Impacts of Tamarisk

 Impacts of Tamarisk:

Tamarisk, also known as Saltcedar, is a small multi-stemmed tree with origins in eastern Asia, northern Africa, and southern Europe. They can reach up to 20ft tall and form very dense thickets. There are 5 species and hybrids between species, but are lumped together as Tamarix sp. for management purposes. 

The impacts of tamarisk on the landscape include:

Accessing more water through deep taproots

• Tamarisk roots reach further and deeper compared to native trees and shrubs
• This allows tamarisk to persist and thrive in prolonged drought

Using high rates of water

• Tamarisk use water at a high rate for growth
• This high water use in combination with the deep-reaching taproots has the effect of drying up the stream or floodplain

Crowding out native vegetation

• Tamarisk reproduces by seed and by cuttings very quickly, which results in dense thickets
• Tamarisk thickets block the sun from native species that would otherwise be germinating and growing

Increasing fire frequency and severity

• The dense tamarisk thickets are more fire-prone due to more continuous plant material as fuel
• Native trees and shrubs in riparian areas recover more slowly post-fire, so tamarisk re-sprouts and recolonizes in another dense monoculture stand
• Tamarisk leaves are more flammable compared to native tree and shrub leaves

Decreasing diversity and complexity in riparian systems

• When tamarisk is the only species making up the vegetation in a river corridor, the habitat becomes one-dimensional and lacks diversity for all organisms

Degrading wildlife habitat

• With a simplified vegetation makeup, the food web associated with that vegetation is also simplified, leading to a decrease in wildlife habitat quality

Channelizing banks

• Tamarisk colonizes in tight thickets and armors riverbanks that would normally participate in erosion and deposition events
• Erosion occurs on the riverbed instead of the banks, which drops the river level and lowers the level of water in the floodplain (also referred to as incising)
• As a result, the surrounding vegetation changes from wetlands and meadows to dry shrublands

Identifying Characteristics of Tamarisk: 

Leaves: Tamarisk leaves are very small, tapering to a point, and strongly overlap each other. The leaves are deciduous and drop every fall. Leaves contain salt glands that collect and secrete salts. 

Stems: Tamarisk is a multi-stemmed small tree/large shrub. Branches are reddish in color and have triangular buds along the young stems. Cut stems will vigorously resprout. 

Flowers: Flowers are found on the ends of branches and are clusters of small pink or white. 

Seeds: Seeds are housed in a small capsule fruit, and are very small and hairy. Mature trees can produce up to 500,000 seeds per year. These seeds are dispersed primarily by wind and water, and typically germinate within 24 hours of contact with water.

Roots: Strong taproots grow upwards of 15 feet down. Once in contact with the water table, lateral roots branch and extend several feet outwards.