Fact sheets
Accessing site productivity in cork oak stands in 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.
Adopting a common protocol for selling cork through tendering procedures in public cork oak woodlands in Sardinia (Italy)
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.
Adoption of a common protocol for describing cork oak woodlands in Sardinia (Italy) for planning and management purposes
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).
Analysis and management of main ecosystem services and multi-functionality of Sardinian cork oak woods
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.
Arboretums in Tunisia: importance and interest
The selection of forest species and the analysis of their behavior variability, considering the main environmental factors, remains a major concern for the forester in Tunisia. This work is prepared to answer the following question: for reforestation needs, which is the most suitable species to reach a sustainable and productive plantation? The answer can be provided in the elimination trials in the arboretum. The arboretums offer an ideal experimental support to know the requirements of the forest species and to make a selection in favor of the best adapted and the most efficient species.
Artisanal value of wood and roots of E.loxophleba of El Hanya Arboretum - Sousse
In Tunisia, handicrafts based on local wood are mostly from olive wood. Due to its physical, mechanical and aesthetic qualities, olive wood is highly sought and appreciated by artisans and buyers. In front of the growing demand for this wood, local people do not hesitate to resort to illicit cuts to satisfy the needs of the market. The objective of this study is to search for forest species offering wood qualities that rival those of olive wood and that can be valorized for artisanal use.
Assessing the proportion of cork that a stopper should have from a mechanical perspective
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.
Climatic impact on cork thickness from different trees located in the same stand
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).
Cork carbon footprint: From forest to products
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.
Cork oak harvesting logistics
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 improvements at the commercialization stage.
Cork oak mortality management
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 pests that cause mortality and the different management of the dead trees according to the biotic agent present.
Cork oak understory vegetation management
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 over soil & plants.
Cork quality assessement on the pile
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.
Delineation of seed collection zones based on environmental and genetic characteristics for Quercus suber L. in Sardinia, Italy
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.
DIAMANT® an innovative solution to the smell of cork in wine
An innovative solution to cork ‘off-flavour’ developed by the company DIAM is presented.
Effect of Short and Long Term Irrigation with Treated Wastewater on Chemical Composition and Herbicidal Activity of Eucalyptus camaldulensis Dehn. Essential Oils
The aim of this work was to evaluate the effect of treated wastewater short and long-term irrigation on essential oil composition from E. camaldulensis Dehn in order to detect allelopathic impacts on seed germination and seedling growth of Amaranthus hybridus L, Chenopodium album L, Echinochloa crus-galli (L) Beauv and Lolium perenne L as important weeds on many crops.
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.
Estimating cork stocks through the National Forest Inventory
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 analysis.
Field sampling methods for cork value evaluation before cork debarking
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.
First assessment of cork oak planting and natural regeneration trials in the PACA region
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.
FSC certification: granting access to payment for ecosystem services in 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 as a validating tool of good management practices.
GOSUBER innovation project for the mechanization of cork debarking
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.
Health status of cork oak in France
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.
How management systems affect soil quality of cork oak woodlands? A case study of south Portugal
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.
How to prevent Platypus cilindrus attacks?
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 region of Sor), currently underway.
Impact of postponing cork extraction on the equivalent annual annuity stands, characterized by varying productivity and cork quality
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 years, on the EAA of different stands by analysing the opportunity to increase the market price of extracted cork.
Influence of cork oak seed origin on budburst and leaf pest damage
- 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.
Inter-tree competition patterns in un-debarked cork oak stands in Portugal
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.
Intraspecific variability and genetic selection of cork oak in 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.
Intraspecific variability of Quercus suber L. acorn morphology in Northwestern Tunisia
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.
Is the plasticity in response to the drought of Quercus suber linked to the geographical origin?
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.
Leptocybe invasa and Ophelimus maskelli, two gall wasps introduced in Tunisia
The main objective of this factsheet is to help technicians and forsters to recognize, in the field, insect gall wasps of Eucalyptus species.
Monitoring of lepidopteran defoliators infesting cork oak in Sardinia
The aim is to monitor the population densities of the lepidopteran defoliator Lymantria dispar in Sardinian oak woodlands. This is done through egg mass counts with the aim of predicting the areas at risk of defoliation and plan insecticide applications accordingly.
Network of Cork Oak Selected Stands of Extremadura
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.
New business models for innovating the cork sector and contrasting cork oak woodland abandonment
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.
Optimizing the debarking and cutting schedule of cork oak stands
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 guidelines for the management of cork oak stands when the aim is to optimize economic profitability.
Post-fire presence and dynamics of xylophagous insects on cork oak ecosystems
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.
Promotion of cork oak recruitment in the Mediterranean
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.
Setting up of a short supply chain based on the valorization of cork waste in the Pyrénées-Orientales region
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 cork for bulk insulation.
Silvo-pastoral systems in southern Portugal: management challenges from the owner's perspective
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 in soil quality, biodiversity and in the survival of tree seedlings. Overcoming annual precipitation reduction is one of the main challenges.
Storage of acorns as a stock management tool for reforestation and fodder use
Solve the problem of the fragility of oak acorns used for reforestation and animal feed by improving the process of their conservation for a period close to a year.
Study of the sensitivity of cork oak to climate change in Corsica
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.
The Archi method applied to 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 resilience capacities.
The cork humidity parameter in the commercialization
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 cork business.
The influence of formation pruning in the cork tree growth rate: a case study.
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.
The use of cork in the thermoregulation of beehives
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 fundamental product and economic source of revenue of traditional agro-forestry systems.
Thickness assessment and weight modeling of cork in Tunisia: case study of Ain Snoussi forest
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.
Towards the economic valuation of ecosystem production from cork oak forests in Sardinia (Italy)
The study aimed at assessing the value and trade-offs of a number of ecosystem services associated to cork oak woodland management under different sylvicultural options in state-owned forests in Sardinia.
Tree damage control in a cork oak forest
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 cork oak vitality.
Using NIRS to assess the presence of cork anomalies
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.
Valorization of a co-product from the manufacture of cork stoppers: creation, production and marketing of an innovative, patented and objectified cosmetic active ingredient.
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.
What are the main variables influencing cork thickness?
- 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.
- 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 breast height, measured over cork.