Variability in vegetation and surface fuels across mixed-conifer-dominated landscapes with over 40 years of natural fire

Exclusion of natural surface fires in warm/dry mixed-conifer forests of the western U.S. has increased potential for stand-replacing crown fires and reduced resilience of these systems to other disturbances, such as drought and insect attack. Tree thinning and the application of prescribed fire are commonly used to restore more resilient ecological conditions, but currently, there is a lack of long-term data with which to evaluate restoration treatment effectiveness in forest types where resprouting shrubs dominate understory communities. At a mixed-conifer site in southwestern Colorado, we compared forest structure and understory vegetation responses to three restoration treatments (thin/burn, burn, and control) over 10 years in a completely randomized and replicated experiment. Forest density, canopy cover, and crown fuel loads were consistently lower, and crown base height was higher, in thin/burn than burn or controls, but the effects diminished over time. Ten years following treatment, >99% of all plant species within both treatments and the control were native in origin. There were no differences between treatments in understory richness, diversity, cover, or surface fuels, but graminoid cover more than doubled in all treatments over the 15-year monitoring period. Similarly, there was more than a 250% increase post-treatment in shrub density, with the greatest increases in the thin/burn treatment. In addition, we saw an increase in the average shrub height for both treatments and the control, with shrub stems >80 cm becoming the dominant size class in the thin/burn treatment. Conifer seedling density was significantly lower in thin/burn compared with burn and control treatments after 10 years. Taken together, these conditions create challenges for managers aiming to reestablish natural fire patterns and sustain mixed-conifer forests. To limit the dominance of resprouting shrubs and facilitate conifer regeneration after overstory thinning and prescribed fire, managers may need to consider new or more intensive approaches to forest restoration, particularly given current and projected climate change.

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Fire history of a mixed conifer forest on the Mogollon Rim, northern Arizona, USA

International Journal of Wildland Fire ◽

10.1071/wf14005 ◽

2015 ◽

Vol 24 (5) ◽

pp. 680 ◽

Cited By ~ 17

Author(s):

David W. Huffman ◽

Thomas J. Zegler ◽

Peter Z. Fulé

Keyword(s):

Fire History ◽

Fire Regime ◽

Conifer Forest ◽

Mixed Conifer ◽

Natural Fire ◽

Landscape Characteristics ◽

Northern Arizona ◽

High Severity ◽

The American South ◽

Fire Intervals

It has been suggested that large, high-severity fires historically structured warm–dry mixed conifer forests in the American South-west. To test this, we reconstructed fire regime characteristics of an 1135-ha (11.3 km2) mixed conifer landscape in northern Arizona using complementary approaches. We analysed composite fire intervals, point fire intervals, natural fire rotation, landscape characteristics and forest age structure. Composite analysis of cross-dated fire scars from 133 trees indicated a mean fire interval (MFI) of 2.0–8.5 years between 1670 and 1879. Frequent fires halted abruptly after 1879. Mean point fire interval (MPFI) was 11.8 years and ranged 2–61 years. Mean fire rotation was 14.4 years. Density of most occurring tree species increased dramatically after fire regime disruption, with south-western white pine (Pinus strobiformis) and white fir (Abies concolor) showing large numerical gains. Tree establishment patterns compared with widespread fire dates did not suggest historical high-severity fires at the site level. Although strong evidence of high-severity fire at finer scales was lacking, spatial locations of ‘young’ plots suggested the possibility of historical high-severity disturbances ≤25 ha in size. The historical fire regime on this landscape was one of high-frequency, low-severity fires. Current conditions call for restoration of forest structure and function.

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Drivers of understory plant communities in Sierra Nevada mixed conifer forests with pyrodiversity

Fire Ecology ◽

10.1186/s42408-021-00111-6 ◽

2021 ◽

Vol 17 (1) ◽

Author(s):

Kate Wilkin ◽

Lauren Ponisio ◽

Danny L. Fry ◽

Brandon M. Collins ◽

Tadashi Moody ◽

...

