Sudden oak death in California: Disease progression in oaks and tanoaks

McPherson, Brice A.; Mori, Sylvia R.; Wood, David L.; Storer, Andrew J.; Svihra, Pavel; Kelly, Maggi; Standiford, Richard B.

doi:10.1016/j.foreco.2005.03.048

Cited by 65 publications

(83 citation statements)

References 16 publications

(16 reference statements)

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“…Charcoal canker disease severity on individual trees was ranked from 1 (no disease) to 5 (dead) based on stem health and crown loss. Includes of 1: asymptomatic; 2: only limited exudates and signs of the fungal activity of B. mediterranea (discoloration and browning of leaves, drying of foliage, viscous liquid exudates observed on trunks) were found; 3: exudates and signs of the fungal activity plus longhorn beetles (Coleoptera, Cerambycidae); 4: exudates and signs of the fungal activity plus beetles and deep canker (caused by the beetles and an associated fungal pathogen) and wood-eating beetle activity have increased the range; 5: dead (McPherson et al 2005;Kelly et al, 2008, Mirabolfathy et al 2011.We analysed the data from the PCQ method in two ways: we estimated the population density of trees across the study area, and then we examined the spatial pattern of the crown mortality and associated symptoms. Population density estimation.…”

Section: Methodsmentioning

confidence: 99%

Spatial pattern and disease severity of charcoal canker in Hyrcanian forests, north of Iran

Karami¹,

Kavosi²,

Babanezhad³

2015

J. For. Sci.

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This research investigated the population density of infected trees with charcoal canker disease and the interaction across the severity of the disease on Quercus castaneifolia in Hyrcanian forests, north of Iran. We used twodimensional spatial analysis tools with data gathered in point-centred quarter format in 2013. We investigated the cooccurrence of the severity of the disease symptoms using the paired quadrat covariance analysis. The results showed that nearly 54% of the oak trees were affected by the disease so that the dead trees and high disease severity were strongly clustered at broader scales (800 m), the trees with only limited exudates and signs of the activity of Biscogniauxia mediterranea (De Not.) Kuntze occurred in the clusters away from the dead trees. The crown mortality and beetle-infested trees cooccurred with mortality and were strongly correlated. Also, the findings of this research showed that the density of trees per hectare was one of the influential factors on the damage severity of the charcoal canker disease, so that reducing the density could increase the damage severity of the disease.

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Section: Methodsmentioning

confidence: 99%

Spatial pattern and disease severity of charcoal canker in Hyrcanian forests, north of Iran

Karami¹,

Kavosi²,

Babanezhad³

2015

J. For. Sci.

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“…Drying of the canopy may occur suddenly and in a short time period (hence the "sudden" in SOD), but often it happens several years after lesions have girdled the cambium. Because of this delayed response of the canopy, secondary organisms such as decay fungi and bark beetles (82,83) appear to accelerate the death process. While it may be true that these secondary organisms accelerate the decomposition process and the onset of the final and visually discernible demise of the tree, it has yet to be proven that they actually increase the mortality rate.…”

Section: Ecology and Impacts Of Sod In California Forestsmentioning

confidence: 99%

“…On the contrary, in areas with significant infestations of P. ramorum, the bay laurel component of the plant community appears to be on the rise, due to their rapid vegetative growth that takes advantage of the space made available by the death of oaks and tanoaks (16, but see reference 103). A strong positive correlation is present between the overall stand incidence of bay laurels and levels of SOD-related mortality of oaks and tanoaks, indicating the primary infectious role played by this species (18,30,53,78,82,83). Additionally, sudden oak death incidence has been associated with higher fuel loads (74,116) and fire-related mortality of medium-sized redwoods has been observed to be significantly higher in areas with higher SOD incidence (87), providing evidence of the cascading effects of the abundance of bay laurels in forest stands affected by SOD.…”

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confidence: 98%

Sudden Oak Death: Interactions of the Exotic Oomycete Phytophthora ramorum with Naïve North American Hosts

Garbelotto

Hayden

2012

Eukaryot Cell

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Ten years after a threatening and previously unknown disease of oaks and tanoaks appeared in coastal California, a significant amount of progress has been made toward the understanding of its causal agent Phytophthora ramorum and of the novel pathosystems associated with this exotic organism. However, a complete understanding of the ecology and epidemiology of this species still eludes us. In part, our inability to fully understand this organism is due to its phylogenetic, phylogeographic, phenotypic, and epidemiological complexities, all reviewed in this paper. Most lines of evidence suggest that the high degree of disease severity reported in California is not simply due to a generalized lack of resistance or tolerance in naïve hosts but also to an innate ability of the pathogen to survive in unfavorable climatic conditions and to reproduce rapidly when conditions become once again favorable.

