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Forest Health and Fire Risk Survey Sterling Pointe August 2006 Douglas County, Colorado Legal Description: A portion of Section 20, Township 9 South, Range 67 West, Sixth Principle Meridian Prepared by: Diana Selby, Forester Colorado State Forest Service Franktown District P.O. Box 485 2068 N. State Highway 83 Franktown, CO 80116-0485
Table of Contents
Objectives of Survey.....................................................................pg. 1 Property Description......................................................................pg. l Location.. .... .. . ........ .... ......... .... .. ...... ... ........................ .........pg. 1 Topographic and climatic characteristics ....................................... pg. 1 Vegetative cover types............................................................. pg. 1 Survey........................................................................................pg. 2 Forest Health....................................................................... .pg. 2 Table 1. Insects............................................................................pg. 3-4 Table 2. Diseases and Other Damage ................................................. pg. 5-6 Fire risk......................................................................................pg. 7 Background.......................................................................pg. 7 Fire Risk in Sterling Pointe....................................................... pg. 7 Management Recommendations........................................................pg. 8 Insects/Disease/Other...............................................................pg. 8 Fire..................................................................................pg. 9 Cautions............................................................................pg. 9 Photos..........................................................................................pg.10 References Used.............................................................................pg. 10 Enclosures Aerial Map of Sterling Pointe and Insects/Diseases Topographic Map of Sterling Pointe and Insects/Diseases Lot and Address Map of Sterling Pointe with Insects/Diseases Home Fire Protection in the Wildland Urban Interface Creating Wildfire-Defensible Zones no. 6.302 Fire-Resistant Landscaping no. 6.303 Forest Home Fire Safety no. 6.304 FireWise Plant Materials no. 6.305 Grass Seed Mixes to Reduce Wildfire Hazard no. 6.306 Landowner Guide to Thinning Protecting Trees During Construction no. 7.420 Mountain Pine Beetle no. 5.528 Preventative Spraying For Mountain Pine Beetle Ips Beetles no. 5.558 Dwarf Mistletoe Management no. 2.925 Franktown District Contractor List
Objectives of Survey This survey was completed at the request of Art Rosenboom on behalf of the Sterling Pointe subdivision. The intentions of this survey are to provide information on general forest health and fire risk for the entire Sterling Pointe subdivision which consists of 116 privately owned lots on 288.5 acres in Douglas County, Colorado. The primary objective of this survey is to provide management recommendations to minimize destructive forest insects, diseases, and reduce the threat of wildfires to the community. Property Description Location The Sterling Pointe subdivision is located northwest of Larkspur in the foothills of Douglas County, Colorado. The area can be accessed from I-25 by taking the Larkspur exit to Perry Park Avenue, then traveling north on Silverheels Drive to Tenderfoot and Independence Drives which form portions of the subdivision boundaries. The subdivision is located on most of the west half of Section 20, Township 9 South, Range 67 West, Sixth Principle Meridian. Some lots of the subdivision also extend into the southwest quarter of Section 17, the southeast quarter of Section 18, and the northeast quarter of Section 19. Topographic and Climatic Characteristics (taken from a forest management plan written by the Colorado State Forest Service in December 1992 for Gene Taylor) "The property features mostly gentle (less than 10 percent) slopes, with elevation ranging from 6,700 to 6,900 feet. The majority of the property has a northern aspect, but slopes facing each of the points of the compass can be found along hillsides and ridges. Annual precipitation is 15 to 21 inches, occurring as spring/summer thunderstorms and winter snow. The Palmer Divide topography has an enhancing effect on local precipitation. The growing season ranges from 115 to 125 days." Vegetative Cover Types The majority of the subdivision is covered by ponderosa pine with an understory of a variety of shrub species. Shrub species in the area include mountain mahogany, sumac, and currant; however, the dominant shrub in the area is Gambel oak. Only a few small areas which are primarily located along the northern edge and southwestern edge of the subdivision are covered by meadow. Several properties scattered throughout the subdivision are covered almost exclusively with Gambel oak and other shrub species. Several non-native, invasive plant species were found throughout the subdivision, particularly on roadsides and in disturbed areas and are listed below. Control measures for the more aggressive species are recommended. Further information, weed identification, and control methods can be obtained from the Douglas County Cooperative Extension Master Gardener program (720) 733-6935 or the Douglas County Weed Inspector at (303) 660-7476. Invasive species found include; knapweed, mullein, Canada thistle, musk thistle, cheat grass, and toadflax. Survey Forest Health Due to drought and the presence of some insects and dwarf mistletoe, the forest in and around Sterling Pointe is stressed and very susceptible to attack from more damaging insects such as mountain pine beetle or ips engraver beetles. Currently there are no highpriority insect or disease infestations in the area aside from a known and ongoing dwarf mistletoe infestation. Management recommendations for improving forest health are encouraged and included later in this