STEMS > Silvicultural Systems > Aggregate Retention

Aggregate Retention

The aggregate retention system retains individual trees and groups of trees within the cutblock for the purpose of maintaining or protecting environmental values and structural diversity during at least one rotation. More than half the total area of the cutblock is within one tree-height from the base of a tree or the cutblock boundary. This study will examine windthrow and the spread of root disease from residual to regenerating trees, which are potential problems with this treatment.

For photos of aggregate retention see Tour Stop 11.

Silvicultural Systems:

1. Patch Cut
2. Extended Rotation
3. Group Selection
4. Clearcut with Reserves
5. Dispersed Retention
6. Extended Rotation with Commercial Thinning
7. Aggregate Retention

Immediately after the first entry

A view of the aggregate retention treatment immediately after harvest and five years later.

Summary Description of Key Features

Silvicultural System: Aggregate Retention
Treatment Unit Size: 25.5 ha
Opening Sizes: 4.4, 6.4, and 11.5 ha
Deferred Areas: 3.2-ha adjacent area temporarily deferred
Retention Structures Objective: 2.6 ha of internal reserves and 5.5-ha riparian reserves
Age Structure: Two-aged