scholarly journals Wildfire-Driven Forest Conversion in Western North American Landscapes

BioScience ◽  
2020 ◽  
Vol 70 (8) ◽  
pp. 659-673 ◽  
Author(s):  
Jonathan D Coop ◽  
Sean A Parks ◽  
Camille S Stevens-Rumann ◽  
Shelley D Crausbay ◽  
Philip E Higuera ◽  
...  

Abstract Changing disturbance regimes and climate can overcome forest ecosystem resilience. Following high-severity fire, forest recovery may be compromised by lack of tree seed sources, warmer and drier postfire climate, or short-interval reburning. A potential outcome of the loss of resilience is the conversion of the prefire forest to a different forest type or nonforest vegetation. Conversion implies major, extensive, and enduring changes in dominant species, life forms, or functions, with impacts on ecosystem services. In the present article, we synthesize a growing body of evidence of fire-driven conversion and our understanding of its causes across western North America. We assess our capacity to predict conversion and highlight important uncertainties. Increasing forest vulnerability to changing fire activity and climate compels shifts in management approaches, and we propose key themes for applied research coproduced by scientists and managers to support decision-making in an era when the prefire forest may not return.

Ecosphere ◽  
2020 ◽  
Vol 11 (9) ◽  
Author(s):  
Sebastian U. Busby ◽  
Kevan B. Moffett ◽  
Andrés Holz

Author(s):  
Pavlova N.R. ◽  
Dzerkal V.M. ◽  
Ponomareva А.А.

In order to preserve, reproduce and effectively use the natural complexes and objects of the DniproDelta as one of the most valuable natural floodplain-littoral complexes in Europe, which have special environmental, recreational, historical and cultural, scientific, educational and aesthetic value, and ensurethe conservationof «DniproDelta»wetland of theinternational importance,the National Natural Park «Lower Dnipro»was created(Decree of the President of Ukraine of November 24, 2015 No 657/2015).The flora of the higher vascular plants of the Park contains 820 species, 40 species of which (4.9% of the total number) are woody plants. Rosaceae Juss. (14 species), Salicaceae Mirb. (7 species), Aceraceae Juss. (3 types) are leading families of the dendroflora of the Park.Biomorphological characteristics of tree plant species in the flora of the Lower Dnipro National Nature Park were carried out according to the following classifications: 1) K. Raunkiersystem of plant life forms; 2) ecological and morphological classification of life forms of I. G. Serebryakov; 3) architectural models of F. Alle, R. Oldeman and P. Tomlinson; 4) classification of the life forms of plants of the temperate zone, which takes into account the vegetative propagation by O. V. Smirnova, L. B. Zaugolnova.AnalysisoftypesofbiomorphsaccordingtotheclassificationofK. Raunkiershowedthatthevastmajorityofdendrofloraspeciesbelongtophanerophytes, amongthem, dependingontheheightoftheplant, therearedifferentgroups-megaphanerophytes(e.g., Populustremula), mesophanerophytes(Salixalba), microphaneorphytes, nanophanerophytes(Amygdalusnana) andhamephytes(Ephedradistachia).According to the ecological and morphological classification of I. G. Serebryakov life forms, the flora of the Park is dominated by forest-steppe trees and forest-type trees.The trees which belong to one life form often differ in the principles of growth and formation of the crown, branching, and general habitus, which is generally considered as an architectural model of a particular species. According to the classification of architectural models by F. Alle, R. Oldeman and P. Tomlinson, in the flora of the Park, there are five models among which the species formed by the model of Tomlinson have a significant representation, and the species formed by the models of Manzheno and Champagne have a smaller representation.Key words:flora, tree, classification, life form, bush. З метою збереження, відтворення і ефективного використання природних комплексів та об’єктів дельти річки Дніпро як одного з найцінніших природних заплавно-літоральних комплексів у Європі, які мають особливу природоохоронну, оздоровчу, історико-культурну, наукову, освітню та естетичну цінність, забезпечення збереження водно-болотного угіддя міжнародного значення «Дельта р. Дніпро» створено Національний природний парк «Нижньодніпровський» (Указ президента України від 24 листопада 2015 року No 657/2015).Флора вищих судинних рослин Парку попередньо складає 820 видів, з них 40 видів (4,9% від загальної кількості) –деревні рослини.Провідні родини дендрофлори Парку –Rosaceae Juss. (14 видів), SalicaceaeMirb. (7 видів), AceraceaeJuss. (3 види). Біоморфологічну характеристику видів деревних рослин у флорі національного природнього парку «Нижньодніпровський» проведено за класифікаціями: 1) система життєвих форм рослин К. Раункієра; 2) еколого-морфологічна класифікація життєвих форм І. Г. Сєрєбрякова; 3) архітектурні моделі Ф. Аллє, Р. Ольдемана і П. Томлінсона; 4)класифікація життєвих форм рослин помірної зони, яка враховує вегетативне розмноження О. В. Смирнової, Л. Б. Заугольнової.Аналіз типів біоморф за класифікацією К. Раункієра показав, що переважна більшість видів дендрофлори належить до фанерофітів, серед них, в залежності від висоти рослини, виділяють різні групи –мегафанерофіти (наприклад, Populus tremula), мезофанерофіти (Salix alba), мікрофанерофіти (Amorpha fruticosa), нанофанерофіти (Amygdalus nana) та хамефіти (Ephedra distachia).За еколого-морфологічною класифікацією життєвих форм І. Г. Сєрєбрякова у флорі Парку домінують дерева лісостепового типу та дерева лісового типу.Дерева, які відносяться до однієї життєвої форми, часто відрізняютьсяпринципами наростання та формування крони, галуженням, загальним габітусом, що загалом розглядається як архітектурна модель конкретного виду. За класифікацією архітектурних моделей Ф.Аллє, Р. Ольдемана і П. Томлінсона у флорі Парку виділено п’ять моделей, серед яких, значне представництво мають види, що формуються за моделлю Томлінсона, менше представництво мають види, що формуються за моделями Манжено та Шампанії.Ключові слова: флора, дерево, класифікація, життєва форма, кущ.


