How resilient is Quercus suber L. to cork harvesting? A review and identification of knowledge gaps

Oliveira, Graça; Costa, Alexandre

doi:10.1016/j.foreco.2012.01.025

Cited by 45 publications

(54 citation statements)

References 94 publications

(161 reference statements)

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“…Similar to other NTFPs (Ticktin 2004;Wadt et al 2008), the long-term sustainability of the cork industry relies on its economic viability, but also, and decisively, on the resilience of the cork oak (Quercus suber L.) to bark harvesting (Oliveira and Costa 2012). Cork oaks are highly resilient to recurrent cork harvesting due to the presence of cork cambium (phellogen), which has a strong inherent capability to regenerate almost immediately (25-35 days) after harvesting (Machado 1935).…”

Section: Introductionmentioning

confidence: 99%

Insights into the Responsiveness of Cork Oak (Quercus suber L.) to Bark Harvesting

et al. 2015

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Insights into the Responsiveness of Cork Oak (Quercus suber L.) to Bark Harvesting The cork oak (Quercus suber L.) is harvested for its bark (cork), a highly valuable non-timber forest product. Recurrent cork harvesting is practiced over the lifetime of the tree and constitutes a stressful action that, while artificially promoting cork growth, may severely deplete tree vigor after an exploitation time span. To date, few long-term studies have been conducted regarding the effect of recurrent cork harvests on cork growth rates, and there is a complete lack of knowledge on the effect of the stress, induced by cork harvesting, on the vigor of the cork oak. In this study we propose to address the resilience of the cork oak to cork harvesting, using cork-ring width as an indicator of tree vigor. We use dendrochronological methods to develop an extended corkring width series that was analyzed by autoregressive integrated moving average modeling with an intervention analysis approach. We show that cork harvesting represents a human-induced loss of tree resilience only after six consecutive harvests, and that only after a single stochastic cork-harvesting event may trigger a sudden collapse in cork oak vigor. Our results also suggest that the tree (optimum) exploitation period of 110-120 years, which includes more than nine consecutive harvests, extends more than 35 years beyond the tree vigor breakpoint (occurring at the sixth consecutive harvest). Within this time frame, the tree is producing cork instinctively to survive, and its vulnerability to other (a)biotic stresses may increase, leading to untimely cork oak decline. These results suggest that there is a great potential in the time-series analysis of cork-ring widths for the development of tools that may enhance typical cork oak management planning by addressing both economic and ecological objectives.Compreender a capacidade de resposta do sobreiro (Quercus suber L.) ao descortiçamento O sobreiro (Quercus suber L.) distingue-se das outras árvores pelas características singulares da sua espessa casca suberosa, a cortiça. Atualmente, a cortiça é considerada um importante produto não-lenhoso da floresta da região Mediterrânica, com elevado valor comercial. A extração da 1 Electronic supplementary material The online version of this article (, Bronx, NY 10458-5126 U.S.A.cortiça (descortiçamento) é feita periodicamente ao longo da vida da árvore, em sucessivos ciclos de produção de cortiça. Após um descortiçamento, a camada geradora de cortiça (felogene) morre e a árvore tem a capacidade de regenerar uma nova que, quase imediatamente, começa a formar novas camadas de cortiça. A longo prazo, os sucessivos descortiçamentos, do mesmo modo que Bforçam^a árvore a produzir novas camadas de cortiça, afetam decisivamente os processos fisiológicos da árvore. Apesar de bem estudadas, as reações fisiológicas imediatas do sobreiro ao descortiçamento e a curva crescimento de cortiça num ciclo de produção, nada se sabe sobre como a árvore reage a sucessivos descortiçamentos, ao lon...

