The Role of Central Texas Forests in Local Climate and Water Supply
Painting by Kathy Rottier commissioned by the Barton Springs/Edwards Aquifer Conservation District
Complex Relations of Global and Local Impacts to Climate
There are largely anthropogenic local impacts to climate.
Other larger scale factors including variation in solar radiation, anthropogenic changes to the atmosphere increasing greenhouse gases, El Nino/La Nina weather cycles (ENSO), volcanism, geomagnetical field reversals, meteorite impacts, etc..
Woodhouse, Connie A.; Meko, David M.; MacDonald, Glen M; Stahle, Dave W.; Cook, Edward R.; A 1,200-year perspective of 21st century drought in southwestern North America: Proceedings of the National Academy of Sciences, December 14, 2010, vol. 107, no. 50, p 21283-21288.
PART 1�Trees Promote Soil Infiltration/Aquifer Recharge and Reduce Flood-Causing Runoff
Forests Diminish Runoff & Increases Infiltration
Bosch JM, Hewlett JD,1982. A review of catchment experiments to determine the effect of vegetation changes on water yield and evapotranspiration. Journal of Hydrology, 55, 3–23.
Ellison D, Morris CE, Locatelli B, Sheil D, Cohen J, Murdiyarso D, Gutierrez V, van Noordwijk M, Creed IF, Pokorny J, Gaveau D, Spracklen DV, Tobella AB, Ilstedt U, Teuling AJ, Gebrehiwot SG, Sands DC, Muys B, Verbist B, Springgay E, Sugandi Y, Sullivan CA. (2017). Trees, forests and water: cool insights for a hot world. Global Environmental Change, 43, 51-61.
Farley, K.A., Jobbágy, E.G., Jackson, R.B., 2005. Effects of afforestation on water yield: a global synthesis with implications for policy. Glob. Change Biol. 11, 1565–1576. https://doi.org/10.1111/j.1365-2486.2005.01011.x
Jackson RB, Jobbágy EG, Avissar R, Roy SB, Barrett DJ, Cook CW, Farley KA, Le Maitre DC, McCarl BA, Murray BC (2005) Trading water for carbon with biological carbon sequestration. Science 310:1944–1947.
Additional Studies
Leite, Pedro A M; Wilcox, Bradford P; and McInnes, Kevin J. 2020. Woody plant encroachment enhances soil infiltrability of a semiarid karst savanna: Environmental Research Communications, Volume 2, Number 11 Available from: https://iopscience.iop.org/article/10.1088/2515-7620/abc92f
Lindley, Adrien L. 2002. The Hydrologic Function of Small Sinkholes in the Edwards Aquifer Recharge Zone: Thesis University of Texas at Austin,Texas. 100 p. https://repositories.lib.utexas.edu/items/144c1c05-518f-467e-bd92-586fad7d3c26
Roots Enhance Soil Infiltration
Thurow, T. L., W. H. Blackburn, and C. A. Taylor. 1987. Rainfall interception losses by midgrass, shortgrass, and live oak mottes. J. Range Mgmt. 40(5): 455‐460.
PART 2
Views of Lake Austin in 1800’s
Site 2.0 miles Mount Bonnell (Hill and Vaughn 1898)
Site 1.2 miles. 1875 panting by Lungkwitz downstream of Mount Bonnell near current Davis Water Treatment Plant intake/Laguna Gloria.
Site 13.7 miles 1890 Santa Monica Springs (adjacent to current Commons Ford Park)
Note:
Austins First Reservoir 1893-1900�
When Austin dam was installed at the current site of Tom Miller Dam in 1893, creating Lake McDonald, the lake depth was 80 feet with storage capacity of 83.5 million cubic yards (Taylor 1900). Within 4 years in 1897 the storage capacity lost 38% due to silting, most intensely 14 miles upstream of Austin dam, around Santa Monica Springs, currently adjacent to Commons Ford Park. This amount of silt accumulation is equivalent to complete loss of 2 ft of soil over a 10,000-acre area.
On April 7, 1900, a large flood caused the severely leaking dam to collapse, killing at least 50. in 1921 federal forester William Ashe noted that the Austin dam “was on the Colorado, one of the clearest streams in Texas” and attributed its failure to upstream deforestation and erosion. (Miller, 2022)
Miller, Char. 2021.”Greed for Land”:W. W. Ashe and the environmental roots of he 1921 flood in Central Texas: Southwest Historical Quarterly v. CXXV,N 1 July 2021 p. 62-73.
Taylor TU. 1900. The Silting Up of Lake McDonald and the Leaks in the Austin Dam: Engineering News Feb 22, 1900 p 135.
Taylor T.U. 1923. Reservoir Loses 84% of Storage Capacity in Nine Years: Engineering News-Record Sept. 6, 1923, V91 N10 P 380-382. Available from: Engineering news-record : Free Download, Borrow, and Streaming : Internet Archive
Commons Ford
At Commons (Watson) Ford 15 feet or 79% of water filled.
Dr. Taylor’s observation that sediment focused near Santa Monica Springs was verified by 1918 river-wide flow survey.
Texas Board of Water Engineers. 1960. Channel Gain and Loss Investigations Texas Streams 1918-1958: Bulletin 5807 D. 270 p.
