Analysis of the patterns of large fires in the boreal forest region of Alaska

2002 ◽  
Vol 11 (2) ◽  
pp. 131 ◽  
Author(s):  
Eric S. Kasischke ◽  
David Williams ◽  
Donald Barry
Keyword(s):  
Forest Cover ◽  
Growing Season ◽  
Fire Frequency ◽  
Lightning Strike ◽  
Data Sets ◽  
Fire Cycle ◽  
Area Burned ◽  
Forest Region ◽  
Large Fires ◽  
The 1960S

Analyses of the patterns of fire in Alaska were carried out using three different data sets, including a large-fire database dating back to 1950. Analyses of annual area burned statistics illustrate the episodic nature of fire in Alaska, with most of the area burning during a limited number of high fire years. Over the past 50 years, high fire years occurred once every 4 years. Seasonal fire statistics indicated that high fire years consist of larger fire events that occur later in the growing season. On a decadal basis, average annual area burned has varied little between the 1960s and 1990s. Using a geographic information system (GIS), the spatial distribution of fires (aggregated by ecoregions) was compared with topographic, vegetation cover, and climate features of Alaska. The use of topographic data allows for a more realistic determination of fire cycle by eliminating areas where fires do not occur due to lack of vegetation above the treeline. Geographic analyses show that growing season temperature, precipitation, lightning strike frequency, elevation, aspect, and the level of forest cover interact in a complex fashion to control fire frequency.

Comment—A re-examination of the effects of fire suppression in the boreal forest

2001 ◽  
Vol 31 (8) ◽  
pp. 1462-1466 ◽  
Author(s):  
K Miyanishi ◽  
E A Johnson
Keyword(s):  
Boreal Forest ◽  
Fire Management ◽  
Fire Suppression ◽  
Fire Frequency ◽  
Stand Age ◽  
Reliable Estimate ◽  
Fire Size ◽  
Fire Cycle ◽  
Large Fires ◽  
In Fire

A report by Ward and Tithecott (P.C. Ward and A.G. Tithecott. 1993. Ontario Ministry of Natural Resources, Aviation, Flood and Fire Management Branch, Publ. 305.) is frequently cited in the literature as providing evidence of the effects of fire suppression on the boreal forest. The study is based on 15 years of fire data and stand age data from Ontario, Canada. A re-examination of this report reveals serious flaws that invalidate the conclusions regarding effects of fire suppression on fire size and fire frequency. The fire-size data from the unprotected zone are censored in the small size classes because of detection resolution, invalidating comparisons of shapes of the distributions between the protected and unprotected zones. Use of different plotting scales gives the false appearance of large differences in the number of large fires between the two zones. Stand age data are used to show a change in fire frequency in the 20th century, and this change is attributed to fire suppression. However, no evidence is presented to conclude that this change in fire frequency is attributable to fire suppression and not to climate change. The estimate of the current fire cycle is based on too short a record to give a reliable estimate given the variation in annual area burned. Therefore, this report does not present sound evidence of fire suppression effects and should not be cited as such.

Wildfires in the southern Canadian Rocky Mountains and their relationship to mid-tropospheric anomalies

1993 ◽  
Vol 23 (6) ◽  
pp. 1213-1222 ◽  
Author(s):  
E.A. Johnson ◽  
D.R. Wowchuk
Keyword(s):  
North America ◽  
Rocky Mountains ◽  
Large Scale ◽  
Fire Frequency ◽  
Fuel Moisture ◽  
Large Fire ◽  
Canadian Rocky Mountains ◽  
Area Burned ◽  
Upper Level ◽  
Moisture Conditions

In this paper we present evidence for a large-scale (synoptic-scale) meteorological mechanism controlling the fire frequency in the southern Canadian Rocky Mountains. This large-scale control may explain the similarity in average fire frequencies and timing of change in average fire frequencies for the southern Canadian Rocky Mountains. Over the last 86 years the size distribution of fires (annual area burned) in the southern Canadian Rockies was distinctly bimodal, with a separation between small- and large-fire years at approximately 10–25 ha annual area burned. During the last 35 years, large-fire years had significantly lower fuel moisture conditions and many mid-tropospheric surface-blocking events (high-pressure upper level ridges) during July and August (the period of greatest fire activity). Small-fire years in this period exhibited significantly higher fuel moisture conditions and fewer persistent mid-tropospheric surface-blocking events during July and August. Mid-tropospheric surface-blocking events during large-fire years were teleconnected (spatially and temporally correlated in 50 kPa heights) to upper level troughs in the North Pacific and eastern North America. This relationship takes the form of the positive mode of the Pacific North America pattern.

