352 years long fire history of a Siberian boreal forest and its primary driving factor

2021 ◽  
Vol 207 ◽  
pp. 103653
Author(s):  
Zhou Wang ◽  
Jian-Guo Huang ◽  
Nina Ryzhkova ◽  
Jingye Li ◽  
Alexander Kryshen ◽  
...  
The Holocene ◽  
2015 ◽  
Vol 25 (12) ◽  
pp. 1912-1922 ◽  
Author(s):  
Mathieu Frégeau ◽  
Serge Payette ◽  
Pierre Grondin

1983 ◽  
Vol 61 (9) ◽  
pp. 2459-2471 ◽  
Author(s):  
David R. Foster

The fire history of the wilderness of southeastern Labrador is marked by a patchy distribution of large fires in time and space. During the 110-year period encompassed by this study, major fires occurred in four decades, 1870–1879, 1890–1899, 1950–1959, 1970–1979. From 1900 to 1951 only 1125 km2 burned; this represents approximately 10% of the total area consumed from 1870 to 1980. Fire records indicate an asynchroneity of the important fire years in southeastern Labrador and adjacent provinces and within Labrador itself. This observation suggests that the meteorological conditions controlling fire occurrence in this portion of the eastern boreal forest are local in nature and extent. The fire rotation for southeastern Labrador is calculated at approximately 500 years, significantly longer than that estimated for other regions of boreal forest. The rare occurrence of large fires is explained by high levels of precipitation and by the preponderance of fire breaks, primarily lakes and peatlands. On the basis of physiographic criteria the region is subdivided into two types of landscape displaying contrasting fire regimes. The large interior plateau, which is covered by extensive peatlands and numerous lakes, has a low fire incidence and extremely long fire rotation. In contrast, large fires are common in the watersheds of the Alexis, Paradise, and St. Augustin rivers where the topographic relief is quite varied and peatlands are scarce. The regional pattern of fire activity has important phytogeographical implications. The lichen woodlands and birch forests are fire-dependent vegetation types; their distribution in the modern landscape is strongly correlated with the historical occurrence of fire during the past 110 years. In addition it is postulated that the historical absence of fire across the large plains in southeastern Labrador has contributed to the development of extensive peatlands in these areas.


2007 ◽  
Vol 363 (1501) ◽  
pp. 2299-2314 ◽  
Author(s):  
Serge Payette ◽  
Louise Filion ◽  
Ann Delwaide

Across the boreal forest, fire is the main disturbance factor and driver of ecosystem changes. In this study, we reconstructed a long-term, spatially explicit fire history of a forest-tundra region in northeastern Canada. We hypothesized that current occupation of similar topographic and edaphic sites by tundra and forest was the consequence of cumulative regression with time of forest cover due to compounding fire and climate disturbances. All fires were mapped and dated per 100 year intervals over the last 2000 years using several fire dating techniques. Past fire occurrences and post-fire regeneration at the northern forest limit indicate 70% reduction of forest cover since 1800 yr BP and nearly complete cessation of forest regeneration since 900 yr BP. Regression of forest cover was particularly important between 1500s–1700s and possibly since 900 yr BP. Although fire frequency was very low over the last 100 years, each fire event was followed by drastic removal of spruce cover. Contrary to widespread belief of northward boreal forest expansion due to recent warming, lack of post-fire recovery during the last centuries, in comparison with active tree regeneration more than 1000 years ago, indicates that the current climate does not favour such expansion.


1981 ◽  
Vol 29 (1) ◽  
pp. 81 ◽  
Author(s):  
B Lamont

Kingia australis, common in the heaths and forests of south-western Australia, is distinguished from all other grass trees in Australia by the presence of a mantle of concealed aerial roots. A ring of up to 50 root primordia is initiated in winter from the stem apex. In plants more than 1 m high, initiation and commencement of elongation of the primary roots are no longer annual but dependent on the fire history of the plant. These roots descend between the stem and persistent leaf bases at about 2 cm per growing month, sending many lateral branches among the leaf bases. Aerial roots gradually replace the space occupied by the leaf bases until they may account for 45% of the dry weight of the aerial caudex. The caudex of one 6-m-high specimen bore up to 27 roots per cm2 transection of the root mantle, with about 3000 primary roots entering the soil. All underground primary roots (except the initial contractile roots) have an aerial origin and are concentrated vertically under the canopy. After 300-400 years the stem starts to die back from the base, and the aerial roots attached to that portion disintegrate. By propping up the stem and bridging the dead zone of the stem, the living aerial roots greatly extend the potential height and longevity of the plant. In addition, the hairy laterals are ideally located to absorb water and nutrients directly from the leaf bases. Protective and aerating functions are also indicated.