Today there are old cut and burned stumps, young junipers, and complete loss of soil on hillslopes of Commons Ford Park.
Historical Association of Deforestation and Erosion
Redman (1999) and Hughes (1975) noted: that historically deforestation by humans over the past 8,000 years has had impacts on vast areas. Cutting trees for construction or fuel, grazing animals, fire, and landscape transformation such as draining wetlands, directing irrigation, enhancement of agricultural production. Over time the pre-existing native trees will not recover at all and with erosion of the soil and other disturbance. The result is destroyed habitat and drier landscapes more prone to wildfire. “In recent millennia humans have become the primary cause of increasing numbers of ecosystems being kept at early stages of the successional sequence.”
Based on cores taken worldwide and pollen analysis, Jenny (et al 2019) concluded that increased sediment accumulation rates associated with upland erosion were tied to deforestation. Sites without deforestation showed more constant sediment accumulation over time. In North America, high sediment accumulation rates did not occur until after widespread use of European agricultural practices.
Hughes, Donald J. 1975. Ecology in Ancient Civilizations. The University of New Mexico Press. 181 p.
Jenny, Jean-Philippe; Koirala, Sujan; Gregory-Eaves, Irene; Francus, Pierre; Niemann, Christoph; Ahrens, Bernhard; Brovkin, Victor; Baud, Alexandre; Ojala, Antti E. K.; Normandeau, Alexandre; Zolitschka, Bernd; and Carvalhais, Nuno. 2019. Human and climate global-scale imprint on sediment transfer during the Holocene: Proceedings of the National Academy of Sciences (PNAS) November 12, 2019 116 (46) 22972-22976; first published October 28, 2019 https://doi.org/10.1073/pnas.1908179116. Available from https://www.pnas.org/content/pnas/116/46/22972.full.pdf
Redman, C.1999. Human Impact on Ancient Environments. University of Arizona Press.240 p.
Deforestation Leads to Landslides on Steep slopes
Part 3 �Local and Worldwide Measurement of Local Vegetation/Soil Effects on Climate
First Austin Site-Scale Rainfall Water Balance
Recharge=Rainfall – Evapotranspiration (ET) – Runoff + Soil Moisture Storage
Runoff is measured using flume that continuously measures flow
Evapotranspiration (ET)
Hauwert, N.M. and Sharp, J.M. 2014. Measuring Autogenic Recharge over a Karst Aquifer Utilizing Eddy Covariance Evapotranspiration. Journal of Water Resource and Protection, 6, 869-879. http://dx.doi.org/10.4236/jwarp.2014.69081
Climate Towers
In 1984, less than 1% of rainfall was (erroneously) calculated to recharge the Edwards Aquifer through soil covered upland areas, which was the basis for much of Austin’s development
Cooperative UT climate tower, (with flumes, rain gauges and soil moisture sensors) along with data from other Central Texas stations.
Recharge=Rainfall – Evapotranspiration (ET) – Runoff + Storage
Found that an average of 28% of precipitation infiltrates through soil and karst features.
Soils are much more pervious than inferred since 1980’s.
Hauwert, N.M. and Sharp, J.M. 2014. Measuring Autogenic Recharge over a Karst Aquifer Utilizing Eddy Covariance Evapotranspiration. Journal of Water Resource and Protection, 6, 869-879. http://dx.doi.org/10.4236/jwarp.2014.69081
Hauwert, N., 2015, New Recharge Studies for Central Texas: From Hauwert N., Johns D, Hunt B ed, Austin Geological Society Guidebook 35. P. 65-74.
Compilation of Evapotranspiration Data Across Central Texas
HQ Flat Sink
Remainder is runoff + recharge + storage change
Losing stored soil moisture
Filling water storage
From Hauwert, N.M. and Sharp, J.M. 2014. Measuring Autogenic Recharge over a Karst Aquifer Utilizing Eddy Covariance Evapotranspiration. Journal of Water Resource and Protection, 6, 869-879. http://dx.doi.org/10.4236/jwarp.2014.69081
Higher ET in savanna than forest
Higher ET in forest than savanna
No difference in ET
Is High Evaporation and Transpiration Bad?
Ellison D, Morris CE, Locatelli B, Sheil D, Cohen J, Murdiyarso D, Gutierrez V, van Noordwijk M, Creed IF, Pokorny J, Gaveau D, Spracklen DV, Tobella AB, Ilstedt U, Teuling AJ, Gebrehiwot SG, Sands DC, Muys B, Verbist B, Springgay E, Sugandi Y, Sullivan CA. (2017). Trees, forests and water: cool insights for a hot world. Global Environmental Change, 43, 51-61.
Schneider U, Finger P, Meyer-Christoffer A, Rustemeier E, Ziese M, Becker A (2017) Evaluating the hydrological cycle over land using the newly-corrected
precipitation climatology from the global precipitation climatology Centre (GPCC). Atmosphere 8:1–17
FIELD MEASUREMENTS OF GRASSLAND VERSUS FOREST
Temperature measurements collected over a year in Meru National Park showed the open grasslands have higher surface temperatures, up to 25℃ (77°F) more than in forests or woodlands (Cerling et al. 2011).
Using Landsat coverages, Clifton Sabajo (2017) found temperature differences between forest and clear-cut land of up to 10° Celsius (18°F) in parts of Sumatra.
