Public Works and Environmental Services

Fairfax County, Virginia

CONTACT INFORMATION: Our office is open 8 a.m. - 4:30 p.m., Monday - Friday

703-324-5033
TTY 711

12000 Government Center Parkway
Suite 448 Fairfax, VA 22035

James Patteson,
Director

Urban Forestry FAQ

  • Place the tree in the prepared hole and ensure the tree is straight from all sides.Remember to remove all burlap, twine and the wire basket (if present) from the tree before planting.
  • Gently backfill the hole while keeping the tree level. Pack soil firmly to eliminate air pockets which can dry out roots. If the tree is in an area where wind is a concern, staking may be necessary.
  • Provide a 2"-4" layer of mulch around the base of the tree, taking care to avoid packing mulch against the trunk.
  • Water the tree at least weekly - more frequently in extremely hot temperatures.
  • Watch the tree for signs of distress; if the tree exhibits signs of distress, contact your retailer or a certified aborist.
  • For additional information on proper tree planting techniques, visit the Virginia Department of Forestry.

Certain tree species are more tolerant and adaptable than others, but planting a tree in the proper location helps promote tree health and longevity. Many trees can tolerate of harsh conditions that make them tolerant to the urban environment. For an extensive list of common native and ornamental trees and their specific environmental requirements and tolerances, see the Public Facilities Manual Table 12.19. You may also wish to visit the Virginia Department of Forestry.

When buying a high-quality tree, look for sturdy trees with strong branches, uniform shape and a root ball without torn roots. Avoid trees with obvious wounds and that have been improperly pruned. Branches should be evenly spaced and be solidly attached to the trunk. For best results, choose a nursery with a solid reputation and one which offers a guarantee of the tree after planting.

A hazardous tree is a tree, or a portion of a tree, that is in danger of falling and presents a threat to life or property. Sometimes the hazard posed by a tree is obvious, such as when a tree is in visibly poor health or leaning precariously. Other times, serious conditions may exist that are not as obvious to the casual observer. The following are some conditions that may indicate a serious problem exists that may create a hazard to the surrounding environment.

  • Dead branches in the tree or on the ground near the tree.
  • Mushrooms near the base of the tree.
  • Excessive leaf loss or dead leaves in the crown (the upper portion) of the tree.
  • Areas of rotten wood or cavities.
  • Nearby trees have died or have significant damage.
  • Noticeable change in the leaning of the tree.
  • Damage to the ground surrounding the tree from construction, erosion or storms.

Additional information on hazardous trees can be found at the USDA Forest Service.

If you are concerned about a hazardous tree situation, please consider the following options first.

  • If a tree presents an immediate life-threatening hazard, including falling onto electric wires or it is blocking a public road, call 9-1-1.
  • If there is a tree fallen across utility lines, please call the appropriate electrical company, such as Dominion Power, 1-888-667-3000, TTY 1-800-522-4015, or NOVEC, 703-335-0500 or 1-888-335-0500, TTY 711.
  • Stay away and never attempt to approach or touch trees or limbs that contact power lines, as they are considered extremely dangerous.

The responsibility for hazardous trees on public property generally lies with the agency that owns or maintains the property. The following links contain contact information for hazardous trees on public and private property.

Use the tax assessment tool. As long as you know the address or the unique parcel identifier (PIN) number of the property you have a question about, then you can find out the ownership.

Using proper pruning techniques is extremely important to the long-term health and viability of trees. Always use clean, sharp tools when making cuts. Pruning is best accomplished during the tree's dormant season before new growth begins. Pruning of young trees should be aimed at establishing a healthy growth pattern for the new tree. Pruning of mature trees is best limited to removal of dead or hazardous limbs. Topping a tree is NOT proper pruning, and is not conducive to the long-term health of the tree. See below for information on why topping is bad for a tree. For more information on how to properly prune a tree, you may also visit the Virginia Department of Forestry.

"Topping" of trees is perhaps the most harmful pruning practice known. By removing a large portion of the tree's upper leaves, new problems can be created. Topped trees are more likely to suffer from stress and become vulnerable to sun damage, insects, disease and storms. If you have a tree that has grown too large, there are ways to correctly prune to reduce the tree crown without damaging the health of the tree. The rapid re-growth of shoots on a topped tree is an indication of stress and a weakened state of health. For appropriate methods to reduce the height or spread of a tree, an arborist can determine the best approach to pruning to preserve the tree's natural beauty, health and safety for the surrounding environment.

