Ana Lourenço

University of Lisbon | UL · Forest Research Center (CEF)

Parinari curatellifolia is the main species used to produce charcoal in Angola. It is chemical, anatomical, and thermal properties were analyzed. The bark is dark grey, rough, and corky, and the wood is brown to yellow-red. Compared to wood, bark fibers presented lower length, lumen, and wall thickness. There is not much difference between height a...

Parinari curatellifolia is an important evergreen tree from the Miombo woodland of south-central and eastern Africa. The bark is corky, suggesting an increased protection against the ecosystem high temperatures and drought conditions as well as against wild fires. The cork in the bark rhytidome of P. curatellifolia was analyzed here for the first t...

Pine nut industry residues, scales and core from pinecones and shells from the nuts from Pinus pinea were fully characterized. The anatomical sections showed differences between the residues. The scales presented vascular bundles with thick tracheids and narrow lumens in the xylem. The core structure presents xylem, phloem, and sclerenchyma tissues...

Lignin is an interesting natural polymer with characteristics that contribute for the development and growth of plants. Lignin presents high variability associated with the diversity of plants, which presents great challenges for its recovery after delignification (technical lignin), because lignin is prone to irreversible degradation, producing re...

The Clean Forest project aims to valorize forest biomass wastes (and then prevent their occurrence as a fuel source in forests), converting it to bioenergy, such as the production of 2nd generation synthetic biofuels, like bio-methanol, bio-DME, and biogas, depending on the process operating conditions. Valorization of potential forest waste biomas...

The main objective of this work was to assess Eucalyptus globulus lignin as an adsorbent and compare the results with kraft lignin, which has previously been demonstrated to be an effective adsorbent. Eucalypt lignin was extracted (by the dioxane technique), characterised, and its adsorption properties for Cr(VI) ions were evaluated. The monomeric...

O período entre 2018 e 2022 mostrou-nos que o problema dos incêndios à escala global não está a diminuir, antes pelo contrário. Parece que as consequências das alterações climáticas já estão a afectar a ocorrência de incêndios florestais em várias partes do Mundo, de uma forma que só esperaríamos que acontecesse vários anos mais tarde. Em muitos pa...

Eight polyhydroxy triterpenoid acids, hederagenin, (4α)-23-hydroxybetulinic acid, maslinic acid, corosolic acid, arjunolic acid, asiatic acid, caulophyllogenin, and madecassic acid, with 2, 3, and 4 hydroxyl substituents, were identified and quantified in the dichloromethane extract of Eucalyptus globulus wood by comparing their GC-retention time a...

The chemical and anatomical properties of Eucalyptus globulus stumps barks collected from fresh stumps (SB) and from industrial stumps bark piles (ISB) were determined. The stump bark showed similar anatomical structure to that of the stem bark, however with abundant prismatic crystals in the axial parenchyma cells. Stumps barks (ISB) presented a g...

Residues of Cistus ladanifer obtained after commercial steam distillation for essential oil production were evaluated to produce cellulose enriched solids and added-value lignin-derived compounds. The delignification of extracted (CLRext) and extracted and hydrothermally pretreated biomass (CLRtreat) was studied using two organosolv processes, etha...

The changes in the cellulose structure of eight Eucalyptus species (E. botryoides, E. globulus, E. grandis, E. maculata, E. propinqua, E. rudis, E. saligna and E. viminalis) in a mild torrefaction (from 160 °C to 230 °C, 3 h) were studied in situ and after cellulose isolation from the wood by solid-state carbon nuclear magnetic resonance (13C NMR),...

Three mature Eucalyptus globulus trees with 40 years of age were studied at three height levels (0%, 35%, and 60% of total tree height) and at three radial regions (sapwood, inner and outer heartwood). The composition of lipophilic extracts was evaluated and an extensive list of 202 compounds was reported for the first time. The fatty acids were th...

Changes in the lignin structure of eight eucalypt species (E. botryoides, E. globulus, E. grandis, E. maculata, E. propinqua, E. rudis, E. saligna, and E. viminalis) upon mild thermal treatment, where the temperature was gradually raised from 160 to 230 °C over 3 h, were studied by solid-state carbon nuclear magnetic resonance (¹³C NMR) and after l...

Different biomass fractions of Cistus ladanifer and solid residues from essential oil distilleries were structurally and chemically evaluated. The C. ladanifer biomass fractions showed chemical differences mainly related to extractives (e.g., 10.8% and 53.7% in stems and leaves) and lignin (e.g., 21.2% and 15.4% in stems and leaves). The distillery...