report. A combination of factors, including insects, drought stress, overly dense stands and dwarf mistletoe infestation are causing tree stress throughout Sterling Pointe. Tables 1 and 2 list the insects, diseases, and abiotic problems found on ponderosa pine in Sterling Pointe during the survey. The attached map provides information as to where some of the damage was found; however, many of the stress factors were found throughout most of the subdivision and are not included on the map. In particular, needle discoloration occurring in the ponderosa throughout the subdivision is a result of one or more factors including ponderosa needleminer, drought and/or winter desiccation, and pine needle scale (see photo). Several trees with dieback of small branches and branch tips are also found throughout the subdivision and are a result of twig beetle presence. Trees with twig beetle and those with needle discoloration were not mapped due to widespread locations and numbers found. Individual property owners may read the tables for signs and symptoms to learn more. Several dead or dying ponderosa pines were found in the survey and are mapped. Beetles that only attack dying or dead trees called wood borers were found on these trees and are not considered a threat to live trees. The cause of death could not be determined and may be a result of drought stress, bark beetles, root damage, or other causes. Because there is a possibility that bark beetles caused the death of these trees, it is important for homeowners to watch for signs of bark beetles on nearby live trees. Signs and symptoms of bark beetle infestations can be found in the enclosed handouts for mountain pine beetle and ips beetles. Red turpentine beetle activity is also mapped. Most red turpentine activity is older; however, their presence indicates substantial tree stress or injury. Most properties mapped with wildlife damage have old porcupine injuries in the ponderosa pine. Trees can survive damage from porcupines unless girdled. Wildlife damage is not considered a threat because activity is not current. One property located on 1971 Lake Drive has several dead saplings due to rodents chewing and girdling the base of the trees. Because the area has abundant trees the death of several saplings is not a forest health concern. There is a high amount of dieback and dead tops in the Gambel oak within the subdivision. This is likely due to drought and late spring frosts. In areas with dieback it is best to remove oak at the base and allow the shrub to re-sprout rather than cutting off only the dead top. Gambel oak re-sprouts readily and will return quickly after cutting. Table 1. Insects on Ponderosa Pine in Sterling Pointe in the August 2006 Survey
Table 1. (Cont.) Insects on Ponderosa Pine in Sterling Pointe in the August 2006 Survey
Table 2. Disease and Other Damage on Ponderosa Pine in Sterling Pointe in the August 2006 Survey
Table 2:(Cont.)Disease and Other Damage on Ponderosa Pine in Sterling Pointe, August 2006 Survey
Fire Risk Background Ponderosa pine forests cover approximately three million acres in Colorado and grow over a wide range of topographical and environmental site conditions. These forests evolved with wildfire, insect and disease infestations, windstorms, and other natural disturbances. The primary agent of disturbance in ponderosa pine forests is wildfire. In low elevation areas (5,500-8,000 feet) along the Front Range these forests have become very dense in comparison to pre-European settlement due to a combination of post-European activities including grazing, logging, and fire exclusion. The increase in dense, homogeneous forests in these areas have resulted in many stands of trees that are approximately the same age and size and are now stressed from competition for resources. These conditions combined with the building of homes and structures in this zone have increased risk from wildfire. Today, as a result of changes in forest structure, increased stressed forest and changes in climate conditions there is a much greater chance of experiencing a large, high-severity, stand-replacing wildfire and/or a large insect or disease outbreak. Communities that are at risk include those that are in or lie within one mile of ponderosa pine forests. The fire risk in the Sterling Pointe subdivision is high; however, individual homeowners can reduce their risk by creating defensible space around homes and properly managing forested lots. The materials of a home, particularly the roof, and the quality of the defensible space surrounding the home are the two most important factors in determining which houses will survive a wildfire. Fire resistant materials with a rating of a Class C or better are recommended for building and roofing homes and adjacent structures. The area around the home where fuels and vegetation are treated is known as defensible space (D-space). A minimum of 100 feet from the house is recommended for partial removal of vegetation and trees (D-space). This area provides a place for firefighters to work; and, while not intended to stop a fire, it can reduce the severity of fire near the home. Other crucial recommendations include cleaning gutters, stacking firewood away from the home, and several other guidelines (see enclosed brochures on Fire Wise Homes and creating defensible space). Fire Risk in Sterling Pointe While several homeowners in the Sterling Pointe subdivision have created well maintained defensible spaces around homes and are actively reducing fuels on properties, there are still many who need to reduce fuel loadings and take "firewise" steps to reduce the risk to homes from wildfire. High risk areas are not mapped because they occur throughout the entire subdivision except for those lots occurring in meadow areas. The following section on management recommendations provides more specific information on what homeowners can do to reduce fire risk. Management Recommendations Insects/Disease/Other To decrease the risk of insect and disease infestations, tree removal and thinning of forest stands is recommended for most areas in Sterling Pointe. Thinning will reduce competition