Restoring Natural Forests for Water Quality and Abundance: Comparison
Please note this is a comparison between Version 1 by Josef Seják and Version 2 by Nora Tang.

Deep rooted native forests are the most efficient land-covers for achieving water quality and abundance and for mitigating climate extremes at continents

  • drinking water
  • ecosystem services
  • Energy-Water-Vegetation Method
  • natural forests

1. Introduction

The map of potential natural vegetation in the Czech Republic [1] was used to simulate the watershed’s natural landscape structure without human influence, while the current landscape structure was assessed using CORINE Land Cover 2018 data; the four main ecosystem services were valued in monetary terms using the Energy-Water-Vegetation Method (EWVM) [2]. The EWVM evaluates ecosystems according to their different efficiencies in transforming solar energy into main supporting and regulating ecosystem services.
Our ancestors always treated access to quality drinking water as a foundation of their existence. In the territory of today’s Czech Republic (with altitudinal range 115–1602 m a.s.l.), situated in a zone of temperate broad-leaved deciduous forest [3], this was not a major problem up to the beginning of the Industrial Revolution (approx. 1750 CE). The Czech Republic is sometimes called “the roof of Central Europe,” as its watersheds drain to three seas, and this “roof” provided enough good-quality drinking water sources even under traditional agricultural cultivation. During the medieval period, traditional agriculture, firmly tied to local land-use and the system of arable and fallow land management, was able to feed up to 30–40 individuals per 1 km2.
The advent of the Industrial Revolution approximately 250 years ago and the efforts of human individuals and groups to quickly obtain the greatest self-interested benefit began to dramatically change the landscape. Accelerating population growth (from 2.5 to 4.8 million during the 18th century, in the territory of today’s ČR) led to a massive conversion of natural forests into agricultural lands, as in many other European countries [4]. The decline in the naturalness of the landscape was also largely driven by industrial forestry, which brought a massive replacement of natural mixed deciduous forests with monoculture stands of spruce with the best yield parameters. This fundamentally disrupted the landscape’s ability to retain water. After the Second World War, the collectivization of agricultural land and the political goal of achieving self-sufficiency in cereal production became another factor in the denaturalization and de-watering of the Czech landscapes. These actions made it possible to create “large wide fields” suitable for the application of large-scale mechanization. The communist slogan of achieving self-sufficiency in cereal production, realized by amelioration, drainage, and linear landscape simplification on more than one million hectares of land, led to the creation of dry agrarian steppes, which after the summer harvest convert solar energy into useless heat.
Those calling for continuous economic growth have not had need of a natural landscape for decades. However, after more than half a century of vulgar anthropocentrism in landscape management, the Czech cultural landscape is increasingly showing its unnatural face. Therefore it is important to understand what the natural landscape is. That answer is provided by nature itself (i.e., what man did not do). In its several hundred million years of development, vegetation has been able to optimally adapt to its environment and the different climatic and soil conditions on Earth and has shaped and controlled the environment itself. The form of the natural landscape of the Czech Republic, as it would establish itself without the presence of people in the form of climax vegetation, can be found on the map of potential natural vegetation of the Czech Republic. It is important to note that while the maps of potential vegetation were created by highly able botanists, they are a broad schematic—a human construct for inspiration. Oak or beech deciduous forest etc. does not mean that it is only a deciduous forest. Pollen analyses and historical findings show the presence of conifers (spruce, fir, pine), according to exposure, as well as the nature of the subsoil and the availability of water. For example, in the thousand-year-old sediments of the Vajgar pond in Jindřichův Hradec lying on the Hamerský stream, which springs at an altitude of 750 m and after 43 km flows into the river Nežárka at an altitude of 464 m above sea level, there is a lot of spruce, fir, and pine pollen [5]. Thus, for the reasons of practical landscape restoration management, these time and space vegetation dynamics and heterogeneities must be considered.
