In the Deep Midwinter: Update on Projects
Suddenly, the mornings are filled with of the sound of white wing doves calling one another. Only a week or two ago temperatures stuck near freezing. Mother Nature sure has had some serious mood swings this winter! Typically we expect the coldest weather to arrive soon after the New Year, but a kink in the jet stream served up raw weather right after Halloween and continued through February. The mornings seemed darker and colder than I remembered. In our old Victorian house in Austin, my husband Jack, like the father in A Christmas Carol, wore a stocking cap to bed. I can deal with the cold, but what is worrying me now is that none of these arctic fronts have brought rain with it, and once promising conditions for a good spring are dwindling.
Winter is a time to pause and evaluate conditions of previous projects, and to plan for the next growing season. It's also the time to do most of the heavy work. Let me recap what has been going on with some of the projects we've been working on.
Early fall of 2013 brought us long-awaited rains following a disappointing winter and spring. In September, Marschall Creek had a five-inch rise, beautifully scouring out the mucky pools and clearing the shrubs and weeds that had colonized the arid sandbars. Can you show me anything more beautiful in Central Texas than the sight of clear, flowing water?
However, abundant fall rains also triggered an explosion of vicious invasive cool season weeds like bastard cabbage (Rapistrum rugosum) on the roadsides, and, in our case, Malta star thistle (Centaurea melitensis). We are noticing this horrible thistle cover big areas where it had never been seen before. Spotting this vicious weed everywhere kind of drains some of the excitement of also seeing germinated bluebonnets and other wildflowers. Previously, I had tried to tackle "hot spots" of Malta star thistle by weeding or mowing, but there is just too much of it this year to even begin to try that method. Chemical control of broad leaf, tap-rooted weeds usually has to be applied in fall as a pre-emergent treatment, and furthermore, herbicides effective on this plant tend to eliminate most plants in the surrounding area, leaving little behind that could have competed with the noxious invaders. So we are left with regarding this year's explosion of Malta start thistle as part of a cycle, and to hope we learn other ways of dealing with it. One report said that Malta star thistle needs light to germinate, so presumably, if we increase our grass cover, this weed will diminish. We shall see.
Landowner Incentive Program Grant Area
In the Landowner Incentive Program (LIP)grant area area (see 2012 archives:"Landowner Incentive Program at Loyal Valley"), we had to make another pass through the zones to clear re-growing white brush, tasajillo, prickly pear, and persimmon. We did not see any fall germination of the seed we had planted the previous year, although the area did fill in somewhat with self-seeding green sprangletop, side oats grama, white tridens, and windmill grass from the surrounding areas. We are going to hold off sowing another round of our original seed mix (yellow Indian grass, Eastern gama grass, inland sea oats, purpletop), until fall of 2014, by which time we should know if these particular species are likely to germinate, even in small amounts, in the desired locations.
We also began to replace the original brush corrals built during the first round of clearing (October 2012) with fencing. The purpose of enclosing trees is to protect naturally occurring hardwood seedlings from browsing by deer. As discussed earlier, we seldom see 3, 4, or 5 ft trees in our woodlands. Nursery grown trees planted in the field generally have a low survival rate, even when given water the first year. While we are not wild about the looks of fencing here and there in the woodlands, it's our only hope of having some trees around for future generations.
Each year brings a different combination of conditions that favor different plants. The lack of consistent rainfall during the winter of 2012 through the summer of '13 suppressed or killed off grasses in certain areas. Yet we were astonished once again at how quickly some grasses recovered and immediately set seed once rains returned in September 2013. Last fall we saw large colonies of grasses such as Arizona and Texas cottontop, showy chloris, windmill grasses, the typical three-awns, and, less welcome, the exotic Wilman lovegrass and KR bluestem. And yet the higher value bunch grasses such as yellow Indian grass, Eastern gama grass, and little bluestem that we sowed in the LIP zones has yet to make an appearance. Why do we want these grasses? Because they have deeper roots and above ground mass which help improve the soil's ability to absorb rainfall, to improve micro-organism activity and soil condition. These are the perennial grasses that help make the ground a "sponge" and thus improve the function of a watershed.
