Water Conserving Benefits of Trees

Determining Landscape NeedsBecause there are so many different types of trees from which to choose, you can select varieties specifically suited to your needs. First identify exactly what function you want your tree to serve. Trees may be used for shade, ornament, screens, reduction of wind and noise, and to shelter wildlife or provide edible fruit and nuts. The intended purpose will influence your selection criteria of planting site, shape, size, type of foliage, and other physical characteristics.

Shade - Providing shade usually requires tall, sturdy, long-living species. Density of foliage and shape determines the amount of shading a tree will provide. Be aware that some trees produce a very dense shade that will prevent grass from growing since grass requires abundant light. Trees such as Green Ash (Fraxinus pennsylvanica) or Little Leaf Linden (Tilia cordata) provide ample shade, while trees like Thornless Honeylocust (Gledetsia triacanthos inermis) cast a much lighter shade and is more compatible with turf.

Size - Consider the growth habit of the tree. Evaluate the size of the tree when mature and where it is to be used. Tall-growing trees, such as the Blue Spruce (Picea pungens) and Chinkapin Oak (Quercus muehlenbergii) are suitable for two-story and larger buildings. However, they tend to dominate the low flat appearance of -- or even hide -- one-story buildings. For attractive and proper balance with one-story buildings, trees that do not grow over 35 feet are better scaled and require less water. Trees can rarely be kept small by pruning, and to do so requires intensive maintenance and makes trees more susceptible to insects and disease. For trees that are 35 feet or smaller, consider planting the Lacebark Elm (Ulmus parvifolia) or Bigtooth Maple (Acer grandidentatum). Careful consideration of mature sizes will reduce the need for pruning.

Selecting the SiteWhen planting trees consider not only what time of year you will be using the space, but what time of day as well.

Tree ConsiderationsMay/June

EventsDaviD Salman

DiScuSSeS Rock GaRDeninG

(GRowinG in Tuff )Salman with Santa Fe

Green House will discuss how to successfully grow plants in tuff or volcanic

ash deposits Thur., May 17th,

7 PM at Fuller Lodge 2132 Central

Los Alamos, NM (505) 662-2656

BeRnD leinaueR’S efficienT TuRf

woRkShopAttend this one day

hands-on workshop about strategies to efficiently irrigate turfgrass with

turf specialist Bernd Leinauer Fri., June 15th,

9AM - 12 PM at the Los Alamos Golf Course

(505) 662-2656

This month’s newsletter is dedicated to trees. An essential element to the waterwise garden, trees offer aesthetic and practical benefits alike. Visually they anchor the landscape design and provide vertical contrast to smaller plants. For water conserving purposes, they reduce heat and evaporation by shading the soil and blocking the wind. Moreover, they provide shade to cool homes, reducing energy and evaporative cooler water use.

However, before going to the garden center or nursery, homeowners should do their homework. Like turf, trees are major water users in the landscape. Proper consideration of landscape needs, examining planting sites, and obtaining pertinent information

on plant materials are crucial to long term success and prudent use of water resources in the garden. Some important plant characteristics are size, hardiness, susceptibility to insects and diseases, and soil and water requirements. The following is offered to assist in making proper choices when considering the addition of trees to the landscape.

Carlos Valdez, Horticulture AgentCooperative Extension Service(505) 662-2656 http://www.l o s a l a m o s e x t e n s i o n . n m s u . e d u

Department of Public Utilities,(505) 662-8130 http://www.losalamosnm.us

Water Conserving Benefits of Trees

This IssueWater Conserving Benefits of TreesTree Considerations

Determining Land-scape NeedsSelecting the SiteNeeds of the TreeWater Needs

Plant of the Month

Drought Outlook

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MAY 2007 WG05-07-JWH

Photo: Robert Villegas, CanyonEcho Graphics, Los Alamos, NM 2006

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Summer Shade - Determine from sketches and observation where the tree should be for maximum summer shade. Then check the shade movement of this spot. Use a long stake or board and fix it at the selected point. Watch the shadows to determine if they coincide with your plans.

Location to Maximize Water - If possible, plant new trees in valleys and/or depressions in the landscape so rainwater will naturally collect and give the tree a good soaking.

