1. Establish a stratified mixture Underplanting
Two stage mixedwoods
Establish a stratified mixture
Underplanting
Understory Retention at harvest
Clearcut, establish Sw and leave
Establish & or protect understory Sw
Harvest aspen ,
release understory spruce and
harvest aspen / spruce at years

2. Two stage mixedwoods
Establish a stratified mixture
Underplanting
Understory Retention at harvest
Clearcut, establish Sw and leave

3. Strip Shelterwood Harvest Method

4. Example of a Management Approach
If aspen stand to be harvested has a spruce understory which is projected to produce > 125 m3/ha at rotation then the spruce would be protected during harvest
Strip shelterwood / 2 stage harvesting model
- aspen windbuffers protect retained spruce from blowdown
- aspen regenerates in openings around released spruce but does not overtop

5. Strip Shelterwood Understorey retention
Projected Understorey
Stands using TASS
Pre-harvest conditions
1600 spruce per ha
12m spruce top height

6. Projected Volume and Trade Values
Top ht = 12m
Top height
tpha
Existing Sw understory
trees / ha
Projected future volume
- includes estimates of harvest damage

7. Strip Shelterwood Understorey retention
Projected Understorey
Stands using TASS
Post harvest conditions
Reductions to spruce:
- 20% of area - roadside processing
- 22% trails
- 8% blowdown / damage
Expect that all healthy Sw
greater than 5 m tall will
keep pace with the At

8. Strip Shelterwood Understorey retention
Projected Understorey
Stands using TASS
Age 80
CD stand
Conifer volume : 217 m3
At regenerating on trails /
roadside processing areas

9. Underplanting Understory Retention at harvest Two stage mixedwoods
Establish a stratified mixture
Underplanting
Understory Retention at harvest
Clearcut, establish Sw and leave

10. Benefits of Underplanting
May help to maintain / increase abundance of mixedwood
Decreased incidence of :
frost damage
overwinter injury
certain types of insect attack
Sw root rot
Decreased site preparation / weeding costs
Ungulate thermal cover
Continuous forest cover
17 year old underplant
R.Kabzems

11. Underplanting cont’d Reducing hare damage
do not underplant when hare cycle is on the increase
avoid underplanting in close proximity to dense young aspen stands or dense Sb stands
underplant in the interior of extensive mature aspen stands to avoid hare damage

12. Underplanting …cont’d
Planting density & distribution can be adjusted to target stand objectives
patches or even distribution
high or low density
strips to reduce damage when At is harvested
Selected stands should not have heavy understory competition(understory layers carry more leaf area than overstory)

13. Two stage mixedwoods
Establish a stratified mixture
Underplanting
Understory Retention at harvest
Clearcut, establish Sw and leave

14. Establish Sw & Leave Plant Sw at 1400 spha Accept aspen densities
treat only as required to establish
Accept aspen densities
low light environment for Sw
slow growth
set up for 2 stage harvesting model

15. Survival for plant & leave
Approximately Aspen on planted mound