Desertification and Land degradation

https://www.ipcc.ch/srccl/chapter/chapter-3/

IPCC SPECIAL REPORT ON CLIMATE CHANGE AND LAND (SRCCL)

Chapter 3: Climate Change and Land: An IPCC special report on climate change, desertification, land degradation, sustainable land management, food security, and greenhouse gas fluxes in terrestrial ecosystems

Cultural, Social and Economic Aspects for Greening of Surface Mining Landscapes On the pages of Greening Deserts and in the entire concept, cultural, social, economic and scientific aspects of professional greening and research projects for mining, surface mining and post-mining landscapes are described. Important and additional points are summarized here.

• Establishment and development of a professional network with experts in the fields of culture, business and science – especially in the field of nature conservation, sustainable greening, agriculture, forestry and greenhouse management
• Development and offer of an extensive sociocultural program with art and music, free of charge and paid • Offer and sale of natural products (medicines and crops) and services, see concept and section ‘Services’ • Exhibitions from and for art, not just landscape art
• Involvement of artists and works of art in the landscape and processes • Introduction of landscape planning, nature conservation and socioeconomic areas or fields by integrating suitable and interested institutions, organizations and partners as well as persons and associations with potential or professional competence
• Promotion of the recultivation and rehabilitation of opencast mining areas for a better future use, sustainable nature conservation, cultural, social and economic purposes in connection with the respective municipalities and regions
• Integration of schools, universities and other educational institutions in the development and development process, but also through extra programs, guided tours, trainings, workshops and events
• Sustainable landscaped recreational use, national and international tourism with the best possible natural experience, cultural and artistic life experience
• Sustainable and economical management, optimization and improvement of the energy industry
• Use and adaptation of conditions and properties of opencast mining deserts for realistic desert exploration, especially in the summer • Continuous research and development of forms or techniques of greenhouse, forestry and agriculture
• Development and research of wind, water and solar systems within the framework of the research projects

Further points and extensive information on the topics are extensively described in the Masterplan “Concept and Study on Sustainable Greening Methods, Greenhouse Management, Forestry, Agriculture and Culture Industry for Surface Mining and Post-Mining Landscapes“.

Author: Oliver Gediminas Caplikas / www.Greening-Deserts.com

Desert research, research and development of sustainable greening methods, greenhouse management, forestry, agriculture and cultural industries are the primary fields of the concept and greening deserts projects. The greening and research camp with a greenhouse, office and laboratory containers or tents for the research and development of greening and irrigation methods is the primary objective for opencast mine or post-mining landscapes. Secondary objectives, such as sustainable recreational use and tourism offers, can be realized during the operation over the years and are not necessary for the successful start of the research project and base camp in the opencast mining area or a post-mining landscape. This also eliminates all associated conditions, provisions and legal regulations, since for the time being no public recreational use or tourism operation takes place. Nevertheless, forward-looking considerations and planning approaches as well as extensive points on the areas or topics were worked out and summarized in this concept. Greening Deserts projects are always planned as long-term and sustainable as possible. Further tasks and goals of the projects are the education, research and realization of a sustainable greening, management and cultivation of all kinds of poor, barren and dry areas, landscapes (drylands) or regions. That’s why the main projects of Greening Deserts treating not only typical deserts but all types of deserts, including surface mining deserts, concrete- or urban-deserts. This can all be done with suitable greening and research camps, stations or centers. In this work or in the concept possibilities are analyzed and discussed on the example of research and greening camps for opencast deserts, mining landscapes or post-mining landscape landscapes. The research camp should be an encounter, education and communication platform in post-mining landscapes, internally for experts, specialists and scientists, and in future open to the public. Earth sciences, natural, environmental and desert sciences are three of the main research areas. For a start, the greening, nature and research projects focus on nature experiences, important experience and research in the particular area or terrain. Everything will be analyzed, documented and informed about interesting findings or developments. In the course of the project, with interested and competent bodies or persons will be communicated – via existing and new networks, and then on site as well. In addition to well-known environmental education instruments (tools) and programs, the active experience of nature and creative forms of exploration and experimentation also should be researched and developed.