Developing an Empirical Yield-Prediction Model Based on Wheat and Wild Oat (Avena fatua) Density, Nitrogen and Herbicide Rate, and Growing-Season Precipitation

Weed Science ◽  
2007 ◽  
Vol 55 (6) ◽  
pp. 652-664 ◽  
Author(s):  
N. C. Wagner ◽  
B. D. Maxwell ◽  
M. L. Taper ◽  
L. J. Rew
Keyword(s):  
Field Data ◽  
Wheat Yield ◽  
Growing Season ◽  
Predictor Variables ◽  
Data Sets ◽  
Wild Oat ◽  
Best Fitting ◽  
Weed Infestation ◽  
Growing Season Precipitation ◽  
Better Than

To develop a more complete understanding of the ecological factors that regulate crop productivity, we tested the relative predictive power of yield models driven by five predictor variables: wheat and wild oat density, nitrogen and herbicide rate, and growing-season precipitation. Existing data sets were collected and used in a meta-analysis of the ability of at least two predictor variables to explain variations in wheat yield. Yield responses were asymptotic with increasing crop and weed density; however, asymptotic trends were lacking as herbicide and fertilizer levels were increased. Based on the independent field data, the three best-fitting models (in order) from the candidate set of models were a multiple regression equation that included all five predictor variables (R2= 0.71), a double-hyperbolic equation including three input predictor variables (R2= 0.63), and a nonlinear model including all five predictor variables (R2= 0.56). The double-hyperbolic, three-predictor model, which did not include herbicide and fertilizer influence on yield, performed slightly better than the five-variable nonlinear model including these predictors, illustrating the large amount of variation in wheat yield and the lack of concrete knowledge upon which farmers base their fertilizer and herbicide management decisions, especially when weed infestation causes competition for limited nitrogen and water. It was difficult to elucidate the ecological first principles in the noisy field data and to build effective models based on disjointed data sets, where none of the studies measured all five variables. To address this disparity, we conducted a five-variable full-factorial greenhouse experiment. Based on our five-variable greenhouse experiment, the best-fitting model was a new nonlinear equation including all five predictor variables and was shown to fit the greenhouse data better than four previously developed agronomic models with anR2of 0.66. Development of this mathematical model, through model selection and parameterization with field and greenhouse data, represents the initial step in building a decision support system for site-specific and variable-rate management of herbicide, fertilizer, and crop seeding rate that considers varying levels of available water and weed infestation.

scholarly journals Lasy wybranych dużych obszarów leśnych = The forests in selected examples of Poland’s Large Forest Areas

2021 ◽  
Vol 93 (3) ◽  
pp. 463-483
Author(s):  
Roman Zielony
Keyword(s):  
Forest Management ◽  
Spatial Planning ◽  
Forest Cover ◽  
De Novo ◽  
Proper Noun ◽  
Nature Protection ◽  
Key Issues ◽  
1960S And 1970S ◽  
The 1960S

Key issues for spatial planning and development, nature protection and forestry in Poland relate to the problems encountered in determining the area of forests included within – and the boundaries of – what are known as the Large Forest Areas (LFAs) in Poland. Even as overall forest cover in the country has increased steadily – by about 2.5 million ha overall – since 1945, the data available for the LFAs relate to measurements made as long ago as in the 1960s and 1970s. Even then, it is often unclear whether it is total areas or areas of forest that are being referred to in relation to the LFAs. There is thus an urgent need for meas-urements to be updated, with a view to the present-day boundaries of the Areas being delim-ited. Some 80‑100 LFAs are in fact distinguished in Poland, in line with definitions relating to total area exceeding 10,000 ha (100 km2) and forest cover exceeding 35%. While many of the LFAs received Proper-Noun names at one point or another in their histories, as used locally in a given region, and in guides and publications, there are also less culturall-defined areas that still await naming. Efforts to determine the boundaries of the LFAs at this point allow, not only for renewed or de novo determination of their overall areas and areas of forest, but also for an advancement of our knowledge regarding any items of cultural heritage that may be present within LFAs. Such data will be useful or essential as new physiographic, economic and tourist guide-studies are developed; and they will encourage and facilitate the more-detailed analysis and assess-ment of forest management taking place within the limits of the LFAs. In line with the effort made to achieve the above goals, this article details selected problems encountered with the delimitation of forest boundaries and areas, as these are exemplified by the Polish LFAs of the Białowieża, Bolimów, Borki, Knyszyn, Kampinos, Noteć, Romincka, Tuchola, Łuków and Chojnów Forests. Figures for overall area and area of forest were indeed obtained and are presented here for the selected examples of LFAs, which are also augmented by the so-called Dobrzejewice and Lubniewice Forests not distinguished in this way before now.

scholarly journals THE STATE OF THE TIMBER INDUSTRY COMPLEX OF THE RUSSIAN FEDERATION IN A SPARSELY FORESTED REGION ON THE EXAMPLE OF THE VORONEZH REGION

