Aug 16, 2019 - 04:15 pm CDT

 

Margret Hofmann was born in Germany in 1925. Growing up during the rise of Hitler and the Second World War, she witnessed the destruction of lives and places she loved. The experience left her committed to fighting for the things she cared for most. “The burden is that you feel you have to fight apathy… I have an increased sense of appreciation to have food, to sleep at night.”

Margret immigrated to the United States in 1946, eventually settling with her husband in Austin, Texas. In Austin, Margret became a mother and raised five children. Remebering the destruction she had left behind in war-torn Europe, she began organizing in support of our city's natural spaces. Margret knew that our city’s trees share oxygen, shade, beauty, and other vital benefits that contribute to creating a healthy and safe place to live and raise a family. She called Austin's trees “our oldest citizens” and worked hard to preserve and protect them.

 

1976 Tree Registry, Courtesy of the Austin History Center

In 1974, Margret established Think Trees Week. Residents planted trees, students made art, and Margret led the creation of Austin’s first tree registry, giving official recognition to the City’s largest and oldest trees. The next year, Marget Hoffman was elected to represent her neighbors and the city’s trees on Austin’s City Council. Thanks in large part to Margret’s efforts, in 1983 the City of Austin adopted its first tree ordinance. Margret is remembered as Austin's “Tree Lady.”

 

  

1974 Think Trees Booklets, courtesy the Austin History Center

In honor of Margret’s legacy and the City of Austin’s longstanding commitment to our urban forest, we continue to encourage Austinites to Think Trees.

After hearing Margret’s story, what will you go out on a limb for? 

Share with us by tagging us on social media using @naturecityatx.

 

The Community Tree Preservation Division is part of the Development Services family of service.

Article written by Jo Dwyer. Banner illustration of Margret Hofmann by Aimee Aubin.

 

To learn more about our urban forest and how you can get involved visit austintexas.gov/trees.

 

Jun 27, 2019 - 02:59 pm CDT

“Hackberry? That’s a trash tree.” Most of us in Central Texas have probably heard someone say this at least a couple of times. Few species of tree are hated as much as the lowly hackberry. But is this justified? Let’s take a closer look at one of our most prolific native species.

Hackberries are in the Genus Celtis. The name “Hackberry” is derived from Scottish “Hagberry,” or “Bird Cherry.” There are nearly 70 species worldwide. Common names include beaverwood, nettlewood, and sugar hackberry. In the Austin area, three species occur naturally:

  • Netleaf Hackberry, Celtis reticulata
  • Lindheimer Hackberry, Celtis lindheimer
  • Sugarberry, Celtis laevigata.

These trees are similar in many ways. They are known as fast growers, gaining up to 24 inches a year in height. As members of the Elm family (Ulmaceae), they have broad, arching branches that form a vase-like shape, but they do not suffer from as many diseases as other elms. Their leaves are yellowish to dark green, with a rough surface and a distinctive pattern in the veins that makes identification of hackberries easy with practice. (Alternate leaves, simple, 2-5 inches, spearhead with strong unequal leaf base, toothed margins.) The scars left behind where the leaves attach are usually shaped like half-circles. Flowers grow from April to May, and are a good source of nectar and pollen for local honeybees. They are followed by a small fruit, called a drupe, which tastes similar to dates and is a valuable food source for wildlife. These fruits are produced every year once the trees reach around 15 years old.

Image result for sugarberry tree

Native Americans began using these trees as early as the 1300s. The dried seeds provide good nutrition, including protein, phosphorus, and calcium. Native tribes added them to corn porridge. Comanches mixed them into meatballs. The flexible wood has also been useful for making things like bows, bowls, and tool handles. Papagos, native to what is now Arizona and Northern Mexico, used the bark to make sandals. Navahos boiled the leaves to create a reddish-brown dye for wool. Today the wood is used mainly for furniture, pallets, firewood, and sporting goods. Bonsai artists also find them to be a good tree to work with.

The most common Celtis species in our area is the Sugarberry, C. laevigata. It reaches a mature size 50 feet tall and 50 feet wide. Young trees have smooth, light-gray bark that develops knobby “warts” as the tree ages. This could be a defense that evolved to protect the trunks from deer that like to rub their antlers against the bark.

The bias some people have against these trees is not completely without cause. The wood can be brittle and weak, even more so when the tree becomes infected with parasitic mistletoe. Branching structure tends toward tight, vee-shaped crotches that are prone to splitting. Left unchecked, mistletoe often spreads throughout the canopy, which can be unattractive as well as sapping the tree’s food resources. Based on requests to the City Arborist for tree reviews, 15% of our diseased, dead, and imminent risk trees are hackberries. They are also affected by various problems that can be unattractive, such as Nipple Leaf Gall and Witches’ Broom.

Despite its problems, the Sugarberry is a Texas Tough champion. It adapts well to a range of soil types and the poor-quality soils common in urban areas. It is highly tolerant of heat and drought. In fact, it is so sturdy, it frequently survives untold abuse from its haters, which can be a contributor to the problems we see in our lawns and rights-of-way. Treated well, sugarberry can be an excellent neighbor and friend of wildlife.

https://www.texasbeyondhistory.net/st-plains/nature/images/hackberry-branch.jpg

Because our soils tend to be highly alkaline, Austin is not a favorable location for most maples or pines. Our oaks are always at risk of infection by a fungus (Ceratocystis fagacaerum, also known as Oak Wilt). American elms and pecans often struggle to survive our long, intense droughts. Ash trees could be attacked any time by the invasive Emerald Ash Borer. In such a challenging environment, Sugarberries and Hackberries are an important part of our diverse forest. In 2014, an Urban Forest Inventory Analysis found over 5 million hackberries in Austin, which make up more than 6% of our canopy coverage. They provide an estimated $3 billion per year in services, such as: shade that reduces electricity usage; filtration of air pollution; control of stormwater and flooding; and reduced erosion. Far from being trashy, Sugarberries are vital part of our urban forest. Please do what you can to take good care of them if you get the opportunity.

 

Article contributed by Keith Babberney, Forester with the Community Tree Preservation Division in the Development Services Department. Questions? Email Keith.

Jun 25, 2019 - 02:46 pm CDT

How Tree Roots Work Part 1  |  How Tree Roots Work Part II: Digging Deeper

Soil Ecosystem

Did you know trees communicate with each other through a network like our World Wide Web? Tree roots live underground, but they are not alone. They are part of a vibrant ecosystem. There are more bacteria in a teaspoon of soil than people on the planet. Of course, soil also contains large organisms like insects, worms, moles, and spiders, but the microsphere is often overlooked for its importance to tree health. Other tiny inhabitants include fungi, algae, and protozoa. Soil inhabitants create pathways through the soil for air and water to soak in and become available to roots. The soil ecosystem helps break down organic material into its basic elements. These become the nutrients that the tree uses to produce its food.

 

This drawing divides soil occupants into photosynthesizers, Decomposers, and three levels of Predators.

Image 1) Soil shelters a vibrant ecosystem. Image courtesy University of Illinois Extension.

