-inch long; crowded in a long, dense mass along the twig; generally 5 in a bundle.
Fruit: Cylindrical, dark purple-brown cones; 2 to 3 inches long; 4-sided cone scales with stiff curved points; brown seeds with black mottling and detachable wing.
Height: 15 to 30 feet
Habitat: On exposed, cold, dry, rocky slopes and high mountain ridges up to timberline; in pure stands or with limber pine.
Associations: Clark's nutcracker collects and stores seeds from the fruits of the bristlecone. These stored seeds are a source of new trees.
Blue spruce (Picea pungens) Colorado's State Tree
Bark: Gray-brown with thick scales on mature trees.
Leaves: Evergreen needles are blue or light green with white lines; 1 to 1-1/4 inches long with thin, long, flexible, and irregularly toothed scales; contains paired, long-winged seeds.
Fruit: Shiny light brown, cylindrical cones; 2 to 4 inches long with thin, long, flexible and irregularly toothed scales; contains paired, long-winged seeds.
Height: 70 to 115 feet.
Habitat: Well-drained, sandy soils; moist sites of narrow bottomlands or along mountains streams; often in pure stands.
Douglas fir (Pseudotsuga menziesii)
Bark: Gray and smooth with resin blisters on young trees; red-brown, very thick and deeply furrowed with broad, often corky ridges at maturity.
Leaves: Evergreen needles are to 1-inch long with bracts at the base.
Fruit: Light brown, short-stalked cones that hang down from the branches; 1-1/3 to 3 inches long; many thin, rounded cone scales on top of long, 3-pointed, winged seeds that stick out beyond scales.
Height: 100 to 130 feet.
Habitat: Rocky soils of moist northern slopes; in pure stands and mixed conifer forests.
Associations: Provide cover for birds and small animals. Seeds are food for many birds and squirrels.
Engelmann spruce (Picea engelmannii)
Bark: Gray-brown, thick, with flaky scales.
Leaves: Evergreen needles are deep blue-green with white lines; 5/8 to 1 inch long; slender, sharp and flexible; skunk-like odor when crushed.
Fruit: Light chestnut-colored, oblong cones; 1 to 2 inches long; in upper part of crown with scales that are paper-thin and ragged along the outer edge. Seeds have a single, long and well-developed wing.
Height: 45 to 130 feet.
Habitat: High, cold forest environments on moist, northern slopes; with subalpine fir and other conifers.
Associations: Moose, elk and mule deer inhabit stands of Engleman spruce.
Limber pine (Pinus flexilis)
Bark: Light gray, thin and smooth on young trees; at maturity, dark brown, thick and furrowed into scaly ridges. Young branches are very flexible, hence the name.
Leaves: Slender evergreen needles are blue-green with white lines on all surfaces; 2 to 3 inches long, typically 5 in a bundle.
Fruit: Yellow-brown, egg-shaped cones; thick, rounded cone scales that end in a blunt point; seeds are large with a very short wing.
Height: 40 to 50 feet.
Habitat: Nutrient-poor soils on dry, rocky slopes; ridges up to timberline and often pure stands.
Associations: The Clark's nutcracker helps the limber pine to grow by prying seeds out of its cones and storing them for long periods where some will germinate.
Lodgepole pine (Pinus contorta)
Bark: Light brown, thin with many small scales.
Leaves: Evergreen needles are yellow to dark green; 1 to 3 inches long; sharply pointed, stiff, stout, slightly flattened and often twisted; 2 needles per bundle.
Fruit: Shiny, yellow-brown, egg-shaped, serotinous* cones; to 2 inches long with raised, rounded cone scales and a tiny point. May be sap or resin covered and not always present.
*Seeds released from cones by exposure to extreme heat.
Height: 20 to 80 feet.
Associations: Can require fire or very hot days to reproduce.
Subalpine fir (Abies lasiocarpa)
Bark: Gray and smooth with resin blisters while young; shallow fissures and scaly when mature.
Leaves: Evergreen needles are dark, blue-green with silvery lines on both surfaces; 1 to 1-1/2 inches long; flat and blunt tipped; crowded and curved upward on twigs at nearly right angles.
Fruit: Upright, cylindrical, very dark purple, 2 to 4 inches long in the upper part of the crown; fine, hairy, cone scales; long, broad-winged seeds. These deciduous cones fall apart when mature so they are rarely found on the ground.
Height: 60 to 100 feet.
Habitat: Cold, high-elevation forests; with Engelmann spruce and other conifers.
Associations: They have a high rate of transpiration, so they prefer wet sites, often where Englemann spruce occur.
Quaking aspen (Populus tremuloides)
Bark: Green-white, smooth and thin with raised dark patches; on very large trees, trunk base is often gray, thick and furrowed.
Leaves: Broad-leaf foliage is bright green above and dull green below; rounded with a pointed tip, 1 to 3 inches wide on a flattened leaf head; nearly round and sawtoothed.
Fruit: Fruit are catkins; up to 4 inches long; many light green capsules contain 6 to 8 tiny, cotton-like seeds.
Height: 35 to 50 feet.
Habitat: Many soil types, especially on well-drained, sandy and gravelly slopes; often in pure stands.
Associations: Young twigs, leaves, and bark are important food sources for porcupine, voles, rabbits, elk, and mule deer. Bears feed on the forbs and berries in the understory of the aspen forest. They are the main food source for beavers and also provide structural support for dams and lodges.