2021 ◽  
Vol 9 (1) ◽  
pp. 62-72
Author(s):  
Irina Marchuk
Keyword(s):  
Russian Federation ◽  
Forest Cover ◽  
Paper Industry ◽  
Far East ◽  
The State ◽  
Timber Industry ◽  
Forest Region ◽  
Logging Industry ◽  
Voronezh Region ◽  
The Russian Federation

The timber industry complex of the Russian Federation ranks fourth among all branches of the country, because in terms of forest area Russia ranks first in the world (8148895 km2), which is about 49.76% of the total area of Russia. The timber industry complex is a complex system and consists of four components (logging industry, woodworking industry, pulp and paper industry, wood chemical industry). Particular attention is paid to this industry in Eastern Siberia, Western Siberia and the Far East, because these regions have the greatest forest cover. In sparsely wooded regions, the timber industry is not a priority and little attention is paid to it, both by the state and by investors. In this article, we examined the state of the forestry complex of the Voronezh region, the forest cover of this territory is only eight percent of the entire territory of the country, all forests are protective, therefore the volume of timber is carried out thanks to sanitary felling and is about 285 thousand m3. In this region there are about 20 large and medium-sized enterprises involved in the timber industry and about 40 small private enterprises. The main problem of the timber industry complex in a low-wooded region is low-quality products, imperfection of regulatory legal acts at the regional level, and lack of investment. In this regard, measures were proposed that will contribute to the development of the timber industry complex in the low-forest region.

scholarly journals Over 16,000 Years of Fire Frequency Determined from AMS Radiocarbon Dating of Soil Charcoal in an Alluvial Fan at Bear Flat, Northeastern British Columbia

Radiocarbon ◽  
2006 ◽  
Vol 48 (3) ◽  
pp. 435-450 ◽  
Author(s):  
A J Timothy Jull ◽  
Marten Geertsema
Keyword(s):  
British Columbia ◽  
Radiocarbon Dating ◽  
Large Scale ◽  
Fire Frequency ◽  
Alluvial Fan ◽  
Before Present ◽  
Ams Radiocarbon Dating ◽  
Soil Charcoal ◽  
Large Fires ◽  
Millennial Time Scale

We present results of radiocarbon dating of charcoal from paleosols and buried charcoal horizons in a unique sequence, which potentially records the last 36,000 yr, from a fan at Bear Flat, British Columbia (BC) (56°16'51’N, 121°13'39”W). Evidence for forest-fire charcoal is found over the last 13,500 ± 110 14C yr before present (BP) or 16,250 ± 700 cal BP. The study area is located east of the Rocky Mountains in an area that was ice-free at least 13,970 ± 170 14C yr BP (17,450–16,150 cal BP) ago. The latest evidence of fire is during the Medieval Warm Period (MWP). The charcoal ages show a periodicity in large fires on a millennial scale through the Holocene—an average of 4 fires per thousand years. Higher fire frequencies are observed between 2200 to 2800 cal BP, ∼5500 and ∼6000 cal BP, ∼7500 to 8200 cal BP, and 9000 to 10,000 cal BP. These intervals also appear to be times of above-average aggradation of the fan. We conclude that fire frequency is related to large-scale climatic events on a millennial time scale.

scholarly journals Recent dynamic changes on Fleming Glacier after the disintegration of Wordie Ice Shelf, Antarctic Peninsula

2018 ◽  
Vol 12 (4) ◽  
pp. 1347-1365 ◽  
Author(s):  
Peter Friedl ◽  
Thorsten C. Seehaus ◽  
Anja Wendt ◽  
Matthias H. Braun ◽  
Kathrin Höppner
Keyword(s):  
Antarctic Peninsula ◽  
Remote Sensing Data ◽  
Data Sets ◽  
Ice Shelf ◽  
Glacier Tongue ◽  
Marguerite Bay ◽  
Grounding Line ◽  
Continuous Dynamic ◽  
The 1960S ◽  
The Antarctic

