Drought has serious effects on forests, especially semi-arid and arid forests, around the world. ... more Drought has serious effects on forests, especially semi-arid and arid forests, around the world. Zagros Forest in Iran has been severely affected by drought, which has led to the decline of the most common tree species, Persian oak (Quercus brantii). The objective of this study was to determine the effects of drought on the anatomical structure of Persian oak. Three healthy and three declined trees were sampled from each of two forest sites in Ilam Forest. Discs were cut at breast height, and three sapwood blocks were taken near the bark of each tree for sectioning. The anatomical characteristics measured included fiber length (FL), fiber wall thickness (FWT), number of axial parenchymal cells (NPC), ray number (RN), ray width (RW), and number of calcium oxalate crystals. Differences between healthy and declined trees were observed in the abundance of NPC and in RN, FL, and FWT, while no differences occurred in the number of oxalate crystals. The decline had uncertain effects on the...
Tree decline is a physiological phenomenon resulting from climatic disturbances that involves dam... more Tree decline is a physiological phenomenon resulting from climatic disturbances that involves damage to forest ecosystems. This study examined the effects of tree decline on nutrient concentrations in the leaves, bark, and wood of Persian oak (Quercus brantii) trees. Trees were categorized by decline severity (healthy, slight, moderate, and severe decline). Leaves were collected from the middle and outer parts of the crowns. Bark and wood samples were taken at breast height (1.3 m). The contents of Mg, Ca, P, Fe, K, and Na were analyzed by atomic absorption spectrophotometry and flame photometry. As decline severity increased, the concentrations of Mg, Ca, P, Fe, K, and Na in the foliage increased. However, the P and K in the bark and the P in the wood were lower in trees in the higher decline classes. Moreover, nutrient contents in the tissues examined varied across the different decline severities. The variations may have been due to defense mechanisms of the trees enhancing toler...
Scots pine blister rust caused by Cronartium pini, which includes the fungal rust pathogen with e... more Scots pine blister rust caused by Cronartium pini, which includes the fungal rust pathogen with either a heteroecious life cycle (previously known as Cronartium flaccidum) or an autoecious life cycle (formerly known as Peridermium pini or Endocronartium pini), is capable of infecting many Eurasian pines including Pinus sylvestris (Scots pine). The heteroecious form of C. pini completes its life cycle alternating between pines and various species of flowering plants (Angiospermae); the related autoecious form spreads directly from pine to pine. If the Scots pine blister rust pathogen possesses or gains the capacity to infect North American pines, the economic and ecological impacts could be significant. Scots pine is one of the most widely distributed conifers in the world, and it has become naturalized in the northeastern and midwestern United States. Scots pine blister rust is also called resin-top disease and top-dieback of pine. Symptoms in pine include stem swelling, branch flag...
Pest introductions via trade in tree seed may result from a lack of adequate survey and validatio... more Pest introductions via trade in tree seed may result from a lack of adequate survey and validation protocols. Developing better diagnostic protocols to identify potentially harmful pests and pathogens in forest tree seed is of critical importance. High-throughput sequencing-based barcoding and metabarcoding provide effective tools for screening potentially harmful organisms in various plant materials, including seeds. However, the sample size needed to detect the total microorganism diversity of a community is a major challenge in microbiome studies. In this work, we examined how increasing sample size (ranging between 100 and 1000 seeds) influences diversity of fungal communities detected by high throughput sequencing in Pinus sylvestris seeds. Our results showed that as sample size increased, fungal alpha diversity also increased. Beta-diversity estimators detected significant differences between the mycobiota from different samples. However, taxonomic and functional diversity wer...