Meanwhile in the Amazon, Michael Coe of the Woods Hole Research Center recently reported a difference of 3 degrees Celsius (5.4°F) between the cool of the forested Xingu indigenous park and surrounding croplands and pastures.
Prevedello et al (2019) used global high-resolution temperature, forest cover, evapotranspiration, and albedo data to show that recently deforested areas have higher temperature rather than lower temperatures predicted from increasing albedo alone.
World-wide deforestation may explain as much as 18% of current global warming trends (Alkama and Cescatti, 2016).
From Cerling et al. 2011
Austin Summer 2021 Measurements
Maximum Daily Temperatures Measure 3 feet above ground
Example of Summer Heat of Surface
Ellison David, Pokorný Jan, Wild Martin. 2024. Even cooler insights: On the power of forests to (water the Earth and) cool the planet: Global Change Biology V 30. 20 p. DOI: 10.1111/gcb.17195 Available from: https://onlinelibrary.wiley.com/doi/epdf/10.1111/gcb.17195
Texas
High Plains summer, warm dry high pressure cell
Texas High Plains
2023 Drought High Pressure System Stationary over Central US Plains
How Do Forests Attract Rainfall?
Namias, Jerome. 1960. Factors in the initiation, perpetuation, and termination of drought: International Association of Scientific Hydrology Commission on Surface Waters Publication 51, p. 81-94.
Makarieva AM, Gorshkov VG, Li B-L (2009) Precipitation on land versus distance from the ocean: evidence for a forest pump of atmospheric moisture. Ecol Complex 6:302–307.
Sheil, Douglas. 2018. Forests, atmospheric water and an uncertain future: the new biology of the global water cycle: Forest Ecosystems (2018) 5:19. https://doi.org/10.1186/s40663-018-0138-y
Anticyclone
Namias, Jerome. 1960. Factors in the initiation, perpetuation, and termination of drought: International Association of Scientific Hydrology Commission on Surface Waters Publication 51, p. 81-94.
Wehrli, K., Guillod, B. P., Hauser, M., Leclair, M., & Seneviratne, S. I. (2019). Identifying key driving processes of major recent heat waves. Journal of Geophysical Research: Atmospheres, 124, 11,746–11,765. https://doi.org/10.1029/2019JD030635
Terrestrial Moisture Promoting Local Rainfall
Shukla, J. and Mintz, Y. 1982. Influence of Land-Surface Evaporation on the Earth’s Climate: Science V 215 p 1498 -1501. 0036-807518210319-1498SO1.0010
Forest Regrowth After 1940’s Livestock Climax Followed by Increasing Streamflow
Wilcox, B. P., and Y. Huang (2010), Woody plant encroachment paradox: Rivers rebound as degraded grasslands convert to woodlands, Geophys. Res. Lett., 37, L07402, doi:10.1029/2009GL041929.
Analysis of Central Texas Temporal Trends Finds Wetter Period Since 1960
Hunt, B. B., B. A. Smith, R. Slade, Jr., R. H. Gary, and W. F. K. Holland, 2012, Temporal trends in precipitation and hydrologic responses affecting the Barton Springs segment of the Edwards Aquifer, Central Texas: Gulf Coast Association of Geological Societies Transactions, v. 62, p. 205–226.
Pielke et al (1999) modeled South Florida vegetation changes between 1900 and 1993 and correlated deforestation with 0.7%C increase in temperature and 11% decrease in rainfall up to 1993.
A study in Malawi found that a 14% deforestation within the last decade corresponded to a 9% decrease in rainfall (Mapulanga and Naito 2019)
Pielke RA, Walko RL, Steyaert LT, Liston GE, Vidale PL, Lyons WA, Chase TN. 1999. The influence of anthropogenic landscape changes on weather in South Florida. Mon Weather Rev. 127:1663–1673.
Mapulanga, Annie Mwayi and Naito, Hisahiro. 2019. Effect of deforestation on access to clean drinking water: Proceedings of the National Academy of Sciences, 116 (17) 8249-8254;
Studies Measuring Modern Rainfall and Deforestation
Wildfire Risk
Campbell, Tristan; Bradshaw, S. Don; Dixon, Kingsley W; and Zylstra, Philip. 2022. Wildfire risk management across diverse bioregions in a changing climate: GEOMATICS, NATURAL HAZARDS AND RISK VOL. 13, NO. 1, 2405–2424 https://www.tandfonline.com/doi/full/10.1080/19475705.2022.2119891
Lindenmayer, David and Zylstra, Phil. 2023. Identifying and managing disturbance-stimulated flammability in woody ecosystems: Biol. Rev. (2023), pp. 1-16. doi: 10.1111/brv.13041
Higher Wildfire Risk with Tree Logging
long-unburned forest was least likely to experience large wildfires. Our results () showed that forest and woodland regions had the strongest and most persistent negative relationship to the likelihood of very large wildfires if less prescribed burning had occurred in the region in the prior 30–45 years.