 

Fungal Communication Network

Among the inhabitants of soil are a special class of fungi called mycorrhizae. These fungi colonize the tips of fine, feeder roots and extend out into the soil. The fungus gets some protection and help from the tree, but provides a much greater service by helping to absorb nutrients and bring them into the tree’s cells. They also help the tree defend against other fungi that might colonize the roots and cause damage. There is even evidence that, when one tree is attacked by a disease or pest, the defensive signals are transmitted through mycorrhizae to other trees, which then begin producing defensive compounds before the attack arrives (http://www.bbc.com/earth/story/20141111-plants-have-a-hidden-internet). So, even though we typically preserve a “critical” root zone based on the tree’s diameter, there is actually often one continuous network of trees, roots, and fungi. It’s important to bear this in mind, particularly in suburban and urban areas where what we do to our soil might affect several of our neighbors.

 

Image 2) Brown tree roots living together with the white mycorrizal fungi. In nature, these fungi would spread outward and join up with other roots on other trees. Image courtesy New York Botanical Garden.

 

How Tree Roots Work Part 1  |  How Tree Roots Work Part II: Digging Deeper

Article contributed by Keith Babberney, Forester with the Community Tree Preservation Division in the Development Services Department. Questions? Email Keith.

 

 

Apr 11, 2019 - 03:35 pm CDT

We’re nearing another Texas summer in Austin and it’s getting easier to imagine the record-breaking 110-degree weather recorded last July. Fascinated by the role that the landscape plays in urban heat and microclimates, students at Texas State University analyzed land surface temperatures across Austin. While this is something anyone can ‘feel’ when they step out in a black t-shirt, it’s interesting to take a step back and view the cityscape and urban heat on a larger scale. Students processed data provided by USGS and NASA, utilizing ArcGIS online to analyze and present their findings.  

A Wealth of Data  

  1. Satellites from the U.S. Geological Survey take pictures of Austin every 16 days—a program that’s been running since the 1970's. What a massive image library! With such a large library and a reputable track record, we can analyze any time in modern history.
  2. The satellite's camera senses heat across land without gaps. This means we can measure local climate everywhere not just at weather stations. 
  3. Temperatures can be averaged for a specific place with images from many time periods. That's exactly what Texas State students did. They averaged seven Landsat satellite images, mapping the hot and cold spots.


What’s hot and what’s not? Trees and water help to cool our surroundings.

Students found average temperatures ranging from 69° F to 103° F from April through September. They found places with trees and creeks had much cooler recorded temperatures. On the other end of the spectrum, students found high heat corresponded to low tree canopy areas, high building density and pavement. Parks were almost always cooler than schools, offices, streets, and parking lots.  

Mapped: Land surface temperature along the Colorado River in east Austin

The importance? We know heat imposes risks involving public health, tree health, and urban ecology. By understanding high heat areas, we can identify places to cool our surroundings by planting trees, adding parkland, and ultimately becoming more climate resilient. What's next? We'll continue to track heat as we repeat this process for other years.

Explore the data for yourself with this online map.

Learn about 6 strategies you can use to cool your space at the Cool Spaces webpage or get a printable PDF here.

 

Article contributed by Alan Halter, GIS Analyst Senior with the Community Tree Preservation Division. Questions?

 

Jan 17, 2019 - 01:32 pm CST

PARD Urban ForestryOn the first Friday of most months, members of the Urban Forestry team of Austin’s Parks and Recreation Department can be found in a maintenance lot off Stratford Drive. Mopac looms to the east. Ready with chainsaws and log lifters, they offer the public a unique free resource: Austin-grown wood. The Parks and Recreation Department (PARD) oversees the management of over 288,000 trees on Austin parklands. Keeping those public spaces safe is the first priority for the Parks Urban Forestry team, especially in a city known for our natural gems like Barton Springs, the Greenbelt, and Town Lake/Lady Bird Lake (depending on who you ask). 

Since trees provide so many benefits to the city, Foresters like Carl Wiggins make sure that removing a tree is the last resort. “When a tree is identified as a safety risk or is in the process of failure, we go check it out. We'll try to mitigate [remove damage to save the tree] or even redirect trails and pathways to protect the roots. Only after mitigation [if it can't be saved] will we cut it down.”

On this particular Friday, Foresters were helping a gentleman fill the back of his minivan with tree slices headed for Shalom Austin's preschool celebration of the Jewish Festival of Trees, Tu BiShevat. Forming a chain, Foresters and resident passed 18 slices of pecan across the lot, tossing each one in a scene that felt miles away from downtown.

One crafty resident had found arm-sized branches to drill and paint as candle holders and one very large slice of pecan destined to become a side table. (Editorial note: I can’t wait to see pictures. My own DIY nature crafting efforts are often more #fail than #fab.)

Already imagining what you might do with reclaimed wood? Members of the public are welcome to take home local and sustainable wood from Wood Reclamation with Parks and Recreation Urban Forestry Unit. For details about the next event visit the Parks Urban Forestry website.

And if you do snag some cedar, pick up a pecan, or win big with black walnut, share your creations with us on Instagram and Facebook using #atxreclaimed!
 

Article submitted by Jo Dwyer, Community Catalyst with the Community Tree Preservation Division. Questions?

Jun 11, 2018 - 02:22 pm CDT

Nature in the City proudly presents

American Biology: Natives, Immigrants, and Humboldt’s Children

This lecture will examine the context and impacts of the emergence of biology as a science in America and the influence of Humboldt on our understanding of American Nature.

Alexander von Humboldt was a role model for 19th century “children of Humboldt” who followed the path of Humboldtian science – explore, collect, measure, connect, and theorize. In particular, his influence on Darwin was profound both in setting Darwin’s life course and in fostering his idea of evolution. The Origin of Species was published in 1859, the year Humboldt died, and, in America, the reaction to the theory of evolution divided Humboldt’s scientific disciples. That debate between Asa Gray and Louis Agassiz was won by Gray and the evolutionists, but Agassiz popularized biology as a science by urging teachers and students to study nature directly in the field. They and professional biologists surveyed American nature during a time of profound ecological change in America, and their legacy is still found in lists of “native” species whose numbers and distribution were in part the result of the ecological change wrought by the settlement of America.

 

June Lecture | 12:00 pm – 1:00 pm 

Free and Open to the Public – bring a lunch and learn

June 21st OTC - One Texas Center - 505 Barton Springs Road, Room 325

 

RSVP AND SHARE THE EVENT THROUGH NATURE IN THE CITY ON FACEBOOK! 

Catch up with the 2018 lecture series with the Nature in the City Podcasts!

http://austineconetwork.com/nature-in-the-city/

 

Additional Dates and Locations in June:

June 13th SAC – Lamar Senior Activity Center 2874 Shoal Crest Ave, ATX 78705

June 16th (Saturday) CER - Austin Water Center for Environmental Research – 2210 South FM 973 at Hornsby Bend

June 27th UT - University of Texas Norman Hackerman Building (NHB) at 100 E 24th St

 

Kevin Anderson Ph.D.

