Canadian Forest Service Publications
Jack pine regeneration at the International Crown Fire Modelling Experiment. 2004. de Groot, W.J.; Alexander, M.E.; Wotton, B.M.; Bothwell, P.M.; Stefner, C.N.; Carlsson, D.H. Pages 203-209 in R.T. Engstrom, K.E.M. Galley, and W.J. de Groot, editors. Proceedings of the 22nd Tall Timbers Fire Ecology Conference: Fire in Temperate, Boreal and Montane Ecosystems, October 15-18, 2001, Kananaskis, Alberta. Tall Timbers Research Station, Tallahassee, Florida, USA.
Issued by: Northern Forestry Centre
Catalog ID: 25112
Factors affecting tree regeneration in the boreal forest after fire are poorly understood. We studied post-fire recruitment and early growth of jack pine (Pinus banksiana) seedlings in a prescribed burn experiment. We burned nine plots (0.56–2.25 ha) of mature jack pine trees near Fort Providence, Northwest Territories, Canada, by crown fires during 1997–2000 and collected depth of burn, post-fire duff depth, seed rain, post-fire precipitation, and temperature data to determine effects on seedling recruitment and early growth. Viable seed rain varied from 26.4 to 431.3 seeds/m2 and was highly variable even between adjacent plots burned within days of each other. Viable seed rain had a highly significant effect on the initial establishment of jack pine seedlings which ranged from 6.9 to 79.1 seedlings/m2 in the first year after burning. Depth of burn on eight plots ranged from 2.0 cm to 2.6 cm, and one plot had a significantly greater depth of burn of 3.6 cm. Depth of burn had no significant influence on seedling establishment or growth. Post-fire duff depth ranged from 2.0 cm to 5.5 cm, but the effect of this factor on seedling establishment was not statistically significant. We detected no significant effects by any of the tested factors on regeneration numbers after the second post-fire year, and the only reliable estimator of regeneration numbers after the second postfire year was the previous years’ regeneration number. Considerable variation occurred in seedling height growth rates. Mean height of third-year seedlings ranged from 5.6 cm to 22.8 cm. Data analysis indicated that pre-fire tree basal area had strong influence on seedling growth rate and this was presumed to be an indication of site quality differences between plots. Seedling numbers and height growth data continue to be collected in this ongoing study. Analysis of seed crop and fire behavior is in progress to determine their impact on viable seed rain.