Developing millennial tree ring chronologies in the fire-prone North American boreal forest

2013 ◽  
Vol 28 (3) ◽  
pp. 283-292 ◽  
Author(s):  
DOMINIQUE ARSENEAULT ◽  
BENJAMIN DY ◽  
FABIO GENNARETTI ◽  
JULIA AUTIN ◽  
YVES BÉGIN
Keyword(s):  
Boreal Forest ◽  
Tree Ring ◽  
North American

scholarly journals Effects of lightning and other meteorological factors on fire activity in the North American boreal forest: implications for fire weather forecasting

2010 ◽  
Vol 10 (14) ◽  
pp. 6873-6888 ◽  
Author(s):  
D. Peterson ◽  
J. Wang ◽  
C. Ichoku ◽  
L. A. Remer
Keyword(s):  
Boreal Forest ◽  
North American ◽  
Meteorological Factors ◽  
Convective Available Potential Energy ◽  
Fire Weather ◽  
Lightning Strikes ◽  
The North ◽  
Lightning Detection ◽  
Western Boreal Forest ◽  
Consecutive Dry Days

Abstract. The effects of lightning and other meteorological factors on wildfire activity in the North American boreal forest are statistically analyzed during the fire seasons of 2000–2006 through an integration of the following data sets: the MODerate Resolution Imaging Spectroradiometer (MODIS) level 2 fire products, the 3-hourly 32-km gridded meteorological data from North American Regional Reanalysis (NARR), and the lightning data collected by the Canadian Lightning Detection Network (CLDN) and the Alaska Lightning Detection Network (ALDN). Positive anomalies of the 500 hPa geopotential height field, convective available potential energy (CAPE), number of cloud-to-ground lightning strikes, and the number of consecutive dry days are found to be statistically important to the seasonal variation of MODIS fire counts in a large portion of Canada and the entirety of Alaska. Analysis of fire occurrence patterns in the eastern and western boreal forest regions shows that dry (in the absence of precipitation) lightning strikes account for only 20% of the total lightning strikes, but are associated with (and likely cause) 40% of the MODIS observed fire counts in these regions. The chance for ignition increases when a threshold of at least 10 dry strikes per NARR grid box and at least 10 consecutive dry days is reached. Due to the orientation of the large-scale pattern, complex differences in fire and lightning occurrence and variability were also found between the eastern and western sub-regions. Locations with a high percentage of dry strikes commonly experience an increased number of fire counts, but the mean number of fire counts per dry strike is more than 50% higher in western boreal forest sub-region, suggesting a geographic and possible topographic influence. While wet lightning events are found to occur with a large range of CAPE values, a high probability for dry lightning occurs only when 500 hPa geopotential heights are above ~5700 m and CAPE values are near the maximum observed level, underscoring the importance of low-level instability to boreal fire weather forecasts.

Responses of boreal conifers to climate fluctuations: indications from tree-ring widths and carbon isotope analyses

1998 ◽  
Vol 28 (4) ◽  
pp. 524-533 ◽  
Author(s):  
J Renée Brooks ◽  
Lawrence B Flanagan ◽  
James R Ehleringer
Keyword(s):  
Climate Change ◽  
Boreal Forest ◽  
Carbon Isotope ◽  
Tree Ring ◽  
Picea Mariana ◽  
Pinus Banksiana ◽  
Annual Growth ◽  
Climate Change Scenarios ◽  
Southern Boundary ◽  
The North

Spatial distribution and species composition of the boreal forest are expected to change under predicted climate change scenarios. Current research indicates that water limitations control the southern boundary of the central Canadian boreal forest and temperature limitations control the northern boundary. As part of Boreal Ecosystem - Atmosphere Study (BOREAS), we examined this idea by comparing annual variation in tree-ring widths and carbon isotope ratios ( delta 13C) of tree-ring cellulose with annual climatic parameters in the northern and southern boreal forest. Contrary to expectations, climate correlations with ring widths at the northern and southern sites were similar in black spruce (Picea mariana (Mill.) BSP). Annual growth was favored by cooler and wetter conditions. For jack pine (Pinus banksiana Lamb.), increased temperature and spring precipitation favored annual growth at both sites. In the north, annual growth was negatively correlated with winter precipitation. The delta 13C - climate correlations in Pinus banksiana followed current distribution theories. In the south, potential evapotranspiration explained significant annual delta 13C variation, whereas in the north, winter and growing season precipitation influenced annual delta 13C variations. Our data support the concept that moisture limits the southern range of Pinus banksiana and cold soil temperatures limit the northern extent. However, colder, wetter conditions favored growth of Picea mariana throughout its range. These observations strengthen the concept that species respond individually to climate change, not as a cohesive biome.

Blood parasites of geese of the McConnell River, N.W.T.

1972 ◽  
Vol 50 (1) ◽  
pp. 1-4 ◽  
Author(s):  
Gordon F. Bennett ◽  
Charles D. MacInnes
Keyword(s):  
Boreal Forest ◽  
North American ◽  
Plasmodium Species ◽  
Blood Parasites ◽  
Canada Geese ◽  
Young Of The Year ◽  
Low Incidence ◽  
Goose Species

Of 736 blue, snow, and Canada geese from the McConnell River, N.W.T. which were examined for blood parasites only 21 birds (2.9%) were found to be infected. Of these, 15 infections were with Leucocytozoon simondi (2.0%) and 2 each with Parahaemoproteus nettionis, Plasmodium species, and microfilaria. Both adults and young of the year were infected. We suggest that the low incidence is an indirect result of adaptations of the simuliid vectors to tundra conditions. It is possible that increased incidence of L. simondi in the boreal forest is a factor contributing to the restriction of five of the six North American goose species to the tundra nesting habit.

Tree-Ring Width Chronologies from the North American Arctic

1981 ◽  
Vol 13 (3) ◽  
pp. 245 ◽  
Author(s):  
John P. Cropper ◽  
Harold C. Fritts
Keyword(s):  
Tree Ring ◽  
North American ◽  
Ring Width ◽  
Tree Ring Width ◽  
The North ◽  
North American Arctic
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