Ernst Haeckel, the author of the term “ecology,” also defined ecology as the economy of nature, and from a thermodynamic point of view, the economy of nature manifests itself precisely in the increasing efficiency of the use of solar energy in each of the subsequent successive phases towards climax. The world-renowned ecologist E. Odum was the first to link the flow of solar energy with succession [6]. He showed that succession is a directed, and thus a predictable, self-organized process of replacing one species with another, culminating in a stabilized climax ecosystem where maximum biomass and symbiotic functions between organisms are generated per unit of solar energy [7]. The climax ecosystem, which in the Czech Republic takes the form of mixed forests dominated by deep-rooted deciduous beech and oak tree species, can convert up to 2/3 of the incoming solar energy by evapotranspiration into latent heat, which provides cooling on summer days, reduces daily temperature amplitude, and equalizes temperature differences. Moreover, it is precisely the mitigation of temperature extremes, together with the maintenance of water in the landscape, which form two basic life-giving and life-supporting ecosystem functions maximized by mixed climax vegetation with the dominance of deep-rooted deciduous tree species. J. Lovelock clearly emphasized this in his book, writing that “the Earth’s natural ecosystems regulate the climate and chemistry of the Earth and are not there merely to supply us with food and raw materials” [8]. Further, these ecosystem functions of natural vegetation that help to control Earth’s climate are so powerful that humans are far from being able to replace them with their technological capabilities.
If, in the territory of the Czech Republic, about 1000–1100 kWh/m2 of solar energy is produced on average per year, and natural vegetation (deciduous deep-rooted forests with plenty of water; wetland ecosystems) is able to efficiently use and convert about 2/3 of this energy through evapotranspiration and latent heat, creating and controlling basic living conditions (air-conditioning, water retention, oxygen production, soil-forming, environment for biodiversity), then the loss of every one square meter of natural vegetation in favor of built-up or otherwise paved surfaces means a permanent annual loss of approx. 660–700 kWh/m2. At a price of approximately €0.12/kWh (1 Euro = CZK 25), this means an annual loss of at least €80/m2, or an annual loss of solar energy of approximately €0.8 million/ha/year due to liquidated natural vegetation [2][9][2,9]. Similarly, all living species on Earth suffer together on all inhabited continents from these mostly man-made thermodynamic losses, which attenuate climatic control power by decreasing natural vegetation.
Increasing climatic extremes provide a warning that the continental landscape is not primarily important for the short-term economic benefit (profit) of human beings and their groups, but for its unique life-supporting ecosystems, because for hundreds of millions of years they have been producing essential ecosystem functions and services without which the human species could neither have emerged, nor exist in the future. These are the supporting and regulating functions and services of natural ecosystems that are used free of charge by humans as gifts of nature and as free public goods (air-conditioning functions such as mitigating temperature extremes, clean air to breathe with sufficient oxygen, clean water resources and water in the landscape, an ozone layer protecting everything living on Earth’s continents, fertile soil as a product of natural forests, etc.). Moreover, these free ecosystem functions and services are increasingly lacking on a global scale under the influence of the expanding economic sector.

