Monika Maeckle

By Monika Maeckle

As official City Forester for San Antonio, Michael Nentwich has spent much of his life among the trees for which he advocates.  The fourth generation San Antonian and graduate of Stephen F. Austin University’s Forest Economics program grew up on the far West side just off Talley Road–a route named after his great-great-maternal grandfather John Talley.  John Talley came to San Antonio in the 1800s and founded the Talley Ranch just outside of what is now Loop 1604.

Nentwich and his extended family still live on Talley Road on what remains of the wooded 6,000-acre working ranch. He and his two rescued pups, Buddy, a blue-heeler border collie mix, and Constellation, a pit bull-Dalmation, inhabit what he calls “the west pasture.”  Nentwich participated in 4-H programs as a kid, raising swine, steers, chickens, goats, horses and rabbits.  “I generally placed well for pigs and steers,” said Nentwich.  “I learned a lot of responsibility.”

Michael Nentwich, San Antonio City Forester, with his favorite tree, an Anaqua at the Bexar County Courthouse
Michael Nentwich, San Antonio City Forester, with his favorite tree, an Anaqua at the Bexar County Courthouse, photo by Carolina Canizales

Today, Nentwich applies his 4-H Club skills of using “head, heart, hands and health as a catalyst for positive change” to the ambitious task of increasing San Antonio’s urban tree canopy.  When he’s not in the field, he works out of the Ron Darner facility of San Antonio’s Parks and Recreation office where he manages a staff of technicians, operators and maintenance crews.  He collaborates with the City’s three staff horticulturists.  He also works closely with  San Antonio “tree cop” and City Arborist Mark Bird.   Their goal: to plant one million trees.

Why one million?  Because a survey conducted by the American Forests Association in 2007 determined that San Antonio needs to increase our urban tree canopy from 38% to 40%.  Commissioning the survey was one of Nentwich’s first tasks as City Forester after he was hired five years ago. The survey looked at the entirety of our city, from Stone Oak to the South Side.  Impervious cover, open spaces, buildings and existing trees were calculated.   “A goal of 40% by 2020 was determined to counter the effects of urban living,” said Nentwich.

City Forester Michael Nentwich demonstrates proper tree planting technique to OLU Students at Rosedale Park, photo courtesy San Antonio Parks and Recreation
City Forester Michael Nentwich demonstrates proper tree planting technique to OLLU Students at Rosedale Park. (Photo courtesy of San Antonio Parks and Recreation Department)

The survey recommended that  454,600 trees be planted over several years.   Assuming that mortality rates of newly planted urban trees is 50%, Nentwich doubled the number and rounded up to one million.

The benefits of protecting and increasing trees are social, ecological, economic.  Nentwich is a tree ambassador to the community, often praising their value in the course of his community outreach work, as he did at a meeting of the San Antonio chapter of the Native Plant Society of Texas (NPSOT) at Lion’s Field recently.

Trees can reduce ambient temperatures by 12 degrees in the heat of a South Texas summer. They reduce energy costs by shielding structures from wind and sun, especially on western exposures.   Trees reduce storm water runoff, fight soil erosion, increase recharge of our sole source of drinking water, and lessen the pollutants and chemicals that drain into our rivers and streams.  They filter our air, produce oxygen, and help reduce pollution and carbon, allergies and other health problems.   And last, but not least, trees offer beauty, and their presence “encourages people to get outside and recreate,” said Nentwich.

Comparisons of urban tree canopies are difficult but irresistible. No two cities have the same weather patterns, geography, community needs, and studies measuring their canopies have used myriad metrics. A 2006 study placed Austin’s tree canopy at 30 %. A community wide discussion known as Imagine Austin is expected to set a new canopy goal sometime in the next year, according to Austin City Arborist Michael Embesi.

The Dallas tree  canopy is 26.2%, according to a 2009 study.   Dallas has no specific tree canopy goal, but has joined 70 other North Texas cities in a pledge to plant three million trees collectively.

Houston enjoys an approximate 30% canopy, according to a a 1999 study.   Houston hasn’t set a specific goal, but the American Forests Association suggests a 40% urban canopy for Houston, according to one study.

