Response of Arizona cypress (Hesperocyparis arizonica) to the Horseshoe Two Megafire in a south-eastern Arizona Sky Island mountain range

2019 ◽  
Vol 28 (1) ◽  
pp. 62
Author(s):  
Andrew M. Barton ◽  
Helen M. Poulos

We examined the response of Arizona cypress (Hesperocyparis arizonica) to the 2011 Horseshoe Two Megafire in the Chiricahua Mountains, Arizona, USA. We documented cover type, fire severity, cypress mortality and seedling establishment in 60 plots. In plots subject to severe fire, most mature cypresses were killed, the canopy opened and seedlings established abundantly. These results were consistent across three canyons differing in topography and vegetation. Successful regeneration of Arizona cypress contrasts with low seedling establishment for pines in the same area after the Horseshoe Two Fire, a difference possibly explained by abundant serotinous seed production in cypress or its preference for riparian sites protected from extreme fire. Our results firmly establish Arizona cypress as a fire-sensitive but fire-embracing species that depends on stand-replacing fire for regeneration. Given the fire sensitivity of Arizona cypress, however, recent increases in the frequency of high-severity fires in the south-west USA could pose a threat to the long-term viability of this species by preventing individuals from reaching sexual maturity during fire intervals. This scenario, termed the ‘interval squeeze’, has been documented in tecate cypress (H. forbesii) in California. A drier future with more frequent wildfires could pose serious threats to all New World cypresses.

2020 ◽  
Vol 457 ◽  
pp. 117704 ◽  
Author(s):  
Helen M. Poulos ◽  
Andrew M. Barton ◽  
Graeme P. Berlyn ◽  
Dylan W. Schwilk ◽  
Charles E. Faires ◽  
...  

2018 ◽  
Vol 69 (3) ◽  
pp. 688-692
Author(s):  
Lucian Nita ◽  
Dorin Tarau ◽  
Gheorghe Rogobete ◽  
Simona Nita ◽  
Radu Bertici ◽  
...  

The issue addressed relates to an area of 1891694 ha of which 1183343 ha are agricultural land (62, 56) located in the south-west of Romania and refer to the use of soil chemical and physical properties as an acceptor for certain crop systems, with minimal undesirable effects both for plants to be grown, as well as soil characteristics and groundwater surface quality. It is therefore necessary on a case-by-case basis, measure stoc or rect the acidic reaction by periodic or alkaline calculations, the improvement of plant nutrition conditions through ameliorative fertilization and the application of measures to improve the physical state, sufficient justification for the need to develop short and long term strategies for the protection and conservation of edifying factors and the need to respect the frequency of field and laboratory investigations at all 8x8 km grids of the National Soil-Grounds Monitoring System (organized by I.C.P.A.) and completing it with the relevant pedological and agrochemical studies.


Fire Ecology ◽  
2019 ◽  
Vol 15 (1) ◽  
Author(s):  
Jessie M. Dodge ◽  
Eva K. Strand ◽  
Andrew T. Hudak ◽  
Benjamin C. Bright ◽  
Darcy H. Hammond ◽  
...  

Abstract Background Fuel treatments are widely used to alter fuels in forested ecosystems to mitigate wildfire behavior and effects. However, few studies have examined long-term ecological effects of interacting fuel treatments (commercial harvests, pre-commercial thinnings, pile and burning, and prescribed fire) and wildfire. Using annually fitted Landsat satellite-derived Normalized Burn Ratio (NBR) curves and paired pre-fire treated and untreated field sites, we tested changes in the differenced NBR (dNBR) and years since treatment as predictors of biophysical attributes one and nine years after the 2007 Egley Fire Complex in Oregon, USA. We also assessed short- and long-term fuel treatment impacts on field-measured attributes one and nine years post fire. Results One-year post-fire burn severity (dNBR) was lower in treated than in untreated sites across the Egley Fire Complex. Annual NBR trends showed that treated sites nearly recovered to pre-fire values four years post fire, while untreated sites had a slower recovery rate. Time since treatment and dNBR significantly predicted tree canopy and understory green vegetation cover in 2008, suggesting that tree canopy and understory vegetation cover increased in areas that were treated recently pre fire. Live tree density was more affected by severity than by pre-fire treatment in either year, as was dead tree density one year post fire. In 2008, neither treatment nor severity affected percent cover of functional groups (shrub, graminoid, forb, invasive, and moss–lichen–fungi); however, by 2016, shrub, graminoid, forb, and invasive cover were higher in high-severity burn sites than in low-severity burn sites. Total fuel loads nine years post fire were higher in untreated, high-severity burn sites than any other sites. Tree canopy cover and density of trees, saplings, and seedlings were lower nine years post fire than one year post fire across treatments and severity, whereas live and dead tree basal area, understory surface cover, and fuel loads increased. Conclusions Pre-fire fuel treatments effectively lowered the occurrence of high-severity wildfire, likely due to successful pre-fire tree and sapling density and surface fuels reduction. This study also quantified the changes in vegetation and fuels from one to nine years post fire. We suggest that low-severity wildfire can meet prescribed fire management objectives of lowering surface fuel accumulations while not increasing overstory tree mortality.