2. Development

Since the 1970s, the New York City water supply system in its Catskill Mountain region has been an excellent example of how to cheaply forego building a filtration plant by protecting the ecosystem services of its watershed [10][23]. However, in a comparison with conditions in the Želivka watershed, large differences cannot be overlooked. In the second decade of the 21st century, the Czech Republic was hit by a several-year period of dry weather, with a shortage of precipitation. The warm and dry five-year period 2014–2018 has led to a high danger that the main source of drinking water for the Prague and Central Bohemian agglomerations will fail, being burdened by extreme water blooming. In such a difficult situation there was no time for bargaining with individual polluters in agriculture and industry to resolve their environmental conflicts (as was done in the Catskill Mountain region), and the construction of second-step filtering station was a necessary technological solution in order to assure a safe surface-water delivery system. Moreover, while in the Catskill Mountain region around 90% of the watershed is covered by natural forests, in the Želivka watershed the agroecosystems and anthropogenized productive spruce forests dominate.
In restoring the natural forests in the Želivka river basin, we recommend the utilization of the internationally verified Miyawaki forestation method [11][24], which offers the most efficient and quickest way to cool the air and generate oxygen, to clean waters and regulate precipitation and wind, to restore terrestrial biodiversity, and to reduce fertilizer runoff into rivers that causes algae blooms.
In the future preservation of the Želivka watershed, the best-practice experience from the New York City watershed in the Catskill Mountain region remains fully valid and recommendable, as it is an example of how to reconcile different economic and environmental interests of principle stakeholders and achieve the cheapest win-win effects in both the farm and municipalities sectors, with polluters on one side and drinking water consumers and their city administrators and political representatives on the other side. Afforestation of the most sensitive areas remains one of the most important measures that should be pursued politically by surface water consumers and their representatives [12][25].
In the current world of growing climatic extremes, access to quality water is becoming a priority goal in most countries. This priority has been underlined at all world sustainability summits starting in 1992 in Rio de Janeiro up to the last meeting in Rio+20 in 2012. Many authors explain the losses of water in the landscape as a result of global climate changes and climate warming, but in most cases that is not the primary cause of such losses. The primary drivers should be sought in anthropogenic transformations and fragmentations of the natural landscape. The drained landscape overheats and the rising warm air sucks moisture from the surroundings and carries the moisture high into the atmosphere, and the water does not return in the form of small and frequent rainfall; in this way, the water circulation is disrupted.
It is not only economic agents and greedy individuals who are willing to exchange environmental quality for personal profit and who contribute to such negative anthropogenic influences on the remaining fragments of natural landscape, but also some scientists, who rely on simplified global climate modelling. One such example is an article by Bala et al., in which the authors found that the global-scale deforestation outside the tropics has a net cooling influence on Earth’s climate [13][26]. Such a modelling conclusion is in direct contradiction with the real functioning of the biosphere and of ecosystems, and with the personal experience of many perceptive individuals, who understand how forest ecosystems behave. If there are any specific characteristics of the forest ecosystem, it is the fact that it has the ability to mitigate the local, regional and continental climate extremes (fluctuation of temperatures in the forest is lower than in open landscape) and it also has the ability to retain water inside the ecosystem (atmospheric moisture is higher than in open landscape). Although the authors warn that deforestation outside the tropics “should not necessarily be viewed as a strategy for mitigating climate change, because, apart from their climatic role, forests are valuable in many aspects”, by reducing the climatic role of forests to albedo only, and by omitting their active mitigating role in control of climate, the authors’ conclusion damages the protection of natural vegetation.
Although many scientists agree that supporting and regulating ecosystem services are irreplaceable preconditions of the human species’ evolution and existence, many of them refuse to incorporate these services into human decision-making in landscape management. Herman Daly recently called such an omission of solar energy flow from our theory of production and from the national income accounting a monumental error [14][27]. The sun is the primary source of energy for Earth’s climate system. By managing the landscape and changing the natural land cover, humans influence the distribution of solar energy and the latent heat/sensible heat ratio, as explained by Bowen in 1926 [15][28].
Valuators of ecosystem services by the standard concept of WTP reiterate that their estimates are very likely to significantly underestimate the true importance of nature and its biomes, because the services assessed are very incomplete, and because respondents have a very limited knowledge of the phenomena being evaluated in the questionnaires to determine willingness to pay. However, the main problem is not an overall underestimation, but the fact that unilateral utilitarian valuations set up a crooked mirror of the wrong value relations for the restoration of the most valuable natural assets in market economies. It is clear that such utilitarian-derived relations are very biased in relation to the actual effectiveness of individual groups of ecosystems and, if not supplemented by solar energy costs from the cultural landscape, directly impede the effective restoration of natural capital in the form of natural forest vegetation species and their supporting, regulating, and cultural services.
The separation of the results of one-sided utilitarian methods of ecosystem services evaluation from their thermodynamic and biophysical bases is even more evident from the comparison of absolute quantities. If ecosystem services of forests are estimated by preferential methods at $3137/ha/year, then their ecosystem functional benefit for maintaining basic life-supporting conditions represents an amount more than three hundred times higher, approximately $1 million/ha/year. This implies that most people still greatly underestimate the real importance of natural ecosystems in maintaining basic living conditions.
