Case studies tagged with cork oak

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Intraspecific variability and genetic selection of cork oak in Tunisia

Cork oak plantation - Tunisia

In Tunisia, the cork oak is facing various difficulties namely: severe ecological conditions, very heterogeneous stands with variable density, and strong pressure on the forest. Reforestation has become an essential alternative to regenerate old cork oak forests and to support natural regeneration. Selecting adequate plant material with good genetic quality is important to ensure high adaptation to environmental hazards. In this context, the main objective is to explore and evaluate the genetic variability among different stands to select and conserve the best genetic material. 


Cork quality assessement on the pile

Cork pile in the field

This document presents the methodology used by the Extremadura Scientific and Technological Research Centre (CICYTEX) for assessing the quality of piled cork. Once the cork has been stripped from the trees, the planks are arranged in ‘piles’ prior to transportation to the factory. Assessing the cork in these piles is particularly useful in forests with difficult access, where direct assessment on the tree is not viable.


The influence of formation pruning in the cork tree growth rate: a case study.

Pruned cork oak trees

The formation pruning is an operation usually defined in forest management plans established for cork oak stands plantations. It aims at removing tree branches, usually the lower ones, therefore promoting the development of a long-straight stem, at least up to the expected future debarking height. This will later on facilitate cork harvesting operations.

It is unclear if the pruning intensity affects the tree growth. This factsheet shows the results of a case study where tree growth was compared between trees not pruned, and trees subject to two pruning intensities.


First assessment of cork oak planting and natural regeneration trials in the PACA region

Cork oak plot in the Var department

For more than 20 years, plantation and natural regeneration trials have been set up by the CRPF PACA in the Maures massif with the collaboration of volunteer forest owners. The age of some of the trials now makes it possible to obtain transferable results, to guide the management of areas favourable to the cork oak, to allow continuity of monitoring and to develop the setting up of new trials in a context of climate change to be considered.


The cork humidity parameter in the commercialization

Pilled cork after debarking

The humidity of cork has always been a parameter considered in its commercialization, and is usually expressed as a percentage discount on the total cork quantity. Percentual moisture discounts are usually incorrectly applied, as they are applied directly to the quantity of cork. The same discount applied to cork with different moisture's content can translate into discounts in quantity of cork and not water.

This factsheet intents to inform the cork producers for the relevance of cork sampling for moisture content determination in order to establish the humidity discount in the...


Influence of cork oak seed origin on budburst and leaf pest damage

Cork aok budburst

- Evaluation of spring shoot phenology (timing of budburst) variation as a function of seed geographic origin.
- Understanding the adaptation potential of cork oak populations to biotic stress, assessing if earlier/later budburst timings have consequences on the amount of leaf pest damages.
- Identify the most frequent pests occurring on the damaged leaves. Relate budburst and plant–pest interactions with climatic conditions.


Valorization of a co-product from the manufacture of cork stoppers: creation, production and marketing of an innovative, patented and objectified cosmetic active ingredient.

The power of Cork Oak

To find a valorization of a co-product resulting from the treatment of the cork stoppers carried out by the company DIAM BOUCHAGE. The partnership between DIAM BOUCHAGE and OLEOS-HALLSTAR has made it possible to evaluate the cosmetic potential of this co-product in the form of a wax containing bioactive cork compounds. The industrial development led to the filing of a European application patent in 2014. The ingredient named DIAM Oléoactif® is a natural concentrate of anti-inflammatory compounds adapted to the care of sensitive and reactive skin.


Setting up of a short supply chain based on the valorization of cork waste in the Pyrénées-Orientales region

Device for crushing cork

This project studied in the Pyrénées-Orientales region for cork waste and the setting up of a short supply chain (building, garden centre, etc.) in order to create local jobs and enable owners of cork oak forests to earn some. The structuring of a value chain for cork waste will allow a return to production of the cork groves favourable to the prevention of fire risks and thus to the conservation of its heritage interest. The project has chosen to use techniques which do not require major investment in equipment or buildings. We focused on the results of a transformation into granulated...


Accessing site productivity in cork oak stands in Portugal

18 years old cork oak stand in Coruche, Portugal.

