Forest age distribution and traces of past fires in a natural boreal landscape dominated by Picea abies

Wallenius, Tuomo

doi:10.14214/sf.558

Cited by 40 publications

(53 citation statements)

References 37 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Studies suggest fi re intervals of 40-70 y in the 1800s, about 130 y in the 1600s and about 200 y around 1700 y BP, but it is not clear over what regions such fi gures could be extrapolated (Pitkänen and Huttunen 1999, Niklasson and Granström 2000, Pitkänen and Grönlund 2001. The longest fi re intervals have been observed on spruce swamps (Hörnberg et al 1995), in northern high-elevation forests (Steijlen andZackrisson 1987, Hyvärinen andSepponen 1988), and in European Russia outside Fennoscandia (Syrjänen et al 1994, Wallenius 2002.…”

Section: Introductionmentioning

confidence: 99%

Forest age distribution under mixed-severity fire regimes – a simulation-based analysis for middle boreal Fennoscandia

Pennanen¹

2002

Silva Fenn.

View full text Add to dashboard Cite

Pennanen, J. 2002. Forest age distribution under mixed-severity fi re regimes -a simulationbased analysis for middle boreal Fennoscandia. Silva Fennica 36(1): 213-231.A simulation model was used to study the age structure of unmanaged forest landscapes under different fi re regimes. Stand age was defi ned as the age of the oldest tree cohort in a stand. When most fi res are not stand-replacing, the theoretical equilibrium stand age distribution is either bell-shaped or bimodal and dominated by old age-classes. Old-growth forests (oldest cohort > 150 y) dominate the landscape unless fi res are both frequent and severe. Simulation results and analytical calculations show that if a regime of frequent fi res (about every 50 y) maintains landscapes dominated by old-growth forests, then old-growth dominance persists when the number of fi res is decreased, despite the associated increase in fi re severity. Simulation results were applied to Pinus sylvestrisdominated landscapes of middle boreal Fennoscandia, which according to empirical results were dominated by old-growth forests when fi res were frequent during the 19th century. Since the changes in the fi re regime can be plausibly explained by changes in the number of human-caused ignitions, old-growth forests have evidently also dominated the landscapes earlier when fi res were less frequent. The simulation model is used to produce plausible age distributions of middle boreal Fennoscandian forest landscapes under different historical fi re regimes. In summary, the frequency of large-scale disturbance alone predicts forest landscape dynamics poorly, and the roles played by fi re severity and residual stands need to be considered carefully. Maintaining and restoring oldgrowth structures is essential to regaining the natural variability of Fennoscandian forest landscapes.

show abstract

Section: Introductionmentioning

confidence: 99%

Forest age distribution under mixed-severity fire regimes – a simulation-based analysis for middle boreal Fennoscandia

Pennanen¹

2002

Silva Fenn.

View full text Add to dashboard Cite

show abstract

“…It seems that despite differences in dominant tree species, historical fire return intervals across large parts of the circumboreal forests have been less than 100 years, with the long-term and large-scale averages being around 50-80 years. However, it has to be noted that infrequently burned regions and forest types with fire cycles of hundreds of years are probably understudied (Wallenius 2002, Wallenius et al 2010.…”

Section: Discussionmentioning

confidence: 99%

Long-term decreasing trend in forest fires in northwestern Canada

2011

View full text Add to dashboard Cite

Abstract. The annual area of forest burned has decreased in recent centuries over large areas of Fennoscandia, Siberia and temperate North America. To determine if this same trend extends to a sparsely populated region of northern Canada, fire scars on living and dead trees, forest stand ages and charred wood were systematically sampled in 85 study plots in an area of 564 000 km 2 in northwestern Canada. A significant negative trend in the occurrence of forest fires was observed: average area burned per year decreased from 2.0% in the first half of the 19th century to 0.33% in the later half of the 20th century. Annually burned areas correlated significantly with a local tree ring based index, July monthly drought code and the Pacific decadal oscillation but not with June-August mean temperature, distance to the nearest road, or the year of road building. None of the climatic indicators or access history (indicative of the start of local fire suppression) could explain the long-term negative trend in fires. Earlier interpretations that humans dominated the causes of forest fires in the past, even in sparsely populated regions, deserve further attention as a possible explanation for the decreasing trend in fires.