The Dietz Site (35LK1529) is well known by most archaeologists, especially those attentive to late Pleistocene and early Holocene human presence in the American West.  This site’s concentration and distributed relationship of Clovis and Stemmed points in Oregon’s Alkali Basin continues to be of significant relevance.  Many may not be acquainted with the Alkali Lake chemical disposal site where, in 1969-1971, over 25,000 barrels of toxic residues from the production of pesticides, herbicides, including Agent Orange, were deposited, then buried. This visual and narrative essay, following emergent practices in geohumanities, explores these and other distinctive traverses and fluctuating uncertainties as aspects of the interrelated spatial and temporal features of the Alkali Basin landscape. In addition to the two sites mentioned, this essay examines a gunnery range, transmission lines, a threatened endemic fish, grazing allotments, a state airport, Highway 395, and the wave-cut terraces of Pluvial Lake Alkali.

Zimbabwe’s problems of land degradation date back to the colonial era when the Rhodesian government created native reserves, the so-called Tribal Trust Lands (TTLs) in 1926. Through the enactment of the Land Apportionment Act of 1930, the country was subdivided into European and Native Lands. Since the Act ignored the population disparities of these areas, an environmental crisis was bound to occur in the near future. Furthermore, the Europeans took the best agricultural land while blacks were relegated to the drier and less productive areas. Due to the introduction of the ox-drawn plough, the communal lands were subjected to massive land degradation in the form of deforestation and soil erosion. Although massive land re-distribution has occurred since 2000, land degradation has spread to the newly-resettled areas as human and livestock populations continue to increase in these former white farms. The demand of timber for building purposes as well as wood fuel in these areas, have w...

In combination with the desiccation of the Aral Sea and the formation of the Aral Kum, the dry sea bed became a new source for dust and sand storms. Due to the highly continental climate and the effects of the global climate change in the region, increasing air pressure differences lead to an increasing frequency of high intensity wind events. The resulting aeolian dust movements can be tracked and split into short and long distance transfers using remote sensing approaches, but hard data about the spatial and temporal distribution of the dust deposition requires excessive ground research and thus is scarce. Therefore, we have analyzed the passive dust deposition data from 23 meteorological stations and assessed the spatial and temporal transfer patterns within several transects from the banks of the former Aral Sea in eastern and southern directions covering parts of Kazakhstan, Uzbekistan and Turkmenistan. Dust was collected on a monthly base as well as during specific dust storm events between 2003 and 2012 in the framework of three research projects for both long-term and event based deposition data. Dust transfer in southern direction was the most important trajectory and the newly formed Aral Kum proved to be an important source region for aeolian dust (besides the natural deserts Kyzyl Kum and Kara Kum). Stations close to these source regions frequently showed deposition rates exceeding international thresholds, resulting in possible negative effects on human and livestock health while the mineralogical and chemical composition of the deposited material influences the arable land in this arid region. This presentation will summarize the most important findings from the three research projects and discuss measures to reduce the wind erosion in the Aral Kum.

Suivi de l'évolution diachronique du piémont sud du djebel Amour (Atlas Saharien, Algérie) par télédétection satellitaire durant la dernière sécheresse (1970-1986).
Développement méthodologique de traitements d'images satellites concernant particulièrement la discrimination et le suivi de la végétation steppique caractéristique de ces milieux, ainsi que les formes et formations sableuses.
Caractérisation des processus d'évolution (dynamique éolienne, dégradation des sols et du couvert végétal, sociaux, …) et de l'impact respectif de l'homme et des sécheresses dans les processus de dégradation des milieux observés.

El manejo de la tierra y el cambio climático están estrechamente relacionados. Además de la importancia de evitar o reducir las emisiones de gases de efecto invernadero, la manera cómo se manejan los recursos de la tierra (bosques, agua, suelos) en los diversos paisajes agrarios  determinará nuestra vulnerabilidad a cambios en los patrones climáticos.  Las áreas degradadas presentan una alta vulnerabilidad al cambio en los patrones climáticos y las poblaciones asentadas en áreas degradadas sufren ampliamente sus impactos Cambios en los patrones de cosecha de alimentos afecta a las poblaciones rurales y esto puede agravarse si la disponibilidad de recursos (agua, vegetación, lluvia) está ya afectada.