1994 ◽  
Vol 4 (2) ◽  
pp. 65 ◽  
Author(s):  
SW Barrett

A fire history investigation was conducted for three forest community types in the Absaroka Mountains of Yellowstone National Park, Wyoming. Master fire chronologies were based on fire-initiated age classes and tree fire scars. The area's major forest type, lodgepole pine (Pinus contorta Dougl. var. latifolia) ecosystems, revealed a predominant pattern of stand replacing fires with a 200 year mean interval-nearly half the length estimated in previous studies of lodgepole pine on less productive subalpine plateaus in YNP. High elevation whitebark pine (P. albicaulis Engelm.) forests had primarily stand replacing fires with >350 year mean intervals, but some stands near timberline also occasionally experienced mixed severity- or non-lethal underburns. Before nearly a century of effective fire suppression in Yellowstone's northern range, lower elevation Douglas-fir (Pseudotsuga menziesii [Mirb.] Franco.) communities adjacent to Artemesia tridentata (Nutt.) grasslands experienced primarily non-lethal underburns at 30 year mean intervals. While short interval fire regimes have been altered by longterm fire suppression, fire exclusion apparently had only limited influence on the area's infrequently burned ecosystems prior to widespread stand replacement burning in 1988.


2010 ◽  
Vol 7 (1) ◽  
pp. 979-1020 ◽  
Author(s):  
Y. Pan ◽  
J. M. Chen ◽  
R. Birdsey ◽  
K. McCullough ◽  
L. He ◽  
...  

