Case studies tagged with cork

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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.


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. ...

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...


Using NIRS to assess the presence of cork anomalies

Different samples of cork stoppers

The cork used in the manufacture of natural cork stoppers or technical stoppers must meet a number of conditions, including being free of certain anomalies. The use of NIRS (near infrared spectroscopy) technology has proven to be a valid technique for detecting yellow stain and corkbark, which are defects that must be avoided due to their harmful effects on the properties of the cork.


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.


Post-fire presence and dynamics of xylophagous insects on cork oak ecosystems

Montado landscape after fire (Grândola, 2017).

Cork oak ecosystems have been experiencing a serious decline in the last decades attributed to different causes, including wildfires. After fire trees may become particularly vulnerable to forest pests, which may further affect the vigor of surviving trees and give rise to massive dispersing offspring affecting surrounding areas, but this was rarely assessed in Mediterranean oak ecosystems. Thus, the objective of this study was to assess the presence and dynamics of xylophagous insects on cork oak forests following fire in central Portugal.


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...


Delineation of seed collection zones based on environmental and genetic characteristics for Quercus suber L. in Sardinia, Italy

Seedlings of cork oak collected in the RoP in Sardinia according to Dir. 1999/105/CE

The main objective of the study is assessing the areas where Quercus suber (cork oak) seeds (acorns) should be collected, taking into account both environmental and genetic variables, identifying uniform climatic areas and investigating the genetic diversity among populations at the regional scale. Combining the two factors, areas of interest for valorising the available germplasm can be identified.


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...


The use of cork in the thermoregulation of beehives

Experimental insulated beehive with cork panel and interior wall detail

The aim of this trial was to : a) increase thermoregulation efficiency of beehives by using cork in the construction of hive walls, thus improving bee health and hive productivity; b) contribute to the maintenance of traditional apiculture practices of Mediterranean agro-silvo pastoral systems, as historical findings indicate a widespread use of cork for the construction of rustic hives;  c) favour a better use of a secondary product of the cork processing industry (granulated cork); d) produce lighter and more resistant hives, compared to wooden hives; e) promote the use of cork as a...


Network of Cork Oak Selected Stands of Extremadura

Cork oak acorns

This document presents the Network of Selected Cork Oak stands of Extremadura, an initiative for the conservation and improvement of forest genetic resources for the production of cork in Extremadura. Its purpose is to promote sustainable management, taking advantage of individuals with the best characteristics for obtaining cork. The Network is described below, as well as the procedure for registering stands in it.


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.


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.



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...


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.


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.



Field sampling methods for cork value evaluation before cork debarking

Cork sample (cala) being extracted from a tree.

The objective of the current work is the analysis of alternative sampling methods and intensities for estimating cork value before its extraction (price per unit of weight), considering the trade-off between sampling precision and costs. The dataset includes 30 sampling clusters for each of the 6 stands, where the measurement of the tree coordinates in each plot allowed for the simulation of several sampling methods and intensities, and the comparison of the percent errors and sampling costs.


Estimating cork stocks through the National Forest Inventory

Quercus suber stand in Extremadura

In the current context in which it can be perceived that climate change is already a reality, one of the issues that most concerns the different sectors dedicated to non-timber forest products (NWFP) is the long-term availability of these forest products, so that a constant supply is ensured. It is important to know the provision of NWFP at the present time in order to know or estimate their future evolution. A key tool in this regard is the National Forest Inventories (NFI). Spanish NFI are a robust, objective and comparable source of information, ideal for carrying out this type of...


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...


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...


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...


Thickness assessment and weight modeling of cork in Tunisia: case study of Ain Snoussi forest

Cork stoppers

Estimate reproduction cork thickness as a criterion to examine the commercial value and to fit a non-linear model for predicting cork weight to guide the forest decision makers toward a reasonable harvest.

The objective is to guide forest decision-makers towards a reasonable cork harvest by:

• examining the thickness of cork as a criterion for estimating commercial value

• evaluating the intensity of the debarking operation on the tree

• establishing a non-linear model for predicting cork weight.


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. 


Analysis and management of main ecosystem services and multi-functionality of Sardinian cork oak woods

Distribution of cork oak in Sardinia compared with distribution of main phytotoponims related to Q. suber.

The work analyses the multifunctionality of cork oak forests and the benefits in terms of ecosystem services (CICES 2018, MAES 2017) in Sardinia. Supply, regulation and cultural services are assessed, also analysing identity, landscape, anthropological and historical aspects. The main factors that threaten the preservation of Cultural Ecosystem Sergices (CES) are taken into account. A set of actions and measures are proposed, consistent with identity and cultural values, for the recovery, conservation and enhancement of Natural and Cultural Capital of cork oak woods.


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.


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.


Health status of cork oak in France

Cork oak decline

In order to be able to follow the evolution of cork oak dieback in the French cork-producing regions in the context of climate change, the South-East Forest Health Interregional Pole has set up since 2013 an annual health monitoring network (defoliation, tree mortality, branch mortality, etc.) of 33 permanent plots of 20 trees each. The study covers the period 2013-2019.


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.


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...


Impact of postponing cork extraction on the equivalent annual annuity stands, characterized by varying productivity and cork quality

Cork pile in Portugal.

The minimum interval between 2 successive cork extractions from the same tree is fixed by law as 9 years in Portugal. Postponing cork extraction to more than 9 years is an option that results (or not) in a variation of the cork price (for the same structure of cork prices). Site productivity, cork thickness and quality and discount rate contribute to the profitability of the farm, which may be evaluated, for example, by the equivalent annual annuity (EAA). The objective is to apply the SUBER model to evaluate the influence of the cork debarking rotation period (CDR) variation, from 9 to 11...



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.


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.  


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...


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.