Robert Morgan, PhD, PE
May 5 through 11, 2019 is celebrated by the American Water Works Association (AWWA) as National Drinking Water Week. The AWWA is made up of over 51,000 professionals from the water sector in America. They are considered to be the go-to source for information on drinking water.
Most of us in the United States and Canada, don’t think much about our drinking water. We go to the tap, give it a turn, and safe, healthy water magically comes out. Surprisingly, those of us in the US turn that tap to the tune of about 80 gallons per day. For a family of four, that means 320 gallons or 2,700 lbs. of water are delivered to our door every day. The cost of that service is on average across the U.S. a bit under $2 per day (https://www.statista.com/statistics/720418/average-monthly-cost-of-water-in-the-us/). Where else can you get over a ton of material delivered to your door for less than $2. To fully appreciate our amazing water delivery system, it might be beneficial to look back at the history of water distribution over time.
One of the earliest well documented water systems was on the island of Crete in the Mediterranean Sea. The Minoans developed water collection and distribution systems as early as 2000 BCE. These systems consisted of rainfall harvesting, cisterns, aqueducts, filtering systems and terracotta pipes for distribution of water and fountains (http://worldwatermuseum.com/the-evolution-of-water-supply-technologies-in-ancient-crete-greece/). Water flowed under the force of gravity down from the source into the cisterns and out into the distribution system. The system was very resilient. Remnants of the piping and cisterns can still be seen on the island today. Most of the time, water was not delivered to individual homes, but to central water stations convenient to homes. Filtration and settling provided for clear and relatively odor free water. The Minoans also had common toilets and sewers to carry waste water away from their cities.
Ancient Rome carried water distribution to the next level. Water for Rome was collected in the mountains around the city and delivered to the city in the famous aqueducts. The first aqueduct was the aqua appia built in 312 BCE. The aqua appia was almost entirely underground. Water flowed entirely by gravity from the source to the city. When water arrived at the city, it was deposited in a central tank or castellum. From the castellum water was then delivered through underground pipes to baths, fountains, water basins and even some individual homes (https://www.pbs.org/wgbh/nova/lostempires/roman/watering2.html). Much of the piping in Rome was made of lead. Lead is no longer used in water piping because of the potential public health impact. Some have hypothesized that lead in the drinking water lead to a loss of mental acuity and ultimately to the downfall of the empire. But the evidence does not support this theory. In Rome, the source water had a high hardness and water was constantly flowing. Leaching of lead out of the pipes into the water was not a problem in that situation. Waste water was allowed to overflow into gutters and channels and flow off into the Tiber River and out of town. Luckily the discharge point was downstream of the intakes.
While the Minoans and Romans were concerned about water quality. The Roman Vitruvius (http://www.romanaqueducts.info/picturedictionary/pd_onderwerpen/quality.htm) recommended criteria such as examining the health of local residents before selecting a source of water, looking for stains when a drop is placed in a brass pot and finding how quickly vegetables boiled. However, they did not fully understand the potential for water borne disease. They did know however that clean, healthy water was essential to their well being as well as the resiliency of their society. Primarily they tried to get water that was clear and odor free. Both the Romans and the Minoans used settling tanks in their systems. These tanks provided for settling of solids from the water and resulted in a clearer product. They did nothing for removal of pathogens.
Not much progress was made in water distribution nor treatment between the fall of Rome and the industrial revolution of the 18th and 19th centuries. As a result of the industrial revolution, many people moved into cities for work in the new factories. Imagine a city of several 10’s of thousands, mostly living in wooden structures and mostly using wood or coal fires for heat and energy. Fire was the major public health hazard of the time. City leaders recognized the need for improvement and began developing piping systems to bring water into town to be available to fire fighters. Drinking water came along as a secondary consideration. Many of these water pipes were made of wood. When a fire broke out, the fire company would dig up the pipe, hack a hole in the top and pump water until the fire was under control. Afterward, they made a plug and drove it into the pipe to stop the flow of water. Hence we now have ‘fireplugs’ scattered about our water systems (http://www.firehydrant.org/info/hist-fp.html). Fire fighting is still a major factor in design of water distribution systems.