El manejo sostenible de la tierra, como una medida para prevenir y revertir la degradación dela tierra y la desertificación, combina una serie de acciones, incluyendo  instrumentos de política, financiamiento y prácticas locales.  Existe una serie de prácticas de manejo sostenible de la tierra que pueden ser aplicadas en diversos paisajes y que aportan a combatir la degradación de la tierra, y a la vez a mitigar y adaptarnos al cambio climático. Estas medidas se han denominado como sinérgicas para la lucha contra la degradación de la tierra y la mitigación y adaptación al cambio climático

El presente documento aborda estos temas con el fin de promover una mayor integracióndel manejo sostenible de la tierra en programas, mecanismos financieros y presupuestos destinados para la adaptación al cambio climático

El objetivo del trabajo fue evaluar el efecto de un vermicompost sobre las propiedades de un suelo salino-sódico del Cebollal de Coro. Se realizó un experimento de incubación para comparar tres dosis de vermicompost. Se implementaron cuatro tratamientos: un tratamiento sin vermicompost (T1); T2: 1% vermicompost; T3: 5% vermicompost y T4: 10% vermicompost, durante un período de incubación de 28 días, con mediciones a los 7, 14, 21, y 28 días. En cada una de estas fechas fueron evaluadas las variables pH del suelo, conductividad eléctrica (CE), porcentaje de sodio intercambiable (PSI), carbono orgánico del suelo (COS), carbono de biomasa microbiana (CBM) y actividad ureásica (AU). El pH, la CE y el PSI disminuyeron durante el ensayo. La CE para T4 mostró una reducción del 62% con respecto a los valores iniciales (3,48 dS/m). La aplicación de los diferentes tratamientos logró reducir los valores iniciales del pH del suelo (8,30); el tratamiento más efectivo fue T4, ya que los suelos pasaron de la condición de alcalinos a suelos neutros (pH ≤ 7,5). Con la aplicación de 10% de vermicompost se logró reducir el PSI en un 50%. El COS aumento en todos los tratamientos evaluados, siendo los valores más altos para T4 el cual fue de 6,7 g/kg en comparación al valor inicial de 2,5 g/kg. Así mismo, el C-BM resultó con incrementos significativo en todos los tratamientos, encontrándose los valores más altos en T4 (612,5 µg g-1) con respecto a los valores iniciales (36,4 µg g-1). La AU aumentó significativamente con la adición del vermicompost. Al cabo de 28 días de incubación se encontraron valores de  67,8 µg NH4+g-1 para T4, lo cual representa un incremento de seis veces con respecto al tratamiento control (T1). La adición de vermicompost demostró ser una buena estrategia para la recuperación integral de suelos salino-sódicos.

Descriptores: Salinidad; Enmiendas Orgánicas; Recuperación de suelo

Madhapur, India — The remains of statues thrown into a lake in Madhapur, India, during Hindu festivals from years past lay scattered on the exposed lake bed. Local annual precipitation is now sufficient only to form temporary pools in the lowest parts of the lakebed. A decade ago, the lake supported local fishermen.  (continued… Download to read)

