Criteria and indicators for sustainable forestry under Mediterranean conditions applicable in Spain at the forest management unit scale

Aim of study: to identify criteria and indicators (C&I) of sustainable forest management (SFM) under Mediterranean conditions. The indicators are meant to monitor changes in the provision of ecosystem services at a local scale (forest management unit, FMU). We support that if a forest provides a bundle of ecosystem services its management can be considered sustainable; thus, we adjust C&I to an ecosystem services classification. Area of study: La Hunde y La Palomera, a public FMU in the region of Valencia (east of Spain), 100km southwest of the city of Valencia. Material and methods: first, a literature review of the following themes took part: SFM, features of Mediterranean forests, ecosystem services and C&I. Some C&I were proposed and, later on, a participatory process in Ayora, the municipality where the mentioned FMU is located, was carried out with different stakeholders (forestry professionals, users for recreation, hunters, environmentalists and professionals of cultural and rural development activities) in order for them to value the C&I proposed according to their management preferences for La Hunde y La Palomera. Research highlights: – 15 criteria and 133 indicators were identified: a balance has been achieved among economic, social and ecological concerns. – People value the ecological issues associated to forestry on top and the economic ones at the bottom. – Results suggest that SFM under Mediterranean conditions is based on more than one product and on the provision of several ecosystem services.


Introduction
The concept of sustainable forest management (SFM) was first used at the Earth Summit held in Rio de Janeiro (UNCED, 1992) in reference to a type of management that considers social and environmental values of forests and other products apart from wood (Wijewardana, 2008).However, there is not a universal definition of SFM (Varma et al., 2000); the relative importance of the different aspects that SFM covers 2 These forests provide a diversity of goods and services, all of them known as ecosystem services (MA, 2005).The goods include edible products (fungus, pine nuts and other fruits), resins, cork or aromatic plants (rosemary).Forests in this region also provide ecological and social services, like protecting soil from erosion, keeping and improving the visual aspect of landscapes and serving as spaces for recreation (Scarascia-Mugnozza et al., 2000).These services are essential for rural development and for the well-being of urban populations (EFI, 2010).
Spain constitutes a case where Mediterranean conditions take place in most of the forests.Besides the features mentioned, forestry in this country presents some peculiarities which are described next: Decentralization: regional governments have the authority in forest regulation (MMA, 1999).The decentralized model allows for adapted forest policies, but results in an uneven development in terms of budget, schedule and so on (MARM, 2008).Property structure: most of the forest area is private (65%) and the forest management units (FMUs) are on the average small-sized (less than 3ha).This discourages many land owners to manage their land as they cannot harvest regularly (Tolosana et al., 2004).Socio-economic conditions: there has been a depopulation of rural areas a few decades ago, so that the management of much land including forest has been abandoned (Marraco, 2004).The main forest product is timber, which together with firewood accounts for a 47.1% of the total forest production in Spain (Tolosana et al., 2004).Most of the timber produced goes to low added value industries like packing cases (Plana & Meya, 1999).Besides, the average price of one m 3 of wood in Spain to be paid to the forest owner in the year 2005 was of 46.49€, which is very low for a small property (MARM, 2010).
This research develops a case study in the region of Valencia (east of Spain).For this region a forestry plan has been elaborated: Plan de Acción Territorial Forestal de la Comunitat Valenciana (PATFOR).This plan proposes a forest management that stems from ecosystem services.Nowadays, most of the ecosystem services provided by Mediterranean forests do not result in any incomes to the forest owners.Besides, PATFOR states that the forests of this region go through an eco-To overcome this weakness of existing C&I standards1 , Pokorny & Adams (2003) suggest that the meaning of C&I has to be clear, which means that their writing should be simple, understandable and specific.
There is general agreement that international C&I standards cover the following thematic areas: (1) area of forest resources, (2) biodiversity conservation, (3) forest health and vitality, (4) and ( 5) productive and protective functions of forests, (6) social functions, and (7) legal, political and institutional framework (FAO, 2006).They are particularly weak in the social and cultural areas.This fact likely reflects the strong emphasis that forestry has traditionally placed on natural sciences and a perceived division over responsibility for the social elements of SFM (Gough et al., 2008).

