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Decays and Defects Affecting Timber Values

and Safety

Timber Measurements Society

April 2019

Dan MillerPrecision Forestry LLC

Moscow, ID

Wood Decays

•Structurally weaken trees – Danger tree•$$ Loss of merchantable volume•Much less common in younger forests•Break down dead material•Recycle nutrients

Wood Decays

Grey-Brown Sap Rot(Pouch Fungus)

◼ Usually spread by bark beetles

◼ Appear in spring a year following beetle attack

◼ Rapid decay

Grey-Brown Sap Rot(Pouch Fungus)

Sapwood Decays

◼ Begin with beetle attacks or tree death

◼ Continues in dead trees and after trees are cut and hauled

◼ Decay rate & amount varies by tree species

◼ Value loss depends on amount of sapwood in the log – varies by species & growth rate

Sap Rot Defect:Merchantable volume loss

Diameter cut from 20” to 16” = 43% scale volume loss

20” to 18” = 25% loss

Deterioration Study

◼ Evaluated trees for losses due to:◼ Stain

◼ Char

◼ Decay

◼ Cracks◼ Reported cubic feet not

board feet

Fire-killed Trees◼ Often attacked by

bark beetles & borers

◼ Begin to dry out ◼ Dry rapidly if bark

scorched

◼ and surrounding trees are killed – no shade

◼ Char

Deterioration = Loss of Value

◼ Rate is Affected by:◼ Tree species

◼ Cause of death

◼ Time since death

◼ Tree size

Blue Stain

◼ Only affects sapwood

◼ Lodgepole pine 100% infected 1 year after burn

◼ Ponderosa pine 95% infected by year 1, 100% by year 2

Douglas-fir Volume Loss

Year 1 Year 2 Year 3 Year 4 Year 5

Decay % 0 1 3 6 16

Cracks % 7 19 29 31 40

Decay

Cracks0

10

20

30

40

Year 1 Year 2Year 3

Year 4Year 5

Decay

Cracks

Grand Fir Volume Loss %

Ponderosa Pine Volume Loss %

Top Logs Deteriorate Faster from Cracks

Douglas-fir (%)

Decay Loss Ranking

◼ Volume lost to sap rots proportional to sapwood thickness

◼ Ranking (high to low):◼ Ponderosa pine

◼ Grand fir

◼ Douglas-fir

◼ Western larch

◼ Lodgepole pine

Cracking Loss Ranking

◼ Volume lost to cracks related to bark thickness

◼ Ranking (high to low):◼ Lodgepole pine

◼ Western larch

◼ Grand fir

◼ Ponderosa pine

◼ Douglas-fir

Conclusions

◼ Thick-barked trees rapidly attacked by insects = decayed more quickly

◼ Thin-barked trees dried more quickly higher loss to cracking

◼ Top logs deteriorated more quickly◼ Smaller diameter

◼ Higher % of sapwood – decay

◼ Thinner bark - cracking

Indian Paint Heart rot

◼ Hosts:◼ Grand fir

◼ Subalpine fir

◼ Western hemlock

◼ Mountain hemlock

Indian Paint Conks

Indian Paint Defect

◼ IDL Scale Manual◼ 4ft. Up and 6 ft.

down from conk or punk knot

◼ Standing timber (U. of I. report)◼ 1 conk = 16 ft. up &

down, 2-3 conks = total cull

◼ Top log usually sound

Often causes breakage

Especially after partial harvests

Advance Regeneration?

Closely spaced dead branches indicate suppressed growth in the past

Red-Brown Root & Butt RotPhaeolus schweinitzii

◼ Hosts = All Idaho conifers, especially;◼ larch

◼ The pines

◼ Douglas-fir

◼ Defect◼ Heartwood 2-24 ft. up from

the butt

Cow Pie Fungus

New

Old

Red Ring Rot(pini)

Early & Advanced DecayRed Ring Rot (pini)

I

A

Red Ring Rot Hosts

◼ Hosts:◼ Common

◼ Western larch

◼ Pines

◼ Occasional◼ Most other species

◼ Defect◼ 4 ft. up and 6 ft. down from conk or

punk knot

◼ Several conks = total cull

Cedar Laminated Butt Rot

Laminated Butt Rot

Defect:Conk

indicates up to 18 ft. of cull in cedar

Cedar Brown Pocket RotPostia sericeomollis

Red Belt FungusThe recycler

Sapwood Width

◼ Sapwood width varies by species.

◼ Width also varies by growth rate

◼ Deterioration study – maybe drier sites, slower growth?

Larch Deterioration %