Influence of water and nutrients on cork oak radial growth – looking for an efficient fertirrigation regime

The widespread cork oak (Quercus suber L.) mortality and reduced afforestation /regeneration are causing an overall reduction in cork production. To enhance trees’ growth and vitality, afforestation techniques using fertirrigation were tested. The main objective was the promotion of trees’ growth on new dense plantations using minimum water requirements until reaching productive forests. The experimental plot – Irricork – was installed in 2017 in a ≈1 ha stand with 14 years’ age cork oaks summer-fertirrigated since plantation. Four fertirrigation treatments were applied during fertirrigation campaigns. Radial growth, meteorological parameters and fertirrigation volume were measured every 15–30 days over four years. It was observed that weather, tree size, debarking and trees’ intra-competition had a significant effect on radial increments. Fertirrigation significantly enhanced growth during summer drought and decoupled increments from air vapor pressure deficit constraints. There was a linear relationship between trees’ radial increments and fertirrigation volume up to 140 m3 week–1. Above this value, increments were smoother. In conclusion, summer fertirrigation of 140 m3 week–1 efficiently enhanced the radial growth of trees with 50–75 circumference at breast height, under the particular edaphoclimatic conditions of the stand. This study showed to be, therefore, promising in the use of efficient fertirrigation the enhance cork oaks’ radial growth.This work was funded by a contract-partnership between Amorim Florestal, Casa Agrícola da Herdade do Conqueiro and University of Évora; by the Rural Development Program for Operational Groups by PDR2020-101-FEADER-031427 “GO-RegaCork”, by Regacork-TraDE Project—ALT20-03-0246-FEDER-000061 and by National Funds through FCT—Foundation for Science and Technology under the Projects UID/AGR/00115/2019 and UIDB/05183/2020

Studies on cork oak decline: an integrated approach

Neste trabalho abordaram-se vários aspectos relacionados com o declínio do sobreiro (Quercus suber). Uma análise exaustiva á bibliografia realçou que o sobreiro é moderadamente susceptível a Phytophthora cinnamomi, ocorrendo declínio quando há encharcamento do solo e limitações à expansão de raízes. Também foram identificados alguns aspectos que foram alvo de investigação mais detalhada, como a utilização de métodos robustos para detecção de P. cinnamomi e conhecimento acerca da fisiologia associada ao declínio. Métodos moleculares para diagnose de P. cinnamomi de amostras de solo revelaram-se inapropriados devido à combinação da baixa concentração do inóculo com a reduzida quantidade de amostra passível de analisar. Em relação à fisiologia do declínio, duas respostas ao défice hídrico foram detectadas, uma levando à morte por falta de fotoassimilados, outra por falha no transporte hídrico. Por fim, a utilização de ectomicorrizas em condições naturais mostrou ser uma abordagem a aprofundar para a melhoria sanitária das árvores; ### ABSTRACT: Studies on cork oak decline: An integrated approach This work integrates various aspects related to cork oak decline. A thorough bibliographic analysis stressed that cork oaks (Quercus suber) are moderately susceptible to Phytophthora cinnamomi, and decline is likely to occur under conditions limiting roots expansion and causing waterlogging. It was also identified some important aspects subjected to detailed research, like the prerequisite of robust methods for P. cinnamomi diagnosis and knowledge about the tree physiology associated to decline. Molecular methods for P. cinnamomi diagnosis from soil samples proved unsuitable because of the combination of reduced inoculum concentration in the soil and low sample size possible to analyze. In relation to the physiology of decline, two responses to water stress were detected, one leading to mortality caused by lack of assimilates and another caused by failure in water transport. Finally, the use of ectomycorrhizal under natural conditions has proven to be an interesting approach for trees health status improvement

Irrigation of Young Cork Oaks under Field Conditions—Testing the Best Water Volume

This study is the beginning of the first long-term study on cork oak irrigation under field conditions, with a structural-functional approach. Cork oaks are currently facing disturbances affecting cork quality and quantity, jeopardizing the future of the economic sector. There is a need for new production techniques that maximize cork oak growth and vitality. In this study, irrigation was implemented in a new intensive cork oak plantations to test the best irrigation volume. The long-term goal is to improve tree growth with minimum water requirements. A 6 ha intensive plantation was installed in Coruche, Portugal. The experimental plot consisted of a subsurface drip fertigation system, buried 40 cm deep; with five independent irrigation treatments. It was tested four irrigation volumes during the dry period—21 weeks in the summer of 2016—ranging from 1.88 mm to 5.62 mm a week. Information on meteorological conditions, soil moisture profile and leaf stomatal conductance were gathered periodically and dendrometric measurements were performed before and after the treatments. Cork oaks’ structural and functional parameters were associated with irrigation volume Response to irrigation showed an inflection point in treatment 2, corresponding to a water supply of 3.12 mm per week: below the inflection point, stomatal conductance was reduced by 15% and relative diameter growth at the base was reduced by 10%. Stomatal conductance also showed a positive relationship with soil moisture below the irrigation tubes and with plants’ stem diameter. In conclusion, irrigation supply during the period of water stress improved function and structure of cork oaks seedlings under field conditions. These results suggest that irrigation can be a viable alternative to improve cork oak growth in afforestation and reforestatio