Abstract. The Antarctic Peninsula is one of the world's regions most affected by climate change. Several ice shelves have retreated, thinned or completely disintegrated during recent decades, leading to acceleration and increased calving of their tributary glaciers. Wordie Ice Shelf, located in Marguerite Bay at the south-western side of the Antarctic Peninsula, completely disintegrated in a series of events between the 1960s and the late 1990s. We investigate the long-term dynamics (1994–2016) of Fleming Glacier after the disintegration of Wordie Ice Shelf by analysing various multi-sensor remote sensing data sets. We present a dense time series of synthetic aperture radar (SAR) surface velocities that reveals a rapid acceleration of Fleming Glacier in 2008 and a phase of further gradual acceleration and upstream propagation of high velocities in 2010–2011.The timing in acceleration correlates with strong upwelling events of warm circumpolar deep water (CDW) into Wordie Bay, most likely leading to increased submarine melt. This, together with continuous dynamic thinning and a deep subglacial trough with a retrograde bed slope close to the terminus probably, has induced unpinning of the glacier tongue in 2008 and gradual grounding line retreat between 2010 and 2011. Our data suggest that the glacier's grounding line had retreated by ∼ 6–9 km between 1996 and 2011, which caused ∼ 56 km2 of the glacier tongue to go afloat. The resulting reduction in buttressing explains a median speedup of ∼ 1.3 m d−1 (∼ 27 %) between 2008 and 2011, which we observed along a centre line extending between the grounding line in 1996 and ∼ 16 km upstream. Current median ice thinning rates (2011–2014) along profiles in areas below 1000 m altitude range between ∼ 2.6 to 3.2 m a−1 and are ∼ 70 % higher than between 2004 and 2008. Our study shows that Fleming Glacier is far away from approaching a new equilibrium and that the glacier dynamics are not primarily controlled by the loss of the former ice shelf anymore. Currently, the tongue of Fleming Glacier is grounded in a zone of bedrock elevation between ∼ −400 and −500 m. However, about 3–4 km upstream modelled bedrock topography indicates a retrograde bed which transitions into a deep trough of up to ∼ −1100 m at ∼ 10 km upstream. Hence, this endangers upstream ice masses, which can significantly increase the contribution of Fleming Glacier to sea level rise in the future.

Causes and history of forest loss in Cambodia

2019 ◽  
Vol 21 (3) ◽  
pp. 372-384 ◽  
Author(s):  
R. TSUJINO ◽  
T. KAJISA ◽  
T. YUMOTO
Keyword(s):  
Forest Cover ◽  
Arable Land ◽  
Growth Period ◽  
Rapid Expansion ◽  
Small Scale ◽  
Forest Loss ◽  
Rapid Economic Growth ◽  
History Of ◽  
Post War ◽  
The 1960S

To reconstruct the history of forest loss in Cambodia, the literature and national/provincial statistics of landuse patterns and the socio-economic situation were investigated. Forest cover in the 1960s was 73.3 % (13.3 Mha). However, this drastically decreased to 47.3% (8.6 Mha) in 2016. In the 1960s, the forest was less-disturbed. From 1970 to 1993, the forest was lost gradually owing to the political instability caused by the Cambodian Civil War. In the post-war reconstruction period from 1993 to around 2002, the need for reconstruction, international demand for timber, and forest logging concessions led to a significant increase in timber production. In the rapid economic growth period from 2002 until present, while several political actions were taken to combat rapid deforestation, economic land concessions, which promoted agroindustrial plantations, as well as small-scale agriculture has been leading to the rapid expansion of arable land and deforestation since 2009.

scholarly journals Getting ready for REDD+ in Tanzania: a case study of progress and challenges

Oryx ◽  
2010 ◽  
Vol 44 (3) ◽  
pp. 339-351 ◽  
Author(s):  
Neil D. Burgess ◽  
Bruno Bahane ◽  
Tim Clairs ◽  
Finn Danielsen ◽  
Søren Dalsgaard ◽  
...  
Keyword(s):  
Forest Management ◽  
Rural Communities ◽  
Forest Cover ◽  
National Forest Inventory ◽  
Data Sets ◽  
Managed Forests ◽  
Participatory Forest Management ◽  
Forest Policies ◽  
Donor Support ◽  
Management Approaches

AbstractThe proposed mechanism for Reducing Emissions from Deforestation and Degradation (REDD+) offers significant potential for conserving forests to reduce negative impacts of climate change. Tanzania is one of nine pilot countries for the United Nations REDD Programme, receives significant funding from the Norwegian, Finnish and German governments and is a participant in the World Bank’s Forest Carbon Partnership Facility. In combination, these interventions aim to mitigate greenhouse gas emissions, provide an income to rural communities and conserve biodiversity. The establishment of the UN-REDD Programme in Tanzania illustrates real-world challenges in a developing country. These include currently inadequate baseline forestry data sets (needed to calculate reference emission levels), inadequate government capacity and insufficient experience of implementing REDD+-type measures at operational levels. Additionally, for REDD+ to succeed, current users of forest resources must adopt new practices, including the equitable sharing of benefits that accrue from REDD+ implementation. These challenges are being addressed by combined donor support to implement a national forest inventory, remote sensing of forest cover, enhanced capacity for measuring, reporting and verification, and pilot projects to test REDD+ implementation linked to the existing Participatory Forest Management Programme. Our conclusion is that even in a country with considerable donor support, progressive forest policies, laws and regulations, an extensive network of managed forests and increasingly developed locally-based forest management approaches, implementing REDD+ presents many challenges. These are being met by coordinated, genuine partnerships between government, non-government and community-based agencies.

Sign in / Sign up

Export Citation Format

Share Document