Kevin is a geographer and philosopher researching the nature of, and the nature in, urban wastelands. He studied at Allegheny College in Pennsylvania [BA], Durham University, England, Ohio University [MA] where he taught philosophy and symbolic logic. He received his Ph.D. in Geography from the University of Texas at Austin with a dissertation entitled: Marginal Nature: Urban Wastelands and the Geography of Nature. His research interests include sewage treatment, soil ecology, and sustainable agriculture, urban ecology and sustainability, riparian ecology, environmental history, philosophy, and literature. He is a co-founder of the Texas Riparian Association and the Upper Tisza Foundation in northeastern Hungary. He runs the Austin Water-Center for Environmental Research which focuses on soil, sewage recycling, and environmental trace contaminants; rivers, riparian ecology, and alluvial aquifers; cities, biodiversity, and avian ecology.

Brought to you by Austin Water Utility, Center for Environmental Research (CER), The University of Texas, Texas A&M University. Nature in the City - Austin is sponsored by the Community Trees Division, and helps to implement the Imagine Austin and Urban Forest Plans. 

CER and Hornsby Bend are on Facebook! Visit to see what's happening today! Want more? Yes! Visit the Marginal Nature Blog and Nature in the City - Austin Blog.

Power Points for previous lunchtime lectures.

http://www.austintexas.gov/page/cer-previous-lunchtime-lectures

 

CONNECT WITH US!

NATURE IN THE CITY IS ON FACEBOOKTWITTER, AND INSTAGRAM.

 

Austin Nature in the City is sponsored by the Community Trees Division and part of the Development Services family. This is an interdepartmental collaboration to implement the Imagine Austin and Austin's Urban Forest Plans.

 

 

May 01, 2018 - 10:48 am CDT

Nature in the City proudly presents

American Natural History: Thoreau and New World Nature

IN MAY WE’LL EXPLORE THE HISTORY OF AMERICAN NATURAL HISTORY AND HOW IT STILL INFLUENCES OUR UNDERSTANDING OF AMERICAN NATURE.

The practice of natural history became a science of describing and classifying nature as America became an independent nation. One of the founders of this new science was the French polymath Comte de Buffon who published his 36-volume encyclopedia Natural History between 1749 and 1788. In it, he argued that, compared to the Old World, all New World species were weak and feeble, since the dismal, cold climate of the New World made them so. Moreover, any species brought to the New World would succumb to the degenerative effects of this swamp-like world - a process, Buffon argued, which applied equally to Europeans immigrating to America. This theory of degeneracy appealed to the prejudices of many European thinkers and leaders, and it meant that describing the natural history of America was closely bound to nation-building and to refuting this European prejudice against American nature. And so, from Jefferson to Thoreau, early American naturalists not only described American nature but defended American nature against this largely forgotten (and profoundly wrong!) theory.

 

May Lecture | American Natural History: Thoreau and New World Nature

Time | 12:00 pm – 1:00 pm 

Free and Open to the Public – bring a lunch and learn

 

May 9th SAC – Lamar Senior Activity Center 2874 Shoal Crest Ave, ATX 78705

May 10th OTC - One Texas Center - 505 Barton Springs Road, Room 325

May 15th CER - Austin Water Center for Environmental Research – 2210 South FM 973 at Hornsby Bend

April 25 UT - University of Texas Norman Hackerman Building (NHB) at 100 E 24th St

 

RSVP AND SHARE THE EVENT THROUGH NATURE IN THE CITY ON FACEBOOK! 

Catch up with Nature in the City Podcasts!

 

Kevin Anderson Ph.D.

Kevin is a geographer and philosopher researching the nature of, and the nature in, urban wastelands. He studied at Allegheny College in Pennsylvania [BA], Durham University, England, Ohio University [MA] where he taught philosophy and symbolic logic. He received his Ph.D. in Geography from the University of Texas at Austin with a dissertation entitled: Marginal Nature: Urban Wastelands and the Geography of Nature. His research interests include sewage treatment, soil ecology, and sustainable agriculture, urban ecology and sustainability, riparian ecology, environmental history, philosophy, and literature. He is a co-founder of the Texas Riparian Association and the Upper Tisza Foundation in northeastern Hungary. He runs the Austin Water-Center for Environmental Research which focuses on soil, sewage recycling, and environmental trace contaminants; rivers, riparian ecology, and alluvial aquifers; cities, biodiversity, and avian ecology.

Brought to you by Austin Water Utility, Center for Environmental Research (CER), The University of Texas, Texas A&M University. Nature in the City - Austin is sponsored by the Community Trees Division, and helps to implement the Imagine Austin and Urban Forest Plans. 

CER and Hornsby Bend are on Facebook! Visit to see what's happening today! Want more? Yes! Visit the Marginal Nature Blog and Nature in the City - Austin Blog.

Power Points for previous lunchtime lectures.

http://www.austintexas.gov/page/cer-previous-lunchtime-lectures

Catch up with Nature in the City Podcasts! 

CONNECT WITH US!

NATURE IN THE CITY IS ON FACEBOOKTWITTER, AND INSTAGRAM.

 

Austin Nature in the City is sponsored by the Community Trees Division and part of the Development Services family. This is an interdepartmental collaboration to implement the Imagine Austin and Austin's Urban Forest Plans.

 

 

Mar 16, 2018 - 09:33 am CDT

March 2018 Lunchtime Lecture

Urban Nature: Perspectives on Nature and the City

"Resilience."

In March we'll assess whether urban nature is really nature at all.

We are now predominately a country of urbanites who have only occasional contact with wilderness or rural nature. To compensate for this urban depravation, we have incorporated “green space” for nature into our cities – preserves, wildscapes, parks, and gardens - to allow for contact with officially sanctioned nature in the urban landscape.

The urban nature that lives outside of these green spaces (or “invasively” transgresses them) is a “degraded” type of nature which the writer John Tallmadge describes as “just too mixed up, chaotic, and confused to fit our established notions of beauty and value in nature. … Maybe it’s not really nature at all, not a real ecosystem, just a bunch of weeds and exotics mixed up with human junk.”

"Waller Creek - Wild Nature" Photos by Kevin Anderson.

 

March Lecture

Urban Nature: Perspectives on Nature and the City

Time | 12:00 pm – 1:00 pm 

Free and Open to the Public – bring a lunch and learn

Mar 14 SAC - Senior Activity Center-Lamar - 2874 Shoal Crest Ave, South Room at 29th and Lamar

Mar 20 CER - Austin Water Center for Environmental Research – 2210 South FM 973 at Hornsby Bend

Mar 28 UT - University of Texas Norman Hackerman Building (NHB) at 100 E 24th St

Mar 29 OTC - One Texas Center - 505 Barton Springs Road, Room 325 at South First Street

RSVP and Share the Event through Nature in the City on Facebook! 

 

Kevin Anderson Ph.D.

Kevin is a geographer and philosopher researching the nature of, and the nature in, urban wastelands. He studied at Allegheny College in Pennsylvania [BA], Durham University, England, Ohio University [MA] where he taught philosophy and symbolic logic. He received his Ph.D. in Geography from the University of Texas at Austin with a dissertation entitled: Marginal Nature: Urban Wastelands and the Geography of Nature. His research interests include sewage treatment, soil ecology, and sustainable agriculture, urban ecology and sustainability, riparian ecology, environmental history, philosophy, and literature. He is a co-founder of the Texas Riparian Association and the Upper Tisza Foundation in northeastern Hungary. He runs the Austin Water-Center for Environmental Research which focuses on soil, sewage recycling, and environmental trace contaminants; rivers, riparian ecology, and alluvial aquifers; cities, biodiversity, and avian ecology.