Abstract. Most forests of the world are recovering from a past disturbance. It is well known that forest disturbances profoundly affect carbon stock and fluxes in forest ecosystems, yet it has been a great challenge to assess disturbance impacts in estimates of forest carbon budgets. Net sequestration or loss of CO2 by forests after disturbance follows a predictable pattern with forest recovery. Forest age, which is related to time since disturbance, is the most available surrogate variable for various forest carbon analyses that concern the impact of disturbance. In this study, we compiled the first continental forest age map of North America by combining forest inventory data, historical fire data, optical satellite data and the dataset from NASA's LEDAPS project. Mexico and interior Alaska are excluded from this initial map due to unavailability of all required data sets, but work is underway to develop some different methodology for these areas. We discuss the significance of disturbance legacy from the past, as represented by current forest age structure in different regions of the US and Canada, tracking back disturbances caused by human and nature over centuries and at various scales. We also show how such information can be used with inventory data for analyzing carbon management opportunities, and other modeling applications. By combining geographic information about forest age with estimated C dynamics by forest type, it is possible to conduct a simple but powerful analysis of the net CO2 uptake by forests, and the potential for increasing (or decreasing) this rate as a result of direct human intervention in the disturbance/age status. The forest age map may also help address the recent concern that the terrestrial C sink from forest regrowth in North America may saturate in the next few decades. Finally, we describe how the forest age data can be used in large-scale carbon modeling, both for land-based biogeochemistry models and atmosphere-based inversion models, in order to improve the spatial accuracy of carbon cycle simulations.


2020 ◽  
Author(s):  
Renee Sniegocki ◽  
Jessica B. Moon ◽  
Abigail L. Rutrough ◽  
Jude Gireneus ◽  
Jaya Seelan S. Seelan ◽  
...  

AbstractLogging and forest conversion are occurring at alarming rates in the tropical forests. These disturbances alter soil chemistry and microbial diversity, and disrupt carbon cycling through shifts in litter decomposition. Direct links between microbial diversity and soil properties such as pH are well established; however, the indirect impacts of logging and forest conversion on microbial diversity and litter decomposition are poorly understood. We investigated how soil properties and soil functions change across a forest recovery gradient in the tropical montane forests of Malaysian Borneo. We used surface (top 5 cm) soil to assess soil physicochemical properties, next-generation DNA sequencing to assess soil microbial diversity, and standardized litterbags to assess litter decomposition and stabilization. Our results show that soils of the older forests harbored significantly greater microbial diversity, decomposed litter faster, and stabilized greater amounts of litter than soils of the younger forests and converted sites. These results suggest that logging and forest conversion significantly affect soil microbial diversity and can have lasting effects on carbon cycling in tropical montane forests.


2013 ◽  
Vol 43 (6) ◽  
pp. 570-583 ◽  
Author(s):  
Melissa Savage ◽  
Joy Nystrom Mast ◽  
Johannes J. Feddema

We examine regeneration dynamics across landscapes under extreme climate conditions and a human-altered fire regime in ponderosa pine (Pinus ponderosa Douglas ex Lawson & C. Lawson) forests of the American Southwest. Our research asks how well these forests recover when unprecedented conditions of a high-severity fire regime combine with historical drought conditions. Tree recruitment is documented at five sites in New Mexico after high-severity fires that burned forests in the drought that prevailed from ∼1945 to 1958. We develop a water-balance type model to evaluate how altered microclimate conditions in the years after a fire and during a drought may inhibit ponderosa pine regeneration in comparison with drought conditions alone. We empirically identify two pathways of forest recovery following high-severity fires during drought: recovery to nonforest types, either dense shrubfields or shrubs in grasslands (four sites) or recovery to hyperdense forest (one site). Model simulations predict fewer favorable opportunities for germination, fewer periods favorable for seedling establishment, shortening of favorable establishment periods, and more adverse conditions because of later spring and earlier fall hard freezes. Our research suggests that a specific climate window critical to the capacity of southwestern ponderosa pine trees to regenerate is narrowed by a synchronous occurrence of high-severity fire and drought.