During the industrial revolution, water quality when it was considered at all was determined by clarity and lack of odor. Some cities did put in slow sand filters to help clarify source water (http://historyofwaterfilters.com/water-filter-technology.html). Paisley, Scotland is generally thought to be the site of the first filtration plant in modern times. The concept of water borne disease was still several decades away. While Typhoid Fever and Cholera were common diseases, but most of the medical profession thought disease was caused by bad air or miasmas not contaminated water.
Dr. John Snow was likely not the first physician to conceive of water borne pathogens, but he was the first to demonstration the potential. During 1853 and 1854, London, England was suffering from an epidemic of Cholera. Dr. Snow suspected a source could be found that was contaminated by the Cholera bacterium. He studiously mapped cases of Cholera across the city along with where the patients got their drinking water. In almost all of the cases, the source was a hand pump on Broad Street. Dr. Snow removed the handle and locked the pump. The Cholera epidemic quickly died out (http://sphweb.bumc.bu.edu/otlt/MPH-Modules/PH/PublicHealthHistory/PublicHealthHistory6.html).
Dr. Snow’s evidence was impressive, but it took a couple more decades before the medical profession was willing to give up their theory of miasmas. Slowly they came around and accepted water borne pathogens as a source of disease such as Typhoid and Cholera. Then in 1908, Jersey City, NJ installed chlorination on its water treatment plant to kill pathogens that might be in the water. Basically, it was less expensive to chlorinate the water than to go out and find a new, less contaminated source. Other utilities in the US quickly followed suit. By the 1950’s, water borne disease was virtually eliminated in the US (https://www.cdc.gov/mmwr/preview/mmwrhtml/00056796.htm).
Drinking water in the U.S. is now delivered efficiently, economically, clean and disease free to over 90% of all Americans. The Center for Disease Control considers control of infectious disease through provision of clean water and sanitation to be one of the 10 most significant achievements in public health from the 20th. century (https://www.cdc.gov/mmwr/preview/mmwrhtml/00056796.htm), So we can rest tonight knowing that our water supply will help to keep us healthy. But the job is not yet over. Sources of drinking water are under pressure from many sides. Over use, quality degradation, potential chemical spills, and nonpoint source pollution all can impact water safety. For the Romans, source water protection meant finding a more remote source and posting Legion along the aqueduct incase the Huns invaded. Today, a site more remote from one city is just closer to another. We have to take care of what we have. In South Carolina, the Anderson Regional Joint Water Systems’ Source Water Protection Program has a vision of 220,000 source water protectors in their watershed. The implication is that every resident of the watershed has a role. Arkansas needs to generate a 3 million source water protectors.
“Man takes root at his feet, and at best he is no more than a potted plant in his house or carriage till he has established communication with the soil by the loving and magnetic touch of his soles to it.” John Burroughs, 1887 in Walking.
The week of April 28 through May 5 is celebrated as Stewardship Week by the National Association of Conservation Districts. The theme for 2019 is: ‘Life in the Soil, Dig Deeper’. Below is a link to the Soil Health Institute where you can view the feature video for Stewardship Week, ‘Living Soil’.https://livingsoilfilm.com/. One of the first points made in the video is that an acre of healthy soil has about the same living mass a two full grown elephants. My lot is roughly an acre in size. It is humbling to think that I now have responsibility to keep two elephant equivalents alive.
It may seem odd that a blog about Forests and Drinking Water has a post about soil. But when you dig deeper, it is clear that without healthy living soil, we don’t have a chance to have either healthy clean water or healthy productive forests. Microbial action in the soil is what allows soil to purify water. At the same time, the trees of the forest rely on soil microbes to process nutrients and make them available for nourishing the tree. So go out into your back yard today, grab a handful and say thanks.