“long-unburned forest was least likely to experience large wildfires. Our results showed that forest and woodland regions had the strongest and most persistent negative relationship to the likelihood of very large wildfires if less prescribed burning had occurred in the region in the prior 30–45 years. “ (Campbell et al 2022)
Worldwide increases in wildfires have increased because of forest disturbance, including tree clearing, prescribed burns and increased agriculture “Where disturbance is found to stimulate flammability, then key management actions should consider the long-term benefits of: (i) limiting disturbance-based management like logging or burning that creates young forests and triggers understorey development; (ii) protecting young forests from disturbances and assisting them to transition to an older, less-flammable state; and (iii) reinforcing the fire-inhibitory properties of older, less-flammable stands through methods for rapid fire detection and suppression.” (Lindenmayer and Zylstra 2023)
Misconceptions about Austin Wildfires
O’Donnell, L. 2021. History of Fire Incidents On and Near Balcones Canyonlands Preserve Western Travis County, Texas April 1961–April 2020: Balcones Canyonland Preserve Investigative Report IP 202002. 92 p. Available from: (19) (PDF) History of Fire Incidents On and Near Balcones Canyonlands Preserve Western Travis County, Texas, April 1961-April 2020 (researchgate.net)
Campbell, Tristan; Bradshaw, S. Don; Dixon, Kingsley W; and Zylstra, Philip. 2022. Wildfire risk management across diverse bioregions in a changing climate: GEOMATICS, NATURAL HAZARDS AND RISK VOL. 13, NO. 1, 2405–2424 https://doi.org/10.1080/19475705.2022.2119891
Kellett, Michael J. ; Maloof, Joan E.; Masino, Susan A.; Frelich, Lee E.; Faison, Edward K.; Bros, Sunshine L. and Foster, David R. 2023. Forest-clearing to create early-successional habitats: Questionable benefits, significant costs: Forest Management Frontiers in Forests and Global Change Front. For. Glob. Change 5:1073677. https://doi.org/10.3389/ffgc.2022.1073677
Available from: https://www.frontiersin.org/articles/10.3389/ffgc.2022.1073677/full
White, J. and J. Thomas, D. Murray, M. Sides, and J. Yao. 2009. The Balcones Canyonlands Preserve fire risk and management: characterization of woodland fuels and simulated fire behavior in the wildland-urban interface. Spatial Ecology Laboratory, Baylor University.
Photos from 2011 Steiner Ranch Fire where houses and grassy areas were burned and tree fires were relatively minor
Air/Water-Quality Degradation by Fires
Feiger Erin. 2023. Research uncovers stunning factor behind nearly 200,000 cases of dementia each year: ‘Toxins for the brain’ :Cool Down 9/14/2023 https://www.msn.com/en-us/health/other/research-uncovers-stunning-factor-behind-nearly-200-000-cases-of-dementia-each-year-toxins-for-the-brain/arAA1gHHlP?ocid=msedgdhp&pc=U531&cvid=8c30c91bd5364edb886e77908ea42c28&ei=6
Lucotte, Marc; Campbell, Linda; Clayden, Meredith; Eckley, Chris; Harris, Reed ; Kelly, Mark; Kidd, Karen; Lean, David; Moingt, Matthieu; Paquet, Serge; Pannu, Ravinder; Parsons, Michael; Paterson, Mike. 2012. Influences of anthropogenic activities on mercury transport, methylation and bioaccumulation: Canadian Mercury Science Assessment Chapter 8. Environment and Climate Change Canada. Available from: Canadian mercury science assessment: summary of key results - Canada.ca (16) (PDF) Influences of anthropogenic activities on mercury transport, methylation and bioaccumulation (researchgate.net)
Cyberwest. 2001. Mercury emissions found in wildfire smoke: Cyberwest Magazine August 24, 2001. Available from: Mercury emissions found in wildfire smoke (cyberwest.com)
Pellegrini, Adam F,. A., Ahlström, Anders Hobbie, Sarah E., Reich, Peter B., Nieradzik, Lars P., Staver, A. Carla, Scharenbroch, Bryant C., Jumpponen, Ari, Anderegg.William R. L., Randerson, James T. & Jackson, Robert B. 2018. Fire frequency drives decadal changes in soil carbon and nitrogen and ecosystem productivity: 553 194-198, doi:10.1038/nature24668
Planas, D., Desrosiers, M., Groulx, S.-R., Paquet S. and Carignan, R., 2000. Pelagic and benthic algal responses in eastern Canadian boreal shield lakes following harvesting and wildfires. Can. J. Fish. Aquat. Sci., 57: 136-145. (17) Pelagic and benthic algal responses in eastern Canadian Boreal Shield lakes following harvesting and wildfires | Mélanie Desrosiers - Academia.edu
Scientific and History Questions Modern Tree Clearing/Prescribed Burning
“Land managers, elected officials, and members of the public must question some of our most deeply ingrained assumptions regarding fire. For the sake of fiscal responsibility, scientific integrity, and effective outcomes, it’s high time we abandon the tired and disingenuous policies of our century-old all-out war on wildfire and fuel treatments conducted under the guise of protecting communities.” Cohen and Stromaier 2020.
