Management strategies of Eremanthus erythropappus (DC.) MacLeish under different initial spacing

Abstract

Eremanthus erythropappus, commonly known as candeia, is an income-generating tree native to Brazil. This is due to the high durability of its wood and its essential oil containing the active component alpha bisabolol. Despite this economic potential, until the early 2000's no studies existed to explore the sustainable management in areas in which the species naturally occurs or for establishing commercial plantations. This study proposes new management strategies based on an individual tree model, and evaluates the growth behavior of candeia trees planted in different spacing. The experiment was installed in March 2002, in Carrancas municipality, Minas Gerais state, Brazil. The experimental area was divided into 4 blocks with 4 different spacings as treatments. The individual model used to propose the best management system uses development of crown area as a function of DBH. The results showed that candeia trees were sensitive to initial spacing variation. With increased initial spacing, candeia trees reached competition later, as demonstrated by crown area development. Thus, candeia trees planted at a wider spacing maintain a desirable growth rate without need for thinning for a longer time, compared to trees planted at narrower spacing. The fitted individual tree model presented in this study showed consistent results and flexibility, providing alternatives for different management strategies. The best growth response was obtained for planting densities greater than 3.75 m² per tree, which corresponds to a spacing of 1.5 x 2.5 m.Index terms: Crown area; stand density; monomolecular model; individual tree model. RESUMOEremanthus erythropappus, conhecida vulgarmente por candeia, é uma árvore nativa do Brasil, geradora de renda devido à elevada durabilidade apresentada por sua madeira e, também, pelo seu óleo produzido conter, como ingrediente majoritário, o alfa bisabolol. Apesar deste potencial econômico, até o início do ano 2000, a espécie não contemplava estudos sobre seu sistema de cultivo, tanto para o manejo sustentável em áreas de ocorrência natural quanto para o estabelecimento de plantios comerciais. Este estudo propõe estudar novas estratégias de manejo com base em modelo de árvore individual, e avaliar o crescimento da candeia em diferentes espaçamentos. O experimento teve início em março de 2002, no município de Carrancas, Minas Gerais, Brasil. A área experimental foi dividida em quatro blocos, com quatro diferentes espaçamentos como tratamentos. O modelo avaliado para definir o melhor sistema de manejo foi baseado na relação entre o desenvolvimento da área de copa e do DAP das árvores. Os resultados mostraram que a candeia foi sensível a variação no espaçamento inicial. Aumentando o espaçamento inicial, a competição entre as árvores de candeia ocorre mais tarde, ou seja, à medida que o espaçamento aumenta demora-se mais para que o plantio perca o ritmo desejado de crescimento. O modelo testado foi consistente e a técnica baseada na árvore individual apresentou flexibilidade, fornecendo alte...

Growth of Eremanthus erythropappus (DC.) MacLeish in Different Planting Spacings

“…In order to produce trees with higher dimensions to be marketed as fence posts or for the extraction of large quantities of oil, lower initial planting densities are indicated such as those achieved with 1.5 × 2.5 m and 1.5 × 3.0 m spacings with pruning. In addition to these treatments not requiring the removal of a large number of trees, the final dimension of the stems allow to obtain a good profit; results which corroborate those found by Scolforo et al (2016b).…”

“…The need for intervention was evaluated for each year using canopy occupancy greater than 78% as a restriction. In the cases where the coverage was higher, the number of trees to be removed per hectare was determined in order to maintain the occupation below this threshold, allowing to achieve an economic rotation for Candeia plantations (Scolforo et al, 2016b), the final density of plants at the end of rotation, the percentage of plants to be removed, and the best schedule for thinning application after 15 years. Table 1 shows the mean values for the DBH, HT and CA variables at 10.25 years, in addition to their standard deviation (SD) and the number of individuals per plot (n) for the evaluated treatments in relation to the plant spacings and pruning applications.…”

“…Therefore, several studies have been developed to evaluate their growth when submitted to planting, seeking to generate recommendations that will contribute to the success of the crop. Among these studies we can point out Scolforo et al (2016b), who evaluated the effect of different planting spacings on growth in young stands of Candeia, Scolforo et al (2016a), who used statistical techniques based on spatial dependence to discriminate the fertilization treatments tested for the species. Both studies highlight the productive potential of these plantations as an alternative to more consecrated forest species, especially for the less productive areas in small rural properties.…”

Potential and Future Geographical Distribution of Eremanthus erythropappus (DC.) MacLeish: a Tree Threatened by Climate Change

“…This tree species has a long history of exploitation, either for use as fence posts, firewood, and on a larger economic scale, for essential oil extraction (Clark et al, 2011;Donadelli, 2012;Scolforo et al, 2016a). In the case of essential oil extraction, the targeted component is alpha-Bisabolol (Scolforo et al, 2016a), which is a key ingredient for skincare and global cosmetics industries (Vieira et al, 2012;Scolforo et al, 2016b). Despite the availability of synthetic substitutes of alpha-Bisabolol (Clark et al, 2011) and also the lengthy period of tree growth, which spans at least 12-15 years (Pérez et al, 2004;Mori et al, 2009), naturally-occurring populations of E. erythropappus are still important sources of alpha-Bisabolol for the global market (GFA Consulting Group, 2006), comprising 80% of the alpha-Bisabolol exported (Clark et al, 2011).…”

In vitro evaluation of anticaries, antimycobacterial, antileishmanial and cytotoxic activities of essential oils from Eremanthus erythropappus and of α-bisabolol, their major sesquiterpene

“…The family Asteraceae, which has about 1,300 genera and 23,000 species, comprises mostly herbs, shrubs and small trees with leaves and stalks whose secretory structures, such as trichomes, secrete essential oils (EOs) (Rios, 2015). These EOs, especially the ones from Eremanthus erythropappus (Asteraceae), are rich in α-bisabolol, a fact that gives them great economic importance, because this sesquiterpene is used for the formulation of several cosmetic products (Scolforo et al, 2016). Extracts and EOs from E. erythropappus have been known for their important biological activities, such as antimicrobial ones against several pathogens -Alternaria carthami, Rhizoctonia solani, Staphylococcus aureus, Escherichia coli, Streptococcus pyogenes, Pseudomonas aeruginosa, Saccharomyces cerevisiae, Candida spp.…”