Management Practices for Different Forest Types
Colorado’s forests contain a diverse mix of tree species that grow in varying conditions, requiring different management approaches.
Colorado has six ecoregions with different forest types, and the trees in these forest types grow in different conditions. Some tree species require more sunlight, water and nutrients than others, and some must adapt to higher or lower elevations.
Because of these different requirements for trees, effective management approaches can vary by forest type. For instance, management practices to encourage a healthy forest of lodgepole pine will not be appropriate for spruce-fir, piñon-juniper or aspen forests.
Contact your local CSFS field office for guidance in managing forests in your area of Colorado.
Lodgepole pine (Pinus contorta) is a familiar species in the montane and subalpine forests of Colorado’s Rocky Mountains that grows at elevations between 6,000 and 11,000 feet. Some lodgepole pine forests are made up of pure lodgepole pine that grew after fires that happened decades ago. Others are mixed with trees such as Engelmann spruce, subalpine fir and aspen at higher elevations.
Lodgepole pine tends to grow in a stand of trees the same age. Once mature, lodgepole pine forests rely on natural, large-scale disturbances, such as wildfires or bark beetle outbreaks, to regenerate a healthy forest. Thinning trees is an effective strategy for managing lodgepole pine because it mimics these natural disturbances by selectively removing trees within a forest. It can restore natural forest nlight that provides the heat required by lodgepole pinecones to open and release their seeds.
After thinning, forests need regular care to stay healthy, which the Colorado State Forest Service can support through landowner programs.
Contact your local CSFS field office for guidance, or consult the lodgepole pine management guide, which offers specific guidance related to mountain pine beetle outbreaks.
Gambel Oak (Quercus gambelii) is a shrub commonly found along the Front Range through to southern Colorado. It grows at elevations between 6,000 and 9,000 feet and can be found between the lower piñon-juniper zone and the ponderosa pine zone above. Gambel oak grows alongside plants like serviceberries, snowberries, mountain mahogany and a variety of grasses and provides cover, nesting materials and food for wildlife.
Management of Gambel oak is important because the shrubs can grow into thick clumps after recurring fires. These clumps make it hard for wildlife and livestock to move through. They may also increase wildfire risk. While Gambel oak does not burn readily except under favorable conditions, such as ongoing drought and spring and fall when vegetation dries out, fires in thick oak brush can spread rapidly under certain conditions.
Various approaches for Gambel oak management include herbicide, mechanical treatment and prescribed burning. Consult the Gambel Oak Management fact sheet for information on these options or contact your local CSFS field office for guidance.
Piñon-juniper woodlands grow in many parts of Colorado at lower elevations. They grow at 4,900 to 8,000 feet on Colorado’s Western Slope and the Eastern Plains. They are common in dry areas with little rain, typically standing below the Gambel oak zone. Piñon-juniper typically grows in harsh areas where annual rainfall is only about 10 to 15 inches per year. Due to this, they have developed resistance to dry and cold conditions.
In some areas of Colorado, forests of piñon-juniper have grown overly dense, increasing wildfire risk and the potential for damaging crown fires.
Thinning a forest can reduce tree density and help create a healthier balance between large trees, young trees and other vegetation.
Thinning can be done through two types of mechanical treatment during the late fall and winter months.
- Single-tree selection removes individual trees in different size groups. This method promotes natural regeneration of trees and other plants.
- Group-tree selection removes trees in small groups. This method recreates conditions where different grasses and shrubs take over spaces created by the removal of tree groups.
- A combination of single-tree and group-tree selection can be used over time to spread out costs and reduce damage to the forest.
Prescribed burning can be successful when combined with thinning treatments. Using burning and thinning together can reduce how crowded the forest is at the crown and help new plants grow.
Consult the piñon-juniper management guide for more information on these options, or contact0 your local CSFS field office for guidance.
Cottonwood trees thrive in Colorado’s eastern plains, mountain valleys and along riparian areas. They represent the largest native broadleaf trees in the state. They are typically found at lower elevations and can grow to more than 80 feet in height. Cottonwoods grow well in wetter soils near rivers, lakes, irrigation ditches and other lowland areas.
Groves of cottonwood trees, or bosques, are often found in riparian zones, which are areas next to rivers and streams. In these riparian zones where cottonwoods are found, the vegetation is influenced by the shallow groundwater that offers shade to lower water and soil temperatures.
Cottonwoods have many benefits:
- Reducing erosion.
- Capturing and filtering sediment.
- Providing wildlife habitats.
- Slowing runoff.
- Increasing water infiltration.
Despite the many benefits cottonwoods have, they can face problems like competition from invasive species. Therefore, management includes invasive species treatment to trees like the Russian-olive and tamarisk. Options to treat these invasive species include:
- Tree removal
- Chemical treatments (follow proper guidelines)
- Replanting native trees
Cottonwood trees are not highly fire-resistant. They can survive low-intensity fires but are in danger of moderate- to high-intensity fires. To protect cottonwood areas from wildfire, the Colorado State Forest Service encourages residents to clear the lower area of trees and large shrubs. This includes removing invasive woody plants, dead branches, woody debris and excess leaf litter. Trees may also need to be pruned up to 10 feet above ground or one-third of the tree’s height.
Basic forest management principles
- Forests are always changing. Other than natural growth and succession, they can be affected by forest fires, windstorms, disease, insects, forest thinning and reforestation.
- A tree’s place in the forest can affect its growth rate and how likely it is to be harmed by changes.
- Where trees grow often depends on the characteristics of that tree species. Not all tree species will grow in the same area.
- Different species respond differently to different silvicultural Silviculture is the art and science of controlling the establishment, growth, composition, health and quality of the forests.
- Basal area is the area of a tree cross-section at chest height (4 ½ ft). This includes the bark and is measured in square feet.
- Agroforestry can help with wind protection, crop production, water storage, wildlife habitat, road protection and improving the landscape.
- When managing forests on private land, the owner’s goals and management.