Context
As aforementioned, the literature on SFM suggests that its objectives and strategies change depending on the type of forest; this fact is especially relevant under Mediterranean conditions, which have to be in mind to evaluate forestry practices (Osem et al., 2008).These conditions have been summarised by Scarascia- Mugnozza et al. (2000), Fabbio et al. (2003) and Madrigal (2003), as follows (Valls et al. 2012): Adaptation to a specific climate: a pronounced biseasonality with dry and hot summers, occasional heavy rains, a large year-to-year variability of total precipitation and strong winds that favour the spread of forest fires.Species richness: the presence of a high diversity of plant and animal species, the Mediterranean area harbors around 25000 plant species whereas in the rest of Europe around 6000 plant species can be found.50% of the Mediterranean flora is endemic.Anthropogenic influence: the diversity of vegetation types, land-uses and landforms, results in a landscape that consists of a mosaic of patches.This is the result of a very long history of human occupation and overlaying of new elements without elimination of the old ones.Fragility: due to heterogeneity, instability and low profitability.Heterogeneity is caused by diversity of species and habitat conditions (climate, soils).Instability results from summer drought, heavy rains, poor soils, and forest fires.Low profitability is derived from low productivity of Mediterranean forests.

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Criteria and indicators for sustainable Mediterranean forestry adapts other existing frameworks to Mediterranean forests.Tables 1, 2 and 3 constitute a classification with examples of ecosystem services, and the references consulted.Then, to identify forestry criteria that maintain and improve their provision, those examples and kinds of the classification whose supply was considered that could be improved through management actions2 were transformed into criteria (Table 4).
It was considered that the provisioning services category could be associated to the economic pillar of sustainable development, the regulating one to the ecological pillar and the cultural category to social issues.The criteria were classified in three groups: economic, social and ecological, according to the ecosystem services categories.4 that the criteria employment and working conditions and participatory processes have not been associated to any ecosystem service kind or example.This is because they constitute requirements of forest management and thus have to be included as criteria, even though they do not maintain or improve the provision of any ecosystem service.On the other hand, no criteria have been associated to the following ecosystem services kinds: -Service group air flow regulation.
-Service group noise pollution reduction.
-Service group air quality regulation.
-Service type regional and local climate.
-Service group water quality regulation.
-Service group nutrient cycling.
-Service type fishing.
The reason for not including them is because they happen either in specific situations or as a result of the management for providing other ecosystem services.The first situation corresponds to noise pollution reduction, air quality regulation and fishing.The first two nomic, social and environmental crisis.The economic crisis derives from the low productivity of these ecosystems.The ecological and the social crisis are connected: the abandonment of forest management increases the density of vegetation favouring the spread of forest fires.The social crisis is also affected by a lack of organisation among the forest actors, bad communication with the society, and conflicting interests between forest owners and users (Generalitat Valenciana, 2011a).
The low productivity and the abandonment of forest lands represent a danger for the continuity in the provision of ecosystem services.It becomes then necessary to identify and define C&I for SFM that take into account ecosystem services together with their economic valuation (Generalitat Valenciana, 2011a).
Another pillar over which PATFOR builds forest management is the inclusion of participatory processes for decision making.This is to make the forest sector closer to people, to achieve a common vision among stakeholders and to share responsibility with society (Generalitat Valenciana, 2011a).

