An approach to cork oak forest management planning: a case study in southwestern Portugal   总被引：1，自引：0，他引：1  

A. Costa  A. C. Oliveira  F. Vidas  J. G. Borges 《European Journal of Forest Research》2010,129(2):233-241

This paper presents results of research aiming at the development of tools that may enhance cork oak (Quercus suber L.) forest management planning. Specifically, it proposes an hierarchical approach that encompasses the spatial classification of a cork oak forest and the temporal scheduling of cork harvests. The use of both geographical information systems and operations research techniques is addressed. Emphasis is on the achievement of cork even flow objectives. Results from an application to a case study in the Charneca Pliocénica of Ribatejo in southern Portugal encompassing a cork oak forest extending over 4.8 thousand ha are discussed. They suggest that the proposed approach is capable of effective spatial classification of cork oak management units. They further suggest that it may be used to select optimal cork even flow scheduling strategies. Results also show that the proposed approach may lead to a substantial increase in net present value when compared to traditional approaches to cork oak forest management planning.  相似文献   

Optimizing the debarking and cutting schedule of cork oak stands     

María Pasalodos-Tato  Timo Pukkala  Isabel Cañellas  Mariola Sánchez-González 《Annals of Forest Science》2018,75(2):61

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Chemical composition and variability of cork from Quercus suber L.     

H. Pereira 《Wood Science and Technology》1988,22(3):211-218

Summary The chemical composition of cork from Quercus suber L. was determined for virgin cork and for reproduction cork. Average chemical composition of virgin cork is: ash 0.7%, total extractives 15.3%, suberin 38.6%, lignin 21.7% and polysaccharides 18.2%. The carbohydrate composition shows that glucose represents 50.6% of all monosaccharides, xylose 35.0%, arabinose 7.0% and galactose and mannose, respectively, 3.6% and 3.4%. Reproduction cork has a composition similar to virgin cork. For the cases studied, reproduction cork had however less extractives and a higher amount of suberin. Significant differences were found for the chemical composition of virgin cork in relation to location of extractives and polysaccharide content. The between-tree variability was large and a variation within the tree was also recorded.The author is grateful for the help of collaborators throughout the chemical analysis of the many samples: Joaquina Ferreira, A. Velez Marques, M. Lurdes Ferreira, Rosa Amorim and Célia Constâncio.The work was financially supported by the Instituto de Ciência e Tecnologia dos Materiais (ICTM), Lisbon, Portugal  相似文献   

Stem modeling and simulation of conversion of cork oak stems for quality wood products     

Sofia Knapic  Isabel Pinto Seppä  Arto Usenius  Helena Pereira 《European Journal of Forest Research》2011,130(5):745-751

Recent research is underway to study cork oak (Quercus suber L.) wood potential for production of wood components. A total of 35 stems of young and mature cork oaks were sampled, live sawn into flitches, scanned using VTT’s WoodCIM^®, and the measured data computed by VTT’s PuuPilot software, allowing stem 3D reconstruction. Sawing simulations were run for 0.5 m and 1 m logs and the whole stem. Sawn products were (1) planks, (2) parquet, (3) lamparquet, and (4) external component of multilayer planks. Cork oak stems showed a moderate to small taper (mean 24 mm/m). Curviness varied between straight to significantly crooked stems (mean value 40 mm) Batch yields for the tested products ranged 25–43% and 37–50% for 0.5 m logs of young and mature trees, respectively; for 1 m logs, batch yields ranged 19–41% and 25–54%. When using the whole stem, batch yields were lower, ranging 11–38% and 15–50%. Higher yields were obtained for all log lengths and samples for production of lamparquet, parquet, and multilayer component.  相似文献   

Differences of raw cork quality in productive cork oak woods in Sicily in relation to stand density     

Giuseppe M. Pizzurro  Federico MaetzkeDonato S. La Mela Veca 《Forest Ecology and Management》2010