Brought to you by Austin Water Utility, Center for Environmental Research (CER), The University of Texas, Texas A&M University. Nature in the City - Austin is sponsored by the Community Trees Division, and helps to implement the Imagine Austin and Urban Forest Plans. 

CER and Hornsby Bend are on Facebook! Visit to see what's happening today! Want more? Yes! Visit the Marginal Nature Blog and Nature in the City - Austin Blog.

Power Points for previous lunchtime lectures.

http://www.austintexas.gov/page/cer-previous-lunchtime-lectures

 

CONNECT WITH US!

NATURE IN THE CITY IS ON FACEBOOKTWITTER, AND INSTAGRAM

 

Austin Nature in the City is sponsored by the Community Trees Division and part of the Development Services family. This is an interdepartmental collaboration to implement the Imagine Austin and Austin's Urban Forest Plans

 

 

Feb 08, 2018 - 12:44 pm CST

February 2018 Lunchtime Lecture

Pastoral Nature: Agrarianism and Rural America

Kevin Anderson's farm in Pennsylvania

In 1785, Thomas Jefferson famously asserted that, “Cultivators of the earth are the most valuable citizens. They are the most vigorous, the most independent, the most virtuous, & they are tied to their country & wedded to its liberty & interests by the most lasting bands,” and he wanted to see America transformed into a democratic pastoral arcadia of farms and ranches. This pastoral nature is the competing concept of American nature focused on farmland and ranchland in contrast to wilderness. Moreover, as American cities grew, rural life and nature in the countryside was seen as a cure for over-urbanized Americans who needed a weekend in the country to recover from the stress of city life. Today, the American small family farm is still an idealized place of encounter and engagement with rural nature, best championed by Wendell Berry, who, like Jefferson, sees small farms as a cure for social problems and modern society’s mismanagement of nature. Thus, there is great cultural tension and a historic divide in the geography of the American mind between wilderness and pastoral nature. Join us as we explore the history of this idea of pastoral nature and its role in shaping contemporary agrarianism in America.

 

February Lecture

Pastoral Nature: Agrarianism and Rural America

Time | 12:00 pm – 1:00 pm 

Free and Open to the Public – bring a lunch and learn

Feb 14 SAC - Senior Activity Center-Lamar - 2874 Shoal Crest Ave, South Room at 29th and Lamar

Feb 15 OTC - One Texas Center - 505 Barton Springs Road, Room 325 at South First Street

 - RSVP and Share the Event through Nature in the City on Facebook!

Feb 20 CER - Austin Water Center for Environmental Research – 2210 South FM 973 at Hornsby Bend

Feb 28 UT - University of Texas Norman Hackerman Building (NHB) at 100 E 24th St

 

Kevin Anderson Ph.D.

Kevin is a geographer and philosopher researching the nature of, and the nature in, urban wastelands. He studied at Allegheny College in Pennsylvania [BA], Durham University, England, Ohio University [MA] where he taught philosophy and symbolic logic. He received his Ph.D. in Geography from the University of Texas at Austin with a dissertation entitled: Marginal Nature: Urban Wastelands and the Geography of Nature. His research interests include sewage treatment, soil ecology, and sustainable agriculture, urban ecology and sustainability, riparian ecology, environmental history, philosophy, and literature. He is a co-founder of the Texas Riparian Association and the Upper Tisza Foundation in northeastern Hungary. He runs the Austin Water-Center for Environmental Research which focuses on soil, sewage recycling, and environmental trace contaminants; rivers, riparian ecology, and alluvial aquifers; cities, biodiversity, and avian ecology.

Brought to you by Austin Water Utility, Center for Environmental Research (CER), The University of Texas, Texas A&M University. Nature in the City - Austin is sponsored by the Community Trees Division, and helps to implement the Imagine Austin and Urban Forest Plans. 

CER and Hornsby Bend are on Facebook! Visit to see what's happening today! Want more? Yes! Visit the Marginal Nature Blog and Nature in the City - Austin Blog.

Power Points for previous lunchtime lectures.

http://www.austintexas.gov/page/cer-previous-lunchtime-lectures

 

CONNECT WITH US!

 

Nature in the City is on Facebook, Twitter, and Instagram

 

Austin Nature in the City is sponsored by the Community Trees Division and part of the Development Services family. This is an interdepartmental collaboration to implement the Imagine Austin and Austin's Urban Forest Plans

 

 

Jan 26, 2018 - 10:23 am CST

How Tree Roots Work Part I  |  How Tree Roots Work Part III: Mycorrhizae

 

Image | Severing roots along one side of the stem often leads to the tree falling the other direction. Image courtesy International Society of Arboriculture.

Image | Courtesy of the International Society of Arboriculture.

Severing roots along one side of the stem often leads to the tree falling the other direction. 

 

There are two main types of tree roots: anchoring roots and feeder roots. Most roots are near the surface, as we described in Tree Roots and How They Work, but anchoring roots are often much deeper. As they grow outward, they can send “sinker” roots straight down to add to their strength. A single root can’t hold up much weight, but the network of large and small roots work together to hold the tree upright and keep the soil in place. Generally, roots on one side of the tree keep it from falling the other way. This is why we should never cut a trench right next to a tree trunk. A trench this close removes almost half the tree’s roots causing instability and reduces access water and nutrients.

 

Image | Tiny root "hairs" as small as .2 mm in diameter help trees absorb water and nutrients. Image courtesy gibneyCE.com

Image | Tiny root "hairs" as small as .2 mm in diameter help trees absorb water and nutrients. Image courtesy gibneyCE.com

 

Anchoring roots live for years and years, but feeder roots die and are replaced often, much like skin cells. They typically live within six inches of the soil surface because they must have access to air and moisture, which are not always present in deep soil. To help take in water, the interior of root cells is slightly salty; water naturally flows into the saltier solution because nature always seeks a balance, i.e. osmosis (click to learn more about osmosis). If a lot of salt is added to the soil (such as road salt or chemical fertilizers), it can cause a reverse effect. Moisture flows out of the tree to dilute the soil salts. The plant can wilt or even die. This is one big reason we should always pay attention to the labels and instructions for any chemicals we apply in our lawns and gardens.

 

Illustration | Idealized drawing of a tree's roots.

Illustration | Idealized drawing of a tree's roots.

 

Roots support the tree and absorb water and nutrients. They transport these liquids through tiny tubes that run all the way up the stem to the leaves. This allows the tree to send its resources from one area to another. Some tubes, called xylem, mostly carry water from the soil to the leaves. Other tubes, called phloem, mainly carry sugar and other products made in leaves to parts where they are needed. When the tree is strong and healthy, it makes more than it needs and stores the excess in roots, trunks, and branches. Then, when the tree is under stress (like from drought, disease, or pests), it can rely on the stored materials to survive until conditions improve. 

