Saltcedar has some positive effects on the ecosystems it has colonized. Its roots stabilize stream banks and it can remove salts from soils. Saltcedar also provides shade, forage for bees and livestock, and firewood.

The same characteristics that make saltcedar valuable also make it a problem. When the extensive roots stabilize a stream, the channel narrows and deepens, sediments are deposited, and water flow increases. This can lead to flooding.

This plant's name comes from its ability to tolerate saline soils. It has special glands on the leaves and young stems that accumulate and release salts, which eventually end up on the soil under the plant. These salts can prevent other species from growing, reducing the diversity of plants and animals.

Saltcedar is better adapted to fire than the native species it replaces. This allows saltcedar to replace cottonwood, willows, and mequite after wildfires. Areas infested with saltcedar burn more frequently, perhaps because saltcedar is more flammable than native vegetation.

Saltcedar is a serious problem in the southwest, where water is scarce, because it uses very large amounts of water. A full grown tree can use up to 300 gallons of water per day. This species can lower the water table and dry up springs, pools, and small streams.