In recent decades, new cork oak plantation areas have been established in Portugal, not only in the traditional areas of distribution of the species but also in the northern parts. Historical records show that the species was formerly present here, and climatic thresholds suggest a possible occurrence. Cork oak site productivity, assessed through site index, was modelled in relation to soil and climate variables. The models were developed to estimate and map the site index value along the cork oak potential distribution area in Portugal.



Cork oak harvesting logistics

Cork collection and transportation

Improving the competitiveness of the cork oak producers, by improving the quality of the production process and the sustainability of the cork oak forest, by introducing new innovative methods and practices applied to the various stages of the production process and commercialization of the raw material, are essential to guarantee the vitality in the sector. 

The profitability of the debarking, transportation and storage operations by promoting or increasing the efficiency of the processes along the potential value chain, with bring greater valorization of the raw material and...


How to prevent Platypus cilindrus attacks?

Platypus signs on cork oak tree

Cork oak vitality, namely the plagues and diseases, is one of the main concerns of forest producers, with the platypus being one of the pests mentioned in Portugal as a factor responsible for the mortality of cork oak trees.

The knowledge of the pest as well as the means/techniques of combat available, its form of use and the characteristics of the cork oak forests that make them more susceptible to the platypus are some of the proposals to be addressed in this document and in the PLATISOR project (Methods for the management of cork oak forest with «Platypus cylindrus» atacks in the...


Cork oak mortality management

Cork oak sudden death phenomena

It is not possible to separate the cumulative effect of: climate change, soil conditions, cultural practices and the presence of biotic agents, the way the trees die, due to progressive decrepitude or sudden death, as well as the physiological processes involved that are necessarily different and must be treated differently when deciding on the urgency and the period of dead trees felling, the management of the wood material, forestry residues and subsequent options for afforestation, natural regeneration or conversion to another species.

This factsheet aims to highlight some of the...


Cork oak understory vegetation management

Cork oak forest

The cork oak forest management involves interventions in the understory with the following objectives: reduction of the fire risk, operationality of the cork harvesting, promotion of cork oak recruitment and reduction of competition for water and nutrients between trees, herbs and shrubs. The techniques currently available for the forest producer to carry out these operations are: the practice of grazing and / or mechanized interventions (harrowing, shrub cutter, shredding). The choice among several mechanical techniques should consider cork oak sustainability and the potential impacts...


FSC certification: granting access to payment for ecosystem services in cork oak woodlands

Cork oak woodlands

This project aims to assess the effects of FSC certification on the conservation of cork oak woodlands namely how certified conservation zones (areas of lower management intervention) affect oak natural regeneration, understory shrub diversity, conservation of water streamlines and associated bird diversity. In addition, at a larger scale, the project also aims to identify geographical areas of conservation value for biodiversity and ecosystem services. Resulting information will contribute to identify target areas to implement payment for ecosystem services schemes using FSC certification...


Climatic impact on cork thickness from different trees located in the same stand

Cork samples and cork rings.

The thickness of cork oak trees varies highly, even when they are located in the same geographical location or stand. The objective was to research how climate variables affect different trees within the same site, for which precipitation and temperature variables were considered. The response variable was the cork growth index (cgi) – the cork thickness of the first eight complete growth years were measured after boiling. The differences between trees were characterised by nine different cork thickness quantiles, from lower (thinnest cork) to higher (thickest cork).


Silvo-pastoral systems in southern Portugal: management challenges from the owner's perspective

New stone pine plantations in Abegoaria.

Silvo-pastoral systems are quite common in the Alentejo region of south Portugal. Bringing together economic profitability and ecological sustainability is challenging and requires a conscientious management.

We present the example of a young forest owner who manages a farm in south Portugal composed of a mixture of cork oak and stone pine grazed by cattle.

The recognition of severe soil degradation problems and the effort in its recovery has been the priority of this owner. The management options carried out in the last 15 years are now positively reflected...


Is the plasticity in response to the drought of Quercus suber linked to the geographical origin?

Seedlings of provenances of Cork Oak

The selection of forest species and the study of their behavior variability relative to the main environmental conditions change remains a major challenge. The aim of this study was to investigate the intraspecific variability responses of Quercus suber L. to drought conditions in order to determine the future sustainability of cork oak forest in Tunisia.