 

Image | Even when the soil under the trunk is eroded, the network of roots holds the tree up.

Image | Even when the soil under the trunk is eroded, the network of roots holds the tree up.

 

Roots support trees and help to reduce soil erosion. They absorb water and other useful compounds from soil that the tree uses to make food and other resources. They sometimes make defensive compounds  to protect the tree when pests invade, and hormones to help control when leaves should drop. Roots also serve as storage centers for resources the tree can rely on during stressful times. 

In our next installment, we will look even more closely at the finest roots and the fungal network that connects trees together in a giant communications network.

 

How Tree Roots Work Part I  |  How Tree Roots Work Part III: Mycorrhizae

Article contributed by Keith Babberney, Forester with the Community Tree Preservation Division in the Development Services Department. Questions? Email Keith.

Jun 27, 2019 - 02:59 pm CDT

“Hackberry? That’s a trash tree.” Most of us in Central Texas have probably heard someone say this at least a couple of times. Few species of tree are hated as much as the lowly hackberry. But is this justified? Let’s take a closer look at one of our most prolific native species.

Hackberries are in the Genus Celtis. The name “Hackberry” is derived from Scottish “Hagberry,” or “Bird Cherry.” There are nearly 70 species worldwide. Common names include beaverwood, nettlewood, and sugar hackberry. In the Austin area, three species occur naturally:

  • Netleaf Hackberry, Celtis reticulata
  • Lindheimer Hackberry, Celtis lindheimer
  • Sugarberry, Celtis laevigata.

These trees are similar in many ways. They are known as fast growers, gaining up to 24 inches a year in height. As members of the Elm family (Ulmaceae), they have broad, arching branches that form a vase-like shape, but they do not suffer from as many diseases as other elms. Their leaves are yellowish to dark green, with a rough surface and a distinctive pattern in the veins that makes identification of hackberries easy with practice. (Alternate leaves, simple, 2-5 inches, spearhead with strong unequal leaf base, toothed margins.) The scars left behind where the leaves attach are usually shaped like half-circles. Flowers grow from April to May, and are a good source of nectar and pollen for local honeybees. They are followed by a small fruit, called a drupe, which tastes similar to dates and is a valuable food source for wildlife. These fruits are produced every year once the trees reach around 15 years old.

Image result for sugarberry tree

Native Americans began using these trees as early as the 1300s. The dried seeds provide good nutrition, including protein, phosphorus, and calcium. Native tribes added them to corn porridge. Comanches mixed them into meatballs. The flexible wood has also been useful for making things like bows, bowls, and tool handles. Papagos, native to what is now Arizona and Northern Mexico, used the bark to make sandals. Navahos boiled the leaves to create a reddish-brown dye for wool. Today the wood is used mainly for furniture, pallets, firewood, and sporting goods. Bonsai artists also find them to be a good tree to work with.

The most common Celtis species in our area is the Sugarberry, C. laevigata. It reaches a mature size 50 feet tall and 50 feet wide. Young trees have smooth, light-gray bark that develops knobby “warts” as the tree ages. This could be a defense that evolved to protect the trunks from deer that like to rub their antlers against the bark.

The bias some people have against these trees is not completely without cause. The wood can be brittle and weak, even more so when the tree becomes infected with parasitic mistletoe. Branching structure tends toward tight, vee-shaped crotches that are prone to splitting. Left unchecked, mistletoe often spreads throughout the canopy, which can be unattractive as well as sapping the tree’s food resources. Based on requests to the City Arborist for tree reviews, 15% of our diseased, dead, and imminent risk trees are hackberries. They are also affected by various problems that can be unattractive, such as Nipple Leaf Gall and Witches’ Broom.

Despite its problems, the Sugarberry is a Texas Tough champion. It adapts well to a range of soil types and the poor-quality soils common in urban areas. It is highly tolerant of heat and drought. In fact, it is so sturdy, it frequently survives untold abuse from its haters, which can be a contributor to the problems we see in our lawns and rights-of-way. Treated well, sugarberry can be an excellent neighbor and friend of wildlife.

https://www.texasbeyondhistory.net/st-plains/nature/images/hackberry-branch.jpg

Because our soils tend to be highly alkaline, Austin is not a favorable location for most maples or pines. Our oaks are always at risk of infection by a fungus (Ceratocystis fagacaerum, also known as Oak Wilt). American elms and pecans often struggle to survive our long, intense droughts. Ash trees could be attacked any time by the invasive Emerald Ash Borer. In such a challenging environment, Sugarberries and Hackberries are an important part of our diverse forest. In 2014, an Urban Forest Inventory Analysis found over 5 million hackberries in Austin, which make up more than 6% of our canopy coverage. They provide an estimated $3 billion per year in services, such as: shade that reduces electricity usage; filtration of air pollution; control of stormwater and flooding; and reduced erosion. Far from being trashy, Sugarberries are vital part of our urban forest. Please do what you can to take good care of them if you get the opportunity.

 

Article contributed by Keith Babberney, Forester with the Community Tree Preservation Division in the Development Services Department. Questions? Email Keith.

Nature in the City – Austin
Jun 25, 2019 - 02:46 pm CDT

How Tree Roots Work Part 1  |  How Tree Roots Work Part II: Digging Deeper

Soil Ecosystem

Did you know trees communicate with each other through a network like our World Wide Web? Tree roots live underground, but they are not alone. They are part of a vibrant ecosystem. There are more bacteria in a teaspoon of soil than people on the planet. Of course, soil also contains large organisms like insects, worms, moles, and spiders, but the microsphere is often overlooked for its importance to tree health. Other tiny inhabitants include fungi, algae, and protozoa. Soil inhabitants create pathways through the soil for air and water to soak in and become available to roots. The soil ecosystem helps break down organic material into its basic elements. These become the nutrients that the tree uses to produce its food.

 

This drawing divides soil occupants into photosynthesizers, Decomposers, and three levels of Predators.

Image 1) Soil shelters a vibrant ecosystem. Image courtesy University of Illinois Extension.

 

Fungal Communication Network

Among the inhabitants of soil are a special class of fungi called mycorrhizae. These fungi colonize the tips of fine, feeder roots and extend out into the soil. The fungus gets some protection and help from the tree, but provides a much greater service by helping to absorb nutrients and bring them into the tree’s cells. They also help the tree defend against other fungi that might colonize the roots and cause damage. There is even evidence that, when one tree is attacked by a disease or pest, the defensive signals are transmitted through mycorrhizae to other trees, which then begin producing defensive compounds before the attack arrives (http://www.bbc.com/earth/story/20141111-plants-have-a-hidden-internet). So, even though we typically preserve a “critical” root zone based on the tree’s diameter, there is actually often one continuous network of trees, roots, and fungi. It’s important to bear this in mind, particularly in suburban and urban areas where what we do to our soil might affect several of our neighbors.

 

Image 2) Brown tree roots living together with the white mycorrizal fungi. In nature, these fungi would spread outward and join up with other roots on other trees. Image courtesy New York Botanical Garden.