Trees and grass are healthier when they are not forced to compete with each other. Both provide benefits to the environment, but when placed next to each other can result in problems to both species. Grass at the base of a tree is often weak and thin. The shade provided by the tree is not suitable for many types of grasses. In addition, the roots of the tree, which are closer to the surface, can disrupt the growth pattern of grasses. In return, grasses take away many nutrients and much needed moisture, causing trees to weaken and produce poor growth. Trees may also be damaged by lawn equipment, causing wounds that allow disease and insects a point of entry. The best approach is generally to allow a mulched area around the perimeter of the drip line of the tree. This keeps grass from competing with the tree for vital nutrients and moisture and reduces likelihood of damage to both species.

Proper mulching helps maintain moisture in dry summer months, reduces weeds that draw away necessary nutrients, acts as an insulation against extreme heat and cold, and provides an aesthetically pleasing base for landscaping. Improper mulching, however, can be the cause of stress and decline in a tree. For instance, mulch that is too deep and piled high against the trunk of a tree may actually prevent the tree from receiving adequate amounts of oxygen and water, cause excessive moisture to be retained causing roots to rot, and may harbor insects and other pests. Mulch should generally be applied in a 2"-4" layer around the base of the tree, extending outward towards the dripline. Avoid mulching directly against the base of the tree; allow several inches between the base of the tree and the surrounding mulch. Whenever possible, use organic mulches to provide beneficial nutrients.

A healthy tree has many built-in methods of resisting normal insect and disease invasions. A tree may become stressed from physical changes in the root zone or from other environmental factors that affect the basic requirements of the tree, including light, oxygen to the roots, water and the balance of essential nutrients. A stressed tree then becomes more vulnerable and unable to sustain the needed resistance to insect and disease invasion. Identifying causes of tree stress and mitigating them early can help a tree to resist or fight harmful agents. A certified tree professional can identify causes of stress and make recommendations to mitigate the stressful situation, and detail any treatments. For more information on identifying common insect and disease symptoms in trees visit the Virginia Department of Forestry.

In general, there are no laws or regulations in Virginia that prohibit you from removing individual trees on your own property.  Some specific regulations, however, might impact your property:

  • If your property is a part of a homeowners association, restrictions on the removal of vegetation may apply.  Contact your homeowners association, if applicable, to determine whether restrictions apply.
  • Harvesting of timber on your property is regulated by the Virginia Department of Forestry.
  • Any land disturbing activity, such as removing trees and stumps, on more than 2,500 square feet of your property requires a permit from Fairfax County.
  • There may be restrictions for the removal of trees used to meet certain Zoning Ordinance requirements such as transitional screening or parking lot landscaping.
  • There may be environmental restrictions on your property.

In Fairfax County, some areas on private property may be designated as Resource Protection Areas (RPA) or conservation easements.  In general, you are permitted to remove trees that are dead, dying or diseased in these areas, provided you remove them by hand and replace them with similar vegetation. In these situations, contact the Customer & Technical Support Center at 703?222?0801 (Option 1), TTY 711.  A County representative will evaluate the tree(s) and determine whether the criteria for removal is met, and then provide recommendations for replacement.

  • If you want to remove a healthy tree(s) from a conservation easement, you would need to be sure of the restrictions specific to your conservation easement.  This information should be available in your property records.
  • Removing healthy vegetation in the RPA should follow the process noted above.  The Chesapeake Bay Preservation Ordinance provides information about tree removal restrictions in these areas.

To find out if there is a RPA on your property, use the Fairfax County Digital Map Viewer and select the Chesapeake Bay Preservation Area map series.

If you believe that your neighbor is removing trees or disturbing land illegally, visit the Reporting Land Development Concerns page for information on how to report such activities.

There are many tree removal contractors and arborists working in our area. An arborist is a specialist in the care of trees.  A certified arborist is an experienced professional who has passed an extensive industry-approved examination covering all aspects of tree care. Certified arborists must continue their education to maintain their certification, so they are more likely to be up to date on the latest arboricultural standards and techniques. Keep in mind that good arborists will only perform accepted arboricultural practices. For instance, topping trees is not an industry accepted practice and you should be wary of any arborist who advertises such services.

The condition of your trees can have a significant affect on the value and safety of your property.  Therefore, it is in your best interest to be an informed consumer when seeking the services of an arborist. Find out how to hire an arborist.

Fall cankerworms feed on a wide range of hardwoods and favors maples, ash, oaks, hickories, beech and cherries.  All of these are found in abundance throughout Fairfax County.

Adult moths begin emerging from the ground in late November, usually following a hard freeze. The wingless female moth climbs a nearby tree to mate and deposit her eggs.

The fall cankerworm program follows an integrated pest management approach which includes strict monitoring of insect populations prior to treatment. The most reliable sampling method for estimating cankerworm populations uses the monitoring bands that are recommended by the U.S. Forest Service. Beginning in mid-November, urban foresters set-up monitoring band stations.

The trees selected for a monitoring band are wrapped with a narrow piece of tar paper and taped to the tree. A tacky, weather resistant gel called Tanglefoot® is applied to the tarpaper.  The gel entraps the female moths as they climb the tree.  From December through mid-January, the monitoring bands are checked weekly and the female moths are counted and removed. 