This report describes the current situation of waste and the problem of waste management
in Dlail, a industry dense municipality in the northern of Jordan. The report will focus on
the feasibility of solving this problem in a market-economic way. This feasibility study is
accomplished through field research, interviews with possible stakeholders, interviews with
other biogas plants in Jordan and an economic analysis. The goal is to find a (the most prof-
itable) way to make money out of waste, while respecting and helping the locals in investing
in a sustainable waste-creating society.
In Dlail a high number of dairy, cattle and poultry farms exist and are relatively close
to each other. A high number of olive industries exist in northern/north-western Jordan,
near Dlail. Furthermore, human waste from Dlail is collected in septic tanks, emptying is a
costly method paid by inhabitants of Dlail. The manure of cattle, poultry, human sewage
and the waste of olive industries are biodigestible wastes, whereby biogas is formed, along
with organic fertilizer.
A study of a business of decentralized biogas plants is done, and seems to be beneficial
for cost-sharing, transportation, reliability of biomass supply, ..., involvement of locals. The
potential amount of biogas produced by cow manure is way higher than what the farmers
would use themselves. Also it is found that biogas turned into gas for heating purposes or
industrial use has more value than biogas turned into electricity (by an engine-generator
system). An own electricity from biogas system seems to be cost ineffective. The secondary
output, organic fertilizer, is of significant value if it is of decent quality. A trade-off between
costs (transport, labour, time, easiness, ...) and profit (gas versus electricity) showed that
there is more business in dealing with gas. A business model is proposed to start a potentially
profitable business in which the local culture, historical problems with biogas, ... have been
taken into account and recommendations are given.
The business proposed is a centralized biogas to natural gas treatment plant. The main
activity will be buying biogas, treating biogas, and selling natural gas/biomethane. This
way a market for biogas, currently lacking in Jordan, is created and connected to the high
demanding gas market. Other activities may include selling biodigesters, monitoring/main-
tenance of biodigesters, CDM contractor, and selling the solid fertilizer. To get the whole
thing started the Rusaifa biogas plant can play an important role: there are two 1.25 MW
electricity generators installed which are currently out of order, because of low biogas produc-
tion at their plant. Through electricity generation at the Rusaifa biogas plant income from
biogas can be made generate so it will be attractive for cattle and poultry farms to invest in
a biogas plant: a market for biogas has been created. When the biogas throughput reaches
a certain point an investment in a biogas to natural gas treatment plant will be interesting,
as treated gas can be sold as household heating gas, which will generate more income.
Other than cattle, poultry and olive waste to biogas, there is human waste. The idea came
up to design and build a DIXI-like [2] toilet: portable, simple design to built everywhere,
but with one extra feature: it will be non-chemical, and waste will be biodegraded. A first
concept includes urine diversion, odor reduction system, solar heating, water evaporator and
condenser, a stirred biodigester, a gas storage tank, and a solid fertilizer storage tank. An
other, even simpler idea came up: a human waste water evaporator: there is enough solar
heat power to evaporate the water content of human waste. This could save households a
significant amount of money. Odor will be a problem.

There has been a long-standing debate within Egyptology whether the decline of the Old Kingdom (dated to about 2200 BCE) was due to internal and/or external factors or a combination of both of them. Equally important has been the question of the duration of this process.  The present study shall make the case that the external environmental factors which contributed to the demise of the Old Kingdom state can be discerned to have happened much earlier than traditionally supposed. There is now sufficient evidence which demonstrates a continual adaptation of the ancient Egyptian society to a changing/worsening environment over a period which lasted almost two centuries. This climate change went hand in hand with several deep internal processes in the society that contributed significantly to the eventual demise of the Egyptian empire. The analysis will use iconographic material from Old Kingdom tombs, evidence from archaeological excavations, interpretation of unique finds of beetles in Abusir and a model describing the functioning of the administrative system of the Egyptian state. The emerging picture will show that the collapse of the Old Kingdom was a long process triggered by several internal crises in combination with a climate change.

Pollen and clay mineralogical analyses of a Holocene sequence from Sebkha Boujmel (southern Tunisia) traces the climatic and environmental dynamics in the lower arid bioclimatic zone over the last 8000 years. During the Mid- to Late Holocene transition, between 8 and 3 ka, a succession of five wet/dry oscillations is recorded. An intense arid event occurs between 5.7 and 4.6 ka. This episode marks the onset of a long-term aridification trend with a progressive retreat of Mediterranean woody xerophytic vegetation and of grass steppes. It ends with the establishment of pre-desert ecosystems around 3 ka. The millennial-scale climate change recorded in the data from Sebkha Boujmel is consistent with records from the south and east Mediterranean, as well as with climatic records from the desert region for the end of the African Humid Period (AHP). Eight centennial climatic events are recorded at Sebkha Boujmel and these are contemporary with those recorded in the Mediterranean and in the...