 

How Tree Roots Work Part 1  |  How Tree Roots Work Part II: Digging Deeper

Article contributed by Keith Babberney, Forester with the Community Tree Preservation Division in the Development Services Department. Questions? Email Keith.

 

 

Nature in the City – Austin
Apr 11, 2019 - 03:35 pm CDT

We’re nearing another Texas summer in Austin and it’s getting easier to imagine the record-breaking 110-degree weather recorded last July. Fascinated by the role that the landscape plays in urban heat and microclimates, students at Texas State University analyzed land surface temperatures across Austin. While this is something anyone can ‘feel’ when they step out in a black t-shirt, it’s interesting to take a step back and view the cityscape and urban heat on a larger scale. Students processed data provided by USGS and NASA, utilizing ArcGIS online to analyze and present their findings.  

A Wealth of Data  

  1. Satellites from the U.S. Geological Survey take pictures of Austin every 16 days—a program that’s been running since the 1970's. What a massive image library! With such a large library and a reputable track record, we can analyze any time in modern history.
  2. The satellite's camera senses heat across land without gaps. This means we can measure local climate everywhere not just at weather stations. 
  3. Temperatures can be averaged for a specific place with images from many time periods. That's exactly what Texas State students did. They averaged seven Landsat satellite images, mapping the hot and cold spots.


What’s hot and what’s not? Trees and water help to cool our surroundings.

Students found average temperatures ranging from 69° F to 103° F from April through September. They found places with trees and creeks had much cooler recorded temperatures. On the other end of the spectrum, students found high heat corresponded to low tree canopy areas, high building density and pavement. Parks were almost always cooler than schools, offices, streets, and parking lots.  

Mapped: Land surface temperature along the Colorado River in east Austin

The importance? We know heat imposes risks involving public health, tree health, and urban ecology. By understanding high heat areas, we can identify places to cool our surroundings by planting trees, adding parkland, and ultimately becoming more climate resilient. What's next? We'll continue to track heat as we repeat this process for other years.

Explore the data for yourself with this online map.

Learn about 6 strategies you can use to cool your space at the Cool Spaces webpage or get a printable PDF here.

 

Article contributed by Alan Halter, GIS Analyst Senior with the Community Tree Preservation Division. Questions?

 

Nature in the City – Austin
Jan 17, 2019 - 01:32 pm CST

PARD Urban ForestryOn the first Friday of most months, members of the Urban Forestry team of Austin’s Parks and Recreation Department can be found in a maintenance lot off Stratford Drive. Mopac looms to the east. Ready with chainsaws and log lifters, they offer the public a unique free resource: Austin-grown wood. The Parks and Recreation Department (PARD) oversees the management of over 288,000 trees on Austin parklands. Keeping those public spaces safe is the first priority for the Parks Urban Forestry team, especially in a city known for our natural gems like Barton Springs, the Greenbelt, and Town Lake/Lady Bird Lake (depending on who you ask). 

Since trees provide so many benefits to the city, Foresters like Carl Wiggins make sure that removing a tree is the last resort. “When a tree is identified as a safety risk or is in the process of failure, we go check it out. We'll try to mitigate [remove damage to save the tree] or even redirect trails and pathways to protect the roots. Only after mitigation [if it can't be saved] will we cut it down.”

On this particular Friday, Foresters were helping a gentleman fill the back of his minivan with tree slices headed for Shalom Austin's preschool celebration of the Jewish Festival of Trees, Tu BiShevat. Forming a chain, Foresters and resident passed 18 slices of pecan across the lot, tossing each one in a scene that felt miles away from downtown.

One crafty resident had found arm-sized branches to drill and paint as candle holders and one very large slice of pecan destined to become a side table. (Editorial note: I can’t wait to see pictures. My own DIY nature crafting efforts are often more #fail than #fab.)

Already imagining what you might do with reclaimed wood? Members of the public are welcome to take home local and sustainable wood from Wood Reclamation with Parks and Recreation Urban Forestry Unit. For details about the next event visit the Parks Urban Forestry website.

And if you do snag some cedar, pick up a pecan, or win big with black walnut, share your creations with us on Instagram and Facebook using #atxreclaimed!
 

Article submitted by Jo Dwyer, Community Catalyst with the Community Tree Preservation Division. Questions?

Nature in the City – Austin
Jun 11, 2018 - 02:22 pm CDT

Nature in the City proudly presents

American Biology: Natives, Immigrants, and Humboldt’s Children

This lecture will examine the context and impacts of the emergence of biology as a science in America and the influence of Humboldt on our understanding of American Nature.

Alexander von Humboldt was a role model for 19th century “children of Humboldt” who followed the path of Humboldtian science – explore, collect, measure, connect, and theorize. In particular, his influence on Darwin was profound both in setting Darwin’s life course and in fostering his idea of evolution. The Origin of Species was published in 1859, the year Humboldt died, and, in America, the reaction to the theory of evolution divided Humboldt’s scientific disciples. That debate between Asa Gray and Louis Agassiz was won by Gray and the evolutionists, but Agassiz popularized biology as a science by urging teachers and students to study nature directly in the field. They and professional biologists surveyed American nature during a time of profound ecological change in America, and their legacy is still found in lists of “native” species whose numbers and distribution were in part the result of the ecological change wrought by the settlement of America.

 

June Lecture | 12:00 pm – 1:00 pm 

Free and Open to the Public – bring a lunch and learn

June 21st OTC - One Texas Center - 505 Barton Springs Road, Room 325

 

RSVP AND SHARE THE EVENT THROUGH NATURE IN THE CITY ON FACEBOOK! 

Catch up with the 2018 lecture series with the Nature in the City Podcasts!

http://austineconetwork.com/nature-in-the-city/

 

Additional Dates and Locations in June:

June 13th SAC – Lamar Senior Activity Center 2874 Shoal Crest Ave, ATX 78705

June 16th (Saturday) CER - Austin Water Center for Environmental Research – 2210 South FM 973 at Hornsby Bend

June 27th UT - University of Texas Norman Hackerman Building (NHB) at 100 E 24th St

 

Kevin Anderson Ph.D.

Kevin is a geographer and philosopher researching the nature of, and the nature in, urban wastelands. He studied at Allegheny College in Pennsylvania [BA], Durham University, England, Ohio University [MA] where he taught philosophy and symbolic logic. He received his Ph.D. in Geography from the University of Texas at Austin with a dissertation entitled: Marginal Nature: Urban Wastelands and the Geography of Nature. His research interests include sewage treatment, soil ecology, and sustainable agriculture, urban ecology and sustainability, riparian ecology, environmental history, philosophy, and literature. He is a co-founder of the Texas Riparian Association and the Upper Tisza Foundation in northeastern Hungary. He runs the Austin Water-Center for Environmental Research which focuses on soil, sewage recycling, and environmental trace contaminants; rivers, riparian ecology, and alluvial aquifers; cities, biodiversity, and avian ecology.

Brought to you by Austin Water Utility, Center for Environmental Research (CER), The University of Texas, Texas A&M University. Nature in the City - Austin is sponsored by the Community Trees Division, and helps to implement the Imagine Austin and Urban Forest Plans. 