Robert Morgan, Ph.D.
January 19, 2018
Source water protection (SWP) is an essential element of any public water systems treatment scheme. Unfortunately, in many utilities the program is underfunded and often under appreciated. Funding for SWP is frequently dependent upon receipt of grants from various federal programs. An effective program requires continuity. Grant funding is good, but programs change and priorities change. Relying on grants to fund the SWP program is a recipe for failure. Making SWP programs sustainable is a priority of the American Water Works Association and other national organizations. So, just what does it cost a utility to implement an effective SWP program?
The answer to the question above is of course, it depends. It depends mostly on what is required of the SWP program. In some situations, it may be sufficient to implement a simple public outreach campaign. Other utilities have gone as far as to buy the entire watershed tributary to their source of water. Most are somewhere between those extremes. A typical program will have some element of monitoring and assessment, public awareness, education and outreach, technical and financial assistance, as well as regulatory involvement, emergency preparedness and reporting. The extent of the SWP program is unique to each utility.
Surprisingly, the extent of the program is not the only factor to consider. Utilities do not exist in a vacuum. Likely there are other organizations and entities already working in the source water protection area that contribute to the overall goal of protecting a water resource. The local regulatory atmosphere is also important. How well are current regulations insuring implementation of construction erosion and sediment control and other land use activities? How good is the local stormwater program implemented? Finally, how available are extramural funds in the vicinity? So the utilities direct cost of SWP is a reasonable question.
The following protocol is certainly not the only way to determine the cost to a utility of implementing SWP. And, it likely is not the best way. But it is the way that we derived the funding target for SWP at Beaver Water District when I managed their program:
Step 1: Develop a long-term strategic plan that lays out what needs to be done to protect the source of water. This plan should have estimates of the quantity of practices and programs needed in the particular source water protection area. Source water protection is never complete, so the plan covers some life-cycle.
Step 2: Estimate the cost of fully implementing the strategic plan over the life cycle of the strategic plan. This will likely be a shockingly large number (ours was close to 300 million). But we are not yet done.
Step 3: Using whatever accounting tool you like, determine the annualized cost of implementing the strategy. This is the effort that needs to be expended annually.
Step 4: This is the fun part. The utility is not alone in working to protect water quality in the source water protection area, and the utility is also not the only beneficiary. As an example, the Natural Resources Conservation Service is active across the county working with farmers and ranchers to implement agricultural best management practices on their land. Those practices help to protect the source water. As another example, a non-governmental organization may have interest in protecting water quality for wildlife habitat or recreation. In that case they may be both a funder and a beneficiary. Cities are implementing stormwater management programs. Construction contractors apply erosion and sediment control to their projects at their own cost. So, money is already being spent in the SWP area. The utility needs to partner with these other groups and also make a good estimate of their current effort and the value of that effort.
Step 5: Make a good realistic estimate of the funds that can be secured in grants annually. This is tricky because the programs come and go and the priorities change over time. But there should be some kind of track record that can be developed. Be conservative.
Step 6: The annualized cost from step three minus the current expenditures from step four and the sustainable grant funding from step five is the gap in funding that needs to be filled.
Step 7: Decide what percentage of that gap is the utilities fair share. Remember the utility is not the only beneficiary. It may be reasonable to expect partners to pick up their effort as well.
Step 8: The funding gap multiplied by the utilities fair share of that gap is a good estimate of the annual cost to the utility for SWP.
A utility might extend this analysis one more step by asking if their contribution to the effort might make more extramural funding available. It is possible that an influx of utility funding would generate additional grants or other efforts. If that is a realistic opportunity, then the utilities cost could be reduced a bit.
Utilities like most institutions have financial constraints. Funding for r SWP frequently is difficult to justify to boards or commissions because it is outside of what utilities are used to doing. Having a realistic estimate of costs helps the SWP manager demonstrate SWP as a business objective. In other words, it puts SWP in terms that directors understand.
