Myrcia suberosa: a new species of Myrcia sect. Eugeniopsis (Myrciinae, Myrteae, Myrtaceae) endemic to the Atlantic Forest

A new species, Myrcia suberosa, is here proposed based in an ongoing taxonomic revision of Myrcia sect. Eugeniopsis, a group nearly endemic to the Atlantic Forest. Myrcia suberosa occurs in Brazil from Southern Bahia to Southern Rio de Janeiro states, but only three collections are known and the real distribution of the species is barely known. The new species is morphologically related to Myrcia pseudomarlierea and Myrcia teuscheriana, differing by sexual system, cork thickness, indument, and leaf and flower morphologies. Morphological description, images and conservation status are provided, as well as discussion about distribution, habitat, phenology and taxonomy.

Understory effect on tree and cork growth in cork oak woodlands

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.

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

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.

The Impact of Industrial Pollution with Toxic Gases on Stem Histological Parameters of Woody Plant Undergrowth under Conditions of the Southern Industrial Zone of the City of Dnipro, Ukraine

The paper examines the influence of industrial emissions of sulphur (IV) and nitrogen (IV) oxides on stem histological parameters of the autochthonous woody plant species undergrowth ofAcer platanoidesL. andFraxinus excelsiorL., which are natural forest edificators in the steppe zone of Ukraine. It shows that stem anatomical characteristics undergo quantitative changes in the annual undergrowth shoots of the two tree species under anthropogenic burden, with the most significant changes in the area of heavy pollution. Results indicate the decrease of such stem parameters as stem and stele diameters, wood radius and primary cortex thickness under high concentrations of SO2and NO2in seedlings of both species. However, this parameter drops inA. platanoidesstems by reducing the collenchyme width, whereas it reduces inF. excelsiorstems due to cork thickness loss. Another difference in the response ofA. platanoidesto the influence of phytotoxic pollutants compared toF. excelsioris the depletion of conducting elements of its phloem, which results in thinning the stem secondary cortex. The research findings prove high vulnerability ofA. platanoidesundergrowth to the chronic SO2and NO2exposure. Therefore, this woody species is suggested to be used as a test object in monitoring research on plants of virginal group in the technogenic areas contaminated with sulphur (IV) and nitrogen (IV) oxides.

A geostatistical approach to cork production sampling estimation in Quercus suber forests

The estimation of cork production in cork oak (Quercus suber L.) forests is complex because of the high heterogeneity of stripped surface distribution (the variable used to quantify cork production) and the importance of cork thickness estimation as a determining factor of cork quality. In this study, the different sources of variation in stripped surface ([Formula: see text]d) estimation and the effects of the spatial structure of the variance were analysed. When indicator kriging was used to determine the cork productive area, ordinary kriging and kriging with measurement errors gave better estimations of [Formula: see text]d (ordinary block kriging estimation of 156.16 m2/ha and standard errors (SE) of 16.40 and 15.7 m2/ha, respectively) than the design-based approach for the whole forest area (66.37 m2/ha, SE = 11.34 m2/ha). The SE lying in the second-stage design was 4.93 m2/ha. The ordinary kriging prediction of cork thickness using an XY(λZ) variogram, where λ is the anisotropy coefficient of the Z axis, gives a smaller SE and less bias than the kriging prediction with the XY variogram (for a mean estimation of 21.91 mm, SE = 3.90 and 4.16 mm, respectively, and sum of errors of 0.42 and 0.85 respectively).