A Cork Cell Wall Approach to Swelling and Boiling with ESEM Technology

The bark of cork oak (Quercus suber L.) is mostly used for cork stopper production; when bark undergoes a series of industrial procedures, boiling usually leads to changes in the characteristics of its tissue. Trees are traditionally grown under natural conditions; however, irrigation is now being used in plantations. This permanent water availability affects cork oak development, while its effects on industrial procedures are unknown. This study provides the first insight into the behaviour of the cell walls of cork during the process of swelling and boiling when trees have been grown under irrigation, that is, subject to a specific water regime. Cork tissue is analysed using environmental and scanning electron microscopy under three regimes: raw conditions, following immersion in water, and after boiling. Additionally, the radial expansion of samples is determined. The results show greater cell wall expansion in cork from the irrigated site than in cork from the traditional rainfed plot when hydrated for 24 h. After boiling, the cell walls of the cork from the rainfed site are thinner than in the raw stage, which is in contrast to the irrigated cork. This study suggests that irrigation during cork oak growth produces a higher capacity for adsorption, increasing cell wall thickness from the raw stage to the boiling stage

Inventário Nacional de Mortalidade de Azinheira na Fotografia Aérea Digital de 2004/2006

O presente estudo completa o 1.º inventário de árvores mortas e de grau de coberto na fotografia aérea digital de 2004-2006 para o sobreiro (Ribeiro e Surový, 2008) e azinheira para a área abrangida pela NUTS III: Alentejo Central; Alto Alentejo, Baixo Alentejo, Alentejo Litoral, Algarve, Médio Tejo, Lezíria do Tejo, Beira Baixa e Área Metropolitana de Lisboa. Os resultados deste estudo sincrónico são de particular utilidade para o conhecimento não só da distribuição como da intensidade dos eventos de declínio e, se repetido para outro conjunto de fotografias aéreas de anos posteriores, poderá fornecer informações relevantes e precisas não só da dinâmica do declínio, como do grau de coberto, permitindo uma definição de políticas florestais com um grau de eficiência espacial muito elevado. As metodologias e as aplicações informáticas desenvolvidas, se sistematizadas, podem servir para construir um sistema de monitorização em tempo real de grande utilidade para a avaliação e planeamento dos recursos florestais como da eficiência das políticas florestais. Finalmente, é importante referir que este estudo não teria sido possível de realizar sem a iniciativa do Instituto da Conservação da Natureza e das Florestas que através da visão estratégica do Eng.º Francisco Lopes e do Eng.º Fernando Coucelo identificaram as competências instaladas na Universidade de Évora e iniciaram os procedimentos de financiamento do inventário da mortalidade para o sobreiro e mais tarde para a azinheira

Influence of water and nutrients on cork oak radial growth – looking for an efficient fertirrigation regime

Abstract The widespread cork oak (Quercus suber L.) mortality and reduced afforestation /regeneration are causing an overall reduction in cork production. To enhance trees’ growth and vitality, afforestation techniques using fertirrigation were tested. The main objective was the promotion of trees’ growth on new dense plantations using minimum water requirements until reaching productive forests. The experimental plot – Irricork – was installed in 2017 in a ≈1 ha stand with 14 years’ age cork oaks summer-fertirrigated since plantation. Four fertirrigation treatments were applied during fertirrigation campaigns. Radial growth, meteorological parameters and fertirrigation volume were measured every 15–30 days over four years. It was observed that weather, tree size, debarking and trees’ intra-competition had a significant effect on radial increments. Fertirrigation significantly enhanced growth during summer drought and decoupled increments from air vapor pressure deficit constraints. There was a linear relationship between trees’ radial increments and fertirrigation volume up to 140 m3 week–1. Above this value, increments were smoother. In conclusion, summer fertirrigation of 140 m3 week–1 efficiently enhanced the radial growth of trees with 50–75 circumference at breast height, under the particular edaphoclimatic conditions of the stand. This study showed to be, therefore, promising in the use of efficient fertirrigation the enhance cork oaks’ radial growth

Influence of water and nutrients on cork oak radial growth – looking for an efficient fertirrigation regime