Bob Morgan, PhD
December 16, 2018
Source water protection (SWP) is a system of procedures, processes,and tools designed to take action to maintain or improve the quality and quantityof a drinking water source (both surface and groundwater) and protect publichealth for current and future generations. The process includes characterizingthe source of water, setting goals and objectives for that water source,developing an action plan to protect the source, implementing that plan,monitoring effectiveness and evaluating results. In Arkansas the Department ofHealth provides utilities with a source water characterization includingdelineation of the protection area and identification of potential sources ofcontamination (PSOCs) of the water source. The Rural Water Association will, onrequest, provide a SWP plan. Implementing the plan is however left up to thelocal utility. Implementing a SWP plan obviously requires some effort andexpenditure on the part of the utility. So how does the utility raise theresources and funds to implement SWP.
I divide the SWP program into two main components, program and project. Program is the ongoing day to day activities such as keeping up with the PSOCs, preparing for emergencies, building networks with stakeholders and partners, public outreach, attending public meetings, grant writing etc. etc. Some one or ones at the utility need to be responsible for the ongoing program. The only really sustainable source of funds for this program component is the utility itself. Some utilities make the SWP program a line item in their annual budget. Others, such as Beaver Water District in NW Arkansas allocate a certain portion of their revenue to SWP, i.e. $0.04 per thousand gallons sold. Then some utilities add a SWP fee onto their monthly bills. Central Arkansas Water has taken the last approach. One way or another, the utility needs to come up with the resources for this component.
The other component of SWP is implementation of projects outlined in the action plan. These projects may include public awareness, education and training, technical assistance, financial assistance, monitoring effectiveness, evaluating success, and possibly land acquisition among others. These projects may be financed by the utility itself. But frequently the cost of implementing projects is beyond the capacity of all but the largest utilities. Also, the utility likely does not have the appropriate expertise for all that has to be done. Luckily, there are a number of alternative financing mechanisms. These alternatives include: government grants, foundation grants, government assistance programs, and increasingly private financing schemes. All of these alternatives have their place.
Government grants relevant to SWP come mostly from the US Environmental Protection Agency (EPA) or the US Department of Agriculture (USDA). Government grants, such as the EPA’s section 319(h) nonpoint source pollution management grants are likely the most frequently used programs to finance SWP projects. Proposals for government grants have to be in line with the granting agencies goals for the program. The grants can be fairly large and comprehensive. However, the grants are competitive so you cannot count on them for sustainably funding projects over time. Foundation grants may be available from local, regional, or national philanthropic organizations. Foundation grants vary from a few hundred to hundreds of thousands of dollars. These grants may be more flexible than government grants. Foundations likely also have fewer restrictions on grant activities than the government grants. The key is finding a foundation whose mission is closely aligned with your SWP program. Then you need to convince the foundation that you are a good recipient of their funds. Foundation grants may be a sustainable source of funds, but usually they are better suited to individual projects.
Government assistance programs differ from grants in that in these programs, the government provides their expertise or funding directly to the consumer. For instance, the USDA’s Environmental Quality Assistance Program provides technical and financial assistance to farmers wishing to implement practices on their land that protect water quality. The United States Geological Survey has a joint funding program where they provide scientific expertise for public projects and share the cost with a local entity. The United States Corps of Engineers also works with local and state entities through providing assistance on planning of water projects. These assistance programs are often better funded than grant programs and they are more dependable year after year. The recently passed Farm Bill directs USDA conservation programs to allocate at least 10% of their funds to projects that protect sources of drinking water. Utilities can tap into these funds by cooperating with their local Conservation Districts and the National Resources Conservation Service.
Another source of government funding for SWP is from the Clean
Water State Revolving Fund and the Safe Drinking Water State Revolving fund.
