Introduction

By Les Conklin

The smoke might have cleared but we’re not out of the weeds yet.

Last week there was a 15-acre fire near East Dynamite Boulevard and 79th Street in north Scottsdale. The blaze was quickly extinguished by Scottsdale firefirghters without damage to nearby homes. Last week’s fire re-kindled memories of the Rio Fire, which began July 7, 1995 a little further east on E. Dynamite.

The Peak has published several articles about the Rio Fire. You will find Pete Chasar’s 1997 article, “Legacy of the Rio Fire,” below. Beneath Chasar’s article, you’ll finnd links to two 1995 Peak articles about the fire.

In his article Chasar identifies the growth of non-native grasses as a legacy of the Rio Fire. The spread of non-native grasses continues both within and outside the Scottsdale’s McDowell Sonoran Preserve. Non-native grasses accelerate the spread of fire. Even more threatening they spread into our very neighborhoods.

Here are links to two recent Peak articles that discuss what is being done about dangerous non-native grasses and how you can help.

Protecting of Native Biodiversity Isn’t Easy by Dr. Helen Rowe Article

Getting Rid of Invasive Grasses: You’d Better Have a Plan by Paul Staker Article

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Now that the smoke has cleared:

Legacy of the Rio Fire

By Pete Chasar
From A Peek at the Peak, August 1997

Bomber Drop of Fire Retardant During Rio Fire, Courtesy of McDowell Sonoran Land Trust.

From a distance, the McDowell Mountains look much as they did when I first set eyes on them 27 years ago – a long row of rocky peaks and deeply folded flanks that glow purple in the fading light of early evening. But, now, as you draw closer to the McDowells, you can detect large swaths on the northern peaks and on Wingate Pass without the Sonoran Desert’s characteristic leopard-spot patterns. Instead of a landscape polka-dotted with the green of Palo Verde and mesquite, many places in these high deserts are now carpeted in a dull tan monotone.

This is the Rio Fire’s legacy: peaks, high canyons and thousands of acres of surrounding desert covered in annual grasses that turn brown and tinder-like in the relentless summer sun. Sadly, ironically, this aftermath of desert fire makes a recently burned landscape even more susceptible to another fire during the first few years of recovery.

The culprits are non-native annual grasses introduced to the Sonoran Desert by early ranchers and other settlers. These grasses sprout fast and thrive in the nitrogen rich post-fire soil, especially in years when there’s abundant winter rainfall. On the other hand, native perennial plants like Palo Verde are easily destroyed by fire and are very slow growing. And, as for the many hundreds of saguaros destroyed by the Rio Fire, it will take at least a century for the next generation to sprout, grow arms and begin to reach adult height. However, there are many encouraging signs of recovery even in the short term.

First, despite the fiery havoc wreaked on the McDowells, the surrounding desert and especially McDowell Mountain Regional Park, there were many patches throughout the burn area that escaped destruction. One of those areas, the steep northeastern canyon leading to Tom’s Thumb, was hardly touched by the fire. Its boulder-filled landscape punctuated by staghorn cholla, prickly pear and saguaro cacti. Areas like this will, over the decades, help seed and restore the surrounding burnt-out landscape.

Also, even in areas that were completely scorched by the fire, some lifeless-looking piles of ashes have fresh green shoots poking through the char. Apparently, the root balls of many Sonoran plants remain viable even though all the aboveground growth has been destroyed. This is especially true of mesquite and yucca. However, six months after the fire, I saw new growth sprouting even from Palo Verde trees that were burned to the ground. More recently I saw new growth sprouting from the ashen remains of a teddy bear cholla that I had also given up for dead.

Still, the next three or four years will be critical for these already-burnt-up areas because of the high probability that re-burns will occur. Prior to the Rio Fire, many areas in the McDowells, especially the peaks and high valleys near East End and Tom’s Thumb, carried the telltale signs of fire damage – an absence of trees and cacti, an abundance of grasses, bursage and brittlebush.

Lightning, the cause of the Rio Fire, also probably ignited most of those old fires. But as more and more homes surround these fire-sensitive areas, a greater and greater fire risk will be posed by human causes – carelessly dis carded cigarettes, children playing with matches and people setting off fireworks.

No, we can’t stop lightning. But we can – and should – do something about these human causes of desert wild fires as our legacy to future generations, enabling them to experience the glorious desert landscape we knew just a few short years ago but often took for granted.

Editorial note. The author, Pete Chasar, was one of the early voices and forces that let to the creation of Scottsdale’s McDowell Sonoran Preserve.