The shells of three important food nuts, walnut, almond, and pine nut, were studied in view of valorization as residues. The shells differed chemically: walnut shells had 10.6% extractives, 30.1% lignin, and 49.7% polysaccharides; almond shells 5.7% extractives, 28.9% lignin, and 56.1% polysaccharides; and pine nut shells 4.5% extractives, 40.5% li...

[This corrects the article DOI: 10.1016/j.heliyon.2019.e02910.].

Sustainability of cork oak (Quercus suber) forests is threatened by biotic and abiotic factors and characterization of potentially differing genetic resources has therefore gained importance. This work addresses the chemical variation of the three tissues of cork oak stems – cork, phloem and wood – in relation to tree and provenance, looking for ge...

The chapter exposes the performance of Acacia melanoxylon wood for pulping production, regarding yields and kappa number but also the pulp and paper properties. The use of spectroscopy techniques is also emphasized.

Four clones of C.cardunculus were produced by micropropagation of selected individuals grown in Portugal and Spain; subsequently, they were tested in a field experiment carried out in central Spain. Plant traits of the four clones were studied in order to get insights into their potential for oil production. Intra-clone variability for some studied...

Cistus ladanifer residues obtained after essential oil distillation were extracted with ethanol and water (CLRext) and subsequently hydrothermally treated (autohydrolysis) in order to selectively hydrolyze hemicelluloses. The extraction removed a significant amount of potentially valuable compounds (40% w/w, dry basis), foremost, phenolic compounds...

E. globulus stumps are recently considered as feedstock for pulp industries. Pre-treatments may improve delignification, increase pulp quality and promote other cellulosic applications. Five environmentally friendly pre-treatments were studied: liquid hot water (LHW), oxalic acid (OA), alkaline peroxide (AHP), sodium xylenesulfonate (SXS) and iron...

Ponytail palm (Beaucarnea recurvata Lemaire) is a succulent plant indigenous to Mexico frequently used as an ornamental plant throughout the world. The mature trees develop a thick corky outer bark that was studied here for the first time and compared with cork of Quercus suber Linnaeus (cork oak) and other species. The anatomical structure of pony...

False banana /Ensete ventricosum [Welw.] Cheesman/ is exploited as a food crop in Ethiopia where it represents an important staple food. The plant is harvested and large amounts of biomass residues are originated, mainly from the pseudo stem (i.e., fiber bundles obtained from the leaf sheaths after being scrapped to produce starchy food) and the in...

Flow chart describing the methodology used in the study. (TIFF)

Industrial chips of eucalypt stumps were evaluated for pulping and bleaching aptitude. Kraft pulps were produced using three H-factors of 400, 500 and 600, and bleached by a D0-E1-D1-E2-D2 sequence. Yields ranged from 47.4 % (Pulp III) to 48.6 % (Pulp I), with Kappa numbers of 34.6 and 40.0, respectively. Black liquors were collected for evaluation...

The chemical composition of cork, phloem and xylem of the cork oak (Quercus suber L.) from young trees of three provenances was determined using three trees per provenance. The objective was to investigate if the provenance of the seeds influences the chemical composition of the different tissues i.e. if there is a provenance effect on the chemical...

This review covers 30 years on cardoon (Cynara cardunculus L.); a perennial plant adapted to the Mediterranean climate conditions of low rainfall and hot dry summers. Its potential as a non-food agricultural crop for set-aside lands and the excellent biomass production created an enthusiastic research interest in this plant and its uses.The review...

Eucalyptus globulus stumps has been used as biofuel for energy production. However, forest biomass presents some disadvantages (high moisture, volatiles and oxygen contents, hydrophilic nature, low calorific value, bulk density and energy density). To overcome this, torrefaction and pelletisation were tested. Based on the assays, 250 °C and 30 min...

The aim of this study was the production of a good quality gasification gas (syngas) with rice husk residues. This material was torrefied before gasification with the aim of improving this last process and the effect of torrefaction time and temperature was investigated. The variation of temperature from 200ºC to 300ºC decreased moisture and volati...

Cardoon (Cynara cardunculus) stalks were submitted to steam explosion (183ºC, 5 min) with a yield of 88%, and a lignin loss of around 7%. Cardoon (C) and steam exploded cardoon (CSE) were characterized by wet chemical analysis and Py-GC/MS. Total lignin and its S/G ratio were 21.6% and 1.35 in C; and 22.4% and 1.40 in CSE. These samples were delign...