"Another potential source of early-successional habitats is the use of intensive forest management to increase climate “adaptation” and “resilience” of forests, which includes clearcutting, thinning, prescribed burning, and “assisted migration” through tree plantings…The assumed loss of management by Native people is also cited as a major cause of the transition now underway of many oak forests to forests dominated by shade-tolerant species. Native burning and other subsistence practices, such as hunting, fishing, plant gathering, and small-scale farming had notable ecological impacts in the immediate vicinity of native encampments and settlements in the Northeast and Upper Great Lakes regions. However, modern land managers seem to be inappropriately misinterpreting a set of novel landscape conditions created by European land use over the last few centuries as having pre-European origins. Extrapolating this misinterpretation to a regional scale has led to claims of widespread and intensive Native manipulation for millennia before European settlement. Unfortunately, these sweeping assumptions are being used to justify large-scale clearing and prescribed burning of established and recovering forests“ Kellett et al 2023.
Cohen, J., Strohmaier, D. 2020. Community destruction during extreme wildfires is a home ignition problem. Wildfire Today September 21, 2020. Available at: https://wildfiretoday.com/2020/09/21/community-destruction-during-extreme-wildfires-is-a-home-ignition-problem/#comments
Kellett, Michael J. ; Maloof, Joan E.; Masino, Susan A.; Frelich, Lee E.; Faison, Edward K.; Bros, Sunshine L. and Foster, David R. 2023. Forest-clearing to create early-successional habitats: Questionable benefits, significant costs: Forest Management Frontiers in Forests and Global Change Front. For. Glob. Change 5:1073677. https://doi.org/10.3389/ffgc.2022.1073677
Available from: https://www.frontiersin.org/articles/10.3389/ffgc.2022.1073677/full
Best Management Practices for Forests �
National Academy of Science 2008:
Of all the outputs of forests, water may be the most important—streamflow from forests provides two-thirds of the nation’s clean water supply. Removing forest cover accelerates the rate that precipitation becomes streamflow; therefore, in some areas, cutting trees causes a temporary increase in the volume of water flowing downstream. This effect has spurred political pressure to cut trees to increase water supply, especially in western states where population is rising. However, cutting trees for water gains is not sustainable: increases in flow rate and volume are typically short-lived, and the practice can ultimately degrade water quality and increase vulnerability to flooding…Removing trees for water yield can also cause degraded water quality (due to increased water temperatures and sedimentation), increased risk of flooding in downstream areas, and negative ecological impacts, such as loss of habitat and other ecosystem services otherwise provided by forests”
”Forest management practices evolve over time. The forces that modify forests today are triggering forest managers to institute novel and contemporary forest management practices. These new practices—such as thinning for fuel reduction and best management practices that manage wider riparian buffers for species protection—have not yet been assessed for their attendant hydrologic effects. Hydrologic effects of these contemporary management practices need to be understood over long temporal and large spatial scales.”
National Academy of Science National Research Council. 2008. Hydrologic Effects of a Changing Forest Landscape. Brief of Committee on Hydrologic Impacts of Forest Management. 4 p. Available from: https://nap.nationalacademies.org/resource/12223/forest_hydrology_final.pdf
Cases Where Deforestation and Soil Loss was Attributed to Climate Change�Case: Africa
Aronson, James L. Hailemichael, Million, Savin, Samuel M.. 2008. Hominid environments at Hadar from paleosol studies in a framework of Ethiopian climate change: Journal of Human Evolution V 55 p 532–550.
Levin, N. E., Brown, F. H., Behrensmeyer, A. K., Bobe, R. & Cerling, T. E. 2011. Paleosol carbonates from the Omo Group: Isotopic records of local and regional environmental change in East Africa. Palaeogeogr. Palaeoclimatol. Palaeoecol. doi:10.1016/j.palaeo.2011.04.026.
Wright DK (2017) Humans as Agents in the Termination of the African Humid Period. Front. Earth Sci. 5:4. doi: 10.3389/feart.2017.00004
Historical Greece
Plato wrote in 360 BC that over nine thousand years, Greece never experienced significant soil loss until after deforestation. As a result, the forests are gone, the soil is eroded away, the rainfall has diminished and springs ceased flowing.
The Greek landscape historically covered in evergreen oaks, pines, cypress, cedar, laurel, carob, and wild olives, was deforested for firewood, charcoal, lumber as well as wildfires that were accidental, or intentionally set for military operations and to create land suitable for livestock grazing (Hughes 1975; Ehrlich and Ehrlich 1980).
Plato wrote in 360 BC:�
The land was the best in the world…Many great deluges have taken place during the nine thousand years, .. there has never been any considerable accumulation of the soil coming down from the mountains, as in other places, but the earth has fallen away all round and sunk out of sight. The consequence is, that in comparison of what then was, there are remaining only the bones of the wasted body..all the richer and softer parts of the soil having fallen away, and the mere skeleton of the land being left. But in the primitive state of the country, its mountains were high hills covered with soil, and the plains, as they are termed by us, of Phelleus were full of rich earth, and there was abundance of wood in the mountains.
Of this last the traces still remain, for although some of the mountains now only afford sustenance to bees, not so very long ago there were still to be seen roofs of timber cut from trees growing there, which were of a size sufficient to cover the largest houses; and there were many other high trees, cultivated by man and bearing abundance of food for cattle. Moreover, the land reaped the benefit of the annual rainfall, not as now losing the water which flows off the bare earth into the sea, but, having an abundant supply in all places, and receiving it into herself and treasuring it up in the close clay soil, it let off into the hollows the streams which it absorbed from the heights, providing everywhere abundant fountains and rivers, of which there may still be observed sacred memorials in places where fountains once existed.
