Seedling Release and Young-Stand Thinning as a Way to Increase Forest Health and Production

Progress report for OW19-350

Project Type: Professional + Producer
Funds awarded in 2019: $49,884.00
Projected End Date: 06/30/2022
Grant Recipient: Northwest Natural Resource Group
Region: Western
State: Washington
Principal Investigator:
Kirk Hanson
Northwest Natural Resource Group
Co-Investigators:
Lindsay Malone
Northwest Natural Resource Group
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Project Information

Abstract:

After timber harvest, Washington’s forestland owners face a task that has become increasingly tricky: re-establishing a new generation of trees on recently logged sites. New trees have always faced competition from native understory plants, but in recent years, they’ve also had to contend with invasive species such as Himalayan blackberry (Rubus armeniacus) and with dry summers punctuated by heat waves, aggravating the impact of moisture competition from shrubs and grasses. Pressure from invasive species and stress from excessive heat are expected to increase (Lipton et al. 2018 and Vose et al. 2018). Heat stress also makes it especially important to thin overcrowded young stands, so that more soil moisture is available for crop trees.

To help forestland owners address these challenges, Northwest Natural Resource Group proposes to partner with six forest producers to examine varied approaches to improving young stands’ prospects in their early years. Through our project, “Seedling Release and Young-Stand Thinning as a Way to Increase Forest Health and Production,” we will collaborate with producers to devise field trials of new prescriptions for brush control and young-stand thinning, and develop controlled experiments that we will implement, monitor, and analyze for the first 2.25 years of the project. We will then hold two workshops for 50 forest producers to share our findings and view them in situ; disseminate the results through fact sheets and on-line videos, and provide 15 site visits for interested producers to help them apply our findings to their situation.

Our project will result in a clearer understanding of how to release forest seedlings from competition with other species and each other, and will translate to more effective forest management, increased forest health, and improved producer profitability by avoiding the need to replant outcompeted seedlings and enabling trees to reach commercial maturity sooner.

Project Objectives:
  1. Evaluate the cost of at least three treatments to release conifer seedlings from competition by shrubs and grasses. We will write specifications describing the treatments, so they can be compared consistently across treatment areas, and monitor the cost of implementation on the sites where they are used. (August 2019 to September 2021)
  2. Evaluate the cost of at least three treatments to pre-commercially thin young hardwood and conifer stands. We will write specifications describing the treatments, so they can be compared consistently across treatment areas, and monitor the cost of implementation on the sites where they are used. (August 2019 to September 2021)
  3. Evaluate the effectiveness of those treatments by monitoring seedling survival and growth on a total of at least 10 treatment areas after one and two growing seasons have elapsed since treatment. (April 2020 to October 2021)
  4. Analyze whether the more intensive treatments are cost effective, based on the data from (1), (2), and (3). (October 2021 to January 2022)
  5. Evaluate the effectiveness of young-stand thinning at reducing mortality rates among the remaining stand. (October 2019 to October 2021)
  6. Disseminate the findings from (4) and (5) to at least 65 forest producers in person. (January to March 2022)
  7. Reach an additional 1,200 forest producers with the conclusions of our work through additional media, such as our newsletter and online presentations. (February to May 2022)
  8. Conduct follow-up surveys among at least 120 forest producers in western Washington to determine whether the results of our study have influenced their management decisions.

Cooperators

Click linked name(s) to expand
  • Rodney Hanson - Producer
  • John Henrikson - Producer
  • Joe Kane - Producer
  • Laurence Reeves - Producer
  • Tammie Perreault - Producer
  • Richard J. Pine - Producer

Research

Materials and methods:

For this project, all of the sites are located on private non-industrial forestland in western Washington.

