Research Project Summary: Prescribed burning experiments in red and eastern white pine forests of eastern Ontario

Smith, Jane Kapler, compiler. 2008. Research Project Summary: Prescribed burning experiments in red and eastern white pine forests of eastern Ontario. In: Fire Effects Information System, [Online]. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory (Producer). Available: [].

Source: Unless otherwise indicated, the information in this Research Project Summary comes from the following paper:

Van Wagner, C. E. 1963. Prescribed burning experiments: red and white pine. Publ. No. 1020. Ottawa, Canada: Department of Forestry, Forest Research Branch. 27 p. [4].

Common names are used throughout this summary. For a complete list of the common and scientific names of species discussed in this summary and for links to FEIS species reviews, see the Appendix.

The study was conducted on the Petawawa Research Forest, Chalk River, Ontario, Canada.

Experimental sites were on nearly level terrain, in sand and gravel deposits along the Petawawa River. Twelve plots were studied, each about 0.25 acre, with 4 burn treatments in each of 3 blocks. Block I was an partially logged area. Blocks II and III were unlogged. Duff averaged 1 to 2 inches deep.

The study sites were dominated by red and eastern white pine up to 80 years old and up to 12 inches in diameter. Block I was an open area that had been logged 7 to 8 years before burning treatments, leaving red and eastern white pine up to 55 years old; this block contained "moderate" amounts of slash and beaked hazelnut. Block II was an uncut stand with little beaked hazelnut in the understory. Block III was an uncut stand with "abundant" beaked hazelnut. Where beaked hazelnut was not prevalent, the understory consisted of a mixture of forbs with tree saplings up to about 8 feet tall.

Since the experimental sites are located in Canada, they do not fall into vegetation community classifications used in the U.S. However, based on the vegetation description, they may be similar to the community described below and may have historically experienced a similar fire regime:

Fire regime information on vegetation communities similar to the forest studied in this Research Project . Fire regime characteristics are taken from the LANDFIRE Rapid Assessment Vegetation Model [3]. This vegetation model was developed by local experts using available literature, local data, and/or expert opinion as documented in the PDF file linked from the Potential Natural Vegetation Group listed below.
Vegetation Community (Potential Natural Vegetation Group) Fire severity* Fire regime characteristics
Percent of fires Mean interval
Red pine-white pine (frequent fire) Replacement 38% 56
Mixed 36% 60
Surface or low 26% 84
*Fire Severities:
Replacement=Any fire that causes greater than 75% top removal of a vegetation-fuel type, resulting in general replacement of existing vegetation; may or may not cause a lethal effect on the plants.
Surface or low=Any fire that causes less than 25% upper layer replacement and/or removal in a vegetation-fuel class but burns 5% or more of the area.
Mixed=Any fire burning more than 5% of an area that does not qualify as a replacement, surface, or low-severity fire; includes mosaic and other fires that are intermediate in effects [1,2].

Plant phenology was not described. Trees and shrubs were probably growing actively during the May and June burns (treatments 1 and 2 below), and growth had probably slowed by the time of the August burns (treatments 2 and 4).

Spring and early summer/Low
Late summer/Moderate
Late summer/High

The study was designed to determine fire effects in mixed red pine and eastern white pine stands, especially to learn if fire can be used to reduce beaked hazelnut.

Burns were initiated in afternoons when moisture content of the surface duff was low. Plots were burned with a mixture of head fire and backfire. Winds varied between 2 and 3 miles/hour. Treatments 1 and 2 had flames 1 to 2 feet long and burned through the litter but consumed little duff. Treatment 3 had flames 2 to 4 feet long and burned through the duff in many locations. Treatment 4, with flames 3 to 8 feet high, burned during very dry conditions and exposed an average of 56% mineral soil. Treatment 4 fires caused some spotting across the 6-foot wide firelines.

Dates, weather and fuel conditions, and fire behavior [4]
Burn treatment/severity Burn date(s) Relative humidity (%) Moisture (% oven dry weight) Rate of spread (ft/min) Fireline intensity (Btu/s/ft)
Litter Litter + duff Headfire Backfire
1/low 24-25 June 1959* 36 18 68 1.2 0.7 not calculated
2/low 31 May 1960 53 19 41 1.1 0.8 20-40
3/moderate 10-11 Aug. 1960 38 16 32 1.5 0.8 30-96
4/high** 19 Aug. 1960 30 10 14 4.7 1.2 216-370
*In the unlogged blocks (II and III), these plots were reburned with low-severity fire in 1960.
**Treatment 4 was not applied in Block III (unlogged, dense beaked hazelnut understory).

Block III, with its dense beaked hazelnut understory, had 6% higher litter moisture and 30% higher duff moisture than other blocks.