Differences of raw cork quality, in terms of thickness and porosity, were observed in productive cork oak (Quercus suber L.) stands in the Nebrodi and Iblei mountains of Sicily in relation to stand density. Five study areas were chosen across a range of different stand density satisfying specific sampling requirements among two managed cork oak woods.Analysis of variance using Fisher–Snedecor‘s F test (p < 0.05) were used to identify statistically significant differences of cork quality and sylvicultural, dendrometric and cork stripping parameters between study areas within each stand. Relationships between cork quality and sylvicultural and dendrometric parameters were also tested using Pearson's correlation coefficient (r). Results shown that sylvicultural practices are a key factor influencing cork quality: statistically significant differences in cork thickness and crown area were observed between areas at different stand density; positive correlations were found between cork thickness and crown area in lower density study areas favouring a significant vegetative activity; negative correlations were found between parameters of cork stripping (cork stripping coefficient, cork stripping surface, maximum height of cork stripping) and cork thickness. No correlations were found between cork porosity and dendrometric or sylvicultural parameters, demonstrating the probable genetic origin of cork porosity. Results shown that cork quality parameters and stand attributes may be used in sustainable management models of cork oak forests.  相似文献   

Radial variation of wood density components and ring width in cork oak trees     

Sofia Knapic  José L. Louzada  Sofia Leal  Helena Pereira 《Annals of Forest Science》2007,64(2):211-218

The radial variation of ring width and wood density was studied in cork oaks (Quercus suber) using microdensitometry. The observations were made in young never debarked cork oaks (30–40 years of age) and in mature trees under cork production (37–60 years of age). The cork oak wood is very dense (mean ring density 0.86 g.cm^?3, between 0.79 g.cm^?3 and 0.97 g.cm^?3) with a small intra-ring variability (mean earlywood density 0.80 g.cm^?3 and latewood density 0.90 g.cm^?3). The density components decreased from pith to bark more rapidly until the 15th ring, and then only slightly. There were no significant differences in the mean density components between never debarked trees and trees under cork production but their outwards decrease was accentuated in the never debarked trees. The annual growth was high, with a ring width mean of 3.9 mm (4.2 mm in the first 30 years) and the latewood represented 57% of the annual growth.  相似文献   

Viability of holm and cork oak seedlings from acorns sown in soils naturally infected with Phytophthora cinnamomi     

M. C. Rodríguez‐Molina  L. M. Torres‐Vila  A. Blanco‐Santos  E. J. Palo Núñez  E. Torres‐Álvarez 《Forest Pathology》2002,32(6):365-372

The emergence and survival of pregerminated holm oak (Quercus ilex) and cork oak (Quercus suber) acorns from two ecologically different dehesas (Mediterranean open woodlands) were studied in two soils from these stands naturally infected with Phytophthora cinnamomi, and in the same soils previously sterilized in the autoclave. Phytophthora cinnamomi was consistently isolated from the radicles of all unemerged and all emerged but dead seedlings from the unsterilized substrates. Seedlings of holm oak were more susceptible to P. cinnamomi than those of cork oak. Mortality of holm oak seedlings was significantly different depending only on soil treatment (sterilized or unsterilized), and it was 100% in unsterilized soils, independent of acorn provenance and soil origin. Mortality of cork oak seedlings was significantly different depending on the acorn origin and soil treatment, and on the interactions acorn origin × soil origin and soil origin × soil treatment. The demonstrated high susceptibility of holm and cork oak young seedlings to P. cinnamomi could be a limiting factor in Mediterranean open woodlands (dehesas) not only in natural regeneration processes but also when reforestation by direct sowing is implemented.  相似文献   

A quantitative approach to cork oak forest management     

《Forest Ecology and Management》1997,97(3):223-229

Mathematical programming is one quantitative technique that can be used for strategic and tactical natural resources planning. It has been extensively used both at private and public forest planning levels. Nevertheless, most applications concentrate on modelling of systems involving timber harvesting. This paper focuses on cork oak (Quercus suber L.) forest management. It summarizes the methodology to follow in order to generate information needed for modelling purposes. It formulates a cork oak forest management problem using a linear programming model. A case study is used to illustrate the procedure used. The results of the research on a modelling approach to cork oak forest management for an area extending over 5272 ha in the Portuguese submediterranean ecological region are presented. Extensions to this study are identified.  相似文献   

Litter flammability in oak woodlands and shrublands of southeastern France     

Thomas Curt  Alice SchaffhauserLaurent Borgniet  Claire DumasRoland Estève  Anne GanteaumeMarielle Jappiot  Willy MartinAminata N’Diaye  Benjamin Poilvet 《Forest Ecology and Management》2011,261(12):2214-2222