What are the main variables influencing cork thickness?

Permanent plot installed in a 20 year's old cork oak plantation (Évora, Portugal)
  1. Evaluate the influence of tree size, stand characteristics, debarking coefficients and climatic variables on cork thickness and its evolution between consecutive cork extraction operations, i.e. between successive cork growth periods (cgp). Cork growth is assessed using the cgi, defined as the radial width of the first eight complete years of cork growth after stripping.
  2. Assess the impact of the increase in debarking intensity on cork growth. Debarking intensity is quantified by the cork debarking coefficient – the ratio of the vertical debarking height to the perimeter at
  3. ...

Adopting a common protocol for selling cork through tendering procedures in public cork oak woodlands in Sardinia (Italy)

Public cork oak woodlands in Sardinia

The aim is to provide a standard reference model to be used by public forest owners of cork oak woodlands to sell cork, both on the tree or in cork piles, through public tendering systems in Italy. The documents represent a good practice developed by the Agency Forestas on the basis of its long term experience in cork tendering systems that may be useful for harmonizing cork selling procedures across the country.  


Inter-tree competition patterns in un-debarked cork oak stands in Portugal

Young cork oak stand (at Machuqueira do Grou, Coruche, Portugal), with 19 years-old.

Assess inter-tree competition in permanent plots established in un-debarked, even-aged stands located in Portugal by i) comparing with the self-thinning line and ii) assessing when stand density affects cork production, iii) stand structure and iv) tree relative growth rate (RGR) pattern over tree size. Spacing coefficient (SC) values < 1.25 are assumed to affect cork production; therefore, detecting when stand density is approaching this value is important. Relative spacing (RS) is easier to evaluate, being important to find the RS value equivalent to a SC = 1.25.


Optimizing the debarking and cutting schedule of cork oak stands

Cork oak stand in Extremadura (Spain)

Cork is a non-timber forest product of great importance due to its excellent characteristics in terms of insulation, elasticity and sustainability. Spain is the second world producer of cork after Portugal. Traditionally, debarking is carried out at intervals ranging from 9 to 14 years, depending on the area. However, the growth of the cork is not constant over the life of the tree, so uneven debarking intervals may be advisable. Despite its economic importance, no silvicultural schedules exist which are based on optimizing the profitability of these stands. This factsheet provides...


New business models for innovating the cork sector and contrasting cork oak woodland abandonment

Abandoned cork oak stands

This example show cases the possibility that some private companies, interested in processing cork, wood chips and wood, take-up forest management on behalf of private or public forest owners in a new private-private or private-public business model. This ensures the conservation of largely abandoned cork oak woodlands. The agreement foresees the possibility for the processing industry to ensure the mid and long-term supply of cork.


Study of the sensitivity of cork oak to climate change in Corsica

Cork oak showing signs of weakening

The objective of this study is to establish a vigilance map to identify the areas where cork oak is adapted or inadapted to the forest station in a context of changing climate, through the BioClimSol tool developed by CNPF. This tool allows the collection and analysis of field data (soil, climate, sanitary conditions, ...). The vigilance map, by forecasting and locating the risks of decline of the Corsican cork oaks, will help managers take management decisions. The objective is to make silvicultural proposals in order to prevent and limit the risks of dieback.



Promotion of cork oak recruitment in the Mediterranean

Cork oak regeneration assessment

Environmental conditions have a great effect on regeneration, especially in arid or semi-arid ecosystems, such as the Mediterranean basin. In these systems the plants suffer a high water stress during the summer, due to the reduced availability in water and the high temperatures, which are limiting for the survival of the natural regeneration. Knowing the factors that influence the success of regeneration and what techniques currently exist to enhance its occurrence, are tools to support the management of the cork oak forests, ensuring the long-term sustainability.


GOSUBER innovation project for the mechanization of cork debarking

Prototype for debarking mechanization

The objective is to present GOSUBER, the supra-autonomous operational group of the European Innovation Partnership (EIP) in the area of Agricultural productivity and Sustainability, which aims to modernize debarking to make it more productive and improve occupational health and safety conditions. The group comprises 13 partners, including private companies, associations, research centres, universities and foundations.