Lessons Learned to Date in the LIP areas:
- Future clearing of re-sprouting persimmon will include selective cut-trunk treatment with triclopyr. We had been told by a number of "experts" that there was no safe chemical treatment for these plants, but Steve Nelle, retired NRCS range specialist, set us straight and now we are ready to try this method. Pruning re-sprouts for two years or more is a ridiculous chore, although the combination of drought and cutting back are finally begin to weaken new growth.
- To hasten recovery in the clearings we made, it might be worthwhile to try a few grass plugs instead of relying only on seeds. We know that these former thickets need a lot of "inputs" of seed, disturbance, and monitoring for brush, but we should have added grass plugs as one component for comparison.
- A forestry mower provides the advantage of not having to burn big piles of brush, and adds organic material to the ground, but we discovered that this equipment is not the right tool to use on re-sprouting species. Cost of the project continued to rise as we found ourselves having to make two more aggressive passes to dig up remnant re-sprouts.
- Even low-value annual grasses like old field three awn have a role in the self-repair of the grasslands. The thin "fuzz" of this grass at least provides organic material over bare ground, some shade and cooling, and helps cushion the soil, which in turn helps make the site more receptive to successful germination of perennial grasses. We will see how long it takes these areas to become dominated by perennial bunch grasses.
In the Creekside Conservation Project area (see archives 2013:"Creekside Conservation Program 2013"), we observed some germination of the seed we planted in January in the areas cleared of prickly pear, but the seedlings did not survive the summer drought. Only under the shade of scattered trees did we see any grass survive and set seed. Returning to the same area a year later, we devoted several days of hard work breaking apart the big dirt and prickly pear piles carelessly made by one contractor, into smaller piles so that they could be burned effectively. After burning a few of these piles in January, we sowed seed and covered with branches for protection. Unfortunately, as the weather turned dry, we were only able to burn about 1/3 of the piles.
Lessons Learned from the Creekside Conservation Project:
- A tractor used in a sloppy, hasty way to scrape the ground is not an effective way to remove prickly pear. The pads scattered by the tractor actually "planted" more pear in different areas. Hogs are also very bad about spreading cactus and tasajillo. Cost of the project continues as we will have to make more passes to pull up scattered pads and overlooked low-growing cactus.
- The up front cost of hand clearing cactus is out of reach for most people. However, careful removal by hand and small tractor means that recovery time is shorter because there is less soil disturbance and certainly less re-growth of cactus. Future reports will show an implement we had custom made for our tractor that should be a good compromise technique for this overwhelming time. Do it right the first time is definitely something to strive for.
Despite erratic weather patterns and the sometimes discouraging results of seedling survival, after nearly five years of ambitious conservation practices, we are slowly seeing results. Increased grassland, greater canopy cover, and less bare ground can be attributed to:
- allowing the land to rest from grazing
- stabilizing areas prone to soil erosion
- selectively removing brush to open up more areas
- always following brush and cactus removal and brush pile burning with sowing native grass seed, and changing the seed mix as we observe what species are increasing on their own.
Searching for the Best Ways to Remove Carrizo (Arundo Donax)?
Last summer, I was asked to help The Contemporary Austin (formerly known as The Austin Museum of Art) to help initiate a stewardship plan for Laguna Gloria - the museum's historic 12 acre property on Lake Austin. Following an ecological assessment report by Siglo Group, I organized a team to work on specific projects designed to hasten the recovery of this site. Although the floodplain woodlands are threatened by aggressive invasive species and diminished by decades of neglect, Laguna Gloria is the third most popular birding site in Austin, with over 160 species observed there. The Contemporary intends to create a place-based sculpture park that showcases nationally and internationally acclaimed artists in a natural setting that represents the fragile and iconic beauty that Austin is so well known for.
