Investigating the impacts of recycled water on a long-lived conifer

Coast redwoods planted in lawn within an urban landscape. (Photo credit LL Nackley)
Coast redwoods planted in lawn within an urban landscape. (Photo credit LL Nackley)

Recycled wastewater is a popular alternative water resource. Although typical salt contents in recycled water are low (< 2.0 dS m-1), levels may still be harmful to salt-sensitive plants. The results of a new study published in AoB PLANTS by Nackley et al. have direct implications for public and private institutions seeking to conserve water by irrigating landscapes with recycled (a.k.a. reclaimed) water. The authors discovered that salt accumulation in soils would negatively impact coast redwoods (Sequoia sempervirens) when recycled water salinity exceeds 1.0 dS m-1. This is the first paper reporting the impacts of salinity on the growth of the coast redwood, an important agricultural, horticultural, and ecological species. The results suggest that irrigation management of long-lived conifers will be essential to protect these important trees.