Project Code: ALPAC-01-006
Program: FRIP
Area:Applied Research
Sponsor:Alberta-Pacific Forest Industries Inc.
Region:NE Alberta
Project Status:Complete

Object & Deliverables


The overall objective of this project was to gain a greater understanding of understory white spruce and its development in mixedwood stands. The purpose of this project was to initiate the establishment of three sub-projects: white spruce understory protection; white spruce understory enhancement; and white spruce understory introduction. This project (ALPAC-01-006) was continued into ALPAC-01-007, which covered the final establishment and ongoing monitoring of the research projects.

Final Report

This study (ALPAC-01-006) examined aspen dominated stands with white spruce understories and evaluated several harvesting methods including the economical, operational and regeneration implications of a two-pass shelterwood system that removes the aspen overstory while protecting the spruce understory. Post-harvest monitoring included wind speed and blow-down losses; losses in spruce understory due to aspen harvesting; aspen and white spruce regeneration on buncher/skidder paths; soil compaction; soil warming; soil moisture; light transmission; growth rates of the released understory and ecological parameters; and digital photos of white spruce crowns.
Sub-Project A: White Spruce Understory Protection
The main objective of this sub-project addresses aspen dominated stands where an understory of white spruce occurs. This specific sub-project evaluated a harvesting method that enables the harvesting of mature aspen overstories in mixedwood stands while protecting the white spruce understory. The harvesting of these types of stands have historically been delayed until the maturation of the white spruce understory at which point the aspen was decadent. This technique will remove the aspen overstories releasing the white spruce understories resulting in increased growth rates. The resulting stand will regenerate an ecologically desireable mixedwood stand that is more productive and decreases silvicultural costs.
Sub-Project B: White Spruce Understory Enhancement
This study evaluated the importance of residual spruce trees serving as a seed source to establish white spruce understory after clear-cutting and natural aspen regeneration through suckering. The objective is to increase white spruce distribution over the landscape while preserving the aspen supply through maintaining seed trees during harvesting to enable natural spruce regeneration over time.
Sub-Project C: White Spruce Understory Introduction
The main objective of this sub-project was to study the effects of underplanting pure young aspen stands as a means of securing white spruce stocking and increasing mixedwood management versus white spruce plantations. Underplanting spruce in these aspen stands was a way of substituting natural spruce regeneration in the absence of a suitable spruce seed source. Increasing conifer stocking through mixedwood management is viewed as being ecologically more desirable than single species white spruce management in plantations.