چکیده (انگلیسی):

Pile burning is a common means of disposing the woody residues of logging and for post-harvest site
Preparation operations, in spite of the practice’s potential negative effects. To examine the long-term
implications of this practice we established a 50-year sequence of pile burns within recovering clear
Cuts in lodgepole pine forests. We compared tree, shrub and herbaceous plant abundance and
documented indicators of soil degradation in openings where logging residue was piled and burned
As part of post-harvest site preparation and the adjacent forests regenerating after clear cutting. We
found that pile burning creates persistent 10–15 m diameter openings with lower tree densities
(<500 trees ha_1; stems >2.54 cm diameter at 1.4 m height) compared to surrounding regenerating pine
Stands (2000–5000 trees ha_1). Low tree seedling and sapling densities (stems <2.54 cm diameter at
1.4 m height) in the openings (10–20% of regenerating forest), suggest they will remain poorly-stocked
Into the future. We observed evidence of high severity burning, including layers of soil charcoal and
hardened red soil across the time series, but no sign that water infiltration, compaction or other indicators
Of soil degradation were consistent barriers to plant recolonization. Forb and graminoid cover,
For example, was higher in the burn scar openings compared to regenerating forests. Pile burn openings
are formed by the loss of pine seed during burning and short-term soil changes, but it is uncertain what
Factors maintain the openings during subsequent decades. As conducted for site preparation, the herbaceous plant-dominated openings are not extensive (<5% cover within clear cut units), and we found
few invasive, non-native plants and no indication that soil conditions were sufficiently altered to
Explain 50 years of poor tree regeneration. Nevertheless, persistence of the openings and recent
increases in the number and size of piles from fuels and bark beetle salvage treatments has prompted
Resource managers to consider options for utilization and on-site retention of harvest residue.