The keys to successful natural regeneration of serotinous pine . Victor Lieffers Dept. of Renewable Resources
Soung-Ryoul Ryu, Hyejin Hwang, Maria Sharpe and Dave Schroeder
Lodgepole pine is adapted to regenerate after wildfire
Serotinous cones Fire breaks the resin bonds
Thick litter or feather mosses are poor seedbeds It is also quite dark for a shade intolerant tree
Fire removes organic matter thereby creating a seedbed
Drag scarification â€“ exposes mineral soil or decomposed OM, positions cones near the ground
Cones landing on prepared seedbed
Seed banks post
Methods - Research sites
Research objectives â€˘ determine if canopy seed release after MPB. If so, the mechanisms responsible for seed release. â€˘ The second objective was to model the temporal changes in the canopy and forest floor seed banks after a MPB outbreak.
After MPB cones are left on the tree.
Feather mosses and litter is retained.
Methods - Cone openness
Results â€“ Canopy cone opening (Partial loss of serotiny)
Flexible Stems and Brittle Twigs
Results â€“ Forest floor-cone opening
Released cones via breakage, open and release seed due to soil-surface heating.
Results â€“ Cone release
Cones are released onto the forest floor due to crown friction resulting in twig breakage.
Results – Forest floor cone opening
Seed predation Ground foraging rodents (forest floor seed) Deer mouse (Peromyscus maniculaturs)
Pine squirrel (Tamiasciurus hudsonicus)
Squirrels (Canopy and forest floor cones)
Methods - Buried cones Embedded in moss
Results â€“ Cone burial
Seed banks post
After 6 years post MPB-outbreak, 45% of the canopy seed remains while 6% are still in cones buried in the forest floor.
Conclusions • Nearly half of the canopy seed is on the ground by 6 years after MPB outbreak. • Cones open on the dead trees faster than living trees.
• Branch breakage, increased cone opening, and squirrel predation. • A small forest floor-seed bank develops due to cone burial of closed cones.
Archer Lake, AB
100 60 40 20 0
Cone opening (%)
4 Char height (m)
What happens to the cones/seed
Cone opening • Dead trees had higher moisture content after a rainy period. • Cones high moisture content from dead trees opened earlier than cones from living trees. • Data suggests more resin breakdown on dead trees.
Seedling Density (seedling/hectare)
Intermittent FBP Fire Type
Conclusions • Fire promoted seedlings success. • Ground fires in girdled stands tended to open more cones, than fires in living stands. • In the red phase, duff moisture content was higher compared to living stands. • Fire in in the red phase, tend to consume less duff but this thicker duff appears to support seedlings.
Summary • Seed will rain down for a decade or more. • Forest floor disturbance is needed for pine seedlings to establish. • Fire or mechanical site preparation might prepare seedbeds.
Fire is unlikely to be applied in most years â€“ Goldilocks effect.
What will happen if we do nothing? â€˘ Hawkins FEM 277: 107-115.
Beyond Beetle • Assess thinning, mechanical site preparation, planting and natural regeneration • Assess recovery of residual trees and diseases • Assess fuel loadings and fire risk
After MPB some pine remain alive
Beyond Beetle â€˘ Examine how specific ecosites recover. â€˘ Assess fuel loadings.
Black spruce understory
Thank You â€˘ Forrest Barrett, Kevin Quintilio, and Keith McLain
Government of Alberta Environment & Sustainable Resource Development