Plato, 360 B.C.E, Critias. Translated by Benjamin Jowett http://classics.mit.edu//Plato/critias.html
Modern Greece
Greece, like many places across the world (Lebanon, Northwest US, Australia, etc..) experienced a succession of deforestation, soil loss, diminishing rainfall, conversion to maquis shrub vegetation, and country-wide wildfire risk. The soil is too thin and degraded for forest succession.
In August 2007, Greece declared a state of emergency as 300 fires burned across Greece, killing 46, reaching the fringes of Athens, and destroying whole villages. (Smith 2007). In July 2018, about 50 brush, forest, and house fires burned across Greece, killing at least 88 (Smith et al., 2018).
Historical Cases (Continued)
Penny, Dan and Beach Tim. 2021. Historical socioecological transformations in the global tropics as an Anthropocene analogue: PNAS 2021 Vol. 118 No. 40 e2022211118. https://doi.org/10.1073/pnas.2022211118
Sequestration of Carbon Emissions
Ellison David, Pokorný Jan, Wild Martin. 2024. Even cooler insights: On the power of forests to (water the Earth and) cool the planet: Global Change Biology V 30. 20 p. DOI: 10.1111/gcb.17195 Available from: https://onlinelibrary.wiley.com/doi/epdf/10.1111/gcb.17195
Benefits of Forested Preserves
Conclusions
END
FOR FOREST – The Unending Attraction of Nature, installed in the 30,000-seat Wörthersee Stadium in Klagenfurt Austrian by curator Klaus Littmann, based on a 1970 drawing by Max Peintner
“Considering all the interests dependent upon the water supply of this region, there would seem to be little ground for opposing the policy of maintaining (and where necessary establishing) a forest cover upon these arid hills.” Bray 1904.
References
Aronson, James L. Hailemichael, Million, Savin, Samuel M.. 2008. Hominid environments at Hadar from paleosol studies in a framework of Ethiopian climate change: Journal of Human Evolution V 55 p 532–550.
Bala G, Caldeira K, Wickett M, Phillips, TJ, Lobell DB, Delire C, and Mirin A. 2007. Combined climate and carbon-cycle effects of large-scale deforestation: PNAS v 104 n 16. P 6550–6555. www.pnas.orgcgidoi10.1073pnas.0608998104
Betts RA. 2000. Offset of the potential carbon sink from boreal forestation by decreases in surface albedo: Nature 2000 Nov 9; v. 408 n. 6809 p 187-90.doi: 10.1038/35041545.
Cerling, Thure E.,; Wynn, Jonathan G.; Andanje, Samuel A.; Bird, Michael I.; Korir, David Kimuta; Levin, Naomi E.; Mace, William; Macharia, Anthony N.; Quade, Jay; & Remien, Christopher H. 2011. Woody cover and hominin environments in the past 6 million years: Nature August 2011, V 476 P. 51-56. doi:10.1038/nature10306
Ellison D, Morris CE, Locatelli B, Sheil D, Cohen J, Murdiyarso D, Gutierrez V, van Noordwijk M, Creed IF, Pokorny J, Gaveau D, Spracklen DV, Tobella AB, Ilstedt U, Teuling AJ, Gebrehiwot SG, Sands DC, Muys B, Verbist B, Springgay E, Sugandi Y, Sullivan CA. (2017). Trees, forests and water: cool insights for a hot world. Global Environmental Change, 43, 51-61.
Hunt, B. B., B. A. Smith, R. Slade, Jr., R. H. Gary, and W. F. K. Holland, 2012, Temporal trends in precipitation and hydrologic responses affecting the Barton Springs segment of the Edwards Aquifer, Central Texas: Gulf Coast Association of Geological Societies Transactions, v. 62, p. 205–226.
Jenny, Jean-Philippe; Koirala, Sujan; Gregory-Eaves, Irene; Francus, Pierre; Niemann, Christoph; Ahrens, Bernhard; Brovkin, Victor; Baud, Alexandre; Ojala, Antti E. K.; Normandeau, Alexandre; Zolitschka, Bernd; and Carvalhais, Nuno. 2019. Human and climate global-scale imprint on sediment transfer during the Holocene: Proceedings of the National Academy of Sciences (PNAS) November 12, 2019 116 (46) 22972-22976; first published October 28, 2019 https://doi.org/10.1073/pnas.1908179116. Available from https://www.pnas.org/content/pnas/116/46/22972.full.pdf
Levin, N. E., Brown, F. H., Behrensmeyer, A. K., Bobe, R. & Cerling, T. E. 2011. Paleosol carbonates from the Omo Group: Isotopic records of local and regional environmental change in East Africa. Palaeogeogr. Palaeoclimatol. Palaeoecol. doi:10.1016/j.palaeo.2011.04.026.
Namias, Jerome. 1960. Factors in the initiation, perpetuation, and termination of drought: International Association of Scientific Hydrology Commission on Surface Publication 51, p. 81-94.International Association of Scientific Hydrology Commission on Surface Waters Publication 51, p. 81-94.
