scholarly journals Towards a better understanding of Siberian wildfires: linking paleoenvironmental fire reconstructions with an individual-based spatially explicit fire-vegetation model

2021 ◽  
Author(s):  
Ramesh Glückler ◽  
Elisabeth Dietze ◽  
Josias Gloy ◽  
Ulrike Herzschuh ◽  
Stefan Kruse
Keyword(s):  
Forest Fires ◽  
Fire Regimes ◽  
Ecosystem Functions ◽  
Spatially Explicit ◽  
Eastern Siberia ◽  
Vegetation Model ◽  
Individual Tree ◽  
Vegetation Models ◽  
The Individual

<p>Wildfires are an essential ecological process, located at the interface between atmosphere, biosphere, and geosphere. Climate-related changes in their appearance and frequency will shape the boreal forest of tomorrow, the largest terrestrial biome responsible for numerous important ecosystem functions. Changing fire regimes could also increase pressure on fire management and become a threat for humans living in Siberia. However, a lack of long-term fire reconstructions complicates the understanding of the main drivers in the larch-dominated forests of eastern Siberia. At the same time, this lack of long-term understanding also aggravates the validation of fire-vegetation models, and thus predictions of future changes of fire regimes in this vital region.</p><p>Here, we present a new fire module being built for the individual-based, spatially explicit vegetation model LAVESI (<em>Larix</em> Vegetation Simulator). LAVESI is able to simulate fine-scale interactions in individual tree’s life stages and detailed population dynamics, now expanded by the ability of wildfires igniting and damaging biomass. Fire-vegetation simulations were computed around the catchment of Lake Khamra (SW Yakutia), which experienced forest fires in the years 2007 and 2014 according to remote sensing imagery. From the lake, we previously contributed a new, sedimentary charcoal-based fire reconstruction of the late Holocene. Testing the fire module at a current study site, where modern and historic data has already been collected, allows us to improve it, and look into ways in which the fire reconstruction might help inform the model, before eventually scaling it up to cover larger regions. This represents a first step towards a reliable fire-vegetation model, able to predict future impacts of fires on both the forests of eastern Siberia, as well as the humans living there.</p>

The potential and limitations of long-term fire regime reconstructions in Eastern Siberia based on sedimentary charcoal and low-temperature fire markers 

2021 ◽  
Author(s):  
Elisabeth Dietze ◽  
Kai Mangelsdorf ◽  
Jasmin Weise ◽  
Heidrun Matthes ◽  
Simeon Lisovski ◽  
...  
Keyword(s):  
Low Temperature ◽  
Boreal Forest ◽  
High Latitude ◽  
Forest Fires ◽  
Fire Regime ◽  
Fire Regimes ◽  
Transport Processes ◽  
Eastern Siberia ◽  
Climate Data

<p>Forest fires are an important factor in the global carbon cycle and high latitude ecosystems. Eastern Siberian tundra, summergreen larch-dominated boreal forest on permafrost and evergreen boreal forest have characteristic fire regimes with varying fire intensities. Yet, it is unknown which role fire plays in long-term climate-vegetation-permafrost feedbacks and how high-latitude fire regimes and ecosystems will change in a warmer world. To learn from fire regime shifts during previous interglacials, prior to human presence, we use lake-sedimentary charcoal as proxy for high-intensity forest fires and monosaccharide anhydrides (i.e. levoglucosan, mannosan, galactosan: MA) as molecular proxies for low-temperature biomass burning, typical for surface fires in modern larch forest. However, MA pathways from source to sink and their stability in sediments are very poorly constrained. Recently, Dietze et al. (2020) found MA in up to 420 kyr old sediment of Lake El’gygytgyn (ICDP Site 5011-1), NE Siberia, suggesting that they are suitable proxies for fires in summergreen boreal forests. Surprisingly, the ratios of the MA isomers were exceptionally low compared to published emission ratios from modern combustions.</p><p>To understand what MA from Arctic lake sediments tell us, we have analyzed the MA and charcoal composition in modern lake surface sediments of Lake El’gygytgyn and three East Siberian lakes and we compare them to late glacial-to-interglacial El’gygytgyn records. The three Siberian lakes were chosen to represent spatial analogues to the El’gygytgyn conditions during MIS 5e and 11c. We discuss first results of the modern sediments in context of recent MODIS- and Landsat-based fire extents and biome-specific land cover data, a wind field modelling using climate data over eastern Siberia, and lake-catchment configurations from TDX-DEM analysis to assess potential fire proxy source areas and regional-to-local transport processes. Thereby, we provide insights into the meaning of sedimentary fire proxies, crucial for a sound reconstruction of long-term fire regime histories.</p>

scholarly journals Variation in fire scar phenology from mixed conifer trees in the Sierra Nevada

