Successful restoration planting of limber pine is essential to sustain healthy populations in the wake of native insect outbreaks (mountain pine beetle) and the spread of a non-native lethal disease (white pine blister rust). Planting guidelines are needed to facilitate the effective introduction of seedling genotypes resistance to white pine blister rust and adapted to future climates.
This study tested if planted seedlings establish and survive preferentially in the same microsites that promote successful natural establishment of limber pine seedlings.The effect of planting seedlings near or far from objects (i.e. logs, rocks, stumps) and under high or low canopy cover was tested at six planting sites across the southern Rocky Mountains. Planting near objects and under some overstory cover results in the greatest seedling survival suggesting that supplemental planting of seedling sources can be successful in the absence of stand-replacing disturbance.
These planting guidelines are the first for limber pine in this region and will facilitate the effective introduction and establishment of seedling genotypes resistant to white pine blister rust and adapted to future climates. In addition, these findings suggest that seedlings can be successfully introduced into stands in the absence of stand-replacing disturbance enabling the immediate and proactive introduction of adapted genotypes into populations.
For the best growth and survival, P. flexilis seedlings should be planted under a modest overstory canopy and near an object.
Planting on the north or west side of an object is particularly important for seedling survival if canopy cover is low or absent.
Conditions that support seedling planting success mimic those that support successful natural regeneration.