Pielke RA, Walko RL, Steyaert LT, Liston GE, Vidale PL, Lyons WA, Chase TN. 1999. The influence of anthropogenic landscape changes on weather in South Florida. Mon Weather Rev. 127:1663–1673
Pyne S.J., 1998. Forged in Fire: History, Land and Anthropogenic Fire. In Advances in Historical Ecology, edited by W. Balee, p. 64-103. Columbia University Press, New York.
Plato, 360 B.C.E, Critias. Translated by Benjamin Jowett http://classics.mit.edu//Plato/critias.html
Sheil, Douglas. 2018. Forests, atmospheric water and an uncertain future: the new biology of the
global water cycle: Forest Ecosystems (2018) 5:19. https://doi.org/10.1186/s40663-018-0138-y
Shukla, J. and Mintz, Y. 1982. Influence of Land-Surface Evaporation on the Earth’s Climate: Science V 215 p 1498 -1501. 0036-807518210319-1498SO1.0010
References Continued
Smith, Helena; Jones, Sam; Farrer, Martin, 2018. Greece wildfires:scores dead as holiday resort devastated: The Guardian July 24, 2018, available from: https://www.theguardian.com/world/2018/jul/23/greeks-urged-to-leave-homes-as-wildfires-spread-near-athens
Smith, Helen. 2007. Fires sweep Greece turning villages to ash and killing 46: The Guardian. Available from: https://www.theguardian.com/world/2007/aug/26/greece
Wilcox, B. P., and Y. Huang (2010), Woody plant encroachment paradox: Rivers rebound as degraded grasslands convert to woodlands, Geophys. Res. Lett., 37, L07402, doi:10.1029/2009GL041929.
Wright DK (2017) Humans as Agents in the Termination of the African Humid Period. Front. Earth Sci. 5:4. doi: 10.3389/feart.2017.00004
Woodhouse, Connie A.; Meko, David M.; MacDonald, Glen M; Stahle, Dave W.; Cook, Edward R.; A 1,200-year perspective of 21st century drought in southwestern North America: Proceedings of the National Academy of Sciences, December 14, 2010, vol. 107, no. 50, p 21283-21288.
Bray’s 1904 Summary of Trees Benefits
Deeper rooted trees increase infiltration, reducing runoff, erosion and loss of soil.
Clearcutting forests increases erosion of soil and flooding problem.
Forests and soils together create water reservoirs.
Bray was aware of hypothesis that forests attracted rainfall but didn’t see enough evidence for it and believed people were simply observing the effects of forest/soil moisture reservoir.
Bray, William L. 1904. The Timber of the Edwards Plateau: Its relation to Climate, Water Supply, and Soil: U.S. Dept. of Agriculture Bureau of Forestry. Bull No. 49.
“Where disturbance is found to stimulate flammability, then key management actions should consider the long-term benefits of: (i) limiting disturbance-based management like logging or burning that creates young forests and triggers understorey development; (ii) protecting young forests from disturbances and assisting them to transition to an older, less-flammable state; and (iii) reinforcing the fire-inhibitory properties of older, less-flammable stands through methods for rapid fire detection and suppression.” (Lindenmayer and Zylstra 2023)
Bray 1904 Observations on Runoff
“One of the most important services of a forest cover is the mechanical effect which it exercises upon falling rain and upon the run-off. In this way it both checks erosion and promotes the entrance of water into the earth. In the first place, the crowns of the trees, especially when the foliage is on, break the force of the rain and cause it to run harmlessly down the trunk, or to drip slowly through the canopy. Further, the organic debris of the forest floor holds back the fallen water until it has time to soak into the soil. The spreading and interlacing network of roots serves the same purpose, and binds the soil fast against erosion. Thus the rain is kept from swift discharge into the streams, gullying is prevented, and the run-off does not gain sudden volume and velocity after a downpour. The removal of timber from broken or mountainous areas is pretty sure to be followed by more frequent and destructive floods.
A forest also increases the water supply from a region by increasing the moisture-holding capacity of the soil. The undecomposed litter which forms the upper layer of the forest floor will itself take up much water, as well as delay its run-off. A thick mat of leaves will be wet at a little distance down long after those on top have become thoroughly dry. Still lower, the half-decayed rubbish is like a sponge in its water-holding power. And finally, the humus, or forest soil proper, with its loose texture and large proportion of organic matter, is peculiarly fitted to delay percolation. Thus the forest builds up a storage reservoir, the loss of which often makes necessary the construction on a large scale of artificial lakes to conserve the water supply. This work the forest does not only without expense, but while itself growing wood. “
Albedo
Millán (2014) hypothesized that recent deforestation resulted in lack of summer storms in the Mediterranean and floods in Europe.
The figure shows the summer storm cycle on Western Mediterranean coasts where the sea, the soil moisture, marshes, river flow, and aquifer discharges all contribute to rainfall.
Millán M. 2014. Extreme hydrometeorological events and climate change predictions in Europe: Journal of Hydrology 518 (2014) 206–224.
Discrepancy in Rainfall Variation with Distance from Ocean
Makarieva AM, Gorshkov VG, Li B-L (2009) Precipitation on land versus distance from the ocean: evidence for a forest pump of atmospheric moisture. Ecol Complex 6:302–307
The amount of vegetation and soil not distance from coast is prevailing factor in rainfall
Sahara Desert of North Africa
Based on albedo alone, the Sahara sands should be reflective of incoming radiation and be cooler than vegetated areas in the same region. However, the average high air temperature of the desert exceeds 38 to 40 °C or 100 to 104 °F.
