09 November 2015

Importance of Trees in South Texas

Importance of Trees in South Texas
By J. Cantu

With a steady increase of the world’s population now residing in cities, there is greater need to understand how the complex interactions between the natural environment and humans affect ecosystem services on multiple levels, especially for those that are particularly important in the functioning and resilience of urban areas. Ecosystem services, or the goods or benefits derived from nature, provide mankind with most necessities of life and survival (Brown, Bergstrp et al. 2007, Wratten, Sandhu et al. 2013), and are often divided into separate categories : supporting services (such as water and nutrient cycling), provisioning services (i.e., production of food, fuel, and timber), regulating services (such as rainwater retention, carbon sequestration), and cultural services (aesthetic and spiritual values) (Sandhu and Wratten 2013). We know nature provides a multitude of services to the community, yet a commonly underappreciated function, is the growth of urban trees.
This is a common sight when it rains in the valley. When looking at the street, many buildings, streets, and sidewalks can be seen. These impervious surfaces prevent water from draining and causes flooding. On the other hand, there is only a handful of trees that can be seen. Trees function like retention/detention structures (Nowak and Dwyer 2007), ultimately slowing down the rate of runoff. As the amount of impervious surfaces increases with urbanization, it becomes increasingly difficult to mitigate storm water runoff and cost-effective options become limited (Barber, King et al. 2003). Due to urban areas consisting of mostly impermeable structures, rainwater tends to collect and cause flooding. When flooding can be attributed to inadequate city drainage, this can be a result of poor urbanization practices (Pelling 2003).  
Anyone who has lived in the Rio Grande Valley, knows about the valley heat, especially in summer. Urban trees cast shade and can shield from the wind, in which alters the neighboring heat islands which can directly reduce solar heat gain through windows, walls, and roofs (Akbari 2002). Trees also lower surrounding air temperatures through evapotranspiration cooling, which can in turn lead to cooler temperatures and less smog formation (McPherson, Nowak et al. 1997, Akbari 2002). According to Dwyer, McPherson et al. (1992), the annual space air-conditioning and heating cost for a home with efficiently placed trees can be 4% lower, while a home with conflicting placed trees can cost up to 9% more.
Trees also help sequester a range of pollutants, even the pesky greenhouse gases. Trees sequester carbon from the atmosphere during their growing phase. Although trees are not the answer for reducing atmospheric carbon, they work as a short term carbon sink as they grow (Jo and McPherson 1995). Airborne pollutants are also a consequence of urbanization, and the removal of airborne particulates is a health benefit that is of interest (Jim and Chen 2009). These airborne chemicals can be sequestered as well by trees, allowing people to avoid harmful pollutants. If urban forests can be promoted as means of mitigating pollution within the scope of urban sustainability, then they can be used to improve quality of life for people around the world (Escobedo, Kroeger et al. 2011).
            In a study completed on the University of Texas- Pan American campus, four regulating services (rainwater retention, electricity savings by shade cast, pollution and carbon sequestration) were estimated and valuated. As seen in the figure, the trees on campus provide services the university. These trees have worth and these trees are not just bound by the services described above. These few services only cover a fraction of what trees can do for the community. These above services only slightly cover the regulating services group. Trees also provide provisioning services (lumber and fruits), cultural services (education and recreation), and supporting services (habitat and biodiversity).

Trees should not be considered only as money sinks, but should be seen more as assets. Trees provide a plethora of services, and should be appreciated for it. With this knowledge, the old proverb rings true, “The best time to plant a tree was 20 years ago, the next best time is today.”

07 October 2015

Population Growth in Texas with Emphasis on South Texas

Population Growth in Texas with Emphasis on South Texas
            Throughout the world, an ever-increasing population has shown to become a concern regarding space and resources.  With resources already limited, there has been interest to implement more sustainable methods of harvesting resources and methods of usage.  There have been multiple estimates done to show how the population will increase in the future. Here we will show how the population in Texas is predicted to increase with a focus on south Texas.

Figure 1. Projected Population in Texas from 2010 to 20501

              In a population projection compiled by the Office of the State Demographer and the Texas State Data Center, three different migration scenarios were considered.  As shown in Figure 1, there is a scenario with zero migration, one with migration patterns observed in Texas between 2000-2010 (scenario 1.0) and another with half the migration of 2000-2010 (scenario 0.5)1.   These three trends show significantly different population outcomes. The 1.0 migration scenario produces almost triple the population of the zero migration option. Growth in Texas will be greatest in four areas- Dallas, Houston, Austin and the Rio Grande Valley (Fig. 2). One of the notable features of south Texas that will be affected by population growth is high biodiversity (lots of species of plants and animals). As with humans, these organisms need space and resources which will become less common.

