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REGENERATION OF PONDEROSA PINE WOODLAND FOLLOWING SEVERE WILDFIRE IN THE NIOBRARA RIVER VALLEY.
Author
Hefner, Amanda M.
Wedin, David A.
Publisher
Society for Range Management
Publication Year
2016
Body

Over the last century, fire suppression has increased fuel loads and led to intense wildfire behavior in ponderosa pine (Pinus ponderosa) woodlands. In 2012, the Fairfield Creek fire burned over 60,000 acres in Nebraska's Niobrara Valley, including ponderosa pine woodlands. Our study examined: 1) post-fire survival of pine and encroaching eastern redcedar (Juniperus virginianus); 2) post-fire recruitment of pine, redcedar, bur oak (Quercus macrocarpa), and grassland across our 1,600 acre study area; and 3) factors limiting seedling establishment in a one-year seed addition study. Regardless of stand structure, which varied from open savanna to pine/redcedar woodland, mortality for both pine and redcedar was almost complete. Out of an estimated 40,000 pines, less than 350 survived. In 2014, we classified our study area into pre-fire woodland density categories and established 400 random sampling points proportionally across the categories. At each point, we measured abundance of herbaceous vegetation, counted tree seedlings, and determined presence or absence of invasive species in a 10m diameter plot. Although there were clear patterns for grassland recovery and invasive Canada thistle (Cirsium arvense), we found less than 5 ponderosa pine and less than 20 redcedar seedlings in the 1600 acre study area. Finally, to examine factors limiting seedling establishment, we created 21 research plots where we planted native grasses, ponderosa pine, and eastern redcedar with and without competing herbaceous vegetation. These research plots included burned and unburned sites ranging from open grasslands to dense woodlands. Our results show poor recruitment of pine and cedar, regardless of natural or planted means. Even when viable seed was experimentally added and competing herbaceous plants experimentally removed, the lack of pine and redcedar recruitment suggests that the window of conditions allowing woodland recovery is small leading to a high potential for the conversion of the former pine woodland to grassland.

Language
English
Resource Type
Text
Document Type
Conference Proceedings
Conference Name
SRM Corpus Christi, TX
Collection
SRM Annual Meeting Abstracts