Objective 1: We will conduct site visits to each of the collaborating producers to observe the condition of potential treatment areas for seedling release , and work with the forest producers to develop a menu of treatments that will be tested against each other. With each producer, we will jointly decide on a list of 2 to 4 seedling release treatments, and designate an area of at least 1.0 – 2.0 acres for each one. We will flag and map the boundaries of the treatment units. NNRG will be responsible for overseeing the field crew’s compliance with the treatment prescription. We will monitor the time and expense needed to implement the prescription. At the end of the implementation phase, we will compile a summary of the cost of implementing each prescription.

Objective 2: We will establish a grid of 0.05-acre, non-overlapping monitoring plots within each treatment area. Before implementation, we will count the live tree seedlings in each plot, measure their height, and document their condition (e.g. browse damage, competition-related damage, etc.). Within each plot we will also document competing vegetation (e.g. species and percent cover). At the end of each growing season thereafter, we will repeat the measurements. We will compare the average growth in height across the 2 to 4 treatments at each site, and determine whether there is a significant difference in tree growth and survival between treatments.

Objective 3: We will synthesize the findings from (1) and (2) by comparing the difference in survival and growth between the treatments. If the costlier treatments yield better results, we will undertake a cost-benefit analysis to determine whether the higher cost is warranted by the improved results. We will consider the cost of interplanting new seedlings to replace the ones that died, and project the cost of the slower growth attained under lower-cost treatments as a result of the delay in the trees’ harvestability Of course, if the less expensive treatment yielded better results, then the preferred treatment would be obvious.

Objective 4: On forest stands aged 10 to 25 years old, which would be candidates for young-stand thinning (also known as “pre-commercial thinning,” or PCT), we will undertake a similar process to the one laid out in Objective #1. Using flagging and GPS mapping, we will lay out one or two treatment areas of approximately 1.0 to 2.0 acres apiece. Within each treatment area we will lay out and monument a grid of 0.05-acre plots. Before treatment, we will measure all live and dead trees within each plot and note their species, height, live-crown ratio, and diameter at breast height. We will oversee the field crew’s compliance with the treatment prescriptions. We will monitor the plots two growing seasons after treatment is carried out, counting and measuring live and dead trees, and noting the number of trees actually removed in the course of thinning. We will compare tree mortality rates across the different thinning regimes and the control. Since it usually takes 6 to 10 years to see a response in terms of growth rates, we will monument the treatment areas with enough permanence that a future study could look at the effect of thinning on growth rates.

Objective 5: We will hold two workshops that will bring forest producers to see the results of these seedling release and young-stand thinning trials. Workshops will be advertised through our newsletter, Washington Department of Natural Resources Small Forestland Owner newsletter, mailing lists of forest landowners, and social media. Each workshop is expected to attract roughly 25 participants.  We will also offer site visits to forest landowners who are interested in getting professional advice about applying the results to their land.

Objective 6: In order to disseminate the results to producers who do not attend the workshops, we will create videos, slideshows, and pamphlets to explain what we learned and how it can be applied. During the implementation phase of the project, we will use a time-lapse camera to document the work being done, and edit that footage into the finished videos.  Those materials will be publicized through our newsletter (which reaches 2500 subscribers), partner organizations, and social media.

Objective 7: We will conduct pre- and post-workshop surveys to find out what participants have learned from the workshops and what changes in management practices they are planning, and also use an online survey tool to follow up with those who downloaded materials about thinning and stand release, in an effort to find out whether it had affected their management decisions for their forest.

Research results and discussion:

To date we have installed treatment sites and inventory/monitoring plots on all five of the project participants’ forestlands. The following summarizes the work to date with project participants:

O’Neill Pine Company

  1. Installed three 2.0-acre pre-commercial thinning treatment sites containing eight 0.05-acre inventory/monitoring plots per treatment site. The pre-commercial thinning sites are located in a 15 year old Douglas-fir plantation.
    1. Thinning prescriptions were developed for each treatment site as follows:
      • Thin to 300 trees per acre.
      • Thin to 200 trees per acre.
      • No thinning. Leave stand at original density.
  2. Installed two 2.0-acre stand release treatment sites containing eight 0.05-acre inventory/monitoring plots per treatment site. The stand release sites are located in a 3 year old Douglas-fir plantation that has become overrun with Scotch broom, a non-native and highly invasive shrub.
    1. Stand release prescriptions were developed for each treatment site as follows:
      • Hand-cut Scotch broom with chainsaws and lop-and-scatter material across the site. Spray resprouting scotch broom in late spring.
      • Hand-cut Scotch broom and pile cut material into multiple discrete piles across the site. Spray resprouting scotch broom in late spring.