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Section: Introductionmentioning

confidence: 99%

Insights into the Responsiveness of Cork Oak (Quercus suber L.) to Bark Harvesting

et al. 2015

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“…This work was the first specifically dedicated to the purpose of evaluating the influence of different understory management options on cork annual growth and tree wood growth, a research question already refered by Oliveira & Costa (2012) and Paulo et al (2016b). For this purpose, the trial allowed to obtain two subsets of cork samples that were used for the analysis …”

Section: Discussionmentioning

confidence: 99%

Understory effect on tree and cork growth in cork oak woodlands

et al. 2018

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Aim of study: Cork oak is one of the main forest tree species in Portugal that typically occurs in montado, where operational practices oriented to the tree, crop or animal management may influence several of the ecosystem components. This study aimed at contributing to fulfil the a lack of knowledge on the effect of these practices on the cork and wood growth, by comparing the wood diameter growth and the annual cork increment under two different understory management options.Material and methods: An experimental trial implemented on an uneven-aged cork oak pure stand during a cork rotation period of 9 years, was established with the specific goal of comparing understory management options: a yellow lupine pasture versus spontaneous vegetation. Cork samples were taken at the beginning and end of the period and were used to measure cork thickness and annual cork rings. The differences between treatments were assessed performing a non-parametric test and a more robust approach using linear mixed model. Precipitation and treatment levels were jointly considered on the analysis.Main results: A slight effect was found on the cork thickness regarding the treatment with lupine application. However, no distinct effect was found, regarding wood and the annual cork increment pattern. Additionally, annual cork ring width showed a positive correlation with precipitation and a negative correlation with ring age.Research highlights: The results of this study indicate no distinct pattern regarding the annual cork and wood increment when comparing the understory effect of yellow lupine pasture versus spontaneous vegetation.Additional keywords: Quercus suber, cork thickness; cork ring; lupine; shrubs; linear mixed model.

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“…Although the relationship between debarking intensity and tree growth and resilience is still an area in need of research (Oliveira & Costa, 2012), landowners are usually conservative concerning debarking intensity, and even adapt it to the tree growing and sanitary conditions. Decision on CDR should consider not only the variables considered in this research, but also growth conditions, taking into account the importance of cork harvesting and climate for stem radial growth of Quercus suber L. (Oliveira et al, 2002;Leal et al, 2008).…”

Section: Decision On Cork Debarking Rotationmentioning

confidence: 99%

Using the SUBER model for assessing the impact of cork debarking rotation on equivalent annual annuity in Portuguese stands

Paulo

Tomé

2017

For. syst.

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Aim of study: Use the SUBER model to evaluate the influence of the cork debarking rotation period (CDR) on equivalent annual annuity (EAA) value.Area of study: Nine simulated stands, varying in site index (14.4, 15.6, 17.1) and cork quality characteristics (high, medium, low). Material and methods:EAA values were computed considering CDR periods varying from 9 to 14 years, two contrasting structures of cork prices (high and low cork price scenarios), and three discount rate values (0.5%, 2% and 5%).Main results: For discount rates of 0.5% and 2% the impact of different CDR on the EAA is similar. In stands characterized by high to average site index values or high to medium cork quality characteristics, CDR of 9 and 11 years are associated with similar values of EAA. The variation of the CDR in stands characterized by low site index values and/or low cork quality characteristics did not have a relevant effect on the variation of EAA. For the simulations carried out with a discount rate of 5% the EAA decreases with the increase of CDR, indicating that the minimum legal value of 9 years for CDR should be applied.Research highlights: In stands characterized by high to average site index values or high to medium cork quality characteristics, a delay in the debarking may result in a significant increase of cork thickness and, as a result, of cork price. Detailed knowledge of cork and stand characteristics and updated information on cork prices structure and values are essential for the best usage of management tools such as the SUBER model, which can contribute to the decision-making process concerning the debarking operation.Keywords: adaptive forest management; cork production; cork price; cork quality; growth and yield model; site index.Correspondence should be addressed to Joana Amaral Paulo: joanaap@isa.ulisboa.pt

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How resilient is Quercus suber L. to cork harvesting? A review and identification of knowledge gaps

Cited by 45 publications

References 94 publications

Insights into the Responsiveness of Cork Oak (Quercus suber L.) to Bark Harvesting

Insights into the Responsiveness of Cork Oak (Quercus suber L.) to Bark Harvesting

Understory effect on tree and cork growth in cork oak woodlands

Using the SUBER model for assessing the impact of cork debarking rotation on equivalent annual annuity in Portuguese stands

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