2018 ◽  
Vol 48 (1) ◽  
pp. 101-104 ◽  
Author(s):  
Scott L. Stephens ◽  
Liam Maier ◽  
Lilah Gonen ◽  
Jennifer D. York ◽  
Brandon M. Collins ◽  
...  
Keyword(s):  
Sierra Nevada ◽  
Fire History ◽  
Fire Regimes ◽  
Fire Season ◽  
Mixed Conifer ◽  
Outer Bark ◽  
Individual Tree ◽  
Fire Scar ◽  
The Individual ◽  
In Fire

Fire scar based studies have provided robust reconstructions of past fire regimes. The season in which a fire occurs can have considerable impacts to ecosystems but inference on seasonality from fire scars is relatively uncertain. This study examined patterns in the phenology of cambium formation and wounding responses in the five common mixed conifer tree species of the Sierra Nevada. The outer bark was shaved on 35 trees and individual locations within the shaved portions were wounded systematically by applying direct heat using a handheld torch. Most of the trees had not commenced annual ring development by the first burning treatment in late May. By the second treatment, scars were identified mostly within the early or middle earlywood, although variation was high compared with other treatment periods. By late October, all scars were recorded at the ring boundary. Although intra-ring scar positions generally followed a logical temporal pattern, there was high tree to tree variation such as Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) burned on 26 June induced scars in the early, mid, and late earlywood depending on the individual tree. This high variation makes it somewhat challenging to precisely assign past fire season to published fire history studies.

Riparian and adjacent upland forests burned synchronously during dry years in eastern Oregon (1650–1900 CE), USA

2020 ◽  
Vol 29 (7) ◽  
pp. 602
Author(s):  
Grant L. Harley ◽  
Emily K. Heyerdahl ◽  
James D. Johnston ◽  
Diana L. Olson
Keyword(s):  
Forest Fires ◽  
Fire History ◽  
Riparian Forest ◽  
Fire Regimes ◽  
Fire Frequency ◽  
Riparian Forests ◽  
Landscape Context ◽  
Blue Mountains ◽  
Study Sites

Riparian forests link terrestrial and freshwater communities and therefore understanding the landscape context of fire regimes in these forests is critical to fully understanding the landscape ecology. However, few direct studies of fire regimes exist for riparian forests, especially in the landscape context of adjacent upland forests or studies of long-term climate drivers of riparian forest fires. We reconstructed a low-severity fire history from tree rings in 38 1-ha riparian plots and combined them with existing fire histories from 104 adjacent upland plots to yield 2633 fire scars sampled on 454 trees. Historically (1650–1900), low-severity fires burned more frequently in upland than in riparian plots, but this difference was not significant (P=0.15). During more than half of the fire years at both sites, fires were extensive and burned synchronously in riparian and upland plots, and climate was significantly dry during these years. However, climate was not significantly dry when fires burned in only one plot type. Historically, entire riparian zones likely burned in these two study sites of the Blue Mountains during dry years. This study suggests that riparian and upland forests could be managed similarly, especially given the projected increases to fire frequency and intensity from impending climate change.

scholarly journals Socioeconomic Development, Demographic Dynamics and Forest Fires in Italy, 1961–2017: A Time-Series Analysis

2019 ◽  
Vol 11 (5) ◽  
pp. 1305 ◽  
Author(s):  
Margherita Carlucci ◽  
Ilaria Zambon ◽  
Andrea Colantoni ◽  
Luca Salvati
Keyword(s):  
Time Series ◽  
Forest Fires ◽  
Socioeconomic Development ◽  
Empirical Studies ◽  
Fire Regimes ◽  
Multivariate Techniques ◽  
Fire Size ◽  
Burnt Area ◽  
Over Time