These two funds were established by the EPA to help states implements the
requirements of the Clean Water Act and the Safe Drinking Water Act
respectively. The Clean Water Act deals with waste water and ambient water
quality. The Safe Drinking Water Act is targeted at public water supplies. State
revolving funds are capitalized by the federal government. The State then
invests the funds by making loans to local government entities needing to
construct new water facilities. The local government entity pays the loan off
over time. Hence the fund revolves back to the State. Interest rates on State
Revolving Fund loans may be very competitive. Both the Clean Water and the Safe
Drinking Water Revolving Funds may be used for SWP or “Green Infrastructure”
projects. States may incentivize SWP projects by giving a lower interest rate
to projects with a SWP
component. The downside is that these are still loans.
The use of private capital to fund SWP projects is a new concept. Two approaches to private capital are now in use. Green bonds are a financial instrument that provides a reduced interest rate on construction project I green infrastructure elements are included in the project. Green infrastructure may be conservation of critical tracts of land or incorporating ‘soft engineering’ such as rain gardens, green roofs, etc. These green elements help to protect water quality. A bonding company may issue ‘Green Bonds’ for the public relations value, they may see reduced risk because of the green infrastructure, or they might see opportunity to sell the bonds to conservation minded investors. Another approach to using private capital is the Forest Resilience Bond. Forest Resiliency Bonds can be used to fund large reforestation or forest restoration projects. These projects tend to be expensive and need to be done quickly. But most utilities and other entities do not have the capital to take the projects on in a reasonable time frame. In a Forest Resiliency Bond, a third party builds a collaborative of two or more entities who have stake in the restoration project and have a source of sustainable funds. Those funds could be used to pay off a bond over several years. The third entity then sells bonds to investors and provides funds to accomplish the project quickly. Investors are attracted because of the low risk of the ongoing funding for the partners.
The science of SWP will continue to advance, but basically,we know what needs to be done. The hard part is actually getting on the groundand implementing effective action plans. As you can see, resources do exist,but putting together a long-term financial plan will require thinking outsidethe box. By effectively using multiple source, sustainability can beaccomplished.
November 28, 2018
Nexus: “A connection or series of connections between two things”
A nexus exists in the food, water supply and energy sectors. It takes water to make food and energy. Energy is needed secure, treat and distribute drinking water as well as collect and treat wastewater. And a good deal of energy goes into producing, processing and distributing food. These three sectors compete for the same water. Those sectors can also impact the quality of our natural resources in many ways.
In the water sector, energy is used primarily for pumping and distributing drinking water. A significant amount of energy is also used to mix, aerate and otherwise treat wastewater. Then there is also the energy required for maintenance of the process as well as the ‘embedded energy’ from construction and installation of treatment and distribution facilities. Just how much energy is used by a water utility is unique to each facility. Berryville, AR once had a source of water on top of a mountain south of town. The elevation was such that water flowed by the force of gravity down to town and throughout their distribution system. It was a spring source, so treatment was minimal. Their energy use at the time was also minimal. Most utilities on the other hand will need to pump raw untreated water from either a surface supply such as a lake or from an aquifer up to their treatment plant. Then they treat the water and pump it again to fill and pressurize their distribution system. Water is heavy. Moving and lifting water takes lots of energy. In fact, the United States Department of Energy estimated in 2006 that the water supply sector used between 3 ½ and 4% of all electrical energy produced in the US.
Roughly 80% of electrical energy in the US is mostly produced either through hydroelectric or thermoelectric processes. The remainder is produced by solar or wind energy processes. With the exception of solar panels, electricity is produced a generator. A force is required to turn the generator. In Hydroelectric power, the force is provided by moving water through a turbine that turns the generator. For thermoelectric power, coal, gas, nuclear or some other fuel is used to boil water creating steam that turns the turbine. In either case, a generous supply of water is needed. The greatest amount of water withdrawn from the environment is by the energy sector. However, most of that water is returned to the environment. Producing electricity is actually responsible for consuming about 3 ½ % of water consumed in the US each year according to the DOE. Crop irrigation is actually the largest consumer of water in the US.