Characterizing the flammability of litter fuels is of major importance for assessing wildland fire ignition hazard. Here we compared the flammability of litter within a mosaic of Quercus suber (cork oak) woodlands and shrublands in a Mediterranean fire-prone area (Maures massif, southeastern France) to test whether the characteristics and the flammability of litter vary with the vegetation types. We tested experimentally the ignitability, the sustainability, the combustibility and the consumability of undisturbed (=non-reconstructed) litter samples with a point-source mode of ignition. Although the frequency of ignition was similar between all the vegetation types, we distinguished four groups having litter of specific composition and flammability: low and sparse shrublands dominated by Cistus species, medium shrublands with cork oak, high Erica shrublands with sparse cork oak woodlands, and mixed mature oak woodlands with Q. suber, Q. ilex and Q. pubescens. As these vegetation types corresponded to a specific range of past fire recurrence, we also tested the effect of the number of fires and the time since the last fire on litter flammability. Litters of plots recurrently burned had low ability to propagate flames and low flame sustainability. We discuss how the recent fire history can modify vegetation and litter flammability, and thus the fire ignition hazard.  相似文献   

Factors affecting post-fire crown regeneration in cork oak (Quercus suber L.) trees     

Filipe Xavier Catry  Francisco Moreira  Inês Duarte  Vanda Acácio 《European Journal of Forest Research》2009,128(3):231-240

Cork oak (Quercus suber) forests are acknowledged for their biodiversity and economic (mainly cork production) values. Wildfires are one of the main threats contributing to cork oak decline in the Mediterranean Basin, and one major question that managers face after fire in cork oak stands is whether the burned trees should be coppiced or not. This decision can be based on the degree of expected crown regeneration assessed immediately after fire. In this study we carried out a post-fire assessment of the degree of crown recovery in 858 trees being exploited for cork production in southern Portugal, 1.5 years after a wildfire. Using logistic regression, we modelled good or poor crown recovery probability as a function of tree and stand variables. The main variables influencing the likelihood of good or poor crown regeneration were bark thickness, charring height, aspect and tree diameter. We also developed management models, including simpler but easier to measure variables, which had a lower predictive power but can be used to help managers to identify, immediately after fire, trees that will likely show good crown regeneration, and trees that will likely die or show poor regeneration (and thus, potential candidates for trunk coppicing).  相似文献   

Analysis of spatial patterns of oak decline in cork oak woodlands in Mediterranean conditions     

Augusta Costa  Helena Pereira  Manuel Madeira 《Annals of Forest Science》2010,67(2):204-204

? Cork oak mortality is a recurrent problem in southwestern Portugal. Despite the perception of increasingly visible damage in oak woodlands on drought-prone sites, the role of the various environmental factors in their decline is not clear.

? To describe the spatial patterns of cork oak (Quercus suber L.) mortality, a cork oak mortality index (MI) was determined for each landscape feature (agroforestry system, soil type, slope and aspect) using a GIS approach. To achieve this goal, a logistic regression model was formulated analyzing interactions between landscape attributes and allowing a prediction of cork oak mortality.

? Maximum values of MI were found in (i) shrublands and open woodlands with shrub encroachment (MI 6 and 3, respectively), where competition for soil water between tree and understory increases; and (ii) on lower slopes in the rounded hilltops and smooth hillsides or shallow soils where access to groundwater resources during summer drought is difficult.

? The model highlighted the importance of the agroforestry systems on cork oak mortality and may be used to identify sensitive areas where mitigation actions should be employed in a scenario of increasing drought severity in these Mediterranean ecosystems.

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The effect of cork removal on the radial growth and phenology of young cork oak trees     

《Forest Ecology and Management》2001,141(3):251-258

The effect of the removal of cork was studied in 11-years old cork oak trees (Quercus suber L.), growing in favorable conditions, in relation to phenology and radial growth during two years. Longevity of leaves was 14–15 months (1996, 1998) and 10 months (1997). Bud burst started in mid-February and leaf flushing in April, extending until June. Neither a distinct two-period flushing nor an autumn bud burst or leaf flushing were observed. Radial growth started in mid-April and continued until the end of November, with the maximum growth in June and July. In trees with the removal of cork, leaf abscission occurred a little earlier and new branches had on average 23% fewer new leaves. The radial growth of the trees and its general seasonal pattern were not affected by cork removal in the year of removal or in the year after. The only observation was a shift of the maximum radial growth rate from June to July for the trees where cork had been removed.  相似文献   

