Many southwestern communities in the Mountain West are looking at importing specific kinds of trees in the battle against extreme heat. What they learn could be a model for other communities in our region.
鈥淭his is Maverick, he鈥檚 a Canadian Goose鈥� said Tara Pike, pointing to one of many animals at her All Friends Animal Sanctuary, a petting zoo in a Las Vegas residential area.
She went on to list the variety of animals at the sanctuary which includes cows, pigs...
All Friends Animal Sanctuary has just about every living thing 鈥� except trees.
But that changed when the sanctuary received its first trees during the Clark County giveaways. She received the first one during last year鈥檚 fall giveaway and another during the county鈥檚 spring giveaway this year. And Pike has applied for a grant to get 30 more.
鈥淵eah it鈥檒l be gorgeous when all these trees and once they get big,鈥� she said.
There is a concerted effort across cities in the southwest to plant more trees.
For example, Phoenix has launched a initiative. And Albuquerque has a program.
Las Vegas has plans to plant nearly 60,000 new trees by 2050.
That means the urban-desert landscape could change significantly in the next 50 years 鈥� as the city moves away from palm trees and cacti 鈥� to trees that provide shade, can survive harsh summer heat and winter freezes as well.
Brad Daseler is the city of Las Vegas鈥� Urban Forester. While walking through the city鈥檚 nursery, he described the diversity of trees.
鈥淏ehind you, we have a Burr Oak. So those would be trees that we would use more in our park spaces,鈥� he said.
Aside from well known desert trees like the Palo Verde and Mesquite, the city is also looking at a variety of trees that can survive the desert climate.
Looking at the Indian Rosewood tree, Daseler said: 鈥淲e would think about being more adaptable to our streetscapes and parking lots on streets where they're surrounded by asphalt and concrete and all this heat load that not every tree is prepared to deal with.鈥�
The city is also looking to other parts of the world for trees that may be good candidates to withstand the challenging environment.
鈥淲e have a variety of eucalyptus trees here that are incredibly tough and tolerant of the heat...and obviously those are predominantly from Australia.鈥�
And, the nursery is training trees to adapt by getting used to using less water.
鈥淪o that's the elm tree. Not native to here,鈥� he said. I would probably put it in like a turf grass park type situation. Something a little bit softer, like a little bit cooler."
When asked if temperature, location and other factors are important, Daseler replied:
鈥淎bsolutely, I think there's a lot of nuance in making the correct decision with tree planting.鈥�
He continued by explaining what can happen if the wrong tree is planted in the wrong place.
鈥淚t kinda stifles its growth. There's no benefit to the citizens, there's no benefit to the community. We have to get that part of it right and then give it the time to mature and grow.鈥�
How do trees cool the air?
Cayenne Ingel, a scientist with the , says there鈥檚 a lot going on in a tree. She explains that trees help cool the environment through their own evaporative cooling process.
鈥淪o just like a swamp cooler, trees will release water through the leaves and through that process, just like sweat from your skin鈥揧ou feel the evaporative cooling,鈥� she said.
But, Ingel points out that these trees can also struggle in extreme heat.
鈥�A lot of trees in our urban arid environments are shutting down their mechanisms during the day and doing the work at night. So we actually are getting less daytime cooling.鈥�
So scientists are studying the qualities in trees that can be leveraged for cooling, down to the diameter of the leaves.
鈥淲e have a little project this summer that we call the Leaf Area Index. So it looks at the overlap of leaves throughout a canopy. And which trees have a greater complete leaf coverage and which have less.鈥�
And, if arid environments reduce evaporization, what more can be done?
There is a study in Tucson that looked into the distribution of trees throughout the city. Their placement is key as they compare an even distribution vs. clusters. Distributed, 鈥渢hey may have a greater effect on cooling the city of Tucson than clustered in parks. However, we also know that trees clustered have a greater effect than sort of the sum of the individuals.鈥�
There鈥檚 still more to learn鈥揵ut what is known is that trees are a natural and effective way to mitigate heat鈥攁nd strategic steps today can make a difference in the future.
This story was produced by the Mountain West News Bureau, a collaboration between Wyoming Public Media, Nevada Public Radio (KNPR) in Las Vegas, Boise State Public Radio in Idaho, KUNR in Nevada, 萝莉少女 in Colorado and KANW in New Mexico, with support from affiliate stations across the region. Funding for the Mountain West News Bureau is provided in part by the Corporation for Public Broadcasting.