Brown spot needle blight, caused by Lecanosticta acicola, is a serious disease of pines worldwide... more Brown spot needle blight, caused by Lecanosticta acicola, is a serious disease of pines worldwide and has become of great concern in Europe over the last decade, with significantly increased outbreaks in pine forests. We examined native and non‐native Pinaceae taxa (four Cedrus and 24 Pinus) in the Atatürk Arboretum, Istanbul, Turkey, for the presence of L. acicola. Needles were sampled from 37 trees at least twice between March 2017 and July 2018. Symptomatic occurrence of the disease was confirmed by isolations, followed by molecular identification via sequencing of the ITS region. Lecanosticta acicola was isolated from symptomatic needles of 10 trees from seven host taxa (Cedrus and six Pinus). Molecular diagnostics of isolates confirmed the identification of L. acicola on Cedrus libani, Pinus sylvestris, P. nigra subsp. nigra, P. nigra subsp. laricio, P. nigra subsp. pallasiana, P. nigra subsp. pallasiana var. fastigiata and P. nigra subsp. pallasiana var. pallasiana f. şenerian...
The number of invasive alien pest and pathogen species affecting ecosystem functioning, human hea... more The number of invasive alien pest and pathogen species affecting ecosystem functioning, human health and economies has increased dramatically over the last decades. Discoveries of invasive pests and pathogens previously unknown to science or with unknown host associations yet damaging on novel hosts highlights the necessity of developing novel tools to predict their appearance in hitherto naïve environments. The use of sentinel plant systems is a promising tool to improve the detection of pests and pathogens before introduction and to provide valuable information for the development of preventative measures to minimize economic or environmental impacts. Though sentinel plantings have been established and studied during the last decade, there still remains a great need for guidance on which tools and protocols to put into practice in order to make assessments accurate and reliable. The sampling and diagnostic protocols chosen should enable as much information as possible about potent...
The import and export of tree seed carries with it risks of inadvertent introduction of pests and... more The import and export of tree seed carries with it risks of inadvertent introduction of pests and pathogens to hitherto unaffected regions. Although trade in seed of specified trees is regulated, phytosanitary requirements for most tree species are minimal, even those related to the most important forest tree species in a given region. A better understanding of the microbiome associated with seed intended for commercial production or ornamental use, and their potential risk with the transport from the source origin of distributors, will help regulatory agencies implement measures to safeguard seed health and avoid trade-related spread of potentially harmful pathogens. In this study we used high-throughput sequencing to show that highly diverse fungal communities were associated with seed of 14 different Pinus species obtained from seed banks (seed orchards) and retail sources (online distributors) in North America and Europe. Fungal diversity differed among the 23 seedlots tested. C...
SummaryAn analysis of incidence of Phytophthora spp. in 732 European nurseries producing forest t... more SummaryAn analysis of incidence of Phytophthora spp. in 732 European nurseries producing forest transplants, larger specimen trees, landscape plants and ornamentals, plus 2525 areas in which trees and shrubs were planted, is presented based on work conducted by 38 research groups in 23 European countries between 1972 and 2013. Forty‐nine Phytophthora taxa were recorded in 670 nurseries (91.5%); within these nurseries, 1614 of 1992 nursery stands (81.0%) were infested, although most affected plants appeared healthy. In forest and landscape plantings, 56 Phytophthora taxa were recovered from 1667 of 2525 tested sites (66.0%). Affected plants frequently showed symptoms such as crown thinning, chlorosis and dieback caused by extensive fine root losses and/or collar rot. Many well‐known highly damaging host–Phytophthora combinations were frequently detected but 297 and 407 new Phytophthora–host associations were also observed in nurseries and plantings, respectively. On average, 1.3 Phyt...
Heterobasidion annosum (Fr.) Bref. s. lato causes severe damage to forests. This study describes ... more Heterobasidion annosum (Fr.) Bref. s. lato causes severe damage to forests. This study describes a model for simulating the infection and spread of Heterobasidion spp. in stands of Picea abies (L.) Karst. and Pinus sylvestris L. The model includes submodels for stand dynamics (plot simulation, growth and yield, and cross-cutting of trees) and disease dynamics: (i) spore infection, (ii) stump colonization, (iii) colonization of stump roots, (iv) vegetative transfer to tree roots, (v) spread of disease in tree roots, (vi) spread of decay in stems, and (vii) disease effect on tree growth and survival. To illustrate the model, a simulation was carried out on a Swedish Norway spruce stand where logging occurred during the high-risk season for spore infection. The model provides a means of incorporating the impact of root disease into forest planning. A change of parameters indicated that model predictions were sensitive to the spread rate and presence of initial disease centers. Further ...