During daytime, the sand temperature is extremely high: it can easily reach 80 °C or 176 °F or more.
Vukovich (et al., 1987) measured the albedo anomaly within the sub-Saharan region of west Africa:
Otterman (1974) used airborne radiometer readings in the Sinai of African continent to find that:
A factor other than albedo is dominating temperatures.
Central United States: Local Soil Moisture Related to Droughts
Findell and Eltahir (1997) tested the hypothesis suggested by Shukla and Mintz (1982) that soil moisture increases local precipitation by comparing a 14-year soil moisture record in Illinois with precipitation. It found that summer initial soil moisture conditions were a strong predictor of drought or flood years.
Englehart and Douglas (2002) examined patterns of drought and flooding from 1910 to 2000 in central United States with large-scale climate modes, including El Niño Southern Oscillation (ENSO), and Pacific Decadal Oscillation, and found that antecedent soil moisture and vegetation growth were better predictors of extended dry conditions.
Englehart, Phil J. and Douglas, Arthur V. 2002. On some characteristic variations in warm season precipitation over the central United States (1910–2000): Journal of Geophysical Research, vol. 107, no. D16, 4286, 10.1029/2001JD000972
Findell, Kirsten L. and Eltahir, Elfatih A.B. 1997. An analysis of the soil moisture-rainfall feedback, based on direct observations from Illinois: Water Resources Research, vol. 33, no. 4, pages 725–735, April 1997
Summary
Ellison D, Morris CE, Locatelli B, Sheil D, Cohen J, Murdiyarso D, Gutierrez V, van Noordwijk M, Creed IF, Pokorny J, Gaveau D, Spracklen DV, Tobella AB, Ilstedt U, Teuling AJ, Gebrehiwot SG, Sands DC, Muys B, Verbist B, Springgay E, Sugandi Y, Sullivan CA. (2017). Trees, forests and water: cool insights for a hot world. Global Environmental Change, 43, 51-61.
Miralles, Diego G.; Gentine, Pierre; Seneviratne, Sonia L.; Teuling, Adriaan J. 2019. Land-atmospheric feedbacks during droughts and heatwaves: state of the science and current challenges. Annals of the New York Academy of Sciences, 1436 p 19-35. ISSN 0077-8923, doi: 10.1111/nyas.13912.Available from: https://nyaspubs.onlinelibrary.wiley.com/doi/epdf/10.1111/nyas.13912
National Academy of Science National Research Council. 2008. Hydrologic Effects of a Changing Forest Landscape. Brief of Committee on Hydrologic Impacts of Forest Management. 4 p. Available from: https://nap.nationalacademies.org/resource/12223/forest_hydrology_final.pdf
William Bray Obsevations on �Geological Influences on Vegetation�
More Recent Vegetation/Geology Correlations
Cuyler, R.H. 1931. Vegetation As An Indicator Of Geologic Format ions: AAPG Bulletin (1931) 15 (1): 67–78. https://doi.org/10.1306/3D932966-16B1-11D7-8645000102C1865D
DeCook, K.J., 1963, Geology and ground-water resources of Hays County, Texas: USGS Water Supply Paper 1612, 72 p.
Eggemeyer, Kathleen D.; Schwinning, Susanne. 2009. Biogeography of woody encroachment: why is mesquite excluded from shallow soils? Ecohydrology 2, 81–87 (2009) (www.interscience.wiley.com) DOI: 10.1002/eco.42
Hauwert, Nico M., 2009, Groundwater Flow and Recharge within the Barton Springs Segment of the Edwards Aquifer, Southern Travis County and Northern Hays Counties, Texas: Ph.D. Diss., University of Texas at Austin, Texas. 328 p. http://repositories.lib.utexas.edu/handle/2152/14107
Small, Ted A., Hanson, J.A., and Hauwert, N., 1996, Geologic Framework and Hydrogeologic Characteristics of the Edwards Aquifer Outcrop (Barton Springs Segment), NE Hays and SW Travis Co., TX: USGS WRI 96-4306. http://pubs.er.usgs.gov/publication/wri964306.
Historic Deforestation
Greely W.B.1925. The relation of geography to timber supply. Economic Geography v 1 p 1-14. https://journalcopernicus.eco/wp-content/uploads/2022/04/TheRelationOfGeographyToTimberSupply_1925.pdf
Central Texas experienced massive deforestation from the late 1800’s through the 1940’s.�
Buckley, S.B. 1874. First Annual Report of the Geological and Agricultural Survey of Texas. State Geologist 142 p.
O’Donnell. 2019. Historical ecology of the Texas Hill Country, Historical Accounts of Vegetation Communities from 1700-1900, with an Emphasis on the Eastern Edge of the Edwards Plateau: Austin Water Balcones Canyonland Technical Report. 35 p. https://www.researchgate.net/publication/331582514_HISTORICAL_ECOLOGY_OF_THE_TEXAS_HILL_COUNTRY
From Bray 1904
HEAT ISLAND
CLOUD FORMATION
HOT BARE SOIL
COOL COVERED SOIL
Cooling Effects of Vegetation
Research References