session 6 ic2011 dykstra

USDA Forest Service, PNW Research Station

Quality of Douglas-fir Lumber from Thinnings

Designed to Improve Habitat for Endangered Species

Dennis P. Dykstra Research Forest Products Technologist (Retired)

PNW Research Station, USFS


Presentation Outline

Siuslaw National Forest

Even-aged management issues

Focus on improving habitat for endangered species

STUDS research project

Wood-quality research questions

Data collection

Simulated sawing of logs

Analysis of lumber quality and value

Management implications of results from the research


Siuslaw National Forest, Oregon

Mid- to late-20th Century: emphasis on clearcutting and planting Douglas-fir

Little diversity in age, species, structure; increase in pests

Current emphasis: habitat for spotted owl, marbled murrelet; increase diversity

Aim is uneven-aged stands with multiple species, larger trees with large limbs, variable understory



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STUDS Project

Siuslaw Thinning and Understory Planting for Diversity Study

Cooperative study (Siuslaw NF, Oregon State University, PNW Research Station)

Three research sites, each involving:

Untreated control plot (1 ac)

Heavy thinning plots (2 x 1 ac)

Moderate thinning plots (2 x 1 ac)

Light thinning plots (2 x 1 ac)

Thinning treatments were both with and without underplanting


STUDS Project

Stands clearcut early 1960s, treated with prescribed fire and herbicides, then planted

Precommercially thinned in the mid-1970s

STUDS Phase I commercial thinnings 1992- 1993: stocking reduced from 223-277 trees/ac to 30, 60, 100 trees/ac

Residual trees in plots given ID numbers, measured at years 0, 4, 8 and spring 2008

Phase II thinnings 2008-2009: further reduced the plots with 60 and 100 trees/ac to densities of about 30 and 50 trees/ac respectively


STUDS Project—Wood Quality Study

Is wood quality significantly reduced by thinnings designed to enhance habitat for endangered species?

Are there differences due to thinning intensity?

Are there differences between sites?

Is there an effect due to the slope aspect on which the trees are grown?

Are knots (i.e., branches) uniformly distributed around the stems of trees in the target area?


STUDS 2008-09 (Phase II) Thinning

2028 trees removed from the three sites

Sample for wood-quality study: 3% of thinned trees + 5 = 66 trees (Yachats: 27)

Random sample stratified by 4” Dbh class

All sample trees yarded with cable systems

Yachats Site


STUDS Project—Log Tracking

Pre-Harvest

Y2 = Yachats

Treatment 2

White ribbon

Tree ID = 1611

Label with Y2-1611

Paint at

breast height

Metal tree tag

(1611) and

checked ribbon



Felling

Y2 = Yachats

Treatment 2

White ribbon

Tree ID = 1611

Label with Y2-1611

Paint at

breast height

Metal tree tag

(1611) and

checked ribbon

Pre-Harvest



Pre-Harvest Felling Bucking

Y2 = Yachats

Treatment 2

White ribbon

Tree ID = 1611

Label with Y2-1611

Paint at

breast height

Metal tree tag

(1611) and

checked ribbon


Effectiveness of Log Tracking

66 sample trees felled

184 sample logs bucked from the sample trees

179 sample logs tracked successfully to the landing

5 lost sample logs were all top logs with SED < 4 inches

1 sample log arrived at the landing with unreadable tags but was identified using data recorded during bucking


Log Profiles & Surface Defects

Peavy for

rolling logs

Measured knots

painted white

Measuring tape

Log

label

Spray paint,

hatchet, clipboard

Sweep offset at point

of maximum sweep

Chalk line running

between log ends

Log ID label (one on

each end of log)

Pith

Offset to knot

Orientation line for

top and bottom

longitudinal axes


Log and knot summary

Attribute All logs Butt logs

2nd logs

3rd logs

Logs 179 66 66 47

Log LED, in 13.0 18.2 12.6 9.9

Log SED, in 9.4 12.7 8.7 5.9

Log length, ft 31.08 36.59 32.52 21.32

Knots 10,970 3,904 4,627 2,439

Knots/ft 2.0 1.6 2.2 2.4


Simulated Sawing with AUTOSAW

AUTOSAW—published by the New Zealand Forest Research Institute, 1994

Improvement on earlier FRI sawing simulators

Lumber recovery and grades estimated according to sweep, crook, wane; knot position, size, and frequency; other defects not considered

Adapted for WWPA Douglas-fir grades ~2000 (PNW Research Station and NZ-FRI)

Written for the MS-DOS operating system; runs in a DOS window in Windows XP but not in Vista or Windows 7