Aim and Objectives
The aim of this research is to answer this research question: "what has to be considered for SFM under Mediterranean conditions?"The specific objectives of this research are: 1.To identify C&I of SFM for Mediterranean forests, applicable at the scale of FMU and adapted to an ecosystem services framework, under the hypothesis that if forestry is oriented to maintain and improve the provision of ecosystem services it can be considered sustainable.2. To test the realism and comprehensiveness of the issues covered by the C&I identified by means of a participatory process.
Further references and legislation were revised for describing and explaining the criteria (Table 5).Later on, some forest management experts were consulted about the criteria and their descriptions.They were both invited to participate and explained what the research was about and which the objectives of the consultation services are relevant for humans in forest that are close to urban and industrial areas; fishing takes place in forests located next to a river, and the management of fish populations is a competence of the Central Government (Gobierno de España, 2001).Air flow regulation, water quality regulation and nutrient cycling occur in forests where vegetation and soils are kept in good conditions; these conditions are taken into account in included by the C&I identified are comprehensive and realistic.For this step, and in order to facilitate the process to participants, the indicators were grouped into aspects, which are defined as the specific issues covered by a criterion.Their meaning is broader and their writing less technical than that of the indicators.
The process was open to anyone living there.Participants were asked to value the criteria and, for each criterion, the aspects that it covers.They valued according to their management preferences for a public forest located in the municipality of the village, which is called La Hunde y La Palomera.Several authors of academic papers propose to identify and pre-select C&I based on relevant literature, followed by a process of verification or refinement by stakeholders (Kurka & Blackwood, 2013).
The participatory process was publicly announced hanging papers on walls and shop windows, and it was advertised in the local radio.Local associations whose interests are related to forest management or forest conservation were personally contacted (via telephone or face-to-face) in order to get a representation of the different stakeholders involved.
Figure 1 displays the structure of the proposed standard for this research.Every participant received a questionnaire with 19 questions, each of them containing a list of elements to value: 15 questions to value the aspects of each criterion, 3 questions to value the criteria of each group and 1 question to value the three groups of criteria.
The weighting method selected corresponds to a multi-criteria analysis (MCA) technique described by were.Attached to the e-mail via which they were contacted, a file with the criteria was sent so that they were able to correct and comment on them.A total of 4 experts participated: 2 university academics and 2 civil servants.They were asked the following questions: 1. Do these criteria cover the relevant issues of SFM in the Mediterranean region at the FMU level? 2. Are these criteria applicable? 3. Rephrase or comment on the writing of the criteria and their definitions if you think they could be improved.
All the indicators taken from the review were classified according to the criteria identified.After this, indicators were rephrased to be simple and easily understandable, as recommended by Pokorny & Adams (2003).The last task consisted of proposing new indicators in the issues for which less attention had been paid in the literature.
Later on, a participatory process in Ayora, a village located 100km southwest from the city of Valencia, was carried out.Its objective was to test if the topics

Persistence and stability of forest resources
Management guarantees that a certain quantity of the forest resources stays in the FMU all the time and that it continues when biotic or abiotic disturbances occur (pests, fire).

Profitability of forest resources
Income generation (in-kind or money) as a result of the management, annual or periodic, variable or regular.

Diversified exploitation of forests
Inventory and determination of best use of present and potential forest goods and services.

Employment and working conditions
The number of job posts in the FMU is suitable to the activities necessary to carry out for the management, workers receive suitable training and there exist health and safety measures.

Recreation
There are infrastructures for the social use in its different kinds: taking a rest, trekking, fauna observation, camping, sports or hunting.

Visual character
Maintenance of the identifying visual properties of the FMU that make it attractive and improvement of them if they have been degraded.

Historical and cultural heritage
Management preserves the features and places of the FMU holding a historical or cultural meaning, either tangible (charcoal kilns) or intangible (pilgrimages), natural or artificial.

Participatory processes
Take account of stakeholders and affected people's experience and points of view in forest management decisions.

Education
Forest management favours society's education and awareness on the cultural, environmental and economic significance of forestry and natural areas.

Research
The use of forests as an object of scientific studies, either to improve the management (and the information on its goods and services) or to increase the knowledge of other disciplines (ecology).
Biodiversity and habitats Management keeps species and habitats diversity and habitats conectivity in order to maintain and improve forest capacity to recover after disturbances.

Hydrological regulation
An important element of the hydrological cycle is vegetation that increases infiltration and reduces the quantity and speed of runoff.This attribute of vegetation offers important services: controls erosion, reduces the number and magnitude of floods and refills aquifers.The aim of this criterion is to maintain and improve these services through the management of vegetation structure and composition.

Mass flows
Management prevents landslides and avalanches.

Forest fires
Management prevents forest fires and facilitates extinction, so as to keep the frequency, intensity and consequences of forest fires in an ecologically sustainable and socially acceptable level.

Carbon storage
Forest management contributes to global climate change mitigation through maximising biomass synthesis and maintaining soil carbon storage capacity.