Forests ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 150
Author(s):  
Lance Jay Roberts ◽  
Ryan Burnett ◽  
Alissa Fogg

Silvicultural treatments, fire, and insect outbreaks are the primary disturbance events currently affecting forests in the Sierra Nevada Mountains of California, a region where plants and wildlife are highly adapted to a frequent-fire disturbance regime that has been suppressed for decades. Although the effects of both fire and silviculture on wildlife have been studied by many, there are few studies that directly compare their long-term effects on wildlife communities. We conducted avian point counts from 2010 to 2019 at 1987 in situ field survey locations across eight national forests and collected fire and silvicultural treatment data from 1987 to 2016, resulting in a 20-year post-disturbance chronosequence. We evaluated two categories of fire severity in comparison to silvicultural management (largely pre-commercial and commercial thinning treatments) as well as undisturbed locations to model their influences on abundances of 71 breeding bird species. More species (48% of the community) reached peak abundance at moderate-high-severity-fire locations than at low-severity fire (8%), silvicultural management (16%), or undisturbed (13%) locations. Total community abundance was highest in undisturbed dense forests as well as in the first few years after silvicultural management and lowest in the first few years after moderate-high-severity fire, then abundance in all types of disturbed habitats was similar by 10 years after disturbance. Even though the total community abundance was relatively low in moderate-high-severity-fire habitats, species diversity was the highest. Moderate-high-severity fire supported a unique portion of the avian community, while low-severity fire and silvicultural management were relatively similar. We conclude that a significant portion of the bird community in the Sierra Nevada region is dependent on moderate-high-severity fire and thus recommend that a prescribed and managed wildfire program that incorporates a variety of fire effects will best maintain biodiversity in this region.


2020 ◽  
Vol 29 (7) ◽  
pp. 611
Author(s):  
Breeanne K. Jackson ◽  
S. Mažeika P. Sullivan

Fires are a common feature of many landscapes, with numerous and complex ecological consequences. In stream ecosystems, fire can strongly influence fluvial geomorphic characteristics and riparian vegetation, which are structural components of stream–riparian ecosystems that contribute to biodiversity and ecosystem function. However, the effects of fire severity on stream–riparian ecosystems in California’s Sierra Nevada region (USA) are not well described, yet critical for effectively informing fire management and policy. At 12 stream reaches paired by fire severity (one high-severity burned, one low-severity burned), no significant differences were found in riparian plant community cover and composition or stream geomorphic characteristics 2–15 years following wildfire. In addition, minimal changes in riparian vegetation and stream geomorphic properties were observed in the first summer following the extensive and severe Rim Fire. However, an upstream-to-downstream influence of multiple fire occurrences was observed over the previous 81 years within each catchment on stream geomorphic metrics, including sediment size, embeddedness and channel geometry, at our study reaches. The inconsistent effects of wildfire on stream–riparian vegetation and geomorphic characteristics over space and time may be related to time since fire and precipitation.


2021 ◽  
pp. 096372142110538
Author(s):  
Wendy Johnson

Increasingly, we are required, encouraged, and/or motivated to track our behavior, presumably to improve our life “quality.” But health and life-satisfaction trends are not cooperating: Empirical evidence for success is sorely lacking. Intelligence has been tracked for more than 100 years; perhaps this example offers some hints about tracking’s overall social impact. I suggest that Huxley’s Brave New World offers a relevant long-term extrapolation and that popular recent tracking activities will accelerate “progress” in that dystopian direction.


2013 ◽  
Vol 46 ◽  
Author(s):  
Monique Fort ◽  
Etienne Cossart

Active mountains supply the largest sediment fluxes experienced on earth. At mountain range scale, remote sensing approaches, sediments provenance or stream power law analyses, collectively provide rough long-term estimates of total erosion. Erosion is indeed controlled by rock uplift and climate, hence by a wide range of processes (detachment, transport and deposition), all operating within drainage basin units, yet with time and spatial patterns that are quite complex at local scale. We focus on the Kali Gandaki valley, along the gorge section across the Higher Himalaya (e.g. from Kagbeni down to Tatopani). Along this reach, we identify sediment sources, stores and sinks, and consider hillslope int eractions with valley floor, in particular valley damming at short and longer time scales, and their impact on sediment budgets and fluxes. A detailed sediment budget is presented, constrained by available dates and/or relative chronology, ranging from several 10 kyr to a few decades. Obtained results span over two orders of magnitude that can best be explained by the type and magnitude of erosional processes involved. We show that if large landslides contribute significantly to the denudation history of active mountain range, more frequent medium to small scales landslides are in fact of primary concern for Himalayan population.


Geografie ◽  
2003 ◽  
Vol 108 (3) ◽  
pp. 191-201
Author(s):  
Piotr Migoń

This paper presents results of selected geomorphological studies published originally in Poland in the last decade and attempts to show the extent to which they complement or diverge from research carried out in the Czechia. It focuses on long-term landform evolution, the role of planation and differential tectonics, glacial and periglacial processes and identifies the scope for joint research efforts, which ultimately may lead towards a comprehensive, synthetic view of geomorphic evolution of the whole mountain range.


2016 ◽  
Author(s):  
Margaux Mouchené ◽  
Peter van der Beek ◽  
Sébastien Carretier ◽  
Frédéric Mouthereau

Abstract. Alluvial megafans are sensitive recorders of landscape evolution, controlled by autogenic processes and allogenic forcing and influenced by the coupled dynamics of the fan with its mountainous catchment. The Lannemezan megafan in the northern Pyrenean foreland was abandoned by its mountainous feeder stream during the Quaternary and subsequently incised, leaving a flight of alluvial terraces along the stream network. We explore the relative roles of autogenic processes and external forcing in the building, abandonment and incision of a foreland megafan using numerical modelling and compare the results with the inferred evolution of the Lannemezan megafan. Autogenic processes are sufficient to explain the building of a megafan and the long-term entrenchment of its feeding river at time and space scales that match the Lannemezan setting. Climate, through temporal variations in precipitation rate, may have played a role in the episodic pattern of incision at a shorter time-scale. In contrast, base-level changes, tectonic activity in the mountain range or tilting of the foreland through flexural isostatic rebound appear unimportant.


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