Empirical studies investigating long-term trends in wildfires’ frequency and severity have been relatively scarce in Europe. Number of fire events, total burnt area and average fire size were studied between 1961 and 2017 in Italy with the aim to identify homogeneous time periods with similar wildfire frequency and severity and correlate them with the background socioeconomic context. Fire attributes had a diverging behavior over time: the number of fires was the highest in the 1970s and the early 1980s; total burnt area was relatively more constant over time with a peak in the 1980s; and, finally, average fire size decreased quite homogeneously from the peak observed in the 1960s and early 1970s. The number of fires and average fire size were significantly influenced by the value of the same variable one year before. Investigating long-term historical outlines of forest fires, a mixed approach based on time-series statistical analysis, multivariate techniques and regressive models intended to define changes in fire regimes and socioeconomic development. In fact, the comparative valuation of the socioeconomic aspects and wildfire trends can reveal a key step to recognizing mitigation and preventive possibilities. Through a multivariate analysis, a substantial difference in the socioeconomic profile can emerge by decade, evidencing a (more or less) rapid socioeconomic development in relation to the evolution of forest fires in Italy.

scholarly journals Modelling Holocene peatland dynamics with an individual-based dynamic vegetation model

2016 ◽  
Author(s):  
Nitin Chaudhary ◽  
Paul A. Miller ◽  
Benjamin Smith
Keyword(s):  
Vegetation Dynamics ◽  
Carbon Fluxes ◽  
Published Data ◽  
Vegetation Model ◽  
Climate Conditions ◽  
Dynamic Vegetation Model ◽  
Fertilization Effect ◽  
Vegetation Models ◽  
Global Vegetation

Abstract. Dynamic global vegetation models (DGVMs) are designed for the study of past, present and future vegetation patterns together with associated biogeochemical cycles and climate feedbacks. However, current DGVMs lack functionality for the representation of peatlands, an important store of carbon at high latitudes. We demonstrate a new implementation of peatland dynamics in a customised "Arctic" version of the dynamic vegetation model LPJ-GUESS, simulating the long-term evolution of selected northern peatland ecosystems and assessing the effect of changing climate on peatland carbon balance. Our approach employs a dynamic multi-layer soil with representation of freeze-thaw processes and litter inputs from a dynamically-varying mixture of the main peatland plant functional types; mosses, dwarf shrubs and graminoids. The model was calibrated and tested for a sub-arctic mire in Stordalen, Sweden, and validated at a temperate bog site in Mer Bleue, Canada. A regional evaluation of simulated carbon fluxes, hydrology and vegetation dynamics encompassed additional locations spread across Scandinavia. Simulated peat accumulation was found to be generally consistent with published data and the model was able to capture reported long-term vegetation dynamics, water table position and carbon fluxes. A series of sensitivity experiments were carried out to investigate the vulnerability of high latitude peatlands to climate change. We found that the Stordalen mire may be expected to sequester more carbon in the first half of the 21st century due to milder and wetter climate conditions, a longer growing season, and CO2 fertilization effect, turning into a carbon source after mid-century because of higher decomposition rates in response to warming soils.

scholarly journals Evidence that modern fires may be unprecedented during the last 3400 years in permafrost zone of central Siberia, Russia

2022 ◽  
Author(s):  
Elena Yu Novenko ◽  
Dmitry A. Kupryanov ◽  
Natalia G. Mazei ◽  
Anatoly Prokushkin ◽  
Leanne N. Phelps ◽  
...  
Keyword(s):  
Biomass Burning ◽  
Forest Fires ◽  
Fire History ◽  
Sediment Cores ◽  
Fire Regimes ◽  
Ice Age ◽  
Fire Dynamics ◽  
Central Siberia ◽  
Recent Climate

Abstract Recent climate change in Siberia is increasing the probability of dangerous forest fires. The development of effective measures to mitigate and prevent fires is impossible without an understanding of long-term fire dynamics. This paper presents the first multi-site palaeo-fire reconstruction based on macroscopic charcoal data from peat and lake sediment cores located in different landscapes across the permafrost area of Central Siberia. The obtained results show similar temporal patterns of charcoal accumulation rates in the cores under study, and near synchronous changes in fire regimes. The paleo-fire record revealed moderate biomass burning between 3.4 and 2.6 ka BP, followed by the period of lower burning occurring from 2.6 to 1.7 ka BP that coincided with regional climate cooling and moistening. Minimal fire activity was also observed during the Little Ice Age (0.7 – 0.25 ka BP). Fire frequencies increased during the interval from 1.7 to 0.7 ka BP and appears to be partly synchronous with climate warming during the Medieval Climate Anomaly. Regional reconstructions of long-term fire history show that recent fires are unprecedented during the late Holocene, with modern high biomass burning lying outside millennial and centennial variability of the last 3400 years.