SFM criteria
A brief description of the resulting criteria and the bibliography consulted is provided in Table 5.A complete description appears in Suppl.file S1 [PDF on line].
A total of 15 criteria were identified: 3 economic, 7 social and 5 ecological.They take account of the multiple products (diversified exploitation of forests) and services of forests (recreation, historical and cultural heritage, biodiversity and habitats).Mediterranean features are considered in criteria like forest fires or biodiversity and habitats.The applicability of the criteria at the FMU scale can be seen in the fact that no consideration has been given to rural development and regular revenues, which are desirable outcomes of SFM but have to be considered at a regional level because they require association and coordinated actions among several forest owners (Madrigal, 2003).Besides, rural development needs the input of other sectors apart from forestry.

Indicators and aspects of the criteria
The number of indicators identified was 133; a subgroup of 24 indicators was proposed.The indicators have a simple writing, and a specific content.There are both quantitative and descriptive indicators.Many indicators serve to evaluate the state of the forest, but there are also indicators saying how to carry out certain management actions.Finally, there are indicators that encourage managers to innovate, like the ones referring to thinking of potential recreation activities and studying their demand.
The aspects that resulted from grouping the indicators to facilitate the participatory process are displayed in Table 6; this table allows an overview of what issues this research proposes to be relevant for sustainable management of Mediterranean forests.The indicators proposed together with the bibliography reviewed are in Table 7.In Suppl.file S2 [PDF on line] appears next to each indicator the references consulted for its identification.
Gómez-Orea (2002) that is applied when participants are asked to value the elements of a list according to a predetermined scale whose values can be repeated.The elements of any question are valued giving a 1 to the most important for the participant and so progressively.As mentioned, the weighting method allowed participants to repeat values: for example, in a question comprising 7 elements, these could be valued 3-4-2-2-1-5-1; this would mean that for that participant there are two elements in the first order of importance and two in the second.
The aggregated weights of every aspect and every criterion, which take into account the values from all participants, are calculated following the method recommended by Gómez-Orea (2002).This method implies that the higher the value the better.However, in this research the lowest value (1) is the best.Therefore, the scale of the answers was inverted like this: value 1 changes into the number of elements of the list and it reduces progressively (this way the answers look like participants had valued according to a scale that equals the number of elements of the list).In the example aforementioned, it would be like asking participants to value 7 elements in a scale from 1 to7, the inverted scale would be: The previous scheme shows for this example how would the values of the answers change when inverting the scale: on the left are the old values and on the right the new ones.The result would be 5-4-6-6-7-3-7.The inversion of the scales was done for all the questions of all the participants.Next, aggregated weights were calculated according to the method indicated, which consists of the following steps: 1.In every question a table was made that put the elements in rows and the participants in columns.
The table was fulfilled with the inverted values from participants.2. The sum of the inverted values of each participant was calculated at the bottom of each column.3. Every number that fulfilled the table was divided by the sum of the inverted values that corresponded to its column.
Table 6.Aspects of the criteria and their descriptions.

New plants
Management facilitates the establishment and growing of new tree individuals.

Tree layer
Maintenance and improvement of its quantity and quality.

Species diversity
Tree layer made of more than one species if possible.

Genetic diversity
Among the individuals of any tree species population present in the forest.Non-wood products Management for their persistence and stability: honey, fungi, etc.

Pest treatments
Preventative and healing treatment of pests, diseases and other disturbances.

Profitability of forest resources
In-kind incomes Management increases the quantity of forest resources in a given amount of time.

Money incomes
Forest management products are sold and generate revenues to the owner.

Demand
Study local demand and possible buyers of forest products prior to management.

Diversification
Forest incomes have to come from more than one product.

Efficiency
Management based in the more profitable product combination.

Employment and working conditions 11
Criteria and indicators for sustainable Mediterranean forestry Table 6 (cont.).Aspects of the criteria and their descriptions.

Criteria Aspects Descriptions
Education Activities Promoting formative actions: excursions, information sessions.

Infrastructures
Panels, information points to promote forest ecologic, economic and social values.

Research
Monitoring Periodic monitoring and reporting on the state of the forest and the management.

Research projects
Promote research to improve management and science knowledge.

Flora diversity
Maintenance and improvement of the number of flora species in the forest.

Fauna diversity
Maintenance and improvement of the number of fauna species in the forest.Endangered species Maintenance and improvement of the populations of endangered species in the forest.

Alien species
Control the entrance and propagation of exotic species.

Habitats
Variety and conservation of existing habitats in the forest.

Ecological connectivity
Connectivity among habitats and vegetation formations.