CER and Hornsby Bend are on Facebook! Visit to see what's happening today! Want more? Yes! Visit the Marginal Nature Blog and Nature in the City - Austin Blog.

Power Points for previous lunchtime lectures.

http://www.austintexas.gov/page/cer-previous-lunchtime-lectures

 

CONNECT WITH US!

NATURE IN THE CITY IS ON FACEBOOKTWITTER, AND INSTAGRAM.

 

Austin Nature in the City is sponsored by the Community Trees Division and part of the Development Services family. This is an interdepartmental collaboration to implement the Imagine Austin and Austin's Urban Forest Plans.

 

 

Nature in the City – Austin
May 01, 2018 - 10:48 am CDT

Nature in the City proudly presents

American Natural History: Thoreau and New World Nature

IN MAY WE’LL EXPLORE THE HISTORY OF AMERICAN NATURAL HISTORY AND HOW IT STILL INFLUENCES OUR UNDERSTANDING OF AMERICAN NATURE.

The practice of natural history became a science of describing and classifying nature as America became an independent nation. One of the founders of this new science was the French polymath Comte de Buffon who published his 36-volume encyclopedia Natural History between 1749 and 1788. In it, he argued that, compared to the Old World, all New World species were weak and feeble, since the dismal, cold climate of the New World made them so. Moreover, any species brought to the New World would succumb to the degenerative effects of this swamp-like world - a process, Buffon argued, which applied equally to Europeans immigrating to America. This theory of degeneracy appealed to the prejudices of many European thinkers and leaders, and it meant that describing the natural history of America was closely bound to nation-building and to refuting this European prejudice against American nature. And so, from Jefferson to Thoreau, early American naturalists not only described American nature but defended American nature against this largely forgotten (and profoundly wrong!) theory.

 

May Lecture | American Natural History: Thoreau and New World Nature

Time | 12:00 pm – 1:00 pm 

Free and Open to the Public – bring a lunch and learn

 

May 9th SAC – Lamar Senior Activity Center 2874 Shoal Crest Ave, ATX 78705

May 10th OTC - One Texas Center - 505 Barton Springs Road, Room 325

May 15th CER - Austin Water Center for Environmental Research – 2210 South FM 973 at Hornsby Bend

April 25 UT - University of Texas Norman Hackerman Building (NHB) at 100 E 24th St

 

RSVP AND SHARE THE EVENT THROUGH NATURE IN THE CITY ON FACEBOOK! 

Catch up with Nature in the City Podcasts!

 

Kevin Anderson Ph.D.

Kevin is a geographer and philosopher researching the nature of, and the nature in, urban wastelands. He studied at Allegheny College in Pennsylvania [BA], Durham University, England, Ohio University [MA] where he taught philosophy and symbolic logic. He received his Ph.D. in Geography from the University of Texas at Austin with a dissertation entitled: Marginal Nature: Urban Wastelands and the Geography of Nature. His research interests include sewage treatment, soil ecology, and sustainable agriculture, urban ecology and sustainability, riparian ecology, environmental history, philosophy, and literature. He is a co-founder of the Texas Riparian Association and the Upper Tisza Foundation in northeastern Hungary. He runs the Austin Water-Center for Environmental Research which focuses on soil, sewage recycling, and environmental trace contaminants; rivers, riparian ecology, and alluvial aquifers; cities, biodiversity, and avian ecology.

Brought to you by Austin Water Utility, Center for Environmental Research (CER), The University of Texas, Texas A&M University. Nature in the City - Austin is sponsored by the Community Trees Division, and helps to implement the Imagine Austin and Urban Forest Plans. 

CER and Hornsby Bend are on Facebook! Visit to see what's happening today! Want more? Yes! Visit the Marginal Nature Blog and Nature in the City - Austin Blog.

Power Points for previous lunchtime lectures.

http://www.austintexas.gov/page/cer-previous-lunchtime-lectures

Catch up with Nature in the City Podcasts! 

CONNECT WITH US!

NATURE IN THE CITY IS ON FACEBOOKTWITTER, AND INSTAGRAM.

 

Austin Nature in the City is sponsored by the Community Trees Division and part of the Development Services family. This is an interdepartmental collaboration to implement the Imagine Austin and Austin's Urban Forest Plans.

 

 

Nature in the City – Austin
Mar 16, 2018 - 09:33 am CDT

March 2018 Lunchtime Lecture

Urban Nature: Perspectives on Nature and the City

"Resilience."

In March we'll assess whether urban nature is really nature at all.

We are now predominately a country of urbanites who have only occasional contact with wilderness or rural nature. To compensate for this urban depravation, we have incorporated “green space” for nature into our cities – preserves, wildscapes, parks, and gardens - to allow for contact with officially sanctioned nature in the urban landscape.

The urban nature that lives outside of these green spaces (or “invasively” transgresses them) is a “degraded” type of nature which the writer John Tallmadge describes as “just too mixed up, chaotic, and confused to fit our established notions of beauty and value in nature. … Maybe it’s not really nature at all, not a real ecosystem, just a bunch of weeds and exotics mixed up with human junk.”

"Waller Creek - Wild Nature" Photos by Kevin Anderson.

 

March Lecture

Urban Nature: Perspectives on Nature and the City

Time | 12:00 pm – 1:00 pm 

Free and Open to the Public – bring a lunch and learn

Mar 14 SAC - Senior Activity Center-Lamar - 2874 Shoal Crest Ave, South Room at 29th and Lamar

Mar 20 CER - Austin Water Center for Environmental Research – 2210 South FM 973 at Hornsby Bend

Mar 28 UT - University of Texas Norman Hackerman Building (NHB) at 100 E 24th St

Mar 29 OTC - One Texas Center - 505 Barton Springs Road, Room 325 at South First Street

RSVP and Share the Event through Nature in the City on Facebook! 

 

Kevin Anderson Ph.D.

Kevin is a geographer and philosopher researching the nature of, and the nature in, urban wastelands. He studied at Allegheny College in Pennsylvania [BA], Durham University, England, Ohio University [MA] where he taught philosophy and symbolic logic. He received his Ph.D. in Geography from the University of Texas at Austin with a dissertation entitled: Marginal Nature: Urban Wastelands and the Geography of Nature. His research interests include sewage treatment, soil ecology, and sustainable agriculture, urban ecology and sustainability, riparian ecology, environmental history, philosophy, and literature. He is a co-founder of the Texas Riparian Association and the Upper Tisza Foundation in northeastern Hungary. He runs the Austin Water-Center for Environmental Research which focuses on soil, sewage recycling, and environmental trace contaminants; rivers, riparian ecology, and alluvial aquifers; cities, biodiversity, and avian ecology.

Brought to you by Austin Water Utility, Center for Environmental Research (CER), The University of Texas, Texas A&M University. Nature in the City - Austin is sponsored by the Community Trees Division, and helps to implement the Imagine Austin and Urban Forest Plans. 

CER and Hornsby Bend are on Facebook! Visit to see what's happening today! Want more? Yes! Visit the Marginal Nature Blog and Nature in the City - Austin Blog.

Power Points for previous lunchtime lectures.

http://www.austintexas.gov/page/cer-previous-lunchtime-lectures

 

CONNECT WITH US!

