Swenson: Don’t Just Hug Your Trees, Water Them!

Courtesy/Richard Swenson
Retired farmer, physicist and metal sculptor
Los Alamos

Many of our trees in town are dying due to the lack of moisture and nutrients, shorter and milder winters, and longer and hotter summers. This combination gives the beetles an advantage in the age-old battle between the beetles and the trees. Let’s water the trees and help the trees defeat the beetles!

Global warming is real and it is not going away. We need to recognize and mitigate its short-term effects and accommodate its long-term climate change. The temperature in Northern New Mexico has gone up 2.5⁰F since 1971 and is predicted to rise an additional 4⁰F to 6⁰F by the end of the century. Global land temperature has risen over 2⁰F and the ocean temperature 1⁰F. Thus, we can expect hotter and drier weather in Los Alamos in the near future and coming years.

In the beginning, i.e., during the Manhattan Project, non-indigenous people were lured into this niche of utopian environmental condition in the New Mexico desert. The moderate winters and monsoon-watered summers supported great outdoor activities such as skiing and hiking.  This city is also nourished by a very generous aquifer. Gradually and thus unnoticeably, these conditions have changed due to global warming. Many of us are not aware of this subtle change or what is to come. Our dying trees are a harbinger of this change. We should recognize it, quantify it, and accommodate it.

Many of our residents do not recognize the severity of this drought and are relying on their watering system to provide moisture to the trees or are blissfully waiting for the monsoon rains.  We can mitigate the loss of our residential trees by watering them now. A pine tree requires approximately 400 gallons of water per month, i.e., about 2 inches of rain. 

My hose/sprinkler delivers about 10 gallons per minute, thus 5 minutes would water approx. 300 square feet? with 50 gallons of water. I water my trees twice a week to supplement my minimal in-ground water system and can focus explicitly on the trees. My trees are healthy. At my water rate of 0.55 cents per gallon, the cost is approximately $2 a tree. The cost of cutting and disposing a dead tree is $800 – $1,500. Hopefully the monsoon rains will alleviate watering but don’t let small showers fool you. The ground is exceedingly dry.

According to the Long-Range Water Supply Plan that Los Alamos County published in October 2017, the County has legal rights to 5,541 acre feet (ac-ft). of ground water. In 2016, the County used 3,700 ac-ft., leaving a margin of 1,841 ac-ft. or about 600 million gallons. Residential water use is 57%, commercial 11% and the lab 27%. A legitimate use of some of this water would be to water our residential trees and help keeping our city green in this drought period.

The per capita water use in Los Alamos is 144 gallons per day in 2016, as compared to the national average of 100 gallons/day. This difference would be expected in our arid community. Our aquifer is dropping about one ft a year, depending on the well.  However, due to the magnitude of the aquifer, the Los Alamos County Department of Public Utilities predicts adequate ground water supplies well into the future.

To accommodate long-term climate change, we will need to landscape our yards to more desert conditions and more moisture-tolerant vegetations. Winter conditions will be significantly affected as they were in 2012 and this past year. The good news is that we will not be directly concerned about the sea level raising. Please water your trees and tie a ribbon on them to show your good deed.

Note: The numbers cited in this article can be found in the Long-Range Water Supply Plan, Los Alamos County and NOAA Reports.