Erosion
Minimise soil losses.

Soil productivity
Maintenance and improvement of this soil capacity.

Soil pollution
Avoid pollution due to fertilisers and pesticides.

Aquifer filling
Vegetation structure that favours aquifer filling.

Floods
Vegetation structure and infrastructures that avoid or control floods and reduce their devastating effects.

Mass flows Infrastructures
Number and conservation state of preventative infrastructures (contention walls, etc.).

Vegetation
Vegetation structure that prevents mass flow.

Forest fires Preventative silviculture
Horizontal and vertical fuel discontinuities.

Extinction aid silviculture
Creation of firebreak areas.

Extinction infrastructures
Water deposits, tracks and other infrastructures that help fire extinction.

Carbon storage Vegetation
Vegetation structure and composition that favour biomass synthesis.

Soils
Maintain and improve soil capacity to store carbon.
tions are in Suppl.File S3 [PDF on line].Besides, participants have not suggested adding any new elements to the standard.Generally, the results show that participants value ecological issues on top and economic ones at the bottom.This is visible in the question in which they are asked to value the groups of criteria (Figure 4), but also in questions like the ones to value the aspects of the criteria mass flows and profitability of forest resources (Figure 2).In the case of mass flows, participants value prevention through vegetation (60%) more than through infrastructures (40%); whereas in the other case, they value in-kind incomes (43%) more than money incomes (24%).This preference towards ecological concerns is also visible in the valuation of the economic criteria (Figure 3), for which the highest

Results of the participatory process
A group of 34 people participated.Their profiles were analysed and they were classified in the following groups: users for recreation (14 participants), environmentalists (9), hunters (2), forestry professionals (4, both with and without a university degree) and professionals of cultural and rural development activities (5).
The aggregated weights of the elements in most of the questions are similar.None of them receives a very low weight compared with the others of the same question.In this chapter only the answers to the questions showing meaningful differences for the aggregated weights of their elements are shown and analysed; these are presented in Figures 2, 3 and 4. Graphs showing the aggregated weights for the elements of all the ques-Table 7. Indicators identified for each criterion and references consulted (1) for the identification.

Criteria Aspects Indicators
Persistence and stability of forest resources

New plants
Number of new plants in harvested area a certain time after harvesting.

Tree layer
Number of tree plants per area unit.Vigour/vitality of the trees of each species.

Species diversity
Number of trees of each tree species per area unit.
Genetic diversity Number of individuals of the population of each tree species.
In case of reforestations and enrichment plantations, the trees or seeds employed must be labelled and authorised.
In case of reforestations and enrichment plantations, trees or seeds come from the same region where the forest is located.
In case of reforestations and enrichment plantations, the origin of trees or seeds must be varied.
Thinnings are not focused just on fast-growing individuals or those with a favourable morphology.

Disturbances
Area affected by disturbances.Species are adapted to site conditions (soil and climate).
A maximum time for harvest remainders is to stay in the forest is detrmined.Integrated pest management: chemical treatments are not used in a preventative manner and always used when there is no possible alternative way.
Forest managers notice and inform on the existence of pests and diseases in their forests.

Profitability of forest resources
In-kind incomes Current value of resources present in the forest.Percentage of forest managed for production.

Money incomes
Incomes resulting from selling forest resources produced.
Expenses resulting management operations.
Incomes due to subsidies and other sources different from forest resources produced.
Commercialisation Demand estimation for the forest resources produced.Existing selling contracts.

Diversification
Forest area managed for the provision of each of the existing forest resources.Identification of possible resources to manage and sell.Demand estimation of possible resources to manage and sell.

Efficiency
The exploitation of forest resources respects the maximum quantity per period that management plans establish.Estimation of the exploitation of possible resources to manage and sell.Estimated value of possible resources to manage and sell.

Employment and working conditions
Job opportunities Number of employees in the forest.Number of job posts is suitable to the activities required for the management.

Training
Workers' training is suitable for their posts.
Training programs for workers and managers.

Contract conditions
Salaries and incentives respect collective agreements and are in accordance with regional standards.Working hours and extra work incentives are established in the contract.Types of contracts depending on contract length and number of contracts of each type.
Health and safety There is a work risk prevention plan.Number of working accidents in a certain time period.Number of working diseases produced in a certain time period.