This report focuses on the results of efforts to eradicate one of the site's most challenging invasive species: giant cane or carrizo (Arundo donax). Carrizo is one of the largest members of the grass family with origins in Arabia or the Near East. It was introduced to Mexico by the Spaniards, and rapidly spread to our area and beyond. Carrizo is a serious threat to lowlands, rivers and other waterways because it forms huge persistent colonies that quickly overwhelm the shoreline, blocking access for wildlife and livestock, smothering other plants, and soaking up large quantities of water. The problems this plant causes, especially in drought cycles is so severe that the The Texas Nature Conservancy decided last year to devote significant resources to removing it from the Blanco River. As we discovered, carrizo is very difficult to remove and control.
Laguna Gloria's 12-acre site had seven significant colonies of carrizo growing in the lower grounds. On June 28, 2013, five colonies were sprayed with herbicide according to protocols established by the City of Austin Watershed Protection Department. One stand of carrizo growing among valued hardwood trees was treated with a 5% solution of imazamox (Clearcast), blended with a 1% solution of methylated seed oil (Intergy) as a surfactant. Imazamox was recommended because it poses less risk to non-target species. The remaining free standing carrizo colonies were sprayed with a 2% imazamox (Clearcast) solution combined with 1% glysophate (Aquamaster), with the same 1% methylated seed oil as surfactant.
In a few short weeks following the initial treatment, it was clear that the carrizo treated with combined herbicide was declining at a much faster rate than the one colony treated with imazamox alone. Also evident was the collateral damage from over-spray, but most non-target species affected in these locations were invasive species such as Japanese ligustrum and Chinese tallow, which were scheduled for removal anyway.
We were advised that herbicide treatment, especially imazamox, requires a significant amount of time (six months to a year) to complete the demise of carrizo, and therefore mechanical removal should not be initiated prematurely. However, we had to remove one large stand two months after being sprayed to clear the location for a sculpture installation in mid-September. Although some canes were still green, this clump was clearly in decline before it was removed.
This particular stand of carrizo was about 90-100 feet long, and about 40 feet wide, growing along the shore of Lake Austin. Here the soils are sandy on the surface, with heavier clay below. Earlier in May 2013, a previous contractor attempted to remove the carrizo with a skid-steer or bobcat tractor. This method was not successful because the excavated rhizomes quickly became mashed, compacted, and buried 24 inches or deeper. Two museum facility staff employees then spent two days trying to separate and load the loosened rhizomes for disposal, until the difficulty of making a significant dent in removing the material overwhelmed them.
The result was a superficial "clearing" that was short-lived. Within a month, the carrizo grew back to almost six feet. The machine had cut and scattered many of the large rhizomes into smaller pieces, thereby distributing it further. More disappointing, future efforts to remove the packed rhizomes was found to be much more difficult than digging an adjacent undisturbed stand.
On June 26, 2013, this same stand of carrizo was sprayed with the combined imazamox/glysophate mixture, and by late August, at least the top growth was 70% dead.
A second "touch up" herbicide treatment of previously sprayed carrizo (except the one removed) took place 8/21/13 to make sure that there were no overlooked live canes growing in any one stand. In addition, two more clumps not included in the first pass were treated.
Still searching for a way to reduce the amount of hand labor, we then brought in a small excavator with track wheels to learn if it would be more effective in digging up the rhizomes. Very quickly it became apparent that this machine also made "double work", as the contractor put it, because the excavator just dug up clumps of heavy soil that then had to be picked apart anyway by the workers to remove the rhizomes.
The workers decided to tackle the entire colony by hand, using picks to remove the rhizomes. After the area was cleared, the crew installed check logs to help stabilize the loose soil along the shoreline.
It's impossible to exaggerate how brutal the work of removing big stands of carrizo is, especially in the summer. Although it is not "skilled" work, it requires tremendous strength and endurance. The challenge of finding and keeping willing workers who will complete a project of this kind is a serious consideration in any carrizo-removal strategy.