The composition and structure of lignin in different tissues—phellem (cork), phloem and xylem (wood)—of Quercus suber was studied. Whole cell walls and their respective isolated milled lignins were analyzed by pyrolysis coupled with gas chromatography/mass spectrometry (Py-GC/MS), two-dimensional nuclear magnetic resonance spectroscopy (2D-NMR) and...

This study focused on the use of industrial eucalyptus globulus bark as an alternative fiber source for bleached pulp and paper production. Bark has high extractives and ash contents (7.7% and 3.5%, respectively) but a mild hydrothermal pretreatment was tested, decreasing its values to 2.8% and 2.4%, respectively. Untreated and pretreated bark were...

Heat treatment improves some wood properties namely: equilibrium moisture, dimensional stability and durability and mechanical properties. In this study, the heat treatment was applied to woods of three natural species from Brazil: Aspidosperma populifolium (peroba mica), Dipteryx odorata (cumaru) and Mimosa scabrella (bracatinga). The woods were h...

Overaged trees of Eucalyptus globulus were evaluated to determine their aptitude for pulping with industrial chips as reference. The overaged wood was separated in sapwood and heartwood. Compared with industrial chips, the overaged E. globulus heartwood and sapwood contained approximately 1.5 times more extractives (3.8% vs. 5.2% and 5.9%), similar...

The wood of a mature (40-year-old) Eucalyptus globulus Labill tree was characterized at different stem height levels (0%, 10%, 35%, and 50% of total height) regarding pulping, bleaching, and paper properties. Pulp yields increased upwards from 46% to 50%, and Kappa number decreased from 17.5 to 12.3 at 0 and 50% height, respectively. The estimated...

The lignin from Cynara cardunculus stalks was isolated by the classical Björkman method and characterized by pyrolysis coupled with gas chromatography and mass spectrometry (Py-GC/MS), two-dimensional nuclear magnetic resonance spectroscopy (2D-NMR), and derivatization followed by reductive cleavage (DFRC). The milled Cynara lignin (MCyL) was const...

Heartwood and sapwood from a 18-yr-old Eucalyptus globulus tree were characterized by Py-GC/MS(FID) in respect to carbohydrates and lignin content, and by the carbohydrates-to-lignin ratio (C/L). Heartwood and sapwood presented similar contents of carbohydrates (74 %) and lignin (23 %) in an extractive-free basis. The C/L ratio was also similar, ar...

This paper summarises our research results on Eucalyptus globulus stumps for fuel, pulp and as a source of active compounds. Stumpwood has 0.67 g cm-3 basic density, 15.1% total extractives (mainly ethanol soluble extractives, 10.5%), 24.8% lignin and 67.0% holocellulose. The thermal properties shows that stumpwood has adequate values for use as wo...

Sapwood, heartwood and bark of 70-year-old teak trees from an unmanaged stand in East Timor were characterized by pyrolysis (Py–GC–MS/FID). Sapwood and heartwood from teak presented a high lignin content (35.4 and 37.3 % of extractive-free wood) and similar composition. Teak wood is characterized by a GS type of lignin (56.0 % of G-units, 42.2 % of...

Mature 40-year-old trees of Eucalyptus globulus harvested in Portugal were studied to determine the heartwood development and variation of basic density and extractives content at different stem height levels. The heartwood radius decreased regularly from bottom to top in all the trees: for instance 22.2 cm, 13.0 cm, and 10.4 cm, respectively, at t...

Four outstanding Cynara cardunculus L. plants were selected from two field experiments located in Sesimbra (Portugal) and Alcalá de Henares (Spain), and used for vegetative propagation, producing four clones. In this work, two plants from each clone were collected. The plant stalks were separated in depithed stalks (Stalks DP) and pith (P) samples,...

Tectona grandis trees with 70-years of age were collected in East Timor. The heartwood and sapwood were characterized by analytical pyrolysis (Py-GC-MS/FID). Heartwood and sapwood presented similar lignin content (37.3% vs. 35.4%). Regarding lignin composition both presented a high values for guaiacyl-units (in average 20.3%), while syringyl-units...

In order to evaluate the radial and axial variations of the extractives in E. globulus, one mature tree with 32 m was harvested and six discs were taken at different height levels: 0%, 5%, 10%, 35%, 50%, and 60%, of height. The heartwood was present at all levels and contained more extractives than sapwood. The bole section from stump to 60% height...

