Silvicultural transformation to multi-aged structures in northern Rocky Mountain ponderosa pine stands
| Authors: | Neil G. Williams, Justin S. Crotteau, Sharon M. Hood, Cheri Hartless, Shelagh Fox |
| Year: | 2026 |
| Type: | General Technical Report |
| Station: | Rocky Mountain Research Station |
| DOI: | https://doi.org/10.2737/RMRS-GTR-446 |
| Source: | Gen. Tech. Rep. RMRS-GTR-446. Fort Collins, CO: U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station. 238 p. |
Abstract
Multi-aged stands dominated by ponderosa pine (Pinus ponderosa) once occupied large areas of the American west at low to mid elevations. Much of this forest type is now even-aged after regenerating from past high-severity disturbance (i.e., wildfire or even-aged harvesting) or is transitioning toward even-aged structure in the absence of natural disturbance processes. Although even-aged forests are well-suited to a subset of management objectives and sites, multi-aged forest structures are often better aligned with the multi-objective framework under which public forestland is commonly managed. Transformation silviculture is the pathway to shifting even-aged ponderosa pine stands to a wide range of potential multi-aged structures, but there are few practical resources to help managers overcome the real and perceived barriers to transformation. This practitioner-oriented guidebook was developed to help forest managers accomplish the transformation process in ponderosa pine stands. Our approach emphasizes flexibility, while providing hypothetical and real-world examples of transformation sequences, sustainable multi-aged structures, and silvicultural practices useful during transformation and in the subsequent long-term management of multi-aged stands. Although we use stands in the northern Rocky Mountain region as our study subject, much of the content is broadly applicable throughout ponderosa pine’s range.