From the above, it can be seen that agriculture is clearly a huge user of water. It is estimated that irrigation of crops accounts for roughly 80 % of water consumed in the US1. And that is not all of the water consumed. Water is also required to process, distribute and prepare food. Much of that processing and preparation water must be at least drinking water quality. Water use during producing, harvesting, transporting, processing etc. of food also are big energy consumers.
Clearly, the Three sectors; food, energy and water, are interconnected in many ways. It may not be as clear that these sectors also have conflicting interests. They all compete for the same water. Providing water for agriculture or energy, may take water away from water supply. Also, using water for water supply means that water is no longer available for energy or food production. And when water is used for energy production, it may no longer be available where needed for water supply or agriculture. As a local example, in Beaver Lake, Arkansas, both the Beaver Water District (BWD) and the Southwest Power Administration (SWPA) have allocations granted by the US Army Corps of Engineers (COE) to take water from the Lake. BWD takes water from the lake to supply NW Arkansas with domestic (drinking) water. SWPA uses water to produce hydroelectric power at Beaver Dam. They then distribute that power into the electric grid. Currently there is plenty of water and there is no conflict. But, some day in the future, if the region continues to grow, water production at BWD will reach the capacity of their allocation. At that point in time, BWD and the SWPA will have an inherent conflict. A prolonged drought may also cause a shortage of water potentially creating competing uses of the lake. Planning for use of the water in the lake then requires consideration of both sectors, i.e. the nexus. Now imagine that Beaver Lake was in a region where there was also a large demand for agricultural irrigation. The situation becomes complicated quickly.
So, what does all of this have to do with Forests and Drinking Water. First of all, the forestry sector is a big user of both energy and water. Back in 2006, the DOE found that pulp and paper processing, a portion of the forest sector, used 3.3% of electricity produced in the US. Roughly the same as the water sector. The amount of water required to process pulp and paper is difficult to determine. In 2002, K. Ravi used a value of 17,000 gallons per ton of pulp. That figure was not documented but is likely in the ball park. Ravi also reported that new equipment was coming on line that was more water efficient. So, let’s just say that producing pulp takes a lot of water. Water is of course used in other aspects of the forestry industry as well. Secondly, forested watersheds provide a reliable, high quality source of water for drinking water production. A nexus exists.
The Food, Water, Energy (and Forestry?) nexus is neither good nor bad. It’s existence merely indicates the need for coordination in planning among the sectors for use of the common resources. Organizations like the Arkansas Forests and Drinking Water Collaborative provide a forum where divers agencies and organizations can meet to discuss issues such as the nexus. Communication is the first step toward effective co-management.
1. US Department of Energy. 2006. Energy demands on water resources, report to congress on interdependency of Energy and Water
2. Ravi, K. 2002. Pulp and paper industry: water use and wastewater treatment trends. Frost and Sullivan Insite Report
November 8, 2018
Shinrin yoku is the Japanese term for ‘forest bathing’. The idea is that when a person spends time immersed in a forest, what they experience and sense provides improved physical and mental well-being. The Japanese have embraced shinrin yoku whole heartedly. They have now dedicated 48 “Forest Therapy” trails so that everyone can have access to a forest, and their national forest agency has funded around $4 million into research about forest bathing.
Florence Williams book, The Nature Fix: Why Nature Makes Us Happier, Healthier and More Creative, peaked my interest in shinrin yoku. Then a bit of internet research revealed a growing trend toward forest bathing in the United States. In fact, the Association of Nature and Forest Therapy (Santa Rosa, CA) is currently training practitioners to guide forest therapy programs around the country. More locally there was a practitioner located in Kansas City, Michael Beezhold, and he was already a linkedin contact of mine. The two of us have a common friend in Carbondale, Illinois. Michael was conducting some forest therapy walks over the next few weeks. So, October 28, my wife, Sharon, and I found ourselves on the road to Kansas City to participate in shinrin yoku.
