Young Stand Management

The first two decades are a very dynamic period in Douglas-fir plantations when components considered critical habitat for several species, such as crown structure and understory vegetation, are changing quickly and are very responsive to manipulations. This study explores alternative management approaches in young plantations to minimize negative aspects of the stem exclusion phase. Specifically, an Observational study quantified how various stand structural components are influenced by stand density over time in young Douglas-fir plantations. As a follow-up, a Manipulative study was setup to determine whether density management can slow down or reverse undesirable trends in young plantations.

The Wildlife Habitat study investigates vegetation and wildlife response to gaps in young plantations and is part of the continuing effort to investigate assumptions critical for successful implementation of the Oregon Department of Forestry’s Northwest Oregon State Forest Management Plan. Specifically, this study will investigate effects of enhancing gaps in young Douglas-fir plantations on large and small spatial scales. Response measurements will include productivity in terms of wood volume and quality, understory vegetation, and wildlife habitat, including usage of stands by songbirds, bats, and small mammals. These responses will be assessed on individual gap and stand scales and results should provide information to assist managers in integrating structure-based management options while following an operational schedule.

Observational Study (OS)

Using a chronosequence approach, stands for the Observational study were selected in winter 2003 along an age continuum between 6-20 years old in three ODF districts (Astoria, Forest Grove, and Philomath). Plots were placed along transects to ensure coverage of low, medium, and high densities (gap, transition, matrix). Tree characteristics and understory vegetation were measured in spring and summer. Data analysis began in late fall and preliminary results were summarized for presentation at the Young Stand Management Workshop (November 25, 2003). The Workshop was organized to gain insight from folks in different agencies on the issue of managing young Douglas-fir stands for structure. Preliminary data were also presented at the State Forests Conference (Adaptive Management and Continuous Change) (March 10-12, 2004) by Klaus Puettmann (Principal Investigator).

OS-Results

Parameter estimates for equations quantifying impacts of age and stand basal area on tree and crown characteristics and understory vegetation.

Figures displaying tree and crown characteristics and understory vegetation from the Astoria district.

Manipulative Study (MS)

The results of the Observational study, findings from other recent studies and discussions with ODF personnel during the Nov. 25, 2003 Workshop and the ODF State Meeting on March 10-12, 2004 determined that gaps (low density areas) can provide opportunities to maintain or enhance biodiversity in Douglas-fir plantations. The specific objective of the Manipulative study was to document development of natural gaps and compare them with managed gaps, i.e., gaps treated to maintain or enlarge their size. In keeping with the goal to avoid, rather than reverse undesirable trends (e.g., crown recession) in stand development, 10 to 13-year old stands studied in the Observational study were used in the Manipulative study. Thus, we followed individual gaps and documented approximately 24 gaps within a stand (one stand per ODF district) in each of the three districts (described above). Plot installation occurred in winter 2004 and tree characteristics and understory vegetation were measured in spring and summer, 2004-2005.

In addition, questions were raised whether standard plantation management practices provide for gaps or whether additional management to create gaps was needed. As a follow up, we initiated a gap inventory study with the objective to provide baseline information about diversity of conditions (i.e., area in gaps versus fully stocked areas) created by standard management operations in plantations on ODF land.

MS-Results

Figures displaying crown diameter, height to base of live crown, and species richness for all three districts.

Percent canopy openness

Periodic (2 to 4 year interval) remeasurements are planned through 2014.

Wildlife Habitat Study (WS)

The overall goal of the Wildlife Habitat study is to investigate management options in young forest stands that allow management for wood production, older forest structure, and wildlife habitat. Specific objectives include to determine the effect of gaps in young plantations at both gap and stand scales on: 1) stand productivity (wood volume and quality); 2) understory vegetation (amount and diversity); 3) crown characteristics (size of crown and branches); 4) wildlife species (songbirds, bats, and small mammals); and 5) wildlife habitat characteristics (e.g., foliage height diversity). Plot installation occurred in March 2005 and tree growth, downed coarse wood, and understory vegetation were measured in spring and summer 2006.

WS-Results

Summary data for tree and understory vegetation measurements.

Publications

Puettmann, K.J. and C.A. Berger. 2006. Development of tree and understory vegetation in young Douglas-fir plantations. Western Journal of Applied Forestry. 21(2):94-101.

Berger, C.A. and K.J. Puettmann. 2005. Development of stand structure in young Douglas-fir plantations. Pp. 65-68 IN: Balancing Ecosystems Values, Innovative Experiments for Sustainable Forestry. USDA Forest Service, Pacific Northwest Research Station, General Technical Report PNW-635. 389 p.

Presentations

Berger, C.A. and K.J. Puettmann. June 2007. Structure based management in young Douglas-fir plantations. Poster for the 6th North American Forest Ecology Workshop, Vancouver, British Columbia, Canada.

Berger, C.A. and K.J. Puettmann. June 2005. Development of tree and understory vegetation in young Douglas-fir plantations. Poster for IUFRO 5th International Conference on Forest Vegetation Management: Useable Science, Practical Outcomes and Future Needs, Corvallis, OR.

Berger, C.A. and K.J. Puettmann. June 2005. Utilizing gaps to encourage diversity in plantation forests. 5th North American Forest Ecology Workshop, Aylmer, Quebec, Canada.

Berger, C.A. and K.J. Puettmann. April 2005. Development of tree and understory vegetation in young Douglas-fir plantations. Poster for the Conference: Science and the Northwest Forest Plan, Knowledge Gained Over a Decade, Portland, OR.

Berger, C.A. and K.J. Puettmann. August 2004. Development of tree and understory vegetation in young Douglas-fir plantations. Poster for Balancing Ecosystem Values: Innovative Experiments for Sustainable Forestry, International Workshop, Portland, OR.

Berger, C.A. and K.J. Puettmann. May 2006. Young Stand Management Study Overview. West Oregon District Reforestation Peer Review Tour: “Creating the Pathway to Complex Structure in Non-Complex Stands”, Philomath, OR.

Puettmann, K.J. and C.B. Berger. March 2004. Young stand management. State Forests Program Conference: Adaptive management and continuous change, Corvallis, OR.

Berger, C.A. and K.J. Puettmann. November 2003. Development of stand structure in young Douglas-fir stands: Preliminary findings. Young Stand Management Workshop, Corvallis, OR.