Soil resources of the Earth are vital for preserving life on this planet due to their unique ecosystem services. Etymologically, humus, human, and humble share, for a good reason, the same root. These resources are, however, limited and non-renewable at a reasonable time scale. In addition, soils are now threatened, as evidenced in the fact that in recent years, the Technosphere (i.e., all material production generated by human activities) has begun to exceed the Biosphere at an accelerated rate, both in weight and diversity. Despite the demand and research efforts to address these problems innovatively, there are currently no onboard sensors dedicated to soils. Nevertheless, operational sensors can provide valuable and sometimes irreplaceable information about the properties and the state of the uppermost layer of the soil, which is called “topsoil”. This layer, ranging from 5 to 30 cm, is usually the first affected by threats such as organic matter decline, erosion, compaction, salinization, contamination, sealing, landslides, or land subsidence. Additionally, climate change can have serious effects on the water and energy budgets of the topsoil affecting the Earth Critical Zone. Numerous publications have already shown that remote sensing technologies can contribute to estimate, map, and monitor topsoil properties and its state. This Special Issue invites you to highlight significant achievements so far, as well as the challenges and limits of current remote sensing technologies to provide useful information on topsoil. We also invite you to show new opportunities offered by the present constellation of satellites, along with data processing advancements that address research gaps you have identified and/or support various policies. (https://www.mdpi.com/journal/remotesensing/special_issues/Characterization_Topsoil_RS)

La Grande muraille verte est le nom d’un programme régional de lutte contre la désertification au Sahel lancé en 2007 sous l’égide de l’Union africaine et des organisations régionales. Il consiste à favoriser le reboisement des territoires semi-arides le long d’un tracé reliant Dakar à Djibouti et traversant onze États, afin de créer un « bandeau végétal dressé face à l’avancée du désert ». Cette thèse a pour but de proposer une lecture géographique et critique de ce projet insolite, appréhendé ici comme une utopie environnementale. À partir d’enquêtes de terrain principalement menées au Sénégal (région du Ferlo) et enrichies par les apports de la political ecology, elle met en lumière la tension qui existe entre d’un côté, la formulation d’un projet de territoire au nom du développement des zones semi-arides et de la gestion des ressources naturelles et, de l’autre, la promotion d’un instrument d’extraversion politique et économique permettant de capter de nouvelles rentes environnementales : en quoi la territorialisation du projet est-elle subordonnée à une quête de visibilité globale ? La première partie montre comment la Grande muraille verte recycle dans un moment historique favorable des pratiques anciennes en matière de lutte contre la désertification. La deuxième partie décrit le déficit d’ancrage territorial de ses aménagements à l’échelle locale. La troisième partie montre que l’appropriation globale du projet est la source principale de sa grande résilience.

This chapter addresses the issue of economic losses due to soil erosion and discusses some well-known methodologies used since the 1990s by different authors in the USA and Europe. Issues related to the reliability of data are analyzed, and the consistency of the basic assumptions in the literature is questioned. A new approach is used considering the lack of empirical and reliable data in order to determine the economic losses of land degradation.

The concepts of degraded forest (pa mai xout xom) and degraded land (din seuam xom) have been variously applied in official Lao government policy narratives and law over the last couple of decades. In this article I focus on the concepts of degraded forest and land, and the relationship with industrial tree plantations, using two examples from southern Laos. I argue that the concepts have been significant in both facilitating and obstructing the development of large-scale industrial tree plantations in different times and spaces, thus significantly influencing access and exclusion, as well as the spatialization of tree plantations. I provide a tentative genealogy regarding the emergence of these concepts in land and forestry policy in Laos, and briefly explain the links between degradation and ‘the land rush’ presently affecting Laos.

Land degradation is extensive, covering approximately 23% of the globe's terrestrial area, increasing at an annual rate of 5e10 million ha, and affecting about 1.5 billion people globally. Such detrimental processes call for urgent and comprehensive action to halt land degradation. In this paper, we assess the causes and extent of land degradation around the world, followed by an outline of the various challenges in implementing a global Zero Net Land Degradation (ZNLD) policy. The concept of ZNLD proposes a scheme under which the extent of global degraded lands will decrease or at least, remain stable. To enable this type of scenario, the rate of global land degradation should not exceed that of land restoration. Restoration efforts should include not only croplands, rangelands, and woodlands, but also natural and semi-natural lands that do not generate direct economic revenues. The United Nations Convention to Combat Desertification (UNCCD) envisages achieving this target by 2030. Despite being seemingly ambitious, the target of ZNLD could be achieved if degraded lands are restored to a considerable extent and, at the same time, land-degrading management practices are replaced with ones that conserve soils. To enable effective implementation of these steps, it is necessary to formulate a ZNLD Protocol aimed at managing assessment actions and maintaining of supportive policies and regulations. Restoration projects could be financed through payments for improving ecosystem services, as well as other economic mechanisms. Achieving the target of land degradation neutrality would decrease the environmental footprint of agriculture, while supporting food security and sustaining human wellbeing.