The thermochemical degradation of cork     

Prof. Helena Pereira 《Wood Science and Technology》1992,26(4):259-269

Summary The thermochemical degradation of cork from Quercus suber L. was studied in the temperature range 150°C–450°C in relation to mass loss, chemical composition and the influence on the cellular structure. The degradation of cork is strongly dependent on temperature and mass losses become significant at 200°C (15% of initial dry weight) and increase rapidly for higher temperatures (27% at 250 °C, 49% at 300 °C, 62% at 350 °C) until ashing at 450 °C. The polysaccharides are the most heat sensitive components: at 200 °C, hemicelluloses disappear and cellulose is degraded to a considerable extent. Suberin is more resistant and degradation starts at approx. 250 °C; 300 °C-treated samples only contain 7% suberin.The cellular structure of cork is also significantly influenced by temperature. Upon heating, cells expand and the cell walls stretch, attaining at 250 °C a maximum cell volume increase corresponding to a factor of approximately 2. Above 300 °C, the structure of cell walls is considerably changed and show profound physical damage; in the later stages of pyrolysis, a cellular structure is no longer observed.We are grateful to Mrs. Joaquina Ferreira for her help with the chemical analysis. The research was financially supported by the Junta Nacional de Investigação Científica e Tecnológica (JNICT) and by the Instituto de Ciência e Tecnologia dos Materiais (ICTM)  相似文献   

Birds as predators of cork and holm oak pests     

Ricardo S. Ceia  Jaime A. Ramos 《Agroforestry Systems》2016,90(1):159-176

The recent decline of Mediterranean oak woodlands in SW Iberian Peninsula is related to insect pests which affect both cork oak (Quercus suber) and holm oak (Quercus rotundifolia). We identified twenty-six bird species as potential regular predators of twenty major pests by reviewing the diet of breeding, wintering and resident species in this ecosystem. Foraging guilds are strongly associated with predation at distinct stages of the pests’ life-cycle: ground-foragers prey on overwintering pupae and larvae of seed-borers, tree-foragers prey on eggs, larvae and pupae of defoliating and wood-boring pests, and aerial-sweepers prey on airborne imagines. Bird predation can cover the complete life-cycle of pest species because different species may be complementary due to a dissimilar exploitation of foraging niches and periods. Small generalist tree-foraging passerines are important pest predators given their high densities and widespread distribution in Mediterranean oak woodlands, but management practices can have a significant negative effect in their populations.  相似文献   

Flammability of some companion species in cork oak (<Emphasis Type="Italic">Quercus suber</Emphasis> L.) forests     

Belkheir Dehane  Carmen Hernando  Mercedes Guijarro  Javier Madrigal 《Annals of Forest Science》2017,74(3):60

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Dieback of cork oak (Quercus suber) in Catalonia (NE Spain) caused by Botryosphaeria stevensii     

J. Luque  J. Girbal 《Forest Pathology》1989,19(1):7-13

Botryosphaeria stevensii Shoemaker (anamorph: Diplodia mutila Fr. apud Mont.) is reported as the cause of canker and dieback of cork oak (Quercus suber L.) in Catalonia (NE Spain). It also causes wilting of trees after cork is removed for industrial purposes. Symptomatology and details of morphology for both anamorph and teleomorph are given.  相似文献   

Carbon sequestration of modern Quercus suber L. silvoarable agroforestry systems in Portugal: a YieldSAFE-based estimation     

J. H. N. Palma  J. A. Paulo  M. Tomé 《Agroforestry Systems》2014,88(5):791-801

Modern alley cropping designs, with trees aligned in rows and adapted to operating farming machinery, have been suggested for Europe. This paper explores the potential for adoption of cork oak (Quercus suber L.) agroforestry in Portugal and estimates the potential carbon sequestration. Spatial modeling and Portuguese datasets were used to estimate target areas where cork oak could grow on farmland. Different implementation scenarios were then modeled for this area assuming a modern silvoarable agroforestry system (113 trees ha^?1 thinned at year 20 for establishing 50 trees ha^?1). The YieldSAFE process-based model was used to predict the biomass and carbon yield of cork oak under low and high soil water holding capacity levels. Approximately 353,000 ha are available in Portugal for new cork oak alley cropping. Assuming implementation rates between 10 % of the area with low soil water capacity (60 mm: 15 cm depth, coarse texture) and 70 % of the area with high soil water holding capacity (1,228 mm: 200 cm depth, very fine texture), then carbon sequestration could be 5 × 10⁶ and 123 × 10⁶ Mg CO₂ respectively. Due to higher yields on more productive land, scenarios of limited implementation in high productivity locations can sequester similar amounts of carbon as wide implementation on low productivity land, suggesting that a priori land classification assessments can improve the targeting of land and financial incentives for carbon sequestration.  相似文献   