Contractors were hired in January & February 2020 to implement the prescriptions described above, and the time and cost of their work was documented. Inventory/monitoring plots within the pre-commercial thinning treatment sites were remeasured immediately following implementation of the treatment.

A case study of this project has been posted to NNRG’s website: https://www.nnrg.org/standrelease/

Hanson Family Forest

  1. Installed three 1.0 – 2.0-acre pre-commercial thinning treatment sites containing four 0.05-acre inventory/monitoring plots/acre in each treatment site. The pre-commercial thinning sites are located in an 18-20 year old mixed hardwood stand that is dominated by red alder and big leaf maple.
    1. Thinning prescriptions were developed for each site as follows:
      • Pre-commercially thin to 250 trees per acre
      • Pre-commercially thin to 180 trees per acre
  2. Installed three 1.5-acre stand release treatment sites containing six 0.02-acre inventory/monitoring plots per treatment site. The stand release sites are located in a 1-3 year old western red cedar/Douglas-fir plantation that has become overgrown with Himalayan blackberry and other assorted native shrubs and hardwood trees.
    1. Stand release prescriptions were developed for each site as follows:
      • Hand-cut all competing vegetation within a 3′ circle surrounding seedling.
      • Hand-cut only competing vegetation that overtops seedling and prevents free growth of tree’s leader.
      • Brush-cut all competing vegetation throughout entire unit.

The stand release prescriptions were completed in June/July 2020. The pre-commercial thinning of the dense alder stands is ongoing but expected to be completed by June 2021. All time and costs are being documented by the landowner who is implemented the project themselves.

A case study of this project has been posted to NNRG’s website: https://www.nnrg.org/standrelease/

Wild Thyme Farm

  1. Installed two 1.0-acre stand release treatment sites containing four 0.05 inventory/monitoring plots per treatment site. The stand release sites are located in a 3 year old mixed conifer plantation that has been colonized by a wide range of native brush species. 
    1. Stand release prescriptions were developed for each site as follows:
      • Control site with no treatment
      • Hand-cut only competing vegetation that overtops seedling and prevents free growth of tree’s leader.

Stand release work has been delayed, but is expected to be completed by June 2021.

A case study of this project will be posted to NNRG’s website by the week of April 5th, 2021: https://www.nnrg.org/standrelease/

Capitol Land Trust

  1. Installed two 1.25-acre treatment sites containing four 0.05 inventory/monitoring plots per treatment site. The treatment sites are located in a 20 year old mixed hardwood/conifer stand.
    1. Pre-commercial thinning prescriptions were developed for each site as follows:
      • Site #1: pre-commercially thin to 200 – 250 TPA (13’x15’)
      • Site #2: no treatment (control site)

Thinning of the treatment site was completed in September 2020 and all time and costs documented. The inventory/monitoring plots within treatment site #1 (thinning site) were remeasured immediately following implementation.

A case study of this project will be posted to NNRG’s website by the week of April 5th, 2021: https://www.nnrg.org/standrelease/

Two Cats Timber

  1. Installed two 1.0-acre treatment sites containing four 0.05 inventory/monitoring plots per treatment site. The treatment sites are located in a 22 year old mixed hardwood/conifer stand.
    1. Pre-commercial thinning prescriptions were developed for each site as follows:
      • Pre-commercially thin to 180 – 220 TPA (13’ – 15’) – 1 acre
      • Pre-commercially thin to 240 – 260 TPA (14’ – 16’) – 1 acre

Thinning of the treatment sites was completed in March 2021 and all time and costs documented. The inventory/monitoring plots were remeasured immediately following implementation.