Nentwich’s tree advocacy is completely funded by fees paid into the San Antonio tree mitigation and canopy fund. Whenever real estate development projects lead to trees removals, developers are given two choices: plant minimum one-and-a-half inch caliper replacements from appropriate species, or pay fines of $200 per diameter inch of removed trees’ trunks to mitigate the losses.

Since 2005, the fund has generated more than $3.3 million for San Antonio tree planting, preservation and advocacy, according to Bird, the city arborist.   “And unlike social security, it really is a separate fund,” said Nentwich, who said his budget can range from $500,000 to $1.5 million a year.

One down, 999,999 to go. Seen on River Road--photo by Monika Maeckle
One down, 999,999 to go. Seen on River Road, photo by Monika Maeckle

Other Texas cities tap various sources for their tree funds.  “As you look around the state, there’s a lot of different ways to get funding,” noted Paul Johnson, chairman of the Alamo Forest Partnership and Regional Urban Forester for the federally funded Texas Forest Service.  Using mitigation funds is a great way of “turning dollars that represent trees back into trees,” said Johnson, adding “San Antonio probably leverages this funding mechanism for getting the most bang for the buck of most programs I’ve seen.”

Increasing and planting trees in Texas became especially challenging last year during the historic drought. Initial estimates released last December indicate 500 million Texas trees perished in the drought in rural areas.  Another 1.5 million were lost in wildfires.  More recently, urban tree losses were estimated at about five million statewide. Nentwich said we won’t really know the drought’s toll for 10 years.

Even during that year of record heat and drought, Nentwich, staff and volunteers were able to meet the SA2020 goal of planting 10,000 trees in San Antonio in 2011.  Of those, 1,000 new trees were planted downtown.  The survival rate of saplings in the first year was an impressive 87%.

Supplemental watering during the drought raised some eyebrows in some circles, said Mark Peterson, conservation project coordinator for San Antonio Water Service, and a certified arborist.  But since  a one-and-a-half-inch tree can be planted and maintained for an entire year on only 218 gallons of water –a little more than the average 191 gallons per day used by the typical San Antonio family, that consternation was misplaced.  The increased water recharge and other benefits far outweigh the water investment, said Peterson.   Johnson pointed out that other communities in the state opted to not plant trees for their Arbor Day celebrations last year.  “That’s the wrong response in a drought,” said Johnson.  “That’s overreacting–we need more trees, not less, during a drought.”

Reaching San Antonio’s one million tree goal by 2020 will rely heavily on community involvement.  With as much as 90% of San Antonio in the hands of private property owners, “It’s going to take everybody to raise this urban forest child,” said Nentwich.   Tree planting initiatives from CPS and the Texas Department of Transportation and heightened public awareness thanks to the SA2020 initiative, the Mission Verde Alliance and the fabulous Mission Reach undertaking have bolstered tree advocacy efforts in recent years.   “We’re getting there,” said Nentwich.

So is San Antonio becoming a city of tree huggers?  “If that’s what it takes to bring people in, that’s all good,” said Nentwich.  “But we have to marry the heart with the science.  I prefer the label ’21st century tree hugger.’”

What can you do to help increase San Antonio’s Urban Tree Canopy?

Check out the City of San Antonio  Tree Planting Challenge.  Submit an application to plant 25 trees by July 27, and the City will pay for the trees if you provide the sweat to plant them and a commitment to care for them.

On June 12, the Alamo Forest Partnership hosts a Tree Social.  Meet other conservation minded San Antonians and watch a screening of Greenfire, a documentary about the legendary Aldo Leopold, father of Modern Conservation.

Certified Arborist Classes are underway via the Alamo Forest Partnership.  Join 25,000 certified arborists worldwide and learn how to care for and maintain trees in your home, neighborhood, or as your profession.  The eight sessions run three hours each–it’s like becoming a Master Gardener for trees.  Open to laypeople and professionals alike.  Email for more information.

San Antonio’s heritage trees:   the Anaqua at the Bexar County Courthouse

Monika Maeckle writes about gardening, butterflies, conservation and the Monarch butterfly migration at the Texas Butterfly Ranch, and covers nature in the urban environment for this website.  You can reach her at

San Antonio Report co-founder Monika Maeckle writes about pollinators, native plants, and the ecosystems that sustain them at the Texas Butterfly Ranch website. She is also the founder and director of...