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Table 7 (cont.).Indicators identified for each criterion and references consulted (1) for the identification.

Flora diversity
Flora species inventory (diversity and abundance).Vegetation layers in each vegetation formation.

Fauna diversity
Wild fauna species inventory (diversity and abundance).

Endangered species
Rare, endangered and endemic species inventory (species and abundance).Biodiversity conservation sites inventory.

Alien species
Exotic species inventory.Study on the convenience and dangers of introducing exotic species.Inventory of species affected or disappeared because of exotic species.

Habitats
Habitat conservation sites invnetory.Forest habitats inventory.Forest prioritary or relevent habitats inventory.
Motor vehicles and forest machinery circulation restrictions.Presence of wood, dead trees and other habitat elements (stumps) where harvesting activities have occurred.

Ecological connectivity
Vegetation formations and their limits inventory.Continuity/naturalness of vegetation formations limits determination.Fauna movement limitations exist to protect new plants or other justified cases.

Erosion
Forest area affected by compaction.Forest area affected by erosion.Determination of the erosion types that occur in each case.Erosion vulnerable areas identification.Compaction vulnerable areas identification.Forest area managed for protection functions.

Soil productivity
Nutrient inventory in plots regularly distributed in the forest every certain time.
Pollutants inventory every certain time where fertilisers or pesticides have been applied.
Restrictions for the application of fertilisers and pesticides: quantity, composition, time of the year and allowed products.

Aquifer filling
Forest area managed to generate water surpluses for aquifer filling.Forest area suffering from soil infiltration problems.

Floods
Human infrastructures (tracks, bridges) allow free water circulation in hillsides and natural water channels.Flood control infrastructures inventory.Vegetation quality in areas managed for protection functions.

Mass flows Infrastructures
Mass flow regulation infrastructures inventory.

Vegetation
Forest cover state in areas managed to prevent mass flow.

Cartography and inventory
Mass flow risk areas identification.Inventory of mass flow events that have taken place.Forest area managed to prevent mass flow.

Forest fires Preventative silviculture
Fuel discontinuities (including harvesting remainders) between vegetation layers.Bush density.

Extinction aid infrastructures
Extinction aid infrastructures inventory.

Soils
Forest area showing dry and cracked soils.
Forest area where soil structure has been broken or altered.
(1) AENOR (2007aAENOR ( , 2007b)); ATO/ITTO, 2003;Blackstock et al., 2007;Commonwealth of Australia, 1998;Eriksson & Lindhagen, 2001;FAO (1997FAO ( , 1999FAO ( , 2002)); Generalitat Valenciana, 2011a;GTC-FSC, 2007; International expert meeting on monitoring, assessment and reporting on the progress towards sustainable forest management, 2001; ITTO, 2005;Kotwal et al., 2008;Madrigal, 2003;Menzel et al., 2012;Montréal Process, 2007;Moote et al., 1997;Mrosek & Balsillie, 2001;Mrosek et al., 2006;Pokharel & Larsen, 2007;Rowe & Frewer, 2000;SFI, 2010;Thompson, 2011;Tuler & Webler, 1999; UNDP/FAO/SADC, 1999.16 searchers of this case study argued that the social dimensions of sustainability are more important where the economic role of forestry activities is marginal, like in most Mediterranean forests (Rodriguez-Piñeros & Lewis, 2013).Ecosystem services are important in forests under all type of conditions.However, in Mediterranean forests they gain relevance because their productivity is low but the society appreciates and benefits from these services.Besides, the special characteristics of these forests make some of the ecosystem services, and therefore their associated criteria, very relevant: -Heavy rains and scattered canopies increase the risk of erosion, mass flows and floods.These issues are considered in the criteria hydrological regulation and mass flows.-The risk of big fires and pests make it necessary to manage resistant and resilient forests.This is mainly achieved through biodiversity, which is also worth maintaining because of its high value in Mediterranean forests.These concerns are tackled in the criteria forest fires, persistence and stability of forest resources and biodiversity and habitats.
-The cultural character of the landscape due to many years of intervention, addressed in the criterion historical and cultural heritage.-Diversified exploitation as another means to overcome low profitability and because of the different products offered by Mediterranean forests: resins, truffles or cork; referred to in the criterion diversified exploitation of forest.
Apart from the benefits mentioned, applying an ecosystem services classification into the thinking of SFM has the advantage of encouraging an integrated approach with other land uses: a common language across sectors and more explicit focus on trade-offs and synergies.Nevertheless, it could happen that an incom-aggregated weight corresponds to persistence and stability of forest resources (44%) and the lowest one to profitability of forest resources (22%).
Concerning the criterion employment and work conditions (Figure 2), training is the aspect that gets the highest aggregated weight (31%) and job opportunities stays at a very similar level (28%).Recreational activity obtains high values for social use (25%) and infrastructures (24%).Finally, even though the three aspects of forest fires do not differ much, extinction aid silviculture has the lowest weight (27%) and preventative silviculture the highest one (39%).Ecological criteria (Figure 3) do not show big differences in their weights, but it can be noticed that biodiversity and habitats, forest fires and hydrological regulation are slightly higher valued (23%, 22% and 21% respectively) than mass flows and carbon storage (16% and 18%).

