Prescribed burning experiments in red and eastern white pine forests of eastern Ontario
Smith, Jane Kapler, comp. 2008. 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: https://research.fs.usda.gov/feis/fire-studies/van-wagner-2008
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. [1].
Species Included in the Summary
Common names are used throughout this summary. For a complete list of the common and scientific names of species discussed in this summary see table A1.
Study Location
The study was conducted on the Petawawa Research Forest, Chalk River, Ontario, Canada.
Site Description
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 a partially logged area. Blocks II and III were unlogged. Duff averaged 1 to 2 inches deep.
Plant Community
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.
Plant Phenology
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 3 and 4).
Fire Description
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.
| 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 | Head fire | 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 type | Initial weight (lb/ft2) | Weight consumed (lb/ft2) | Percent 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. | |||
Fire Season/Severity Classification
- Spring and early summer/Low
- Late summer/Moderate
- Late summer/High
Fire Effects on Plant Community
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:
| Fire severity | Moderate severity (treatment 3) | Severe (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:
| Crown scorch (%) | Percent 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%.
| Biophysical Setting | Mean Fire Interval (years) | Fire Severity Percent (%) | ||||||
|---|---|---|---|---|---|---|---|---|
| Code | Fire Regime Group | Low | Mixed | Replacement | All | Low | Mixed | Replacement |
| Series 13620 - Laurentian-Acadian Northern Pine(-Oak) Forest | ||||||||
| 13620_51_63_64_65_66 | III-A | 65 | 447 | 309 | 48 | 73 | 11 | 16 |
| Summary | ||||||||
| Minimum | 65 | 447 | 309 | 48 | 73 | 11 | 16 | |
| Maximum | 65 | 447 | 309 | 48 | 73 | 11 | 16 | |
| Mean | 65 | 447 | 309 | 48 | 73 | 11 | 16 | |
| Median | 65 | 447 | 309 | 48 | 73 | 11 | 16 | |
| Percentage of fires in 3 fire severity classes, derived from LANDFIRE succession modeling. Replacement-severity fires cause >75% kill or top-kill of the upper canopy layer; mixed-severity fires cause 26%-75%; low-severity fires cause <26%. | ||||||||
| LANDFIRE. 2020. Biophysical settings models and descriptions, [Online]. Washington, DC: U.S. Department of Agriculture, Forest Service; U.S. Department of the Interior; U.S. Geological Survey; Arlington, VA: The Nature Conservancy, (Producers). Available: https://www.landfirereview.org/search.php [96496] | ||||||||
| Common name | Scientific name |
|---|---|
| beaked hazelnut | Corylus cornuta subsp. cornuta |
| white spruce | Picea glauca |
| red pine | Pinus resinosa |
| eastern white pine | Pinus strobus |
1. 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]