My thesis is that current cities and the way that cities are being developed is unsustainable and poses global problems for the long-term flourishing of the world’s inter-related and interdependent economies, for matters of justice and happiness in socio-cultural relations between peoples, and for the health of our natural environments. I argue that “urban desertification” happens in the complex relationship between cities (both urban and suburban) and rural environments that support them as both a natural and ethical phenomenon that I study using a form of analysis called phenomenological ethics. First, I briefly present sketches of phenomenology and sustainability in order to introduce the method of phenomenological ethics to develop a more adequate understanding of urban sustainability. Then, I make a connection between desertification and urbanization. Finally, I focus on the city of El Paso, Texas in order to provide an empirical and relevant case study of the existing problems of desertification and sustainability.

The sensitivity map to desertification of Eastern Algeria (Aures region) has been elaborated by the crossing of four thematic layers (vegetation, climate, soil and the socioeconomic states), which have the main impact on the evolutionary process of desertification.  The followed methodology is inspired from the desertification model MEDALUS (Mediterranean Desertification And Land Use), which use qualitative index to define the land zones sensitive to desertification.  The cartographical information of vegetation, climate variation, soil and the socioeconomic states obtained from cartographic data were transformed to numerical data then seized on, structured and managed by an algorithm dedicated to a geographical information system.  So, the main goal of this study is to identify places with different sensitivity to land degradation in Aures (East Algeria) by means of a modeling approach developed in the European Commission funded MEDALUS project (Mediterranean Desertification Land Use), which identifies such areas on the basis of an index (ESA index, Environmental Sensitive Area index) in which environmental quality (climate, vegetation, soil) as well as anthropogenic factors (management) are included as weighted layers.

Most of soil degradation processes are human induced; however some physical environmental factors have accelerating functions. The quantitative approach of land degradation assessment is rather important in sizing the environmental obstacles and realizing the maximal benefit of soil resources. The use of panchromatic aerial photographs facilitates the monitoring of some soil degradation indicators. Moreover, the Geographic Information Systems (GIS) made it easier to handle the huge amount of data, calculate degradation indices and detect the changes in soil conditions.
In the current investigation, Quantitative assessment of human induced land degradation and monitoring the changes in land qualities of El Sharkiya governorate were performed. Aerial photo-interpretation, fieldwork and laboratory analysis data provided the main input data. Comparing the obtained data with RISW reports of 1975 made it possible to determine the rate of land degradation during the period 1975 – 2006. Land degradation rate, relative extent, degree and severity level were assessed.
The results indicate that the most active land degradation process are water logging, salinization, alkalinization and soil compaction. The main causative factors of human induced land degradation types include excessive irrigation, human intervention in natural drainage, improper use of heavy machinery and the absence of conservation practices.

Keywords: Physiography and soils, land degradation, land qualities, El Sharkeia Governorate.

In Niger una forte pressione demografica su un territorio caratterizza-to da un clima avverso sta assottigliando le risorse naturali rinnovabili. Di questo passo già nei prossimi anni foreste, zone arbustive, pascoli, terre coltivabili, fauna non basteranno ad approvvigionare in legna e in alimenti le zone più densamente abitate e, fra una generazione, ben più vaste regioni. Una popolazione povera, che pur raddoppiando ogni vent'anni continua a praticare un'agricoltura arcaica e a non avere accesso a fonti energetiche alternative al legno, rischia di degradare le terre sino a tro-varsi in una condizione permanente d'insicurezza alimentare. A meno che non gestisca l'ambiente con approcci più efficaci di quelli sinora praticati. Un'occasione potrebbe essere offerta dai processi di sviluppo locale che il decentramento amministrativo da poco avviato tenta di favorire.

Siwa Oasis is a natural depression about 23m below sea level. Siwa depression covers about 295,198 feddans boundary around human activities in Siwa Oasis, of which about 48347 feddans have been cultivated in 2015. Siwa Oasis is located north of the sand dunes belts of the Great Sand Sea. The study aims to economically evaluate hazards of sand dunes movement (SDM) and its impact on agriculture development in south of Siwa Oasis and the required adaptation measures. The total area affected by the SDM is about 50629 feddans. The total cost of economic losses as a result of SDM risk is estimated to 485.9 Million LE. The total protecting cost the cultivated area, roads and drainage of SDM risk in Siwa Oasis are estimated to 47.9 Million LE.