Avoid Sites Near Utilities -Determine location of overhead and underground utility lines. Remember, trees are more than just what you see overhead. Often, the root area becomes larger than the branch spread above ground. Please call New Mexico One Call at 1-800-321-ALERT (2537) before you begin to dig. The location of these facilities should directly correlate to your choices of tree type and site selection.

Needs of the TreeOnce you have determined placement of the tree, you must evaluate what you have to offer it. Additional site characteristics that should be reviewed include the space available, the environment, soil conditions, and potential pests. Consider both the size and the shape of the available space and how that will change as the tree matures.

Environmental characteristics include extreme heat or cold, drought, exposure to wind and street-side pollution. Soil pH, drainage, and depth are all factors to consider when selecting trees. Most trees will require a minimum of 18-24” of well drained soil. Soils with high salinity, low fertility, or toxic pollutants will limit tree selection. Potential pests include insects, diseases, mammals like deer and rabbits. The likelihood of future wildfires should also be a consideration. Coniferous evergreens burn hotter and longer. Use the information about your site to select a species or variety that is well suited to the challenges to which it will be subjected.

Consider how much maintenance the plant will require and any possible disadvantages. Fast growing trees such as poplars and willows, although providing quick shade, are short-lived, have brittle wood that is easily damaged by wind and ice and use a

great deal of water. Fruits and seeds that are large, messy, smelly, or otherwise obnoxious should not be selected for use in lawns or

near patios and decks. Also consider abundant shedding of twigs and small branches, allergenic or poisonous parts, thorns, weediness, longevity, etc. Finally, strive for diversity. A diverse urban forest will lessen the impacts of disease and insect epidemics such as the recent pine bark beetle outbreak.

Water NeedsNewly Planted Trees- Irrigate newly planted trees at the base, making sure to wet the entire

root ball area. Water as needed, perhaps as often as twice a week during the first growing season. Young trees (up to two years after planting) should continue to be watered at the base, but the diameter of the zone of wetted soil should expand outward as the tree grows. Check the soil periodically to see if it is dry; allow the soil to dry moderately between waterings.

Watering Established Trees- Established trees should not be watered at the trunk. Instead irrigate from the drip line (the edge of the tree’s leaves) outward. The distance will depend upon the size of the tree and the nature of the tree’s root system. As a basic rule of thumb, apply water in a circular band that’s at least half as wide as the distance from the trunk to the drip line.

Trees prefer to be watered slowly and deeply. Watering trees deeply, but less often will keep roots from surfacing and make them less susceptible to mechanical damage from lawn mowers and weed-whackers. Use a bubbler, multiple drip emitters, or a hand-held hose to deliver water to the tree’s root zone. Moisten the soil about 18 inches deep each time you water, and let the surface dry between waterings. Water established trees once every two weeks during the growing season, and once a month during the dormant season.

Plant of the Month

New Mexico State University is an equal opportunity, affirmative action employer and educator. NMSU, the U.S. Department of Agriculture and Los Alamos County cooperating.

Western Bigtooth Maple Tree (Acer grandidentatum)Vermonters may boast, but for landscape color as dazzling as a sunset just look in our own backyard - the Bigtooth Maple of the mountain west is imposing in all seasons but its autumn coloration is spectacular. The color variation is genetically determined. In early September the maples begin to change colors. The color variation from one tree to the next is quite striking. They’re not really bushes, but neither would one consider them trees according to the standard of the Eastern hardwood forests. These natives of the intermountain states grow to heights ranging from 20 to 25 feet with trunks 9 inches in diameter. The height variation depends on soil conditions and available moisture. So what if a Vermonter would scoff at our maples -- things are different west of the Mississippi.

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Shade patterns of a 20-foot tree during summer.

Released April 19, 2007 Author: David Miskus, JAWF/CPC/NOAA

U.S. Drought Monitor

The Drought Monitor focuses on broad-scale conditions. Local conditions may vary. Visit http://drought.unl.edu/dm for additional text summary for forecast statements.

NMAZ

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UTNV

http://www.drought.unl.edu/dm/DM_west.htmIntensity:

D1 Drought - ModerateD2 Drought - Severe

D0 Abnormally Dry

D3 Drought - ExtremeD4 Drought - Exceptional