Drought has serious effects on forests, especially semi-arid and arid forests, around the world. ... more Drought has serious effects on forests, especially semi-arid and arid forests, around the world. Zagros Forest in Iran has been severely affected by drought, which has led to the decline of the most common tree species, Persian oak (Quercus brantii). The objective of this study was to determine the effects of drought on the anatomical structure of Persian oak. Three healthy and three declined trees were sampled from each of two forest sites in Ilam Forest. Discs were cut at breast height, and three sapwood blocks were taken near the bark of each tree for sectioning. The anatomical characteristics measured included fiber length (FL), fiber wall thickness (FWT), number of axial parenchymal cells (NPC), ray number (RN), ray width (RW), and number of calcium oxalate crystals. Differences between healthy and declined trees were observed in the abundance of NPC and in RN, FL, and FWT, while no differences occurred in the number of oxalate crystals. The decline had uncertain effects on the...
Tree decline is a physiological phenomenon resulting from climatic disturbances that involves dam... more Tree decline is a physiological phenomenon resulting from climatic disturbances that involves damage to forest ecosystems. This study examined the effects of tree decline on nutrient concentrations in the leaves, bark, and wood of Persian oak (Quercus brantii) trees. Trees were categorized by decline severity (healthy, slight, moderate, and severe decline). Leaves were collected from the middle and outer parts of the crowns. Bark and wood samples were taken at breast height (1.3 m). The contents of Mg, Ca, P, Fe, K, and Na were analyzed by atomic absorption spectrophotometry and flame photometry. As decline severity increased, the concentrations of Mg, Ca, P, Fe, K, and Na in the foliage increased. However, the P and K in the bark and the P in the wood were lower in trees in the higher decline classes. Moreover, nutrient contents in the tissues examined varied across the different decline severities. The variations may have been due to defense mechanisms of the trees enhancing toler...
Scots pine blister rust caused by Cronartium pini, which includes the fungal rust pathogen with e... more Scots pine blister rust caused by Cronartium pini, which includes the fungal rust pathogen with either a heteroecious life cycle (previously known as Cronartium flaccidum) or an autoecious life cycle (formerly known as Peridermium pini or Endocronartium pini), is capable of infecting many Eurasian pines including Pinus sylvestris (Scots pine). The heteroecious form of C. pini completes its life cycle alternating between pines and various species of flowering plants (Angiospermae); the related autoecious form spreads directly from pine to pine. If the Scots pine blister rust pathogen possesses or gains the capacity to infect North American pines, the economic and ecological impacts could be significant. Scots pine is one of the most widely distributed conifers in the world, and it has become naturalized in the northeastern and midwestern United States. Scots pine blister rust is also called resin-top disease and top-dieback of pine. Symptoms in pine include stem swelling, branch flag...
Pest introductions via trade in tree seed may result from a lack of adequate survey and validatio... more Pest introductions via trade in tree seed may result from a lack of adequate survey and validation protocols. Developing better diagnostic protocols to identify potentially harmful pests and pathogens in forest tree seed is of critical importance. High-throughput sequencing-based barcoding and metabarcoding provide effective tools for screening potentially harmful organisms in various plant materials, including seeds. However, the sample size needed to detect the total microorganism diversity of a community is a major challenge in microbiome studies. In this work, we examined how increasing sample size (ranging between 100 and 1000 seeds) influences diversity of fungal communities detected by high throughput sequencing in Pinus sylvestris seeds. Our results showed that as sample size increased, fungal alpha diversity also increased. Beta-diversity estimators detected significant differences between the mycobiota from different samples. However, taxonomic and functional diversity wer...
