Forest management has become progressively more complex and subject to sharper and wider social demands (
Forest systems, especially Mediterranean systems, provide a number of extremely valuable and varied functions, from timber and non-wood forest products to soil protection, biodiversity, landscape, CO
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fixation, water regulation, habitat, and more. Furthermore, climate change is expected to have deep consequences for the conservation and functionality of Mediterranean forests (
Forest management guidelines (FMG) are widely used technical tools for improving sustainable forest management. Many countries have forest management guidelines or directives: Canada has issued “Guidebooks” (
Guidelines provide practical, applicable and updated information to forest managers at operational level. They usefully inform multifunctional forest planning and decision-making, including the efficient allocation of public resources, and in the wider picture, they serve as a scaffold for adapting forest management decisions and practices to climate change.
In parallel, a key management focus for Mediterranean forests is the integration of forest fires as the main disturbance (
In 2004, the Forest Ownership Centre (Catalan Ministry of Agriculture) commissioned the elaboration of Sustainable FMG for the Catalonia region, NE Spain (ORGEST) to ensure sustainable and multifunctional forest management in today’s context of global change.
The objectives established for the FMG were: guiding the management of private- and public-owned forests in Catalonia; giving technical information for efficiently meeting management objectives; bridging forest planning instruments from regional level (strategical natural resources planning) to stand level (applied forest management planning); ensuring the continued ecological and socioeconomic value of the forests; providing a technical scaffold for efficient allocation of public funds within forest management policies.
The main aim of the present work was to expose the general process to elaborate the ORGEST and present the main silvicultural models and tools developed to guide sustainable forest management in Catalonia region.
Forest types
Prior to creating the FMG, we developed a classification of forest types at stand level, based on analysis of National Forest Inventory (NFI) data (
The combination of forest types (species composition and site quality at stand level) with other relevant indicators reveals the stand’s vocation and; from there, the main objectives and appropriate FMG to assign (Fig. S1).
Concerning species composition (
Concerning site-quality classifications, experts determined that only two or three quality classes need to be differentiated for most species, based on the premise that it is only rational to set different site qualities when they lead to different goals and management schemes.
The process of defining site-quality classes for each species based on ecological variables involved two stages. First, we led expert-panel group sessions to establish the number of classes needed and identify the key ecological variables related to site quality, including their relative importance and ranges. Second, we ran statistical analyses on the relationship between growth indicators obtained from the NFI and certain ecological variables readily identifiable by managers (
Forest management guidelines (FMG)
Silvicultural models and FMG were also developed based on NFI data and other field-base data, combined with complete bibliographic review of growth and yield models (
Initially, we established a set of scenarios combining site quality, fire risk, stand structure and different objectives. Then, draft silvicultural schemes were developed for each scenario in an iterative elaboration process starting with a design of the different stand stages. Stand parameters were calculated at each stage based on site index, mortality and growth models, allometric relationships, and competition indexes.
Inside the iterative process, we led an economic and silvicultural evaluation of each proposed scheme. Treatments and products obtained were valuated, and the behaviour of the whole management cycle was assessed using a common framework. Strength tests were carried out by varying the price increase rate and the production output obtained. The working groups discussed and validated the schemes to help settle on the final silvicultural models.
We further integrated wildfire prevention into the guidelines. To do this, we developed keys for ranking crown fire hazard based on the main forest stand variables that play a significant role in crown fires (
ORGEST consists in a set of FMG covering almost every conifer and broadleaf species-dominated forest in Catalonia (including pure and mixed forests), which together represent over 90% of Catalonia’s forest area. The Forest Ownership Centre has published the ORGEST FMG as manuals through its open-access website (see ags.ctfc.cat/?p=649 for the links).
For each species-dominated forest considered, ORGEST offers site quality charts and different guidelines for various management scenarios. They were built considering 2–3 site quality classes (depending on species), high or low risk of large wildfires in the area, even- or multi-aged forest structure, and different objectives such as timber production, non-wood forest products, wildfire prevention, or enhancing forest vitality and resilience.
Site quality charts developed for the main species (
ORGEST introduces silvicultural models and FMG for pure forests, including even- and multi-aged stands (
The silvicultural models for even-aged stands give a table with typical forest variables (dominant height, mean diameter, density, basal area, volume, etc.) plotting time–course evolution, including extracted basal area and volume when silvicultural treatments are applied (
Moreover, the FMG also include a complete and applied description of all treatments (clearing, thinning, regeneration cutting, selection felling, etc.) and a code of best forest practices in order to ensure correct implementation of the silvicultural models.
Both the forest types classification and FMG provide forest administrators and managers with technical information for achieving management objectives and more efficient allocation of public funds in forest management.
Forest types provide information that helps reduce inventory costs and may ease strategic planning at larger scales (promoting certain objectives depending on forest types). The site quality charts based on ecological factors enable site quality to be classified fast, despite the current stand conditions used. The ORGEST approach enables stand-level-adaptable forest management, which is vital in our context due to the huge diversity of species, structures, site qualities and objectives involved at stand level.
In summary, the methodology used, combining expert knowledge, NFI data analysis, existing growth and production models, and in-field validation with stakeholder participation has proven to be very useful not just for establishing the forest types and FMG but also in driving acceptance of the guidelines by practitioners and forest technicians. We anticipate that our methodology could be replicated to other forested regions and that the silvicultural models and FMG could be directly applied in other areas with similar conditions, mainly within the Mediterranean basin.
The authors thank to the Forest Ownership Centre (CPF) and to the GRAF team of the Fire Fighting Department of the Ministry of Interior of the Catalan Government, for their collaboration in the elaboration of the silvicultural models. Also, we are very grateful for the collaboration of all experts involved in the process of ORGEST development.