Increasing forest health through
young-stand thinning & seedling release. 

Hanson Family Forest

The Hanson Family Forest near Bucoda, WA is a 102-acre property that hosts a wide array of stand types ranging from newly established conifer plantations to young, naturally regenerated hardwood stands to 26-year-old Douglas-fir plantations. Two management challenges facing the forest owners include natural hardwood stands which are extremely dense and in a competitive exclusion phase, and newly established conifer plantations which are becoming overgrown with competing vegetation.

Newly established conifer plantation is becoming overgrown with Himalayan blackberry.
Dense hardwood stands in a competitive exclusion phase.

The two projects hosted by Hanson Family Forest will attempt to address these management challenges. A dense stand dominated by red alder, bigleaf maple and cascara will be pre-commercially thinned in three types of treatments; a young Douglas-fir/western redcedar plantation will receive treatments to release it from competition with Himalayan blackberry; and a second young Douglas-fir plantation will receive treatments to release it from competition with bigleaf maple. 

 

Young hardwood stand pre-commercial thinning (PCT)

 


Young Douglas-fir/western redcedar stand release from competing Himalayan blackberry 

Young hardwood stand pre-commercial thinning (PCT)

Project
Status

Project underway. Study results will be collected through 2019 and 2020, analyzed, and published here.

Location

Bucoda
Thurston County
Washington

Project Description

This project will treat a dense stand dominated by red alder, big leaf maple and cascara with the following three prescriptions:

  1. Pre-commercially thin to 180 TPA (14′-16′)
  2. No treatment
  3. Pre-commercially thin to 250-300 TPA (12′-13′)
A PDF of the map to the right is available here

Stand Summary

Site
Acres
# of Plots
TPA
TPA > 5″
Average DBH
QMD > 5″
Average HT
BA
Curtis RD
Volume (mbf)
Thinning Treatment
1
1
4
770
225
4.2
5.7
45
79
38
0.0
Thin to 180-220
2
1
4
680
155
4.2
9.7
49
145
56
1.6
No treatment
3
2
8
555
275
5.6
7.3
48
103
43
2.3
Thin to 250-300

These stands naturally regenerated following clearcut harvesting approximately 18 – 20 years ago. The sites were not replanted, and consequently red alder, and a wide diversity of other hardwoods, quickly colonized the area. Other hardwood species include: bigleaf maple, bitter cherry, willow, cascara, and some minor species such as birch and western crabapple. Cascara often forms dense thickets of small diameter saplings. Limited conifers also occur sporadically throughout these stands, ranging from newly regenerating seedlings to canopy trees of a similar age as the alder. Conifer species include Douglas-fir, grand fir and western red cedar. 

Site
RA
CA
BM
DF
GF
CH
OT
All
1
530
210
0
15
0
15
0
770
2
370
150
0
105
0
0
55
680
3
185
123
123
13
103
0
10
555

RA: Red Alder | CA: | BM: Bigleaf maple | DF: Douglas-fir | GF: Grand fir | CH: | OT: 

Current stocking across these stands range from 280 – 1,000 TPA, including all species. Tree diameters range from 2.0” – 10” DBH, averaging 4.2” – 5.4” DBH. Nearly 90% of the trees have diameters less than 4.5” DBH. Live crowns across most of the dominant and co-dominant alder have receded to less than 30%. There has been a high rate of storm damage across the unit, primarily affecting alder and cherry, resulting in broken tops and multi-forked stems. A dense understory shrub layer grows beneath the porous hardwood canopy. Himalayan blackberry is dominant in many places, with salmonberry and sword fern comprising the bulk of the native species present. Other understory shrub species include: elderberry, Oregon grape, red huckleberry, and Nootka rose.

Objectives

The objective of the PCT treatments is to retain the most dominant and highest quality trees of each species. The thinning treatments allow long-term comparisons of the relationship between stocking density, diameter and height growth, and timber quality. Alder and all conifers will be favored as the primary crop trees. High quality bigleaf maple will also be retained, although sprouting stumps will be thinned to 1-3 dominant and high quality stems. 

Cascara will be retained as a secondary forest product for both short and long-term harvesting. Other hardwood species (e.g. bitter cherry, western crabapple, birch, willow, etc.) will be retained for biodiversity, but thinned where they are dense, and/or removed where they are competing with a preferred crop tree. 

Understory brush (e.g. vine maple, salmonberry, ocean spray, etc.) will not be treated, with the exception of non-native species (e.g. Himalayan blackberry, English holly, etc.) which will be removed.