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“…Oaks are declining due to fire exclusion and mule deer (Odocoileus hemionus) predation [3,4]. The pathogen that causes sudden oak death (Phytophthora ramorum) has not yet arrived in the Sierra, but if it does, it will also threaten the region's black oaks (Quercus kelloggii) [5]. A loss of sugar pines will likely have a cascading effect on the associated wildlife, especially if it coincides with a reduction in oaks, but with little existing research on these associations, the impacts are difficult to predict [6].…”

mentioning

confidence: 99%

Implications of the variable availability of seasonal foods on the home ranges of black bears, Ursus americanus, in the Sierra Nevada of California

Mazur

Klimley

Folger

2013

Animal Biotelemetry

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Background: Sugar pine (Pinus lambertiana) seeds and oak (Quercus spp.) acorns are both important fall food sources for a variety of wildlife in the Sierra Nevada, but both have variable mast production and are in decline. Sugar pines are in decline due to white pine blister rust (Cronartium ribicola) infection and oaks are in decline due to fire exclusion and mule deer (Odocoileus hemionus) predation. To examine how a change in availability of seed and acorn crops from these trees could have a cascading effect on associated wildlife, we studied their relationship to black bear (Ursus americanus) fall ranges in Sequoia National Park, California. The distribution of seed-bearing sugar pines overlaps with the bears' summer range, whereas acorn-bearing oaks occur at lower elevations. We used GPS collars and field observations to collect location data on ten wild, adult, female bears during the summer and fall of both 2005 and 2006, and then compared these data on habitat use with the Park's vegetation map of available habitat. Results: Our results indicate that the inter-annual variability in the availability of these natural foods is closely related to the seasonal ranges of black bears. In the fall of 2005, when blue and black oak acorns were scarce but other acorns were abundant, bears remained within their summer ranges to feed on sugar pine seeds. In the fall of 2006, when blue oak acorns were abundant, bears shifted out of their summer ranges to feed on acorns and forego sugar pine seeds, even though the seeds were more abundant than in 2005. Incidents between humans and black bears were highest in 2006 while bears were moving between their summer ranges and the oak belt. Conclusion: In the fall, black bears make heavy use of both sugar pines and oaks. Although they prefer acorns to sugar pine seeds, the loss of either food source would lead to an increased dependence on the other. When both are unavailable due to continued decline or simultaneously low mast crops, an increase in human-bear incidents is likely.Keywords: Acorn production, Black bear, Blister rust, Home range, Preference, Sudden oak death, Sugar pine, Ursus americanus Background In California's Sierra Nevada, white pine blister rust (Cronartium ribicola) threatens the continued existence of sugar pines (Pinus lambertiana). This fungal pathogen appeared in the Southern Sierra in the 1960s, infecting many of the region's sugar pines, which are now in decline [1,2]. Oaks are declining due to fire exclusion and mule deer (Odocoileus hemionus) predation [3,4]. The pathogen that causes sudden oak death (Phytophthora ramorum) has not yet arrived in the Sierra, but if it does, it will also threaten the region's black oaks (Quercus kelloggii) [5]. A loss of sugar pines will likely have a cascading effect on the associated wildlife, especially if it coincides with a reduction in oaks, but with little existing research on these associations, the impacts are difficult to predict [6]. To begin addressing this gap in information, we studied the impo...

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Sudden oak death in California: Disease progression in oaks and tanoaks

Cited by 65 publications

References 16 publications

Spatial pattern and disease severity of charcoal canker in Hyrcanian forests, north of Iran

Spatial pattern and disease severity of charcoal canker in Hyrcanian forests, north of Iran

Sudden Oak Death: Interactions of the Exotic Oomycete Phytophthora ramorum with Naïve North American Hosts

Implications of the variable availability of seasonal foods on the home ranges of black bears, Ursus americanus, in the Sierra Nevada of California

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