Discussion
This research dives into the considerations of SFM under Mediterranean conditions.A collection of 15 criteria applicable at the FMU level have been identified.These criteria intend to maintain and improve the provision of ecosystem services and cover the three pillars of SFM: economic, social and ecological.The existing C&I standards treat mainly ecological and resource quantity topics.
An assortment of 7 of the criteria identified in this research is social.The relevance of this type of issues is emphasized by other works.A similar study developed by Maroto et al. (2013) in the same region as this research (Valencia), but applied at a regional scale, highlights that social criteria of SFM are more important than economic ones for most stakeholder groups.Likewise, in a Mexican local community case study, the health of the forest was highly respected because the forest represented community pride, spiritual enjoyment, personal health and family cohesion.The re- Criteria and indicators for sustainable Mediterranean forestry can be made among criteria and aspects but, on the other hand, it suggests that the standard proposed is applicable.Similarly, Mendoza & Prabhu (2000) propose the use of the Analytic Hierarchy Process (AHP) as the one most involved and also providing the most information but also most complex and time consuming.They recommend the use of AHP to examine the relative weights at the indicator level because it is there where the principles and criteria are measurable and observable, and this is how it is intended to proceed with this research in next stages.
A similar study to this one shows that the methods followed is quite common and that the indicators presented here constitute a starting point from which more work is needed.Maes et al. (2011) developed an indicator framework to be applied at stand level in Flanders (Belgium).Their framework was set up by the authors and a few experts, resulting in 19 criteria and 157 indicators, which were selected from literature and assigned to a criterion.Later on, a validation step was carried out.In words of Maes et al. (2011), only a validation procedure can transform a potential set of indicators into a suitable set.Future steps of this research will consider the performance of the indicators in a specific FMU for different management scenarios.