Brown spot needle blight, caused by Lecanosticta acicola, is a serious disease of pines worldwide... more Brown spot needle blight, caused by Lecanosticta acicola, is a serious disease of pines worldwide and has become of great concern in Europe over the last decade, with significantly increased outbreaks in pine forests. We examined native and non‐native Pinaceae taxa (four Cedrus and 24 Pinus) in the Atatürk Arboretum, Istanbul, Turkey, for the presence of L. acicola. Needles were sampled from 37 trees at least twice between March 2017 and July 2018. Symptomatic occurrence of the disease was confirmed by isolations, followed by molecular identification via sequencing of the ITS region. Lecanosticta acicola was isolated from symptomatic needles of 10 trees from seven host taxa (Cedrus and six Pinus). Molecular diagnostics of isolates confirmed the identification of L. acicola on Cedrus libani, Pinus sylvestris, P. nigra subsp. nigra, P. nigra subsp. laricio, P. nigra subsp. pallasiana, P. nigra subsp. pallasiana var. fastigiata and P. nigra subsp. pallasiana var. pallasiana f. şenerian...
The number of invasive alien pest and pathogen species affecting ecosystem functioning, human hea... more The number of invasive alien pest and pathogen species affecting ecosystem functioning, human health and economies has increased dramatically over the last decades. Discoveries of invasive pests and pathogens previously unknown to science or with unknown host associations yet damaging on novel hosts highlights the necessity of developing novel tools to predict their appearance in hitherto naïve environments. The use of sentinel plant systems is a promising tool to improve the detection of pests and pathogens before introduction and to provide valuable information for the development of preventative measures to minimize economic or environmental impacts. Though sentinel plantings have been established and studied during the last decade, there still remains a great need for guidance on which tools and protocols to put into practice in order to make assessments accurate and reliable. The sampling and diagnostic protocols chosen should enable as much information as possible about potent...
The import and export of tree seed carries with it risks of inadvertent introduction of pests and... more The import and export of tree seed carries with it risks of inadvertent introduction of pests and pathogens to hitherto unaffected regions. Although trade in seed of specified trees is regulated, phytosanitary requirements for most tree species are minimal, even those related to the most important forest tree species in a given region. A better understanding of the microbiome associated with seed intended for commercial production or ornamental use, and their potential risk with the transport from the source origin of distributors, will help regulatory agencies implement measures to safeguard seed health and avoid trade-related spread of potentially harmful pathogens. In this study we used high-throughput sequencing to show that highly diverse fungal communities were associated with seed of 14 different Pinus species obtained from seed banks (seed orchards) and retail sources (online distributors) in North America and Europe. Fungal diversity differed among the 23 seedlots tested. C...
SummaryAn analysis of incidence of Phytophthora spp. in 732 European nurseries producing forest t... more SummaryAn analysis of incidence of Phytophthora spp. in 732 European nurseries producing forest transplants, larger specimen trees, landscape plants and ornamentals, plus 2525 areas in which trees and shrubs were planted, is presented based on work conducted by 38 research groups in 23 European countries between 1972 and 2013. Forty‐nine Phytophthora taxa were recorded in 670 nurseries (91.5%); within these nurseries, 1614 of 1992 nursery stands (81.0%) were infested, although most affected plants appeared healthy. In forest and landscape plantings, 56 Phytophthora taxa were recovered from 1667 of 2525 tested sites (66.0%). Affected plants frequently showed symptoms such as crown thinning, chlorosis and dieback caused by extensive fine root losses and/or collar rot. Many well‐known highly damaging host–Phytophthora combinations were frequently detected but 297 and 407 new Phytophthora–host associations were also observed in nurseries and plantings, respectively. On average, 1.3 Phyt...
Heterobasidion annosum (Fr.) Bref. s. lato causes severe damage to forests. This study describes ... more Heterobasidion annosum (Fr.) Bref. s. lato causes severe damage to forests. This study describes a model for simulating the infection and spread of Heterobasidion spp. in stands of Picea abies (L.) Karst. and Pinus sylvestris L. The model includes submodels for stand dynamics (plot simulation, growth and yield, and cross-cutting of trees) and disease dynamics: (i) spore infection, (ii) stump colonization, (iii) colonization of stump roots, (iv) vegetative transfer to tree roots, (v) spread of disease in tree roots, (vi) spread of decay in stems, and (vii) disease effect on tree growth and survival. To illustrate the model, a simulation was carried out on a Swedish Norway spruce stand where logging occurred during the high-risk season for spore infection. The model provides a means of incorporating the impact of root disease into forest planning. A change of parameters indicated that model predictions were sensitive to the spread rate and presence of initial disease centers. Further ...
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