Trees and the Drought

The record drought over the last two years has taken a toll on our water resources. With Lake Travis at its third lowest level since Mansfield Dam was constructed in 1941 and the City implementing Stage II Water Restrictions, water conservation is on every one's mind. Whether to save money or save the environment, many Austin area residents are watering less and letting their lawns and landscape decline. However, it is important to remember that these good intentions can have detrimental effects on our urban forest. It is one thing to replace your lawn or landscape, it is another thing entirely to lose a 200 year old live oak. As an aware citizenry, we can ensure that our urban forest continues to prosper and thrive for future Austinites!

The City's Watershed Protection Department is urging residents to be mindful of tree health until the rain starts falling again. Here are a few tips from the City Arborist's Office (or read the entire release):

• Focus on watering more mature trees, very young trees, trees suffering from pests or disease, or any trees showing signs of stress.
  
• Look for signs of stress and decline such as leaves wilting, turning brown, or dropping early or branches dying
• How often? Water at least every two weeks, without significant rainfall.
• When? To limit the amount water lost to evaporation, water between 7 pm and 7 am.
• How much? In general, for each inch of trunk diameter (width across at knee height) the tree needs about 10 gallons of water. So, for a 20" tree, you will need to water 20 x 10 = 200 gal.
• You can determine your application rate by turning on your hose at a given pressure, then timing how long it takes to fill an empty 1 gallon milk jug. Multiply this time by the number of gallons and Viola! that's how long you need to have your hose on.
• OR, in general a hose at medium pressure will produce 10 gallons in 5 minutes. So, for your 20" tree you will need to water 20" x 5 = 100 minutes or 1 hour 40 min.
• Slower application rates are better because the water is able to infiltrate into the soil and be absorbed by the tree roots rather than running off.
• Don't forget to set a timer or some other reminder to avoid over watering and water waste.
• Where? Water under the tree's entire canopy (within the drip line) and avoid watering within 3' of the trunk. Root systems of very young trees (two yrs and less) are not yet developed, so water in the planing area.
• A 3-4" layer of hardwood mulch around your trees insulates the roots from the extreme heat and also retains water. Be sure to keep the mulch at least 6" away from the trunk of the tree to avoid moisture in constant contact with the trunk.
• And remember, be sure to follow the City's Stage II Water Restrictions or you could be handed a citation with a hefty fine!

If you run across problems watering your trees or you just need someone that keep track of a watering schedule, just contact me and I'd be glad to help out!

Happy Gardening and Watch our for your Trees!