There are more than 700 species of eucalypts worldwide although only a few are suited and used as pulpwood. In this work we compared the delignification yield and Kappa number of pulps obtained from 12 eucalypt species. We also conducted and compared the chemical analysis regarding ash, extractives, lignin and holocellulose contents, as well as car...

a In this study, Eucalyptus globulus stumpwood samples collected from six different sites in Portugal were evaluated for their ease of pulping, using two delignification processes (kraft and alkaline sulfite-anthraquinone-methanol (ASAM)). Morphologically, the stumpwood included fibers with a mean length of 0.930 mm, diameter of 21.4 µm, lumen widt...

Cynara cardunculus L. was installed for biomass production in a total of 8.1 ha in Sesimbra (Portugal), using common agricultural practices and machinery. Installation by sowing was successful, in spite of the extreme drought during the first cycle (only 382 mm). In the second year, the rainfall was 683 mm and the plants developed well, with a mean...

The behavior of Cynara cardunculus L. was studied during fluidized-bed (FB) combustion and gasification. The Cynara had a low moisture content and considerable lower heating value (LHV). Cynara presented significant quantities of S, Cl, and ash, which contained high levels of Na, K, P, Ca, and Si. The fuel N conversion to NO x was high because of t...

Resumo A Eucalyptus globulus é uma espécie muito usada para a produção de pasta para papel devido às suas caracteristicas químicas, em particular o conteúdo e composição da lenhina. Para este trabalho, o cerne e o borne do eucalipto foram caracterizados por pirólise (Py-GC/MS(FID)). O cerne e o borne apresentaram conteúdos semelhantes em lenhina (L...

The kraft pulps produced from heartwood and sapwood of Eucalyptus globulus at 130 ºC, 150 ºC and 170 ºC were characterized by wet chemistry (total lignin as sum of Klason and soluble lignin fractions) and pyrolysis (total lignin denoted as py-lignin). The total lignin content obtained with both methods was similar. In the course of delignification...

Heartwood and sapwood samples from Eucalyptus globulus were char-acterized by Py-GC/MS and GC-FID in respect to composition and content of lignin. The pyrolysis lignin-derived compounds were assembled by groups:-units). Heartwood and sapwood had similar lignin content in an extractive-free basis (23.7% and 23.0%, respectively) and in lignin composi...

The influence of heartwood and sapwood in kraft pulping was studied in an 18-year-old Eucalyptus globulus tree at 130, 150 and 170ºC along different reaction times (0 to 180 min). The wood and the delignified samples where characterized by wet chemistry (summative analysis) and pyrolysis (total lignin and carbohydrates, syringyl-to-guaiacyl (S/G) a...

Eucalyptus globulus Labill. is managed in commercial plantations for the pulp and paper industry as a coppice system. For stand reforestation the stumps are uprooted and at present used as biofuel. In this study, the biomass of stumps collected in six eucalypt stands in Portugal was evaluated in terms of physical, chemical and fuel properties. Stum...

Heartwood and sapwood were separated from a 18-yr-old tree of Eucalyptus globulus, and characterized by Py-GC/MS and GC/FID in respect to composition and content of lignin. Heartwood and sapwood presented similar lignin content in an extractive-free basis (23.7% and 23.0% respectively), with no differences in lignin composition in respect to S-unit...

Eucalyptus globulus is the most species used in Peninsula Iberica for pulping, due to its anatomical and chemical characteristics, in particular its low lignin content. In this context the aim of this work was to study the influence of heartwood from E. globulus during the pulping process. For this purpose a tree with 18 years was chosen due to its...

Nowadays the discussions about integrated biorefineries in pulps mills considers pre-extraction of hemicelluloses before the traditional pulping process. Currently, tree stumps are emerging as woodfuels feedstock for energy production. The stump is the basal part of the tree, including the near-the-ground stem portion and the woody roots that remai...

Eucalyptus globulus sapwood and heartwood were delignified at 130°, 150°, or 170°C by kraft pulping. Pulp yields of heartwood were lower than those of sapwood (46.5% vs. 50.4% at 170°C). Delignification was modeled using consecutive and simultaneous kinetic models. The modeling was similar for heartwood and sapwood, and either approach could be use...

Large scale cultivation of the cardoon Cynara cardunculus L. for biomass production was installed using common agricultural practices and machinery in a total of 77.4 ha in southern Portugal in a region characterized by very hot and dry summers. This species is a perennial with an annual growth cycle. Installation by sowing was successful in spite...