Standard economists are reluctant to use the replacement cost method for evaluating ecosystem services because they believe it is not an economic value (or, in their conception, a value as an individual’s marginal benefit), but a cost. However, if the actual economic value is always the result of an equating comparison of the costs and benefits of a given good or service, and if the social costs of the loss of ecosystem functions significantly dominate, then they must be compared with the results of non-market ecosystem valuation demand methods. The need for the perception of economic value as a result of constant cost-benefit comparison was aptly illustrated by perhaps the greatest of the neoclassical economists, A. Marshall, comparing it ironically to shearing scissors: “We might as reasonably dispute whether it is the upper or the under blade of a pair of scissors that cuts a piece of paper, as whether value is governed by utility or cost of production” [16].
A technique that partly competes with our EWVM is the open-access software, already frequently used, of the Soil Water Assessment Tool (SWAT). The SWAT model is a deterministic, continuous, watershed-scale simulation model developed by the USDA Agricultural Research Service [17][29]. The model was developed to assist water resource managers in assessing the off-site impacts of climate on the water balance in watersheds and larger river basins [18][19][30,31].
An important gap in SWAT is the lack of attention given to the active role of vegetation and crop processes. None of the SWAT-applying papers reported any adaptation to the crop parameters, or any crop related output such as leaf area index, biomass, or crop yields. A proper simulation of the land cover is important for obtaining correct runoff generation, evapotranspiration, and erosion computations, as shown by van Griensven et al. [20][32].
But even if in direct forest restoration we try to avoid long-term succession processes by the direct application of climax forest strata, we must decide carefully, as specific climatic factors and soil conditions must be respected, as well as specific disturbance regimes.
The restoration of natural forests with complex layers of various natural trees is the basis for the restoration of natural capital in the Želivka river basin; it is the safe way to ensure a sufficient inflow of water with a low nutrient content into the accumulating wetlands and ponds and further into the Švihov reservoir. The issue will be how to restore and manage forests intelligently, in the fields, and how to treat water from wastewater treatment plants, so that we retain water for its transpiration and nutrients in a human-populated landscape. In the Želivka river basin, it is a matter of restoring climatically functional forests, while in agricultural fields it is about agricultural management technics and capturing eroded nutrients necessarily flowing from fields into newly constructed wetlands and especially also ponds, thus keeping waters in Švihov reservoir as clean as possible.
To this day, and especially in the last two centuries, people have been making totally counterproductive uses of nature. They displace and remove natural vegetation and water from the land and, in accordance with the prevailing anthropocentric concept of economic value, perversely place the least value on the ecologically most valuable parts of the landscape, ascribing higher values to urban lands. This removes energetically powerful free-of-charge services that mitigate temperature extremes and enable the maintenance of water and nutrients in ecosystems, leading to long-term desertification, increased climate extremes, environmental erosion, and loss of ecosystem services.
Healthy ecosystems (with plenty of water and vegetation) can use up to about 60–70% of the incident solar radiation in their free-of-charge air conditioning and retention services (water and nutrient retention), two to three orders of magnitude higher than people’s technological capability to replace these services of natural vegetation.
The transition to sustainable land use includes understanding the high social cost and counterproductive quality of the short-term use of nature for our own benefit, respecting the nutritional needs of society, using ecological valuation methods, and starting to return natural vegetation wherever possible. The obligation to return natural vegetation and water to the surface layers of the land must be reflected in all projects linked to the imposition of environmental damage. In this sense, the Czech Republic’s Act on the Prevention of Environmental Damage and the EU Environmental Liability Directive need to be amended so that they apply not only to selected parts of specially protected areas, but to the whole territory of the Czech Republic and other EU member countries.
The most effective way to restore the sustainability of agricultural land and aging agricultural soils is to restore natural mixed beech and oak forests and to create pond-type wetland ecosystems at morphologically appropriate locations that can fulfil a variety of production and ecological functions and services [21][33]. In this sense, the Czech concept of the Territorial System of Ecological Stability [22][34] is an excellent start, but at the same time only an insufficient skeleton, which lacks the living muscle for firm connection and real landscape performance of the extended natural vegetation in the form of life-giving ecosystem functions and services [23][35].
These basic findings and recommendations on the need for an integrated economic and ecological valuation of the Czech and European landscape meet the objectives of the 7th and the draft of 8th EU Environment Action Programs [24][25][36,37], in which natural capital recovery has been set as one of the most important Union objectives and environmental measures in the landscape are given a higher preference than in previous programs.

3. Conclusions

Water in the cultural landscape is an important topic in the framework of current climate changes. The results of this paper highlighted the active environmental role of natural forests in providing water quality. The paper results fill a knowledge-gap in the scientific literature related to forest ecosystem services based on the Energy-Water-Vegetation methodology, which has been emerging in the literature as a new methodological concept for ecosystem service assessment. As the results of this study indicated, in the scale of the river basin, the vegetation of the cultural landscape is able to utilize only about sixty percent of its solar energy potential. In only 1.5% of the territory of the Czech Republic, society annually loses the supporting ecosystem services at a level higher than 25% of the annual national GDP. Water retention in the landscape needs to be re-evaluated and addressed in accordance with the thermodynamic principles of life and ecosystem functioning in the biosphere. The authors of this study believe that this concept of solar energy transformation in vegetation will be a focus of international environmental research on ecosystem services and climate changes in the near future.
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