Trap counts of 90 or more per band indicate a high cankerworm population and probable defoliation.

Monitoring for fall cankerworm takes place in late fall, towards the end of November, and lasts through early January.  Once the survey bands are in place they are monitored once a week.  Approximately seven percent of staff time is spent on monitoring for fall cankerworm during the Forest Pest Management Branch’s annual cycle.

If surveys indicate that a suppression program is needed for fall cankerworm, staff time increases considerably.  Approximately 15 to 20 percent of staff time can be spent preparing for and conducting a suppression program for fall cankerworm.

Although high cankerworm populations in forested residential and recreation areas can cause severe nuisance issues, alleviating the nuisance is not a factor in determining whether there is going to be a spray program or where the treatment areas are going to be located. The alleviation of the nuisance is a secondary benefit of the suppression program.  The primary goal of the treatment program is to bring the pest population down to a level where defoliation of the trees will not occur. Please note, the cankerworm suppression program is completely voluntary.

Tree weakened by repeated defoliations may be more susceptible to secondary pests.  It is difficult to determine how many trees in Fairfax County have died due to cankerworm.   The Forest Pest Management Branch has been very successful in achieving the goal of preventing cankerworm defoliation and the resulting possible tree decline and mortality.

Fall cankerworm is a spring defoliator of hardwood trees.  Typically, trees defoliated early in the season will re-leaf by mid-summer and suffer only moderated growth loss.  Successive defoliations combined with other environmental stressors commonly found in an urban/suburban environment may lead to dieback and eventual death.

Fairfax County’s Tree Action Plan (TAP) is a 20-year strategic plan to conserve and manage the county’s urban forests.  The TAP does not address any specific forest pests by name, other than to cite two examples of exotic forest pests.  One of the core recommendations of the plan is to use ecosystem management to improve and sustain the health and diversity of the urban forest.  A key strategy to accomplish this goal is to implement a comprehensive and proactive forest pest and invasive species management program.  It is essential that the Forest Pest Program identify forest insect pests and diseases and formulate control strategies to minimize their effects.

All pesticides must go through an exhaustive review process conducted by the U.S. Environmental Protection Agency (EPA) before they are registered for use in the United States.  As part of the review, the impacts that a pesticide may have on humans and non-target organisms, an organism which may be unintentionally affected by a pesticide, is examined thoroughly.  In addition, Bacillus thuringiensis (Bt) has been extensively studied for use in forested and residential forested areas primarily as it pertains to the control of the gypsy moth caterpillar.  Below are inks to Bt studies as it pertains to non-target organisms:  

http://www.bt.ucsd.edu/bt_history.html
http://www.fs.fed.us/foresthealth/technology/pdfs/btmanage.pdf
http://www.fs.fed.us/foresthealth/technology/pdfs/BtkNontargetStudy_v7.pdf
http://na.fs.fed.us/pubs/misc/seis/gm_ineviron_impact_statemnt_draft.pdf

A property owner or resident can set-up monitoring sticky bands around their property in the fall and winter. This can provide for moderate control of fall cankerworm in small areas. This is not an efficient method of control in forested or forested-residential situations as the bands serve primarily as a population monitoring tool.

Sticky banding is used to capture crawling insects.  It is comprised of a strip of tar paper or plastic that is wrapped around a tree trunk and covered with a sticky glue called Tanglefoot. It is used to monitor insect populations and can also reduce the number of pest insects on individual trees.

Fall cankerworm (Alsophila pometaria) is a native insect found throughout much of North America.  It feeds on the leaves of a variety of hardwood trees including oaks, maples, elms and ash.

Any crawling insect or small organism that happens to land on the sticky area of the trunk has the potential to be caught including male and female fall cankerworms.  However, the period when fall cankerworms are active is a low activity time for most other insects.

Tanglefoot is a very sticky, non-drying glue which forms a barrier against crawling insects.  It can be messy and will permanently stain fabrics that it comes into contact with.  It is important not to apply the Tanglefoot directly to tree trunks because it can cause permanent staining.

Tree bands should be installed in early to mid-Dec., right after the first hard freeze and once all leaves have fallen from trees.

Tree banding is a pesticide-free, easy method of insect monitoring and a limited control technique. It captures the female fall cankerworm as they crawl up the trunk and reduces the number of eggs laid on a tree. This can lessen the degree of defoliation on a banded tree from the cankerworm caterpillars in the spring. As a result it is a good option for managing small areas such as individual homeowner properties.

The band should be removed a month after putting up the trap. How to remove the bands.

More questions?  Watch our slideshare presentation on fall cankerworm banding or contact the Forest Pest Branch at 703-324-5304, TTY 711, or via email.