Tree mortality caused by Diplodia shoot blight on Pinus sylvestris and other mediterranean pines

AbstractNeedle defoliation by diprionid sawflies decreases the increment and timber yield of Scots pine Pinus sylvestris L. The aim of this study was to provide approximate estimates of this decrease and preliminary estimates of the economic value of growth losses and tree mortality. Growth loss after needle damage by Diprion pini(Linnaeus) was studied in western Finland. Increment cores were sampled for radial growth measurements from trees subjected to slight, moderate and heavy defoliation. A literature survey was carried out to estimate radial growth losses after defoliation by Neodiprion sertifer (Geoffroy). Calculations for economic consequences were based on previous estimates and on the ongoing 9th Finnish National Forest Inventory. Moderate defoliation by N. sertifer and D. pini reduced volume growth by 21% and 86% and heavy defoliation by 38% and 94%, respectively. Tree mortality in defoliated stands was recorded as approximately 4%after an outbreak of N. sertifer and 30% after an outbreak of D. pini. The estimated average economic value of the losses due to reduced growth and tree mortality reached $40 ha−1 after a single-year outbreak of N. sertifer and $310 ha−1 in the case of D. pini. These preliminary estimates of economic losses indicate a much higher impact of pine sawflies than those revealed by the few earlier studies in Europe.

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Seasonal occurrence and spatial distribution of resinosis, a symptom of Sirex noctilio (Hymenoptera: Siricidae) injury, on boles of Pinus sylvestris (Pinaceae)

The Canadian Entomologist ◽

10.4039/tce.2012.96 ◽

2013 ◽

Vol 145 (1) ◽

pp. 117-122 ◽

Cited By ~ 13

Author(s):

Kathleen Ryan ◽

Peter de Groot ◽

Sandy M. Smith ◽

Jean J. Turgeon

Keyword(s):

Spatial Distribution ◽

North America ◽

Pinus Sylvestris ◽

Southern Hemisphere ◽

Tree Mortality ◽

Forest Stands ◽

Sirex Noctilio ◽

Northeastern North America ◽

Major Pest ◽

Established Population

AbstractAn established population of the exotic woodwasp Sirex noctilio Fabricius (Hymenoptera: Siricidae) was first detected in North America in 2004. In order to develop survey guidelines for the detection of this major pest of Pinus Linnaeus species in the Southern Hemisphere, we examined 231 Pinus sylvestris biweekly to establish the timing and spatial distribution of resinosis symptoms of attack, and the timing of subsequent tree mortality. Fresh resin appeared between mid-July and late August, and on 70% of infested trees was observed on the mid bole. The occurrence of tree death varied between sites, from 2 weeks after the first detection of resinosis in one site to several months in seven other sites. Findings from our study provide key information to improve detection of S. noctilio and predict its impact on forest stands in its new range in northeastern North America.

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Predicting the mortality of Pinus sylvestris attacked by Gremmeniella abietina and occurrence of Tomicus piniperda colonization

Canadian Journal of Forest Research ◽

10.1139/x05-012 ◽

2005 ◽

Vol 35 (4) ◽

pp. 860-867 ◽

Cited By ~ 8

Author(s):

Ulf Sikström ◽

Gunnar Jansson ◽

Jan Weslien

Keyword(s):

Pinus Sylvestris ◽

Tree Mortality ◽

Basal Area ◽

Tomicus Piniperda ◽

Coniferous Species ◽

Permanent Sample Plots ◽

Diameter At Breast Height ◽

Breast Height ◽

Ct Value ◽

Critical Range

The fungus Gremmeniella abietina (Lagerb.) Morelet is widely distributed in the northern hemisphere and causes scleroderris canker in several coniferous species. In Sweden, large areas, mainly with 30- to 40-year-old Scots pine (Pinus sylvestris L.) forests, were attacked by the fungus in 2000. The main aim of this study was to investigate the relationship between tree crown transparency (CT) induced by G. abietina and P. sylvestris tree mortality. Furthermore, regenerationcolonization by Tomicus piniperda (L.) was monitored in the investigated stands. Thirty-five permanent sample plots were established in five P. sylvestris stands (3846 years old) infected by G. abietina and located in the central part of Sweden. During the 2 years following the attack, the total tree mortality accounted for 380 trees·ha1 and 6.2 m2·ha1 on average in the five stands, corresponding to 35% of the trees and 27% of the basal area at the time of the attack. Galleries with broods of T. piniperda occurred in trees with a CT value higher than 97%. A model was derived for predicting the probability of P. sylvestris tree mortality. The mortality of individual trees was found to be related to CT, position of needle loss within the crown (CTPOS), and tree diameter at breast height. Furthermore, there was an interaction between CT and CTPOS and a tendency for CT and site to interact. For a P. sylvestris tree with a 0.16-m diameter at breast height and a CT value of 90% spread throughout the crown, the model indicated a mortality probability of 0.03. Above this CT value, the probability of mortality increased substantially. For coniferous species, irrespective of the cause of damage, a CT value of 90%95% appears to be a critical range; any values greater than this indicate a high probability of mortality.

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