At the end of the job, the crew estimated that they had removed 95% of the rhizomes and cut material. Yet not one week had gone by before we saw a dozen or so new sprouts emerging from pieces of rhizomes left behind. At this stage, though, they are easy to remove. A second pass two months later removed the remaining sprouts, but it will still be important to monitor this area next spring, particularly along the shoreline.
In January 2014, the crew returned to dig up the two largest remaining carrizo colonies, to make room for sculpture installations, and to give visitors more views of Lake Austin, which had been completely blocked off. Workers found that most of the top growth of the treated clumps was dried and dead, but many of the rhizomes still had active buds and full, fleshy structure with the potential to re-sprout when conditions are right.
- On this site, heavy equipment did not prove effective in digging up the rhizomes. After this experience, the contractor said that even in gravelly or sandy soils, it would still be a problem separating the rhizomes from the soil. Trying to save labor costs by using heavy equipment to remove large amounts of soil that would then have to be disposed – with live rhizomes – to us seems to result in trading one problem for another, with the possible risk of also spreading carrizo. Furthermore, removal of carrizo growing along the shore could have unintended consequences of erosion and instability.
- As Mary Gilmore with the Watershed Protection department reported, the combination of glysophate and imazamox hastened the decline of carrizo much faster than imazamox alone.
- Budget planning for removal of carrizo should include haul off, chipping, check log installation along shore line, short-term and regular follow up monitoring, and, ideally over-seeding or planting of native shoreline plants. The rhizomes hauled from Laguna Gloria were chipped with other brush to make compost, thus eliminating the risk of re-distribution. However, this resource is not available in all communities.
- Because decisions were made after the project was initiated to speed up the timeline for removal of all the larger stands of carrizo on this site, the herbicide treatment could have been eliminated and the money spent directly on mechanical removal. For larger scale projects, such as long stretches of waterways chemical treatment and follow up is obviously more practical.
What I Learned From Aldo
Autumn in the upper Mid-West in early October was in its full glory the day we made our pilgrimage to Aldo Leopold's shack (now managed by the Aldo Leopold Foundation.) As we drove north from Madison, Wisconsin, the soft grey morning light shone on fields still green with standing corn ready for harvest. Along the rippling hills the leaves were turning russet and gold, signaling the change of seasons.
After a tour of the remarkable Foundation's visitor's center, we drove down a narrow rural road (once a faint wagon track for pioneers), to the Leopold family's small weekend cabin or "shack" so famously memorialized in The Sand Country Almanac. From Foundation director Buddy Huffaker, we learned that the landscape we explored that day is very different from what Leopold first saw when he bought the property in 1935. Instead of dense woodlands and open meadows, Leopold had purchased the depleted remains of a farm that was suffering from the added disaster of prolonged drought. The shack- a former chicken coop - was all that remained of farm structures.
In places you can still see the deep, exposed sand – as hard to walk across as any dune on Padre Island – that lies beneath the current vegetation. In this devastated scenery, Leopold mobilized his five children to plant tens of thousands of tiny pine trees. The Soil Conservation Service provided these and other trees (each the size of a No. 2 pencil) as part of the shelterbelt program designed to reduce soil erosion during the Dust Bowl era. (shameless self- promotion alert: I profiled several legacy shelterbelts in the Texas Panhandle in my last book, Yard Art and Handmade Places: Extraordinary Expressions of Home). Despite an over 90% mortality rate for the first three years, the family kept planting until finally they got a break in the weather pattern that allowed the seedlings to survive. The pine trees stabilized the eroding land, provided shelter and structure for wildlife, and shady protection so that hardwoods and other plants could slowly fill in.
Eighty years later some of those same trees were harvested to build The Leopold Center - -a LEED platinum-rated visitors education center.