Conclusions
This research set out to identify C&I of SFM under Mediterranean conditions, adapted to an ecosystem services framework, and applicable at the FMU level.The process followed for the identification includes literature review of themes related to the research topic, an expert consultation to improve a set of criteria previously proposed and a participatory process to verify the issues considered in the C&I set.A standard comprising 15 criteria and 133 indicators has been developed as a result.
SFM is based on the multifunctional use and exploitation of forests and it considers the social and environmental implications and consequences associated to forestry.The concept of SFM and its application have to be adapted to the particular conditions of each case; this is especially relevant in Mediterranean forests due to their specific characteristics.
Existing C&I standards and studies focus on the ecological and productive issues of SFM; social and cultural ones usually appear all together in a single criterion.The development of a C&I standard based on the maintenance and enhancement of the provision of ecosystem services searches for a balance among the three pillars of sustainability: economic, social and ecological.The criteria identified in this research adapt plete valuation of the services pushes attention on the ones that are already quantified and monetised.Besides, emerging markets for single services may discourage multifunctional forests (Quine et al., 2013).
Regarding the indicators, an effort has been made for them to be simple and easy to know what has to be measured or considered.These two characteristics are hardly found in existing standards.For example, the indicators of FSC-Spain (GTC-FSC, 2007) are perceived as clear in what they refer to but made of very long sentences.On the other hand, the indicators of PEFC-Spain (AENOR, 2007a;AENOR, 2007b) are seen like having a simpler wording, quite clear in their objectives, but less clear on what variables or qualities to look at.The standard proposed in this work just intends to offer another option for forest managers that overcomes these perceived weaknesses, but not to stay above the work developed by others.
Concerning the participatory process developed to verify that the issues addressed by the C&I proposed are sensible, the groups of participants are representative of the stakeholders related to the forest.However, the amount of members in each group is not even but, on the whole, the total number of participants is considered enough to draw conclusions.Results reveal that participants value ecological issues on top, followed by social ones, and noticeably economic ones at the bottom.The study by Maroto et al. (2013) also acknowledges the lesser relevance of economic criteria and the greater importance of ecological criteria in sustainable and participative management of Mediterranean forests.
With respect to the valuing and aggregation method, Mendoza & Prabhu (2000) conclude that MCA techniques are excellent for prioritizing a list of C&I.They describe two similar methods (ranking and rating) for establishing a hierarchy among principles and criteria (similar to criteria and aspects, as it has been done in this research).The aggregated weights that result from the participatory process show that participants cannot establish preferences easily.Therefore, few priorities to an ecosystem services classification and so they cover these three pillars.The indicators proposed overcome another shortfall of existing C&I standards, whose wording is ambiguous and long.A big effort has been done for the indicators to have a simple and specific writing.
The results of the participatory process do not reveal big differences for most of the aggregated weights of the elements of the different questions.This findings make it difficult to establish priorities among criteria and aspects, but also suggest that the topics covered by the C&I proposed are suitable to Mediterranean conditions and that a standard adapted to ecosystem services is applicable.
This work has been conceived as an exploratory research.It has included top-down and bottom-up approaches to develop a proposal of C&I, which serves as a checklist of "what to look at" when managing Mediterranean forests sustainably.However, it remains to be seen whether the selected C&I can be successfully employed for decision making processes, by testing them in different scenarios in a specific case study.Besides, more case studies are needed to develop a general set applicable in Spanish forests under Mediterranean conditions.Nevertheless, this proposed set can serve for similar research or decision making situations as a starting point for C&I pre-selection.C&I constitute a piece of the puzzle; a sustainable management based on ecosystem services depends upon many drivers, not all of them coming from the forest sector (subsidies, payments for ecosystem services).

Figure 1 .
Figure1.General structure of the criteria and indicator standard developed in this research.There are three criteria groups: economic, ecological and social; each group consists of several criteria, every criterion is made of various aspects, and a few indicators correspond to every aspect.

Figure 2 .
Figure 2. Aggregated weight (%) of the aspects of the criteria profitability of forest resources, employment and working conditions, recreation, mass flows and forest fires.

Figure 3 .
Figure 3. Aggregated weight (%) of the criteria of the groups economic and ecological.

Figure 4 .
Figure 4. Aggregated weight (%) of the three groups of criteria.

Table 1 .
Provisioning ecosystem services: this category corresponds to tangible benefits that people get from forests with either material purposes (food, construction or decoration) or energetic.This table shows the sources where the ecosystem services kinds and examples are taken or inspired from.The ecosystem services examples that are relevant in Mediterranean forests are underlined.

Table 2 (cont.). Regulating
ecosystem services: this category refers to different ecosystem processes that are relevant for life itself and for humankind.This table shows the sources where the ecosystem services kinds and examples are taken or inspired from.The ecosystem services examples that are relevant in Mediterranean forests are underlined.

Table 3 .
Cultural ecosystem services: this category includes psychological benefits (tranquility, reflection, isolation) and social benefits (group activities, maintenance and improvement of cultural heritage, promotion of science and education).They are difficult to measure and subjective in many cases.This table shows the sources where the ecosystem services kinds and examples are taken or inspired from.The ecosystem services examples that are relevant in Mediterranean forests are underlined.

Table 4 .
Criteria of SFM identified in this research as a result of the association of management actions to the different classes, groups, types and examples of ecosystem services that appear in the classification adapted for this research.Notice that all of the economic criteria are associated to the provisioning services category.The rest of the criteria are associated to specific ecosystem services kinds and examples.Forest fires The example greenhouse gases (only refers to CO 2 ), from the service type global climate, from the service group climate regulation

Table 5 .
Description of the criteria identified and references consulted (1) for the identification.

Table 7 (
cont.).Indicators identified for each criterion and references consulted (1) for the identification.