El Valle del Bermejo se ubica entre el Cerro Pie de palo y la Sierra de Valle Fértil-La Huerta, en la Provincia de San Juan, constituyendo una extensa planicie recorrida por el río Bermejo, el cual presenta un cauce de agua efímero y de hábito meandroso, conduciendo aguas ocasionalmente durante la época de crecidas (Suvires, 1984). En este valle se encuentran las localidades rurales de Vallecito, Bermejo, Nikizanga, Marayes y Las Chacras, pertenecientes al departamento de Caucete (Fig. 1. Area de estudio). En estas localidades predomina como actividad económica la ganadería caprina de carácter extensiva, la explotación forestal y el turismo religioso (Agüero, en prensa). Cabe destacar que el área de estudio se encuentra dentro de la Reserva Provincial de Usos Múltiples Valle Fértil, creada en 1971 bajo Ley Provincial 3666.De acuerdo a estudios llevados a cabo por Rojas et al. (2009), se estima que, en las provincias de San Juan y Mendoza, entre 1900 y 1942, se despacharon un total de 2.055.362 toneladas de productos forestales (entre leña, durmientes, postes, rollizos, aserrín y carbón de leña), de los cuales corresponden 445.582 toneladas para San Juan. La estimación de la pérdida de bosques nativo en San Juan, a partir de la cantidad de productos forestales transportados sólo por el ferrocarril entre los años citados, es de 278.216 toneladas, sin contar las cargas transportadas desde el Valle de Tulúm (Rojas et al., 2009), ni otros tipos de extracción forestal transportadas por otros medios, antes, durante y después del tránsito de los FFCC. Lo cual elevaría bastante la cifra final. Cabe destacar que a esta estimación habría que sumarle la extracción de productos no forestales, como es el caso de la intensa extracción de cera de retamo, desde el siglo XIX, y que ha sido insuficientemente estudiada. Por otra parte la Bulnesia retama fue una de las especies que se incorporó a la Ley provincial de Bosques (año), debido a sus funciones ecosistémicas en esta región, a lo cual se suma la importancia de ésta especie en las economías locales. Por todo ello, que resulta importante poder estudiar y evaluar el estado actual de este recurso forestal, los procesos de uso histórico de esta especie. Otro aspecto a considerar en relación a lo expuesto, es la actualización del Ordenamiento Territorial de Bosques Nativos (OTBN), de acuerdo a lo establecido en la Ley Provincial 8.174 (2010), por el cual resulta necesario conocer el estado actual de los recursos forestales de la zona estudiada, para posibilitar la elaboración de planes de manejo desde un enfoque participativo.El Valle de Bermejo ha sido históricamente una fuente de recursos forestales madereros y no madereros para las comunidades locales y los oasis circundantes, donde los usos actuales principales se encuentran vinculado a la cría de ganado caprino y la extracción de leña para uso doméstico. En cuanto al uso forestal no maderero, la extracción de cera de retamo constituyó una actividad clave hacia fines de la década de los 80, existiendo diversas áreas en la zona de estudio destinadas para tal fin. Sin embargo, a pesar que el bosque nativo en el Valle de Bermejo han sido históricamente una fuente de recursos forestales madereros y no madereros; estos ecosistemas han sido poco estudiados desde el punto de vista de sus posibilidades de manejo sustentable. Generalmente han sido aprovechados con un criterio intensamente extractivo, sin tener en cuenta la tasa de regeneración de las comunidades y tampoco los procesos socio-territoriales que han producido dichos desmontes (Alvarez et al., 2006, Rojas, 2013). Por este motivo, el objetivo de este trabajo es presentar los resultados preliminares sobre los procesos históricos de uso del bosque nativo y la determinación de unidades forestales (UF) y de uso (UUF), que contribuyan a comprender el actual estado de conservación de bosque nativo, como así también contribuir a futuros planes de ordenamiento territorial del bosque nativo el área de estudio.