During a forest therapy walk, the participants strive to immerse all five senses (sight, hearing, feeling, taste and smell) into the experience of the forest. By focusing everything on the walk, other concerns and distractions go by the wayside. It might be thought of as a guided meditation. We started our forest therapy by sitting in a small clearing for a few minutes. There were nine of us in all. Michael asked us to just pay attention and note what we experienced. After we sat long enough to clear our minds, we then shared those experiences. My initial response was noting the way gusts of wind moved through the forest. Others noticed sounds, the coolness, the feeling of their bare feet on dirt etc. We spent about 15 minutes on this ‘invitation’. Our next experience was to walk slowly through the forest to a second gathering place. Michael encouraged us to get off the trail, pay attention to smells and tastes, make mental notes of what we saw. It took about another 15 minutes to walk the quarter mile down to the second clearing. There we sat again and share our experiences during the walk.
After another 15-minute walk we stopped at a small stream. It was surprisingly clear and fresh for an urban stream. Michael referred to these stops as ‘invitations’. We were invited to look at the surface of the water, then to look at the streambed, then we felt the surface and finally we pushed down our into the water and finally just listened. Once again, we were invited to share our feelings.
Our last invitation was a traditional forest bath. No, we didn’t remove our clothes and dive in! A forest bath is merely finding a quiet place in the forest to sit and listen, smell, feel, taste or see. We broke up our group and each headed out on their own. The bath lasted possibly half an hour. By now I had totally lost track of time. Then when Michael blew the whistle, we re-emerged from the forest and came together one more time. That time we raised a toast to the forest using an infusion of pine and spruce needles in water. It really didn’t taste all that bad. Most of us hung around a talked a bit, then walked back to our cars. Over the afternoon, the walk may have covered a mile or less.
There is no defined outcome expected form forest therapy. Sharon and I agreed that it was a relaxing afternoon and that we felt refreshed. Research shows that participants in forest therapy as a group have significantly lower blood pressure, a slower pulse rate, less cortisol (a stress hormone) in their system and a decrease in sympathetic nerve activity after the experience compared to prior to the therapy (See Florence Williams book or check out the scientific papers posted on the Association of Nature and Forest Therapy’s website, https://www.natureandforesttherapy.org/about/science). Other research indicates that regular forest therapy alleviates depression, attention deficit hyperactivity disorder and Alzhteimers (https://www.scientificamerican.com/article/why-getting-away-in-nature-is-good-for-your-mental-health/). Why forest therapy works is still a field for study. According to Williams, researchers are looking into an aroma therapy type of response to chemicals in the forest air and soil, a response to the diversity of the microbiome in the forest, a response to the relaxation effect or just to getting away from stress for a while. Hendriksen’s article mentioned above gives several theories related to the improved metal health documented in participants. Those theories include reduction of attention fatigue, evolutionary remnants from our history as a forest species, and what was called ‘soft focus vs. hard focus’. Hard focus is what you experience driving in heavy traffic or playing video games. Soft focus is what you experience gazing at a stream or mountain. During soft focus, your mind has free time to heal itself. Not being a neuroscientist, I can’t claim to know which theory is best. My expectation is that it is some combination of all of the above and it will be very hard to single out a single cause.
Shinrin yoku is a positive step toward maintaining a healthy and reduced stress lifestyle. After participating in Michael’s walk, I realize that I have been practicing shinrin yoku my whole life. I just didn’t have a good name for fooling around in the woods. Hopefully I can keep at it for several more years.
Last weekend in Northwest Arkansas we had our first real taste of fall weather. Temperatures dropped from the low 80’s into the 40’s and even 30’s. Then a misty rain and a breeze came along and provided a perfectly miserable couple of days. This cold snap is a reminder that our trees will soon start turning and then shedding their leaves for the winter. We are all set for three to four weeks of glorious color followed by a blizzard of falling leaves.