Figure 2. Counties along the southern border and select counties in the Panhandle are expected to experience rapid growth now to 2050. Source: http://osd.state.tx.us/Publications/2014-11_ProjectionBrief.pdf

With the inevitable increase in population, people must consider the availability of resources. Such resources would include water, agricultural products, mining products and even space.  The Texas Water Development Board released a report for south Texas called Region M (Table 1) with the expected population increase from 2020 to 2070. As can be seen, the population of south Texas is expected to roughly triple in the next 50 years. With this increase in population life in the LRGV will change; there will be great increase in the development of land, a greater  need for already limited water, a greater demand of a variety of resources, decrease in air quality, etc.  This increase in population will not only effect people, but will also spread to other animals. The development of land for human use reduces the land available for native plants and animals, which can endanger their populations and even further endanger already sensitive populations.

Table 1 Projected Population for Counties in the LRGV2
Examining the range of impacts a larger human population can have on the surrounding environment should be considered such as habitat loss and/or degradation. A population (human or animal) must be able to survive with the resources available and to do so resources must be managed in a sustainable manner.To sustain any human or animal population, the availability of resources must be done in a sustainable manner to maintain adequate yields for present and future populations.  People might also consider the effect that the increase of human population will have on the other living creatures.  Animals also need space to populate and food sources (like plants) to be readily available.  Many animals are already suffering from the presence of humans, especially animals that require large roam areas, such as deer, bison, moose, and elephants.

08 September 2015

Sept. 15- Public Hearing for proposed natural gas well in Edinburg

The hearing will be at Edinburg City Hall. This well site is the second site proposed by the company, Royal Production Company. The first was in McAllen and was not received well by residents near the proposed drill site.

See link below for Monitor article on the hearing:


For images of gas wells being drilled see:


26 June 2015

Getting and Producing Liquid Natural Gas (LNG)

Getting and Producing Liquid Natural Gas (LNG)

Figure 1: Hydraulic Fracturing4
Natural gas, along with oil, is found in deposits that form below the ground in geological formations that consist of shales, which are tight rock formations that can be a mile or more below the earth’s surface2. To obtain the gas deposits people must drill into the subsurface using a combination of hydraulic fracturing and horizontal drilling.
Before drilling can start scientists use imaging technologies to locate the gas reservoirs2. When the reservoir is located drilling of the well can begin, which takes about 6 to 8 weeks2. Once completed, hydraulic fracturing (Figure 1) is used to release the natural gas from the tight shale formation2. The natural gas is then brought to the surface where it then gets transported to a pipeline to be distributed for processing and use2.
Figure 2: LNG Process5
Natural gas processing consists of several  stages (Figure 2).  First, the gas needs to be treated to remove impurities such as carbon dioxide and organic sulfur compounds since too much CO2 can raise the temperature at which the gas will freeze3.  Once these compounds have been removed, the gas must be dehydrated since the presence of water can cause the gas to freeze during the liquefaction process3.  Mercury is then removed since it is corrosive and can damage the LNG heat exchangers used in the liquefaction process3.
After all of the contaminants are removed, the gas is cooled down by a variety of  processes to a finished temperature of about -260 F (-160 C).  The finished product is then stored at approximately atmospheric pressure and then eventually transported.
The conversion of natural gas to LNG is a process that reduces its volume by about 600 times1. This reduction in volume is beneficial since the resulting product can be easily transported via cargo ships in high abundance. Once delivered to its destination, the LNG is heated to its gaseous state so it can be distributed to homes and businesses1.

Exponents correlate to references

Works Cited

1. Center for Liquefied Natural Gas. (2015). Basics. Retrieved from About LNG.
2. Texas Natural Gas Now. (2015). How We Get It. Retrieved June 24, 2015
3. The University of Oklahoma. (n.d.). Refrigeration Cycles. Retrieved from The University of Oklahoma.
4. Figure 1 taken from Total E&P Denmark B.V. (n.d.). What is Hydraulic Fracturing (fracking)? Retrieved from Total E&P Denmark B.V.: http://en.skifergas.dk/technical-guide/what-is-hydraulic-fracturing.aspx
5. Figure 2 taken from Goldboro LNG. (2012-2015). What is LNG? Retrieved from Goldboro LNG: http://goldborolng.com/about-lng/what-is-lng/