About the treatment

Releasing naturally regenerated alder stands at this age and density is frequently discouraged for two reasons: 1) by 20 years of age alder has achieved the majority of its height growth, and continued height growth rapidly tapers off. High density natural alder stands tend to have poor height growth, and releasing at a later age may not result in significant additional growth. 2) thinned alder stands may be more susceptible to storm damage, in particular in the first few years following thinning.

The decision to thin these stands was based on the following considerations:

  1. The alternative to attempting to improve the timber value of the existing stand was to start over, which would incur a cost and lose 18 – 20 years of growth. 
  2. Dominant trees average 45’ – 50’ tall, which is sufficient to produce a long-log.
  3. Although continued height growth may be marginal, releasing the crowns of the dominant and co-dominant trees should sustain moderate diameter growth.
  4. Dominant and co-dominant trees average nearly 6” DBH. At current growth rates, 10 – 15 years of additional growth should yield merchantable trees averaging 12”+ DBH.
  5. Since apparently few people attempt to thin natural alder stands to improve value, we thought we’d try.

Pre-Treatment Plot Data

The pre-treatment stand plotcard data for this project are available below.
Site 1: PDF | Excel worksheet
Site 2: 
PDF | Excel worksheet
Site 3: 
PDF | Excel worksheet

Labor/Cost Statistics

Labor and materials costs will be updated as this project progresses. Stay tuned!

Young Douglas-fir/western redcedar stand release from competing Himalayan blackberry

Project
Status

Project underway. Study results will be collected through 2019 and 2020, analyzed, and published here.

Location

Bucoda
Thurston County
Washington

Stand Description

This project will treat a newly established plantation of western redcedar and Douglas-fir by controlling Himalayan blackberry and various native competing vegetation. Redcedar was planted across the unit in 2016 and Douglas-fir was planted across the unit in 2018. The following three treatments are proposed:

  1. Hand cut competing vegetation within 2’ radius of seedling.
  2. Cutting all vegetation across the site with a brush cutter.
  3. Cutting all vegetation across the site with a brush cutter, followed by spot spray of herbicide.
A PDF of the map to the right is available here

Stand Summary

Site
# of Plots
TPA (all species)
TPA DF
TPA RC
TPA RA
Avg height (conifer)
1
6
408
142
267
0
2.8′
2
6
525
175
242
108
3.0′
3
6
550
167
300
83
2.3′

This stand was originally scarified of all vegetation using a bulldozer by the previous landowner, then planted with western redcedar at 350 TPA in 2016. High browse damage on the cedar led the owner to replant the unit with Douglas-fir at 350 TPA in 2018. However, despite browse, many of the cedar have survived, resulting in areas of this stand with very high stocking levels including both cedar and fir.

Treatment goals

The objective of each stand release treatment is to release the conifers and promote their growth towards a free-to-grow height above competing vegetation, after which no further stand maintenance will be required until conifers reach either pre-commercial thinning or commercial thinning age.  Although Douglas-fir and western redcedar are the primary crop trees, naturally regenerating alder will also be retained where it is not directly competing with conifers. Further, bitter cherry will be thinned, but also retained where it is not competing with conifers.This variety of treatments will allow observations on the effectiveness of several stand release strategies that are commonly used to control Himalayan blackberry.

Study Design

Each project will include treatment sites ranging from 1.0 – 2.0 acres in size. Within each treatment site four 1/20th-acre (0.05 acres) permanent monitoring plots/acre will be installed prior to implementation of prescribed treatment. Each plot will be permanently monumented with a rebar stake and 4’ white PVC pipe with bright orange ribbon tied to the top. For each plot, the following macro-data will be recorded: Average stand age, Soil type, Site index & class, Elevation, Rainfall, Aspect, Slope. Pre-activity data will be collected from the treatment sites, the respective treatments will be implemented, then post-activity data will be collected immediately following treatment. Plots will be remeasured at 12 months and 24 months following treatment.

Pre-Treatment Stand Data

The pre-treatment stand plotcard data for this project are available below.
Site 1: PDF | Excel worksheet
Site 2: 
PDF | Excel worksheet
Site 3: 
PDF Excel worksheet

Labor/Cost Statistics

Labor and materials costs will be updated as this project progresses. Stay tuned!

Project Photos

Funding and support for this project comes from Western Sustainable Agriculture and Education (Western SARE).

Western Sustainable Agriculture and Education is supporting the research and training provided through this project with grant #OW19-350 – Seedling Release and Young-Stand Thinning as a Way to Increase Forest Health and Production