show abstract

“…On pakutud, et uuritud viljakates kasvukohatüüpides võiks inimese intensiivse vahelesegamiseta leht-ja segametsades eeldada väikeseskaalalise häiludünaamika olulist mõju rohurinde kooslusele. Häildünaamikaga kombineeruvad suure ajaintervalliga ka juhuslikud suureskaalalised häiringud nagu tormid ja põlengud (Fries et al, 1997;Angelstam, 1998;Kuuluvainen, 2002;Wallenius, 2002). Peamine intensiivse metsamajandamise ja looduslike häiringute erinevus viljakates parasniisketes metsades seisneb keskkonnatingimuste järsus ja ulatuslikus muutumises intensiivse majandamise käigus, mille osaks on suurepinnalised lageraied, (okaspuude) monokultuuride rajamine ja mitmete oluliste looduslähedaste metsade struktuurielementide pidev eemaldamine.…”

Section: Aruteluunclassified

Factors influencing the species composition and richness of herb layer in old boreo-nemoral forests

Sepp

Liira

2009

Forestry Studies / Metsanduslikud Uurimused

View full text Add to dashboard Cite

Abstract. We aimed to study the composition of herb layer in old Estonian boreonemoral forests (Aegopodium and Hepatica forest site-types) and estimate factors that influence the vegetation. Besides forest management and other anthropogenic disturbances, stand age, geographic location and tree species composition were analysed as potential driving factors. We surveyed 169 forests, mostly as a contrasting pair of intensively managed and possibly near-natural forest within each sub-region of a forest site-type. Later, for analyses, we reclassified forests into three groups by weighted summing of the observed signs of disturbances. Analyses revealed the distinction in herb layer composition among forest site-types and dominant-tree species. Geographic location of a stand also appeared to affect the understorey, while stand age had no statistically significant impact on herb layer in old and over-matured forests. We did not detect explicitly the direct effect of forest management and disturbances on herb layer composition and diversity. However, indirectly, only in Hepatica site-type, the management increased herb layer species richness and the proportion of graminoids, by providing more light via reduced closure of a stand. Species characteristic of managed stands were mostly light-demanding, dry soil tolerant and apophytic species. Undisturbed stands were characterized by presence of nemoral and vernal herbs that typically grow in broad-leaved or mixed stands. Consequently, the dominance of conifers in managed forest, can limit the growth of characteristic species of boreonemoral forest site-types. Therefore, to improve the state of plant diversity in boreo-nemoral forests, tree species diversity and small-sized gap-initiation should be supported.Key words: forest biodiversity, boreonemoral forest, DCA, herb layer, forest management, species richness, indicator species analysis.Authors' address: Institute of Ecology and Earth Sciences, University of Tartu, Lai St. 40, 51005 Tartu, Estonia, *e-mail: jaan.liira@ut.ee SissejuhatusLooduslike ja inimhäiringutega metsades kaasnevad, sõltuvalt metsatüübist, erineva pindalaga, sageduse ja avaldumise tugevusega keskkonnatingimuste muutused, mis mõjutavad koosluse liigilist koosseisu, struktuuri ja dünaamikat, ja seda nii puistu kui metsamaastiku tasandil (Runkle, 1985;Niemelä, 1999;Kuuluvainen, 2002). Ajalooliselt, pärast atlantilise perioodi (6000-3000 a. e.m.a.) lõppu on laialehiste puuliikide levikuala viljaka mullaga aladel vähendanud nii klimaatilised tegurid kui inimtegevus (Laasimer, 1965;Saarse & Veski, 2005). Intensiivne metsamajandus on loodusliku metsa osakaalu vähendanud nii Eestis kui mujal. Kaasaegsetes metsamaastikes on metsade majandamine domineerivaks, ruumilist struktuuri ja Forestry Studies|Metsanduslikud Uurimused 50, 23-

show abstract

Forest age distribution and traces of past fires in a natural boreal landscape dominated by Picea abies

Cited by 40 publications

References 37 publications

Forest age distribution under mixed-severity fire regimes – a simulation-based analysis for middle boreal Fennoscandia

Forest age distribution under mixed-severity fire regimes – a simulation-based analysis for middle boreal Fennoscandia

Long-term decreasing trend in forest fires in northwestern Canada

Factors influencing the species composition and richness of herb layer in old boreo-nemoral forests

Contact Info

Product

Resources

About