Variability of the compression properties of cork   总被引：1，自引：0，他引：1  

Vanda Oliveira  M. Emília Rosa  Helena Pereira 《Wood Science and Technology》2014,48(5):937-948

The variability of the compression properties of cork was determined after field sampling covering the main production area in Portugal (10 sites) with samples taken from 20 trees per site at the time of cork stripping. In all cases, cork showed compressive stress–strain curves typical for cellular materials, which are characterized by an approximately “elastic” region up to a 5 % strain, followed by a large plateau up to 70 % strain caused by progressive buckling of cell walls, and a steep stress increase for higher strains corresponding to cell collapse. The radial direction of compression offered higher strength. The Young’s moduli averaged 10.4 and 9.2 MPa for radial and non-radial directions, respectively, spreading from 3.5 to 22.5 MPa for the non-radial and 4.2 to 21.5 MPa for the radial directions. The geographical location of cork production was the major factor of variability. Density, annual growth ring width and chemical composition influenced compression. Cork samples with higher density showed overall larger resistance to compression. The energy absorbed per unit volume to achieve the maximal deformation with full densification of cork is higher when the average annual ring width is smaller. Cork samples with relatively higher suberin content required less stress for deformation. The results encompass the natural variability of cork and are the most extensive to characterize cork. They allow a better insight into the differences that may explain the variation in cork properties and strengthen its use either in the known applications, i.e. as a sealant, or in novel applications.  相似文献   

Method for evaluation of coarse cork oak root system by means of digital imaging     

P. Surovy  N. A. Ribeiro  F. Brasil  J. S. Pereira  M. R. G. Oliveira 《Agroforestry Systems》2011,82(2):111-119

Digital imaging is becoming a powerful tool for data storage and information retrieval. Image comparison and similarity evaluation has become part of the information market and it is today a common part of, for example, web search engines. The cork oak tree (Quercus suber L.), the dominant species of the ??montado?? woodland system is, due to its cultural and socio-economic value, protected by law that prevents extensive destructive studies on an essential part of the tree??the root. Especially in the Mediterranean zone, where the water is the limiting growth factor, the root development studies are of significant interest. In this work we present a method of using digital images for cork oak coarse root systems-evaluation by means of digital imaging. Acquired images of structural roots are processed automatically to prevent subjective decisions by the human observer. The performance of the method, its potential for semantic retrieval and similarity assessment is demonstrated, having as example eight young cork oak root systems, and critical issues for evaluation and conclusion-making, are discussed.  相似文献   

Chronic cork oak decline and water status: new insights     

Constança S. P. Camilo-Alves  Margarida Vaz  M. Ivone Esteves Da Clara  Nuno Manuel De Almeida Ribeiro 《New Forests》2017,48(6):753-772

Chronic decline and Sudden death are two syndromes of cork oak (Quercus suber) dieback. Mortality is associated with water stress, but underlying physiological mechanisms are poorly understood. Here, we investigated the physiological performance of declining trees during the summer drought. Leaf water potential, gas-exchange, fluorescence of photosystem II and leaf and root starch concentration were compared in healthy (asymptomatic) and declining trees. Low annual cork increment in declining trees indicated tree decline for several years. All trees showed similar water status in spring. In summer, declining trees showed lower predawn leaf water potential (?2.0 vs. ?0.8 MPa), but unexpectedly higher midday leaf water potential than healthy trees (?2.8 vs. ?3.3 MPa). The higher midday water potential was linked to by means of strongly reduced stomatal conductance and, consequently, transpiration. This study is pioneer showing that declining trees had high midday water potential. A tendency for lower sap flow driving force (the difference between predawn and midday water potential) in declining trees was also associated with reduced photosynthesis, suggesting that chronic dieback may be associated with low carbon uptake. However, starch in roots and leaves was very low and not correlated to the health status of trees. Declining trees showed lower water-use efficiency and non-photochemical quenching in summer, indicating less resistance to drought. Contrarily to chronic decline, one tree that underwent sudden death presented predawn leaf water potential below the cavitation threshold.  相似文献