Birds ◽  
2021 ◽  
Vol 2 (2) ◽  
pp. 147-157
Author(s):  
Chad T. Hanson ◽  
Derek E. Lee ◽  
Monica L. Bond

The Spotted Owl is a rare and declining raptor inhabiting low/middle-elevation forests of the Pacific Northwest, California, and the Southwest in the USA. It is well established that Spotted Owls select dense, mature, or old forests for nesting and roosting. High-severity fire transforms such forests into a unique forest type known as “snag forest habitat”, which the owls select for foraging. This habitat is disproportionately targeted by post-fire logging projects. Numerous recent articles have explored the influence of high-severity fire and post-fire logging on this species. Studies have shown that post-fire logging significantly reduces Spotted Owl occupancy, but efforts have generally not been made to disentangle the effects of such logging from the influence of high-severity fire alone on Spotted Owls. We conducted an assessment of published, peer-reviewed articles reporting adverse impacts of high-severity fire on Spotted Owls, exploring the extent to which there may have been confounding factors, such as post-fire logging. We found that articles reporting adverse impacts of high-severity fire on Spotted Owls were pervasively confounded by post-fire logging, and in some cases by a methodological bias. Our results indicate a need to approach analyses of high-severity fire and Spotted Owls differently in future research.


2021 ◽  
Vol 69 (1) ◽  
pp. 21
Author(s):  
Heidi Zimmer ◽  
Jan Allen ◽  
Rob Smith ◽  
Rebecca Gibson ◽  
Tony Auld

Changing climate is predicted to result in increased frequency and size of wildfires in south-eastern Australia. With increasing area burnt there is increased potential for entire species distributions to be burnt in a single fire event. This is particularly the case for range-restricted threatened species. Eucalyptus canobolensis (L.A.S.Johnson & K.D.Hill) J.T.Hunter is restricted to Mount Canobolas, New South Wales, Australia. In 2018, the majority of the E. canobolensis population was burnt by wildfire. One-year post-fire, we measured recruitment, resprouting and mortality of E. canobolensis. At higher fire severities, smaller trees were more likely to resprout from their bases only, as their stems were killed (i.e. ‘top kill’). Seedling regeneration only occurred in burnt plots. Our study demonstrates that E. canobolensis has a fire response typical of many eucalypts, characterised by seedling recruitment and larger trees resprouting epicormically, even after high-severity fire. Nevertheless, E. canobolensis response to repeat and short-interval fire remains unknown, and smaller trees appear to be vulnerable to top kill. Although much of Australia’s flora can respond to fire, this response is likely to be challenged as fire extents increase, especially if this is combined with increasing fire severity and/or frequency. These changes to the fire regime are a particular threat to species with restricted distributions.


2011 ◽  
Vol 8 (3) ◽  
pp. 715-732 ◽  
Author(s):  
Y. Pan ◽  
J. M. Chen ◽  
R. Birdsey ◽  
K. McCullough ◽  
L. He ◽  
...  

Abstract. Most forests of the world are recovering from a past disturbance. It is well known that forest disturbances profoundly affect carbon stocks and fluxes in forest ecosystems, yet it has been a great challenge to assess disturbance impacts in estimates of forest carbon budgets. Net sequestration or loss of CO2 by forests after disturbance follows a predictable pattern with forest recovery. Forest age, which is related to time since disturbance, is a useful surrogate variable for analyses of the impact of disturbance on forest carbon. In this study, we compiled the first continental forest age map of North America by combining forest inventory data, historical fire data, optical satellite data and the dataset from NASA's Landsat Ecosystem Disturbance Adaptive Processing System (LEDAPS) project. A companion map of the standard deviations for age estimates was developed for quantifying uncertainty. We discuss the significance of the disturbance legacy from the past, as represented by current forest age structure in different regions of the US and Canada, by analyzing the causes of disturbances from land management and nature over centuries and at various scales. We also show how such information can be used with inventory data for analyzing carbon management opportunities. By combining geographic information about forest age with estimated C dynamics by forest type, it is possible to conduct a simple but powerful analysis of the net CO2 uptake by forests, and the potential for increasing (or decreasing) this rate as a result of direct human intervention in the disturbance/age status. Finally, we describe how the forest age data can be used in large-scale carbon modeling, both for land-based biogeochemistry models and atmosphere-based inversion models, in order to improve the spatial accuracy of carbon cycle simulations.


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