Fuels were measured before and after burning in one plot (burn treatment 3 in Block II, a moderate-severity burn: unlogged site with sparse beaked hazelnut). A total of 8.6 tons/acre was consumed:

Fuel weight and percent consumption on 1 study plot [4]

Fuel type Initial weight (lb/ft2) Weight consumed (lb/ft2) % of fuel type consumed
Shrubs 3-8 feet tall, total weight* 0.012 0.002 17
Foliage below 3 ft 0.028 0.025 88
Dead and downed wood 0.353 0.154 44
Litter 0.073 0.073 100
Duff 0.359 0.141 39
*88% of shrub stems were beaked hazelnut.

Crown scorch was recorded within 1 month of burning, and mortality was recorded in October 1961, 1 full growing season after all burns were completed. Because of limitations in the study design, no statistical analyses were performed.

Crown scorch in red and eastern white pine was negligible for all plots burned with low-severity fire (treatments 1 and 2), including twice-burned plots. Crown scorch and mortality were also negligible for moderate burns in Block III (unlogged with dense beaked hazelnut). Severe burns in the other two blocks (partially logged and unlogged with little beaked hazelnut) caused high levels of crown scorch:

Average crown scorch (%) on pines > 6 inches DBH [4]

Fire severity Moderate severity
(treatment 3)
(treatment 4)
Block I (previously logged) 42 72
Block II (unlogged, little beaked hazelnut) 0.1 38

Trees with high crown scorch showed high levels of mortality 1 year after treatments:

Red and eastern white pine crown damage and mortality after prescribed burns. Diameter of pines ranged from 2 to 12 inches [4]

Crown scorch (%) % dead 1 year after fires
95-100 100
80-94 76
40-79 24
5-39 15
0-4 0

Shrubs (88% beaked hazelnut) were top-killed by fire, but sprouting was observed within a few weeks after the burns. The number of sprouts exceeded the original number of stems on all burn treatments except in Block I, treatment 4 (previously logged, severe burn) and in the twice-burned plots (unlogged blocks, initially treated in June 1959). Although the double burns were of low severity, beaked hazelnut occurred after fire in only a few patches, which may have been left unburned by one or both fires.

In unburned areas, pine and white spruce seedlings 1 year after treatments numbered 0 to approximately 1,000/acre. Seedlings were more plentiful on burns, especially in plots where more mineral soil was exposed. Number per acre ranged from 600 to 17,000 in burned plots where mineral soil exposure was less than 30%, and from 11,000 to 26,000/acre where mineral soil exposure was greater (up to 56%).

Fire Management Objective: White and red pine mortality was high where crown scorch was greater than 75% to 80%. This occurred mainly moderate to severe burns in the previously logged block and in the unlogged block with sparse beaked hazelnut. Tree regeneration in postfire year 1 was positively related to fire severity and mineral soil exposure.

Plots burned by 2 low-severity fires in 2 consecutive years had very little beaked hazelnut the following year. A single severe fire also reduced beaked hazelnut density. The species sprouted prolifically after all other treatments.

Other Fire Management Implications: Prescribed fire can be used for tree regeneration in mixed eastern white and red pine stands even when conditions are "very dry". Fireline intensity must be controlled to minimize crown damage, possibly by using backfires. Head fires with flames less than 4 feet long did not scorch crowns above the 20-foot level, but the 2 fires with highest fireline intensity and flames up to 8 feet high scorched all foliage up to approximately 40 feet high.

Fire removed duff only where duff moisture was less than 40%.
This Research Project Summary contains fire effects and/or fire response information on the following species. For further information, follow the highlighted links to the FEIS reviews for those species.


Common name Scientific name
beaked hazelnut Corylus cornuta subsp. cornuta
white spruce Picea glauca
red pine Pinus resinosa
eastern white pine Pinus strobus


1. Hann, Wendel; Havlina, Doug; Shlisky, Ayn; [and others]. 2005. Interagency fire regime condition class guidebook. Version 1.2, [Online]. In: Interagency fire regime condition class website. U.S. Department of Agriculture, Forest Service; U.S. Department of the Interior; The Nature Conservancy; Systems for Environmental Management (Producer). Variously paginated [+ appendices]. Available: [2007, May 23]. [66734]
2. LANDFIRE Rapid Assessment. 2005. Reference condition modeling manual (Version 2.1), [Online]. In: LANDFIRE. Cooperative Agreement 04-CA-11132543-189. Boulder, CO: The Nature Conservancy; U.S. Department of Agriculture, Forest Service; U.S. Department of the Interior (Producers). 72 p. Available: [2007, May 24]. [66741]
3. LANDFIRE Rapid Assessment. 2007. Rapid assessment reference condition models. In: LANDFIRE. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Lab; U.S. Geological Survey; The Nature Conservancy (Producers). Available: [66533]
4. Van Wagner, C. E. 1963. Prescribed burning experiments: Red and white pine. Publ. No. 1020. Ottawa, Canada: Department of Forestry, Forest Research Branch. 27 p. [13642]

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