Increase in the Content of Extractives in Scots Pine ( Pinus - - PowerPoint PPT Presentation

Increase in the Content of Extractives in Scots Pine (Pinus sylvestris L ) in Scots Pine (Pinus sylvestris L.) during ISPM-15 Heat-Treatment and Correlation with Fungal Discoloration

Gerda Lambertz, Johannes Welling

Johann Heinrich von Thuenen-Institute (vTI) Federal Research Institute for Rural Areas, Forestry and Fisheries; Institute of Wood Forestry and Fisheries; Institute of Wood Technology and Wood Biology Hamburg, Germany Wood EDG Conference 23rd April 2009, Bled/Slovenia

Topics p

I.

Fundamentals

Background Problems Problems

II.

Research

Cause of fungal infestation Scientific approach

III.

Results

Effective measures to avoid infestation T ti ti kil d i ? Temporary active preservatives vs kiln drying ?

IV.

Outlook

Wood EDG Conference 23rd April 2009, Bled/Slovenia

• G. Lambertz

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Facts

Wood packaging material:

freshly cut, undried sawn timber (in Germany: mostly Scots Pine) l lit

ntals

low quality low-priced and disposable just in time

damen

complete kiln-drying is often too expensive f f ti l h i l d ti

Fund

free of conventional chemical wood preservatives must be phytosanitary treated before exporting (ISPM No 15)

I.

Wood EDG Conference 23rd April 2009, Bled/Slovenia

• G. Lambertz

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ISPM No15

2002 IPPC adopted ISPM Nr.15:

to avoid the spreading of quarantine harmful organisms (insects)

ntals

(insects) in more than 40 non-European countries required

damen

treatment only in certified companies treated material must be marked immediatly

Fund

treated material must be marked immediatly two approved measures for phytosantitary treatment:

I.

Methyl bromid fumigation Heat-treatment

Wood EDG Conference 23rd April 2009, Bled/Slovenia

• G. Lambertz

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Adopted measures p

Methyl bromid fumigation [MB]

not allowed anymore in most European countries

ntals

„Heat-treatment“ [HT]

min 56°C for at least 30 minutes core temperature

damen

• min. 56 C for at least 30 minutes core temperature

carried out in ordinary kilns

Fund

can be combinded with drying operations no requirements regarding moisture content therefore

I.

no requirements regarding moisture content, therefore minimized length of stay in the kiln (MC before HT ~ MC after HT)

Wood EDG Conference 23rd April 2009, Bled/Slovenia

• G. Lambertz

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Problem

Fresh, heat-treated and undried sapwood shows a

much higher affinity towards mould and blue stain than normal material

ntals

visual defect

hygenical problem

damen

hygenical problem

Remember:

Fund

Remember:

• complete kiln-drying is often too expensive

I.

• no conventional chemical wood preservatives

Wood EDG Conference 23rd April 2009, Bled/Slovenia

• G. Lambertz

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Fungal infestation after one week g

h earch

• I. Res

II

Control HT

Wood EDG Conference 23rd April 2009, Bled/Slovenia

• G. Lambertz

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Control HT

Fungal infestation after two weeks g

h earch

• I. Res

II

Control HT

Wood EDG Conference 23rd April 2009, Bled/Slovenia

• G. Lambertz

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Control HT

Objectives j

Inhibition of fungal growth on non-dried heat

treated wood and green wood until it has dried sufficiently

h

Alternatives to conventional preservatives and

kiln drying should be:

earch

y g

• ecologically harmless
• i

ll d t

• I. Res
• economically advantageous
• temporarily effective

II

Wood EDG Conference 23rd April 2009, Bled/Slovenia

• G. Lambertz

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Scientific procedure p

Chemical analysis

→ Reason for increasing fungal risk

h

Based on analytical results

earch

y

→ Identification of low-cost methods to minimize the

problem by providing temporary protection against

• I. Res

p y p g p y p g discoloring fungi

II

Wood EDG Conference 23rd April 2009, Bled/Slovenia

• G. Lambertz

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Chemical analysis y

Att ib t HT C t l Attribute HT : Control Moisture content No significant difference

sults

Moisture distribution No significant difference

• II. Res

pH-value Significant difference Free sugar content at surface Significant difference

II

Free sugar content at surface Significant difference Amount of lipophilic extractives Significant difference

Wood EDG Conference 23rd April 2009, Bled/Slovenia

• G. Lambertz

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Explanation p

Lipophilic extractives (fats, fatty acids,

triglycerides) as well as free sugars are an important foodstuff for wood discoloring fungi

sults

Heat treatment

• II. Res

Release of extractives in parenchyma cells

II

Release of extractives in parenchyma cells additional nutrition source

Wood EDG Conference 23rd April 2009, Bled/Slovenia

• G. Lambertz

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Idea

chemical bonding of lipophilic extractives

to withdraw foodstuff

Saponification Saponification

change of surface conditions

sults

g

to inhibit germination of fungal spores

I f h l

• II. Res

Increase of ph-value

II

Alkali-treatment

Wood EDG Conference 23rd April 2009, Bled/Slovenia

• G. Lambertz

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Fungal infestation after three weeks (HT) g

sults

• II. Res

II

No treatment with Caustic soda 7,5% + No treatment with chemicals Caustic soda 7,5% surfactant

Wood EDG Conference 23rd April 2009, Bled/Slovenia

• G. Lambertz

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Temporary treatment vs kiln drying p y y g

Alkalization Kiln drying

sults

Costs of treatment ++

• D

ti f t t t +

• II. Res

Duration of treatment +

• Effectiveness

+ ++

II

Duration of effectiveness

• ++

Wood EDG Conference 23rd April 2009, Bled/Slovenia

• G. Lambertz

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Conclusion

Alkalization of fresh sapwood as a first and temporary protection

tlook

p y p + Drying (either natural or technical) as a

• V. Out

Drying (either natural or technical) as a long- term protection

IV

= Optimal protection against mould and blue stain

Wood EDG Conference 23rd April 2009, Bled/Slovenia

• G. Lambertz

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Wood EDG Conference 23rd April 2009, Bled/Slovenia

• G. Lambertz

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