A synopsis of fire research in the boreal mixedwood forest.

S. G. Cumming, Ph. D.
Boreal Ecosystems Research Ltd.
6915 106 St.
Edmonton, Alberta.

April 16, 2000

Technical Report BERL-2000-02

Contents

1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

2 Fire return intervals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2
2.1 Definitions and models . . . . . . . . . . . . . . . . . . . . . . . . . . .2
    2.1.1 An alternate fire model . . . . . . . . . . . . . . . . . . . . . . . 4
2.2 Existing rate estimates . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

3 Changes in fire return interval . . . . . . . . . . . . . . . . . . . . . 9
3.1 Fire history evidence . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
3.2 Age-structural evidence . . . . . . . . . . . . . . . . . . . . . . . . . 10
3.3 Paleoecological evidence . . . . . . . . . . . . . . . . . . . . . . . .12

4 Forest composition and fire return intervals . . . . . . . . . 13
4.1 Ignition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
4.2 Fire spread . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

5 Fire intensity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .18
5.1 Residual islands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
    5.1.1 Why islands? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
5.2 Patterns of forest biomass loss from fire . . . . . . . . . . . . .22
5.3 Work in progress . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .24

6 Fire in riparian areas . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
6.1 Large lakes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
6.2 Big river valleys . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .28
6.3 Small lakes and streams . . . . . . . . . . . . . . . . . . . . . . . . . 29

7 Fire size distribution . . . . . . . . . . . . . . . . . . . . . . . . . . . . .30
7.1 Describing the distribution . . . . . . . . . . . . . . . . . . . . . . . 32
7.2 Has it changed? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .34

8 Fire in the future . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
8.1 Climatic change . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
    8.1.1 Ignitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .37
    8.1.2 More severe fire weather . . . . . . . . . . . . . . . . . . . . 38
    8.1.3 Extended fire season . . . . . . . . . . . . . . . . . . . . . . . . 39
    8.1.4 Consequences of an increased burn rate . . . . . . . . . 40
8.2 Forest management and other human activities . . . . . . .  40
    8.2.1 Passive fuels management . . . . . . . . . . . . . . . . . . . . 40
    8.2.2 Active fuels management or “cooling” the forest . . .41
    8.2.3 Human access . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41

References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50

The full report in pdf format can be downloaded at: http://www.berl.ab.ca/fire.pdf  Because of the large size of the file (5.1 MB) it is best to copy the file to your hard drive for viewing.  [With Internet Explorer: right-click the above link with your mouse and select the "Save Target As" option].  Please report any problems in downloading this file to Steve Cumming at: stevec@berl.ab.ca