By Nebraska Today
Though planting the eastern redcedar tree in grasslands often began as an effort to establish windbreaks against dangerous gusts and detrimental erosion, the woody vegetation has since spread well beyond those shelterbelt origins. In the past 20 years, Nebraska has seen the planting and expansion of more eastern redcedar than almost any other state. Even the Nebraska Sandhills, a semiarid region once thought too dry for eastern redcedar, has experienced a 30-fold increase in the tree’s presence over the past two decades.
Much of the concern over redcedar encroachment stems from the fact that it transforms native wildlife habitat, reduces the forage on which livestock depends, and multiplies the risks of uncontrollable wildfire. Less attention has focused on how the encroachment of eastern redcedar — whose thirsty roots may plunge as deep as 25 feet — could curb the quantity and possibly the quality of Nebraska’s water.
Relying on a combination of historical water data and model-based simulations, Nebraska’s DWFI Faculty Fellow Aaron Mittelstet and five Husker colleagues, including DWFI Faculty Fellows Tirthankar Roy and Troy Gilmore, examined how further redcedar encroachment in the Sandhills might influence the state’s future water supply.
The team found that if redcedar coverage increased, it could have negative impacts through reduced streamflow, as well as an increase of nitrate and atrazine concentrations in the Platte River.
Integrating another model, this one better at simulating groundwater, could improve estimates of just how redcedar encroachment might alter both that groundwater and thousands of lakes in the Sandhills. And future studies should try to account for factors introduced by climate change, the researchers said. But the findings represent yet another warning against allowing eastern redcedar to continue spreading, the team said — and another impetus for halting that spread before doing so becomes logistically and financially impossible.