NATURE IN THE CITY IS ON FACEBOOKTWITTER, AND INSTAGRAM

 

Austin Nature in the City is sponsored by the Community Trees Division and part of the Development Services family. This is an interdepartmental collaboration to implement the Imagine Austin and Austin's Urban Forest Plans

 

 

Nature in the City – Austin
Feb 08, 2018 - 12:44 pm CST

February 2018 Lunchtime Lecture

Pastoral Nature: Agrarianism and Rural America

Kevin Anderson's farm in Pennsylvania

In 1785, Thomas Jefferson famously asserted that, “Cultivators of the earth are the most valuable citizens. They are the most vigorous, the most independent, the most virtuous, & they are tied to their country & wedded to its liberty & interests by the most lasting bands,” and he wanted to see America transformed into a democratic pastoral arcadia of farms and ranches. This pastoral nature is the competing concept of American nature focused on farmland and ranchland in contrast to wilderness. Moreover, as American cities grew, rural life and nature in the countryside was seen as a cure for over-urbanized Americans who needed a weekend in the country to recover from the stress of city life. Today, the American small family farm is still an idealized place of encounter and engagement with rural nature, best championed by Wendell Berry, who, like Jefferson, sees small farms as a cure for social problems and modern society’s mismanagement of nature. Thus, there is great cultural tension and a historic divide in the geography of the American mind between wilderness and pastoral nature. Join us as we explore the history of this idea of pastoral nature and its role in shaping contemporary agrarianism in America.

 

February Lecture

Pastoral Nature: Agrarianism and Rural America

Time | 12:00 pm – 1:00 pm 

Free and Open to the Public – bring a lunch and learn

Feb 14 SAC - Senior Activity Center-Lamar - 2874 Shoal Crest Ave, South Room at 29th and Lamar

Feb 15 OTC - One Texas Center - 505 Barton Springs Road, Room 325 at South First Street

 - RSVP and Share the Event through Nature in the City on Facebook!

Feb 20 CER - Austin Water Center for Environmental Research – 2210 South FM 973 at Hornsby Bend

Feb 28 UT - University of Texas Norman Hackerman Building (NHB) at 100 E 24th St

 

Kevin Anderson Ph.D.

Kevin is a geographer and philosopher researching the nature of, and the nature in, urban wastelands. He studied at Allegheny College in Pennsylvania [BA], Durham University, England, Ohio University [MA] where he taught philosophy and symbolic logic. He received his Ph.D. in Geography from the University of Texas at Austin with a dissertation entitled: Marginal Nature: Urban Wastelands and the Geography of Nature. His research interests include sewage treatment, soil ecology, and sustainable agriculture, urban ecology and sustainability, riparian ecology, environmental history, philosophy, and literature. He is a co-founder of the Texas Riparian Association and the Upper Tisza Foundation in northeastern Hungary. He runs the Austin Water-Center for Environmental Research which focuses on soil, sewage recycling, and environmental trace contaminants; rivers, riparian ecology, and alluvial aquifers; cities, biodiversity, and avian ecology.

Brought to you by Austin Water Utility, Center for Environmental Research (CER), The University of Texas, Texas A&M University. Nature in the City - Austin is sponsored by the Community Trees Division, and helps to implement the Imagine Austin and Urban Forest Plans. 

CER and Hornsby Bend are on Facebook! Visit to see what's happening today! Want more? Yes! Visit the Marginal Nature Blog and Nature in the City - Austin Blog.

Power Points for previous lunchtime lectures.

http://www.austintexas.gov/page/cer-previous-lunchtime-lectures

 

CONNECT WITH US!

 

Nature in the City is on Facebook, Twitter, and Instagram

 

Austin Nature in the City is sponsored by the Community Trees Division and part of the Development Services family. This is an interdepartmental collaboration to implement the Imagine Austin and Austin's Urban Forest Plans

 

 

Nature in the City – Austin
Jan 26, 2018 - 10:23 am CST

How Tree Roots Work Part I  |  How Tree Roots Work Part III: Mycorrhizae

 

Image | Severing roots along one side of the stem often leads to the tree falling the other direction. Image courtesy International Society of Arboriculture.

Image | Courtesy of the International Society of Arboriculture.

Severing roots along one side of the stem often leads to the tree falling the other direction. 

 

There are two main types of tree roots: anchoring roots and feeder roots. Most roots are near the surface, as we described in Tree Roots and How They Work, but anchoring roots are often much deeper. As they grow outward, they can send “sinker” roots straight down to add to their strength. A single root can’t hold up much weight, but the network of large and small roots work together to hold the tree upright and keep the soil in place. Generally, roots on one side of the tree keep it from falling the other way. This is why we should never cut a trench right next to a tree trunk. A trench this close removes almost half the tree’s roots causing instability and reduces access water and nutrients.

 

Image | Tiny root "hairs" as small as .2 mm in diameter help trees absorb water and nutrients. Image courtesy gibneyCE.com

Image | Tiny root "hairs" as small as .2 mm in diameter help trees absorb water and nutrients. Image courtesy gibneyCE.com

 

Anchoring roots live for years and years, but feeder roots die and are replaced often, much like skin cells. They typically live within six inches of the soil surface because they must have access to air and moisture, which are not always present in deep soil. To help take in water, the interior of root cells is slightly salty; water naturally flows into the saltier solution because nature always seeks a balance, i.e. osmosis (click to learn more about osmosis). If a lot of salt is added to the soil (such as road salt or chemical fertilizers), it can cause a reverse effect. Moisture flows out of the tree to dilute the soil salts. The plant can wilt or even die. This is one big reason we should always pay attention to the labels and instructions for any chemicals we apply in our lawns and gardens.

 

Illustration | Idealized drawing of a tree's roots.

Illustration | Idealized drawing of a tree's roots.

 

Roots support the tree and absorb water and nutrients. They transport these liquids through tiny tubes that run all the way up the stem to the leaves. This allows the tree to send its resources from one area to another. Some tubes, called xylem, mostly carry water from the soil to the leaves. Other tubes, called phloem, mainly carry sugar and other products made in leaves to parts where they are needed. When the tree is strong and healthy, it makes more than it needs and stores the excess in roots, trunks, and branches. Then, when the tree is under stress (like from drought, disease, or pests), it can rely on the stored materials to survive until conditions improve. 

 

Image | Even when the soil under the trunk is eroded, the network of roots holds the tree up.

Image | Even when the soil under the trunk is eroded, the network of roots holds the tree up.

 

Roots support trees and help to reduce soil erosion. They absorb water and other useful compounds from soil that the tree uses to make food and other resources. They sometimes make defensive compounds  to protect the tree when pests invade, and hormones to help control when leaves should drop. Roots also serve as storage centers for resources the tree can rely on during stressful times. 

In our next installment, we will look even more closely at the finest roots and the fungal network that connects trees together in a giant communications network.

 

How Tree Roots Work Part I  |  How Tree Roots Work Part III: Mycorrhizae

Article contributed by Keith Babberney, Forester with the Community Tree Preservation Division in the Development Services Department. Questions? Email Keith.

Nature in the City – Austin