scholarly journals Langzeit-Feuerökologie der Schweiz | Long-term fire ecology of Switzerland

2010 ◽  
Vol 161 (11) ◽  
pp. 424-432 ◽  
Author(s):  
Marco Conedera ◽  
Willy Tinner
Keyword(s):  
Forest Fire ◽  
Forest Fires ◽  
Tree Species ◽  
Fire Ecology ◽  
Abies Alba ◽  
Ecosystem Functions ◽  
The Alps ◽  
Swiss Plateau ◽  
Long Term Impact

Understanding past natural and anthropogenically induced forest fires and their long-term impact on the environment is a prerequisite for modern fire management. Thanks to modern paleoecological approaches it was possible to reconstruct the long-term role of fire for ecosystems, landscape properties and functions in various parts of Switzerland. In order to test and calibrate the paleoecological approach on a local scale, we compared the forest-fire statistics of the last 70 years around the small Lago di Origlio (southern Switzerland) with the yearly charcoal influx in the lake sediments. We demonstrated that the yearly deposition of microscopic charcoal particles (0.01−0.2 mm) correlates well with the regional forest-fire frequency 20 to 50 km around the lake, whereas macroscopic charcoal particles (> 0.2 mm) matched local fire events within a 2 km distance. Furthermore, the pilot study of lake Origlio provided insights into the different origins of forest fires and their long-term impact on vegetation. Studies in other areas in Switzerland suggest that that the long-term effects of forest fire are not limited to the southern slope of the Alps, but also concern the forests of the Swiss Plateau and the Alps. There, the diffusion of fire-sensitive tree species such as Ulmus spp., Tilia spp., Fraxinus spp., Acer spp. at the colline to mountain level, as well as Abies alba and Pinus cembra at the subalpine level was significantly reduced compared to the natural environmental conditions prior to the beginning of widespread slash and burn practices. The abundance reduction of tree species during the past millennia occurred in the southern and the northern Alps, on the Swiss Plateau, but not in the fire-prone dry valleys of the central Alps, where forest fires were more frequent naturally and exerted relevant ecosystem functions. Our results show that without considering sedimentary paleoenviromental information it is hardly possible to gain correct assessments of current and future fire, environmental and forest dynamics. The implementation of paleoecological results into practical management activities is thus indispensable, especially in the view of the expected climatic changes.

Données LiDAR aériennes: pertinence de l'interprétation visuelle pour la foresterie

2017 ◽  
Vol 168 (3) ◽  
pp. 127-133
Author(s):  
Matthew Parkan
Keyword(s):  
Cross Sections ◽  
Forest Edge ◽  
Airborne Lidar ◽  
Visual Interpretation ◽  
Individual Tree ◽  
Small Areas ◽  
Interactive 3D ◽  
The Individual ◽  
Airborne Lidar Data ◽  
Stem Position

Airborne LiDAR data: relevance of visual interpretation for forestry Airborne LiDAR surveys are particularly well adapted to map, study and manage large forest extents. Products derived from this technology are increasingly used by managers to establish a general diagnosis of the condition of forests. Less common is the use of these products to conduct detailed analyses on small areas; for example creating detailed reference maps like inventories or timber marking to support field operations. In this context, the use of direct visual interpretation is interesting, because it is much easier to implement than automatic algorithms and allows a quick and reliable identification of zonal (e.g. forest edge, deciduous/persistent ratio), structural (stratification) and point (e.g. tree/stem position and height) features. This article examines three important points which determine the relevance of visual interpretation: acquisition parameters, interactive representation and identification of forest characteristics. It is shown that the use of thematic color maps within interactive 3D point cloud and/or cross-sections makes it possible to establish (for all strata) detailed and accurate maps of a parcel at the individual tree scale.

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