Assessing the proportion of cork that a stopper should have from a mechanical perspective

Fig. 1. Different wine stoppers.

The objective of this study is to determine the proportion of cork that micro-agglomerated and synthetic cork stoppers should contain to assure that their mechanical properties are similar to those of a natural cork stopper. The properties that characterize the mechanical behaviour of the stoppers in the corking and uncorking operations are: compression, relaxation and extraction.


Cork carbon footprint: From forest to products

Cork products distribution by cork type, calculated by the Cork Carbon Footprint Model

In the life cycle of cork, carbon dioxide (CO2) and methane (CH4) gases are released from biological material combustion or decomposition as well as from burning fossil fuels. The biogenic carbon emissions from forest-based products are usually not included because they are released into the atmosphere during the processing and end-of-life stages. The carbon footprint for the cork sector should be considered at different stages, from forest management activities, across the manufacturing processes and product distribution, to the product end-of-life.


How management systems affect soil quality of cork oak woodlands? A case study of south Portugal

Improved pasture

Evaluate and compare physical, chemical and biochemical soil properties, regarding soil organic matter accumulation and soil fertility development, in cork oak woodlands, located in south Portugal, managed with two different systems: 1) a 5-year old improved pasture grazed by cattle, and 2) a natural understorey with shrubs control every 4-6 years (rotary mower), ensuring cork oak seedling are protected by adjusting cutting height to a maximum distance to soil surface, and preventing sapling damage by postponing this operation in shrub patches were natural regeneration is identified.


Tree damage control in a cork oak forest

Cork oak trunk damage by mechanical operation

Reducing the amount of damages in the cork oak forest is very important in terms of the sustainability of this ecosystem. Although some of the wounds may have a natural origin (e.g. lightning), most of them have a human source linked to the management operations. The cicatrisation rate of the wounds differs from tree to tree, according to wound size, the tree vitality and the time of the year (5). The establishment of simple recommendations for the forest managers to identify the potential risks associated with the operations and consequences of these wounds can contribute to increase the...


Intraspecific variability of Quercus suber L. acorn morphology in Northwestern Tunisia

cork oak acorns

The cork oak forest suffers from serious problems of natural regeneration following anthropic action and overgrazing. As a result, we are witnessing continuous aging and disappearance of the oak grove. The object of the investigation is to study the variation of the size of the acorns of Quercus suber collected from different sites according to an altitudinal gradient in Kroumirie (North-West of Tunisia) in order to make the right choice of acorns for a plantation successful and adapted from cork oak.


Adoption of a common protocol for describing cork oak woodlands in Sardinia (Italy) for planning and management purposes

Panoramic view of cork oak woodlands in the Forest of Fiorentini (Sardinia, Italy)

The objective of the protocol is the adoption of a common standard for the description of pure or mixed stands with cork oaks for planning and/or management purposes. The aim is ultimately to contribute to the creation of coherent and complete information bases at the regional level, to improve cork oak forest planning, and thereby foster their development, in accordance with the indications of the Regional Forestry Law (Law no. 8/2016 art. 33) and of regional sectorial regulations on cork (Law no. 4/1994).


The Archi method applied to cork oak

Mature and healthy cork oak

Cork harvesting, every 10 to 15 years depending on the region, requires trees in good phytosanitary conditions and is a potential source of stress, especially if debarking is poorly done. Hence the interest in having a tool to assess the trees phytosanitary conditions, which can be used as a decision support tool when carrying out silvicultural operations. This tool is based on a visual diagnostic method called Archi, developed by CNPF. ARCHI is based on the reading of tree crown architecture using a specific identification key referring to different architectural types related to...


Estimate of the quantity of cork on pile in Tunisia

- Defining a simple and reliable methodology for the quantitative evaluation of stacked cork at cork parks that will serve as a mean of controlling the quantity weighed previously,

- Create a database at each cork park to determine the weight of a cubic meter of cork reproduction.

- Train forest technicians to generalize this method on all cork parks in Tunisia from the 2020 harvest.