Keyword(s):

Sierra Nevada ◽

Plant Communities ◽

Canopy Cover ◽

Conifer Forests ◽

Mixed Conifer ◽

Natural Fire ◽

Mixed Conifer Forests ◽

Tree Canopy Cover ◽

Understory Plant ◽

Understory Plant Communities

Abstract Background Fire suppression in western North America increased and homogenized overstory cover in conifer forests, which likely affected understory plant communities. We sought to characterize understory plant communities and their drivers using plot-based observations from two contemporary reference sites in the Sierra Nevada, USA. These sites had long-established natural fire programs, which have resulted in restored natural fire regimes. In this study, we investigated how pyrodiversity—the diversity of fire size, severity, season, and frequency—and other environment factors influenced species composition and cover of forest understory plant communities. Results Understory plant communities were influenced by a combination of environmental, plot-scale recent fire history, and plot-neighborhood pyrodiversity within 50 m. Canopy cover was inversely proportional to understory plant cover, Simpson’s diversity, and evenness. Species richness was strongly influenced by the interaction of plot-based fire experience and plot-neighborhood pyrodiversity within 50 m. Conclusions Pyrodiversity appears to contribute both directly and indirectly to diverse understory plant communities in Sierra Nevada mixed conifer forests. The indirect influence is mediated through variability in tree canopy cover, which is partially related to variation in fire severity, while direct influence is an interaction between local and neighborhood fire activity.

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Abstract #130: Adrenal Functioning Carcinoma in a Woman with History of Adrenal Tumor of Over 40 Years of Evolution

Endocrine Practice ◽

10.1016/s1530-891x(20)42499-1 ◽

2015 ◽

Vol 21 ◽

pp. 17

Author(s):

Jose Paz-Ibarra ◽

Sofia Saenz ◽

Natali Jauregui ◽

Marialejandra Delgado ◽

Jose Somocurcio

Keyword(s):

Adrenal Tumor ◽

History Of ◽

Over 40 Years

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36. Practicing medicine and music II: Ophthalmology and music

Clinical & Investigative Medicine ◽

10.25011/cim.v30i4.2796 ◽

2007 ◽

Vol 30 (4) ◽

pp. 46

Author(s):

L. P. Hwi ◽

J. W. Ting

Keyword(s):

Chamber Music ◽

18Th Century ◽

Johann Sebastian Bach ◽

Active Member ◽

Active Researcher ◽

Silver Medal ◽

Medical Career ◽

The One ◽

The University ◽

Over 40 Years

Cecil Cameron Ewing (1925-2006) was a lecturer and head of ophthalmology at the University of Saskatchewan. Throughout his Canadian career, he was an active researcher who published several articles on retinoschisis and was the editor of the Canadian Journal of Ophthalmology. For his contributions to Canadian ophthalmology, the Canadian Ophthalmological Society awarded Ewing a silver medal. Throughout his celebrated medical career, Ewing maintained his passion for music. His love for music led him to be an active member in choir, orchestra, opera and chamber music in which he sang and played the piano, violin and viola. He was also the director of the American Liszt Society and a member for over 40 years. The connection between music and ophthalmology exists as early as the 18th Century. John Taylor (1703-1772) was an English surgeon who specialized in eye diseases. On the one hand, Taylor was a scientist who contributed to ophthalmology by publishing books on ocular physiology and diseases, and by advancing theories of strabismus. On the other hand, Taylor was a charlatan who traveled throughout Europe and blinded many patients with his surgeries. Taylor’s connection to music was through his surgeries on two of the most famous Baroque composers: Johann Sebastian Bach (1685-1750) and George Frederick Handel (1685-1759). Bach had a painful eye disorder and after two surgeries by Taylor, Bach was blind. Handel had poor or absent vision prior to Taylor’s surgery, and his vision did not improve after surgery. The connection between ophthalmology and music spans over three centuries from the surgeries of Taylor to the musical passion of Ewing. Ewing E. Cecil Cameron Ewing. BMJ 2006; 332(7552):1278. Jackson DM. Bach, Handel, and the Chevalier Taylor. Med Hist 1968; 12(4):385-93. Zegers RH. The Eyes of Johann Sebastian Bach. Arch Ophthalmol 2005; 123(10):1427-30.

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