A case study of this project will be posted to NNRG’s website by the week of April 5th, 2021: https://www.nnrg.org/standrelease/

Participation Summary
5 Farmers participating in research

Educational & Outreach Activities

5 Consultations

Participation Summary

5 Farmers
Education/outreach description:

The majority of the education and outreach activities planned for this project are not scheduled to occur until later in the project timeline. However, some of the educational and outreach activities that have occurred to date include:

  1. On-site consultations with the five forest owners who are also study participants in this project.
  2. Announced project through NNRG’s monthly newsletter.
  3. Outlined educational and resource web page for this project
  4. Developed and posted detailed case studies for each project on NNRG’s website (https://www.nnrg.org/standrelease/)

Learning Outcomes

5 Farmers reported changes in knowledge, attitudes, skills and/or awareness as a result of their participation
Key changes:
  • The educational and outreach components of this project are scheduled later in the project timeline.

Project Outcomes

5 Farmers changed or adopted a practice
5 Farmers intend/plan to change their practice(s)
2 Grants received that built upon this project
1 New working collaboration
Project outcomes:

Although this project has yet to yield the full results of the various pre-commercial thinning and stand release studies, the process of developing the study sites and study parameters, as well as developing prescriptions for implementation, has provided useful information that will be of benefit to other small woodland owners. The first benefit is the inventory/monitoring protocol we developed to document the proposed forest management practices. This protocol, including cartography, design of treatment sites and inventory plots, field data collection standards, etc., will be made available to other forest owners who are interested in accurately monitoring similar projects on their own lands. Similarly, the development of pre-commercial thinning and stand release prescriptions will provide forest owners template language they can use when developing similar prescriptions for their own forestlands. Lastly, we have fully implemented two stand release and three pre-commercial thinning activities and documented the labor and material costs for these two projects. This information will be useful to forest owners who are either planning to conduct work themselves, or contract out the work. 

Success stories:

We will provide these once we complete the stand release and pre-commercial thinning projects. 

Recommendations:

Over the first 12 months of this grant we have learned the following lessons:

  1. The time/cost to install inventory/monitoring plots is very high. In order to stay within the budget of the grant, the study design had to be simplified by reducing the size of the proposed treatment sites, and the number of plots in each treatment site.
    1. Plot design is usually driven by a desire to achieve a certain statistical accuracy in the sampling of a given population. Given that the objective of this project is to document costs and effectiveness of various forestry practices, and not measure timber growth or other biological metrics, it was determined that accurately documenting general site conditions was the main priority of the plots, and a statistically accurate sample of the individual trees within each site was not paramount.
  2. We originally hoped that each study participant would have an opportunity to apply for funding through the federal Environmental Quality Incentives Program (EQIP) in order to offset costs of implementing the various pre-commercial thinning and stand release projects. However, in most cases the timing of planned activities did not coincide with the funding cycle of the EQIP, thereby limiting study participants opportunities to apply and receive funding with the project timeline.
    1. A key lesson is to encourage forest owners to apply for EQIP funding as soon as they conceptualize forest restoration projects. Given the extended timeline on which the EQIP funding cycle operates, forest owners will often have ample time to refine the parameters of a forest restoration project before the project is actually evaluated for funding by the EQIP.
  3. Working with thinning contractors proved challenging relative to ensuring the contractor hit the thinning target as prescribed uniformly across a stand. It was observed that contractors have a tendency to thin trees to a density, and use tree selection criteria, that they are most familiar with, which tends to favor uniform industrial plantations. Achieving a high rate of compliance with more nuanced prescriptions proved challenging.
Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the view of the U.S. Department of Agriculture or SARE.