It was deeply reassuring to walk beneath these trees and realize that it is possible to redeem certain exploited landscapes after all their resources had been used up. Our trip to the Leopold Center was part of the International Conference for the Society for Ecological Restoration held this fall in Madison. All week long I had been listening to scientists from around the world report on research aimed at understanding the complex mechanisms involved in helping landscapes to recover or to remain intact in the face of accelerating pressures. Underlying almost all the presentations were adjustments to the once confident assertions of 25 years ago that scientific know-how would be able to return compromised natural systems to an idealized historic state. In 1991, SER defined restoration as “The intentional alteration of a site to establish a defined indigenous, historic ecosystem that emulates the structure, functioning, diversity, and dynamics of previous ecosystems”. In 25 years, this relatively young science has revised that definition to reflect a new reality of overwhelming challenges. Restoration is now described as “The process of assisting the recovery of an ecosystem that has been degraded, damaged, or destroyed.” The question remains, however, what does recovery look like, and how long does it last?
Like an enchilada, language and terminology can be very rich and satisfying, but you don't know what exactly it's made up of until you unwrap it. Listening to the presentations, I was struck by the scientist's ardent search for a common vocabulary that they could load with values and meanings. Like most disciplines, terminology is often used as a sort of special code recognized by insiders, and as a short-hand reference to multi-layered concepts. What is not so clear is how this vocabulary influences action on the ground. Does it inform our strategies or does it distance us from the real work involved?
Replacing the formerly ambitious quest to restore ecological communities to historic (meaning, in North America, pre-European settlement) conditions, the words at the conference were much more urgent and restricted. Scientists used words like "triage" "recovery" and "resiliency" to describe objectives and strategies required to rescue those landscapes that had the greatest likelihood of responding positively to intervention. Correspondingly, presenters discussed the necessity of admitting defeat when certain landscapes pass a tipping point, placing them beyond redemption. Instead of "historic reference communities", terms like "novel landscapes", (not to be confused with novelty landscapes like The Magic Kingdom). Novel landscapes are those places inhabited by a combination of indigenous and exotic species, in which invasive species, like the Visigoth swarms of yore, often get the upper hand. Today, our measurement for success is more often according to "ecological services" that natural communities can provide (like erosion control, water quality enhancement, habitat, etc.) rather than species purity or even biodiversity.
To me, these assessments of the global situation are by necessity much more realistic and effective in terms of planning strategies for action, and reflect what experience in this new field has taught us as we now recognize that we face diminished possibilities in a world under assault by climate change, population surge, invasive species, and loss of biodiversity. Even so, when researchers borrow terms from medical trauma protocol to describe a course correction in research that limits scope and expectations, it's hard to not feel discouraged about the overall picture. Somehow it doesn't just feel different, it feels less.
Still, there were voices at the conference who asserted the importance – even necessity – of maintaining an aspirational approach to work in this field. "If we can't hope that some of our work might make a difference, then what are we doing here?" one professor from New Zealand asked the audience. "We have to try something".
I stood in the deep sand along the banks of the Wisconsin River on Leopold's property and tried to process all the information and messages I had been listening to all week. I thought of Aldo Leopold, who saw this used up piece of land's potential to serve as a laboratory in which to work out his ideas of conservation and the concept that all of nature is connected, necessary, and has purpose. By planting non-native pine trees, he created a "novel landscape" that was desperately in need of triage so that it could recover and become resilient. In the distance, the drone of the interstate highway could be heard, stressing the point that Nature as an isolated idyll is, sadly, hard to find. The prairies reestablished by Leopold and the Foundation face new threats from climate change and invasive species, and require continual management to keep them intact. "How can we assure," he wrote," that both people and the land will prosper in the long run?" Through their own physical effort, the Leopolds engaged in partnership with their land, initiating positive change that would extend beyond their lifetimes in ways they could not predict. They acted in the faith that doing something had to be worthwhile. I may not have the right words for it, but I hope to do the same.