AUTOSAW Data Requirements

Mill-length logs only (< 21 ft = 6400 mm)

Sawing data: headrig & edger kerf

carriage dimensions

nominal and actual widths & thicknesses

trim lengths

3-dimensional data for each log: Diameters at each profile point

Sweep and crook offsets

Location of each whorl along the log length

Branch data for each whorl (number of branches, location of each surface knot, radius of knot, rake angle of branch)


3D Geometry—Bucking Logs


AUTOSAW Results

Autosaw Lumber summary by piece size:

Lumber Production Report Size Pieces Volume Pct 2-in

2 x 4 180 1354.67 98.4%

Lumber produced from: 2 x 6 43 643.00

Short logs from Cataract 2 2 x 8 52 1137.33

2 x 10 49 1368.33

Date of preparation of this report: 2 x 12 51 1804.00 Pct 1-in

Friday, January 14, 2011 1 x 4 21 78.33 1.6%

1 x 6 4 24.00

1 x 8 0 0.00

1 x 10 0 0.00

1 x 12 0 0.00

Totals 400 6,409.67

Log ID

Lumber

Piece ID

Thickness,

in Width, in Len, ft

Autosaw

Grade Board Feet WWPA Grade

C2-1009-1-1 7A 2 4 18 N 12.00 SelStr SLF

C2-1009-1-1 6A 2 8 18 D 24.00 No3 J&P

C2-1009-1-1 5A 2 8 18 A 24.00 SelStr J&P

C2-1009-1-1 4A 2 4 8 N 5.33 SelStr SLF

C2-1009-1-2 8A 2 6 18 D 18.00 No3 J&P

C2-1009-1-2 7A 2 6 18 E 18.00 Econ J&P

C2-1009-1-2 6A 2 4 9 Q 6.00 No3 SLF

C2-1009-2-1 6A 2 4 14 N 9.33 SelStr SLF

C2-1009-2-1 5A 2 6 14 B 14.00 No1 J&P

C2-1009-2-1 4A 2 4 10 N 6.67 SelStr SLF

C2-1009-2-2 7A 2 4 14 O 9.33 No1 SLF

C2-1009-2-2 6A 2 4 9 P 6.00 No2 SLF

C2-1009-2-3 4A 2 4 9 N 6.00 SelStr SLF

C2-1013-1-1 11A 2 4 8 O 5.33 No1 SLF

C2-1013-1-1 10A 2 10 16 C 26.67 No2 J&P

WWPA Rule Autosaw Grade

Joists & Planks A SelStr J&P

Joists & Planks B No1 J&P

Joists & Planks C No2 J&P

Joists & Planks D No3 J&P

Joists & Planks E Econ J&P

LtFrame&Studs F Const LF

LtFrame&Studs G Std LF

LtFrame&Studs H Util LF

LtFrame&Studs I Econ LF

LtFrame&Studs J Stud

LtFrame&Studs K Econ Stud

SpecDim L Scaffold1

SpecDim M Scaffold2

StrLtFraming N SelStr SLF

StrLtFraming O No1 SLF

StrLtFraming P No2 SLF

StrLtFraming Q No3 SLF

StrLtFraming R Econ SLF

Common 1 Com1

Common 2 Com2

Common 3 Com3

Common 4 Com4

Common 5 Com5


Lumber Grade by Log Position


Knot Density per Tree

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

8 10 12 14 16 18 20 22 24 26

Kn

ots

pe

r F

oo

t o

f M

erc

ha

nta

ble

He

igh

t

Tree Diameter at Breast Height, inches

Trees on South-Facing Slopes

Trees on North-Facing Slopes

Cataract

Yachats

Wildcat


Lumber Value Recovery by Tree

0

50

100

150

200

250

300

350

6 8 10 12 14 16 18 20 22 24 26

Lu

mb

er

Va

lue

, $

/CC

F T

ota

l L

og

Vo

lum

e

Tree Diameter at Breast Height, inches

Lumber Value by Tree

Cataract Observed Values

Wildcat Observed Values

Yachats Observed Values


Management Implications

Preliminary conclusions: analysis is incomplete

Apparently no statistical difference in quality of lumber from trees removed in the second treatment of light and moderate thinnings

Apparently no significant site effect

Possibly a slightly higher density of knots in logs from trees grown on south-facing slopes

Knots are not uniformly distributed around the tree bole; higher density toward the south

Thinnings do no major harm to wood quality

session 6 ic2011 dykstra

Technology

research usda forest

research sites

usfs usda forest service

multiple species

diversity aim

ac thinning treatments

ac heavy thinning plots

ac moderate thinning