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Forest ecosystem attributes and their spatial variation across the landscape have the potential to subsequently influence variations in fire behavior. Understanding this variation is critical to fire managers in their ability to predict fire behavior and rate of spread. However, a fine-scale description of fuel patterns and their relationship with overstory and understory attributes for north-central Appalachia is lacking due to the complicated quantification of variations in topography, forest attributes, and their interactions. To better understand the fire environment in north-central Appalachia and provide a comprehensive evaluation based on fine-scale topography, ninety-four plots were established across different aspects and slope positions within an oak–hickory forest located in southeast Ohio, USA, which historically fell within fire regime group I with a fire return interval ranging from 7 to 26 years. The data collected from these plots were analyzed by four components of the fire environment, which include the overstory, understory, shrub and herbaceous layers, surface fuels, and fuel conditions. The results reveal that fuel bed composition changed across aspects and slope position, and it is a primary factor that influences the environment where fire occurs. Specifically, the oak fuel load was highest on south-facing slopes and in upper slope positions, while maple fuel loads were similar across all aspects and slope positions. Oak and maple basal areas were the most significant factors in predicting the oak and maple fuel load, respectively. In the shrub and undergrowth layers, woody plant coverage was higher in upper slope positions compared to lower slope positions. Overstory canopy closure displayed a significant negative correlation with understory trees/ha and woody plant variables. The findings in this study can provide a better understanding of fine-scale fuel bed and vegetation characteristics, which can subsequently feed into fire behavior modeling research in north-central Appalachia based on the different characterizations of the fire environment by landscape position.
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Relationship between local-scale topography and vegetation on the invasive C 4 perennial bunchgrass buffelgrass ( Pennisetum ciliare ) size and reproduction
Abstract Buffelgrass [Pennisetum ciliare(L.) Link] is an invasive C4perennial bunchgrass that is a threat to biodiversity in aridlands in the Americas and Australia. Topography influencesP. ciliareoccurrence at large spatial scales, but further investigation into the relationship between local-scale topography andP. ciliaregrowth and reproduction would be beneficial. Further, density-dependent effects onP. ciliaregrowth and reproduction have been demonstrated in greenhouse experiments, but the extent to which density dependence influencesP. ciliarein natural populations warrants further investigation. Here we present a study on the relationships between local-scale topography (aspect and slope gradient) and vegetation characteristics (shrub cover,P. ciliarecover, andP. ciliaredensity) and their interactions on individualP. ciliareplant size and reproduction. We measured slope gradient, aspect, shrub cover,P. ciliarecover,P. ciliaredensity, and the total number of live culms and reproductive culms of 10P. ciliareplants in 33 4 by 4 m plots located in 11 transects at the Desert Laboratory at Tumamoc Hill, Tucson, AZ, USA. We modeled the relationships at the local scale of (1)P. ciliarecover and density with aspect and slope gradient and (2)P. ciliaresize and reproduction with abiotic (slope gradient and aspect) and biotic (P. ciliarecover and density and native shrub and cacti cover) characteristics. Aspect and slope gradient were poor predictors ofP. ciliarecover and density in already invaded sites at the scale of our plots. However, aspect had a significant relationship withP. ciliareplant size and reproduction.Pennisetum ciliareplants on south-facing aspects were larger and produced more reproductive culms than plants on other aspects. Further, we found no relationship betweenP. ciliaredensity andP. ciliareplant size and reproduction. Shrub cover was positively correlated withP. ciliarereproduction. South-facing aspects are likely most vulnerable to fast spread and infilling by newP. ciliareintroductions.
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- Award ID(s):
- 1924016
- PAR ID:
- 10484733
- Publisher / Repository:
- Cambridge University Press
- Date Published:
- Journal Name:
- Invasive Plant Science and Management
- Volume:
- 16
- Issue:
- 1
- ISSN:
- 1939-7291
- Page Range / eLocation ID:
- 38 to 46
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1017/inp.2023.9