2015 ◽  
Vol 24 (6) ◽  
pp. 731-741 ◽  
Author(s):  
Jennifer L. Clear ◽  
Heikki Seppä ◽  
Niina Kuosmanen ◽  
Richard H. W. Bradshaw

1986 ◽  
Vol 16 (5) ◽  
pp. 1013-1018 ◽  
Author(s):  
Lauren Fins ◽  
Lisa W. Seeb

Seed samples from 19 stands of Larixoccidentalis Nutt. were analyzed for electrophoretic variation at 23 loci. Because sample sizes consisted of only 9 or 10 trees per stand (18–20 alleles per locus per stand), samples were grouped by geographic proximity into four larger samples. For all measures of variation, this species scored lower than most, but within the range observed for other western conifers. Most of the variation was found within rather than between the population groups. The single southern sample appeared to be genetically distinct from the others. Although some variation was observed between individual stand samples in expected heterozygosity, the consistently low values for all samples suggest that genetic drift has played a major role in the genetic history of the species in the Inland Empire, both through its glacial history in postulated refugia and through fire history in recent times.


Author(s):  
Jesper Sørensen

English abstract: This article has a double focus. First, and in line with the special theme of this issue, it will address and discuss the celebrated, later rebuked and finally almost forgotten ‘hero’ from our discipline’s historical cabinet of curiosity, the Dutch phenomenologist of religion and theologian, Gerardus van der Leeuw (1890-1950). Van der Leeuw’s work had its primary impact in the first part of the 20th century, but came to play a special role in Denmark when his Introduction to the Phenomenology of Religion was published in Danish in 1969 – a book which influenced a whole generation of Danish high school teachers. Second, taking my departure from van der Leeuws emphasis, I reevaluate the concept of mana in order to explore its relevance in the contemporary, academic study of religion. My point of departure is, that we need a concept covering broad notions of force. Further I argue that a rejuvenated notion of mana should build upon results from the cognitive sciences regarding causal representation as well as from the notion of force-dynamic representations argued in cognitive linguistics. Finally, in a more speculative manner, I shall present a number of hypotheses concerning the relation between social organization and mana and argue that this relation can be understood as a driving factor in a general history of religion. Dansk resume: Denne artikels formål er dobbelt. For det første vil den, i tråd med dette nummers overordnede tema, diskutere en hyldet, udskældt og nu nærmest glemt ’helt’ fra det forskningshistoriske raritetskabinet, den hollandske religionsfænomenolog og teolog, Gerardus van der Leeuw (1890-1950). Van der Leeuw havde sit virke i første halvdel af det 20. århundrede, men fik en særlig i indflydelse i Danmark fra 1969, hvor hans indføring i religionsfænomenologien udkom på dansk under titlen Mennesket og Mysteriet – en bog, som fik stor indflydelse på en hel generation gymnasielærere. For det andet vil den, med afsæt i van der Leeuws brug af mana som central eksplanatorisk kategori, revurdere dette begreb for at undersøge dets relevans for den moderne religionsvidenskab. Udgangspunktet er, at religionsvidenskaben har brug for et begreb, der dække kraftforestillinger bredt forstået, og at nyere kognitive forklaringer på kausale forestillinger samt den kognitive lingvistiks fokus på kraftdynamik i sproget kan fungere som udgangspunkt for et moderne mana-begreb. Afslutningsvis vil artiklen mere spekulativt udkaste en række hypoteser om forholdet mellem social organisering og mana som en central drivkraft i den generelle religionshistorie.


Sign in / Sign up

Export Citation Format

Share Document