Impact of Ceratocystis wilt on eucalyptus tree growth and cellulose pulp yield

Abstract

In this study, we determined the effects of Ceratocystis fimbriata wilt on volumetric growth and cellulose pulp yield of eucalyptus. Sevenyear-old healthy and infected trees were separated into different classes of severity, and the individual volume of each whole tree with bark was determined. Volumetric losses were found regardless of the class of disease severity, resulting in reduction in volumetric growth of the trees from 65% to 87%, depending on the infection level. Two approaches were used for evaluating the effects of the disease on cellulose pulp yield: (i) evaluation of wood basic density and chemical composition, contents of ethanol/toluene extractives and Klason lignin, and the alkaline load and screen yield across Kraft pulping to kappa number 18 AE 0.5 for both healthy and discoloured materials; (ii) determination of the alkaline load and yield across Kraft pulping to kappa number 18 AE 0.5 of woods with different levels of discoloration (0, 25, 50, 75 and 100% of discoloured wood). Discoloured wood presented lower basic density, higher ethanol/toluene extractives and Klason lignin, higher alkaline load and lower pulp screened yield at kappa number 18 AE 0.5 compared with the healthy ones. Increasing the fraction of infected wood in chip furnishes resulted in proportionally increased alkaline load demand and decreased screen yields. Adding 50% of infected wood in the chip furnish resulted in 23.8% increase in the alkali load and 13.7% reduction in the pulp screen yield at kappa number 18 AE 0.5. The results obtained have proved that the disease reduces volumetric growth, increases wood consumption and reduces yield in eucalyptus pulp production.

Ralstonia solanacearum decreases volumetric growth of trees and yield of kraft cellulose of Eucalyptus spp.

“…Mafia et al. () observed that eucalypt trees infected by C. fimbriata required a greater alkaline load (23.8%) during cooking and yielded less pulp (13.7%). The authors also reported that volumetric growth in infected trees decreased by 65%–87%, depending on disease severity.…”

Aggressiveness, cultural characteristics and genetic variation of Ceratocystis fimbriata on Eucalyptus spp.

“…In addition to the death of plants and reduction of volumetric growth in the field, diseased trees have lower cellulose yield, and their wood has lower commercial value for timber (Alfenas and Ferreira ; Mafia et al. ).…”

Responses of resistant and susceptible hybrid clones of Eucalyptus urophylla × Eucalyptus grandis to infection by Ceratocystis fimbriata

“…Among them, Ceratocystis wilt, which is caused by Ceratocystis fimbriata Ellis & Halsted, is currently one of the most important diseases in eucalypt. This pathogen has a wide geographic distribution and a broad host range and results in significant yield losses (Alfenas et al 2009;Fernandes et al 2014;Mafia et al 2013). This disease can reduce the volumetric growth of trees in the field by up to 87%, the cellulose yield by approximately 14%, and the value of wood for sawing (Mafia et al 2013).…”