At the Morgan house, we can let leaves lay where they fall in the back of our lot. That practice provides cover for insects through the winter and as a result food for over-wintering birds and other small animals. The leaves also return valuable carbon and nutrients into our soil for the next season. However, neighborhood convention is that lawns be cleaned of dead leaves to keep up a neat appearance. So, we go along with the neighbors. The leaves from our lawn are collected and chopped up. The first group is used to fill the compost bin that has become depleted over the summer. The rest are put into wire cages and allowed to age for a couple of seasons. Eventually, Sharon spreads that leaf mulch in her native plant beds. No fertility is allowed to leave the property. If we are lucky, we even get some of our neighbor’s leaves that blow up against our fence.
Beyond providing for a few weeks of color and sightseeing, leaf fall is an important event for both the terrestrial and aquatic ecosystems. Leaf fall is a part of cycling of minerals and nutrients through our ecosystem. An idea of the importance of the event is simply the mass of material that is involved. Take the Ozark National Forest as an example. The forest covers roughly 1.2 million acres (https://www.stateparks.com/ozark.html). To simplify this calculation, I am assuming that the forest can be characterized by Red Oak. That is not a good assumption, but it will provide an order of magnitude estimate. Next assume that 75% of the area in the forest is actually forest. Leaf area index is the ratio of the surface area of the leaves on a tree (one side only) to the surface area of the ground covered by the tree’s spread. Breda (Journal of Experimental Botany, Volume 54, Issue 392, 1 November 2003, Pages 2403–2417,) estimated the leaf area index for a Red Oak in a dense forest as 4 to 4.5. So for every acre of trees, there are 4 to 4 ½ acres of leaves. The weight of Oak leaves according to Jurik (Amer. J. Bot. 73(8): 1083-1092. 1986.) is around 40 grams per square meter. Doing a little math to convert everything to metric and multiplying, it turns out that just shy of 600 million kilograms (1.3 billion pounds) of leaves fall in the Ozark National Forest each autumn. Those leaves may be up to 13% protein (https://www.fs.fed.us/database/feis/plants/tree/querub/all.html). Rounding to 10% protein and multiplying, it is found that 60 million kilograms (130 million pounds) of protein fall within the forest each year.
Given the mass of material falling as leaves, it is not surprising that leaf fall is a significant source of energy in forested ecosystems. For headwater streams (those near the streams source) in forested watersheds, leaf fall may be critical to the energy balance for the entire year with respect to the aquatic community. In those streams the forest canopy covers nearly the entire stream blocking sunlight. With little direct sunlight reaching the stream, there is little photosynthesis taking place within the stream. Leaf fall into the stream makes up the shortage. The leaves provide a source of carbon, nutrients and minerals to the stream system. Vannote et al. (Canadian Journal of Fisheries and Aquatic Sciences, 1980, 37(1): 130-137) noted this relationship in their 1980 paper, the River Continuum Concept). It was pointed out in the paper that stream ecosystems could not be studied simply on a square meter basis like lakes. Streams flow. So it is necessary to consider where along the continuum of the stream the square foot being studied existed. Headwater streams, without photosynthesis were dependent upon material falling into the stream from the watershed, primarily leaves and woody debris, for energy.
When leaves fall into a stream or other body of water, they are quickly colonized by fungi and micro-organisms which start the decomposition process. As the leaves decompose, they become more palatable and soon macroinvertebrates (bugs) start munching. Those bugs are then eaten by larger organisms in the familiar food pyramid. Left over parts from the leaves and waste products from the bugs and fishes drift on downstream helping to support those communities as well. Leaves then are a critical part of the nutrient and carbon cycling in streams.
Good streamside management maintains a healthy forest in the riparian zone. In headwater streams especially, that forest helps to maintain a healthy stream including reinforcing the streambanks and providing for the aquatic community. Healthy streams are better able to process nutrients and provide us all with clean, dependable water.