Always be on the look out for damage to your tree, insect problems or disease. Since you walk by the tree everyday, you are the one best suited to monitor its health.

If you need to report a diseased, dying, or dead tree, or if you need to report dangerous or fallen branches, make your request immediately to the Citywide Call Center at (202) 727-1000. You can also make your request online.

Insects and Disease
If you see a lot of bugs, eggs, chewed up leaves, or spotted leaves, call please D.C. Greenworks for help.

In particular, please keep an eye out for:

• Dutch elm disease: Look for wilting elm leaves that turn yellow, then brown. The wilting can occur in late spring or summer, and the most affected leaves will usually be at the ends of large branches.
  
  Dutch elm disease has already killed a significant number of the American elm trees in D.C., and it still threatens those that have survived this long. Luckily, elm varieties resistant to the disease are now being planted throughout the District.
• Bacterial leaf scorch: Look for leaves that have brown sections along their edges with a yellowish border between the green and scorched leaf tissue. Symptoms will appear in summer or early fall.
  
  This bacterial disease affects American elms, sycamores, mulberries, and most maple and oak species.
• Anthracnose diseases (sometimes called leaf blight): Look for leaves with dead areas that are black, brown or purple in color. The dead sections may range in size from tiny spots to large blotches, and these dead areas may merge until the whole leaf dies.

These diseases are caused by fungi and attack many species, including maples, oaks, elms, sycamores and ashes. On infected oaks and sycamores, the fungi may also cause damage to the twigs and buds.

Staking
Street trees do not usually need staking. In fact, staking a tree can do more harm than good, and most tree companies no longer stake their trees for this reason. Trees will develop stronger branches and trunks if they grow up learning to adapt to wind.

Staking not only spoils the tree and produces weak wood, but when left on too long, staking wires will damage the bark and girdle your tree. If you see any street trees in your neighborhood with stakes and wires wrapped around their trunks, please remove the wires right away.

Fertilizing
Street trees usually DO NOT need fertilizer. In fact, fertilizer from a garden store often does more harm than good. Street trees need to be ultra-tough to survive sidewalk traffic, cars, pollution and road salt. If the soil is too fertile, street trees will get spoiled, producing weak wood and attracting pests.

The best thing you can give your tree to help it get the nutrition it needs to survive harsh city living is mycorrhizae (my-ko-rye-zay). Mycorrhizae is a harmless soil fungus that lives naturally in healthy forests, and it helps tree roots absorb minerals and water from the soil. The soil in most tree pits tends to be very poor and therefore does not have any mycorrhizae living in it. By adding mycorrhizae to the soil, you will help restore the natural balance that trees need to survive.

Tree Saver® is one common brand of mycorrhizae. It comes in a small packet with enough fungus for one tree. Spread the black powder evenly over the bare, weeded soil in your tree pit. Then use a trowel or garden fork to carefully scratch the powder into the first inch or two of soil, avoiding any tree roots. Follow by spreading mulch and watering.