and will ultimately increase the overall health of the forest. More specific recommendations are outlined below under fire management recommendations; however, recommendations for thinning in ponderosa pine on the Front Range generally suggest leaving 50-60 trees per acre in trees that are five inches in diameter and above. The ideal basal area for ponderosa pine is somewhere between 40.50 square feet per acre. In almost all areas in Sterling Pointe the basal area is much higher; therefore, proper thinning will result in much more open stands (see photos for an example). Fortunately, removing fuels for fire risk reduction and for forest health can often be achieved simultaneously in ponderosa pine systems. Tree removals should focus on those that have the presence of insects or disease, those with broken tops, many broken branches or injuries, those that have been bent by snow and trees with poor growth form such as those with multiple tops. Trees that are considered highly valuable to homeowners and have signs of stress or other insects such as needle discoloration or twig dieback may be good candidates for bark beetle preventative spraying. Neither ips nor mountain pine beetle were detected in the Sterling Pointe area during this survey; however, tree susceptibility to attack by these insects is high. The bark beetle preventative spray can be applied two to three times during the year with the first application in spring and the last in the fall to provide the most protection. The same spray will also be effective on twig beetles; however, it is highly recommended that a professional be hired to spray valuable trees to ensure proper mixing and spraying which will achieve the greatest effectiveness. Preventative measures most homeowners can take are to continually survey their properties for new insect or disease infestations. If possible, supplemental watering or mulching around valued trees is also recommended in order to decrease tree stress during dry months. For those areas with heavy dwarf mistletoe infestations it may be necessary to remove the most heavily infested trees with ratings of 5 or 6 altogether (see dwarf mistletoe rating guide in attached handout on dwarf mistletoe management). Heavily infested branches may also be pruned. For those areas with infestation in all trees on a property it may not be possible to remove all mistletoe from the area without removing all trees. In these particular cases landowner may wish to use ethephon sprays to reduce the spread of infection to smaller, un-infested or lower infestation rated trees. Re-treatment is necessary until heavily infested trees are removed; however, this may allow time for understory trees to grow without the risk of infection from nearby larger trees. Removing larger infested trees and retaining smaller trees may allow for control of dwarf mistletoe in the area and also provide diversity of tree age and size for the entire subdivision.
Fire Efforts to reduce fire risk need to take place throughout most of the Sterling Pointe subdivision. Removing "ladder" fuels or fuels that provide a ladder from the forest floor to the tree crowns should be a priority. Low intensity fires that are burning through the understory have a much lower chance of traveling to the tops of trees when there are no fuels to carry the flames. Most ladder fuels in Sterling Pointe are shrubs such as Gambel oak and small understory trees growing below larger ponderosa. The intent of removing ladder fuels, particularly those beneath the drip-line (directly under the tree and as far out as the branches reach), is to create a vertical break between continuity of fuels on the ground and fuels in the air (tree crowns). For most areas, larger-diameter trees should be retained and ladder fuels, particularly those beneath the drip-line should be removed. These larger trees have thick bark and are fairly "fire resistant" to low-intensity ground fires. The horizontal continuity of fuels should also be addressed. Thinning of trees, creating openings, and "clumping and grouping" oak are all efforts that can be utilized in order to create breaks between the crowns of trees and between shrubs. If a wildfire does happen to move from the ground to a tree crown (torching), the opening between the tree and nearby fuels will reduce the likelihood that the fire will travel through the crowns {crown fire}. The same principle works for lower vegetation such as oak. Generally, shrubs and brush should be left in widely scattered clumps. All Gambel oak with dead tops and dieback should be removed. Oak will re-sprout quickly so continuous maintenance will be necessary. In areas where clumps of oak are retained, it may be necessary to remove those clumps in 3-5 years and allow new growth of oak to survive in initial openings. This will ensure that some openings are maintained in the oak and that oak with dead tops and dieback is continuously removed. If individual properties do not contain many larger trees it is acceptable to retain smaller trees and clumps of younger trees in order to maintain a diverse age and size structure. Overall, efforts can take place individually; but, it may be more cost effective for landowners to coordinate efforts by working together. Cautions When thinning, removing, or treating trees for fire risk reduction and/or forest health it is important to remember a few safety precautions. A list of contractors that provide tree removal and preventative spray services is enclosed for landowner use. 1. Have a qualified individual remove trees, especially those near homes or roads. 2. Proper safety equipment should be utilized when cutting shrubs and trees with chainsaws including ear protection, eye protection, chaps, boots, gloves, and a hardhat. 3. Hire a licensed professional or follow directions and safety guidelines on labels when utilizing pesticides or herbicides. 4. Remove freshly cut branches (slash) or material promptly from property or "treat" by chipping, covering or burning in order to prevent attracting bark beetles into the area (See ips beetle handout).
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