The widespread cork oak (Quercus suber L.) mortality and reduced afforestation /regeneration are causing an overall reduction in cork production. To enhance trees’ growth and vitality, afforestation techniques using fertirrigation were tested. The main objective was the promotion of trees’ growth on new dense plantations using minimum water requirements until reaching productive forests. The experimental plot – Irricork – was installed in 2017 in a ≈1 ha stand with 14 years’ age cork oaks summer-fertirrigated since plantation. Four fertirrigation treatments were applied during fertirrigation campaigns. Radial growth, meteorological parameters and fertirrigation volume were measured every 15–30 days over four years. It was observed that weather, tree size, debarking and trees’ intra-competition had a significant effect on radial increments. Fertirrigation significantly enhanced growth during summer drought and decoupled increments from air vapor pressure deficit constraints. There was a linear relationship between trees’ radial increments and fertirrigation volume up to 140 m3 week–1. Above this value, increments were smoother. In conclusion, summer fertirrigation of 140 m3 week–1 efficiently enhanced the radial growth of trees with 50–75 circumference at breast height, under the particular edaphoclimatic conditions of the stand. This study showed to be, therefore, promising in the use of efficient fertirrigation the enhance cork oaks’ radial growth

Natural regeneration of cork oak forests under climate change: a case study in Portugal

The sustainability of forest species is directly related to the success of stand regeneration. Assuring success is particularly critical in stands where perpetuity relies on natural regeneration, as is often the case with cork oak forests. However, 59% of the stand in Portugal have no natural regeneration, and climate change could further worsen the sustainability of the system. The study summarizes the factors that affect the natural regeneration of cork oak (Quercus suber L.) based on current knowledge and presents a case study on a forest in Northeast Portugal, where the natural regeneration of Quercus suber under the effect of climate change have been monitored and analyzed. The present work focuses on the effect of stand density, i.e., tree cover, on the production of acorns, the establishment and survival of seedlings, and the impact of the summer season on seedling mortality. The monitoring was carried out in February, June, September 2022, and January 2023 in two stands with distinct stand canopy cover, when the region was under extreme drought. Data analysis was performed using the analysis of variance for repeated measures and the Mann–Whitney-Wilcoxon test. The study showed that cork oak regeneration is influenced by stand density, which promoted the establishment success and survival of natural regeneration in a period of reduced precipitation, despite possible competition for water resources. The mean number of seedlings differed significantly between the two stands. However, there were no significant differences in the mean number of seedlings throughout the field measurements. Additionally, the percentage of dead seedlings was low even after the summer season (9.5% of the total seedlings) in the denser stand. These results indicate that high canopy cover can have a protective effect for extreme climatic events and should be considered in forestry management to promote regeneration of the cork oak forests

MANUAL TÉCNICO DE PRÁTICAS SILVÍCOLAS PARA A GESTÃO SUSTENTÁVEL EM POVOAMENTOS DE SOBREIRO E AZINHEIRA

Prefácio: Em Portugal Continental, segundo os dados do 6º Inventário Florestal Nacional (IFN6)(ICNFa), os espaços florestais (floresta, matos e improdutivos) ocupam 6,2 milhões de hectares (69,4%) do território, ocupando a floresta uma área de 3,2 milhões de hectares. Os “montados”, os sobreirais e os azinhais constituem a principal ocupação florestal, com 1.069.300 hectares, representando cerca de 1/3 da floresta. Em Espanha ocupam uma área de cerca de 3.515.920 hectares (Campos et al., 2010), o que representa cerca de 1/5 dos espaços florestais,equivalente a 6,95% do território peninsular espanhol, sendo 75% das explorações privadas. De acordo com os dados do Inventário Florestal Nacional (ICNFa) o sobreiro ocupa no território continental uma área de 719.900 hectares e a azinheira de 349.400 hectares. Na região do Alentejo a área ocupada pelo sobreiro é de 609.400 hectares e pela azinheira de 315.500 hectares, representando, assim, 84,6% e 90,2%, respetivamente, das áreas ocupadas por estas espécies no território continental. Na floresta os habitats mais representados são os que derivam das florestas de quercíneas, os montados (4%, habitat 6310), os sobreirais (4%, habitat 9330), os carvalhais (3%, habitat 9230) e os azinhais (2%, habitat 9340) (ICNFa)

Moving in the anthropocene: global reductions in terrestrial mammalian movements

Animal movement is fundamental for ecosystem functioning and species survival, yet the effects of the anthropogenic footprint on animal movements have not been estimated across species. Using a unique GPS-tracking database of 803 individuals across 57 species, we found that movements of mammals in areas with a comparatively high human footprint were on average one-half to one-third the extent of their movements in areas with a low human footprint. We attribute this reduction to behavioral changes of individual animals and to the exclusion of species with long-range movements from areas with higher human impact. Global loss of vagility alters a key ecological trait of animals that affects not only population persistence but also ecosystem processes such as predator-prey interactions, nutrient cycling, and disease transmission