Wood Inhabiting Fungi – Friends Or Foe?

Home , Meripilus giganteus, Xylaria longipes

Materials Sci ence & Technolog y

Wood inhabiting fungi – friends or foe?

Prof. Dr. Francis W.M.R. Schwarze Curriculum vitae • 1962 Brighton, UK • 1991 National Diploma in Arboriculture, UK • 1992 MSc in Pure and Applied Plant and Fungal Taxonomy, UK • 1995 PhD, University of Freiburg, D • 2001 Associate Professor University of Freiburg, D • 2003 Empa, CH • 2006 Professor University of Freiburg, D Hazard risk 100 % 0 % ugeMutisUrban Mountains Jungle Hazardous potential oftreesondifferentsites forest Park street Side Centre City- Failure potential of cavities or large decay columns

Frequency 15

0.35-0.3 0.3-0.25 0.25-0.2 0.2-0.15 0.15-0.1 <0.1

t/R

Trees plotted by t/R against Distribution of the frequency of radius. Mattheck and Breloer t/R classes for 820 broken (1994). trees. Reproduced from Mattheck et al. (2006), with x- axis converted. Comparison of results obtained on standing and broken trees by Gruber 2007 and Mattheck and Breloer 1994. Note missing range of broken trees with t/R. ≥ 0.32. Reproduced from Gruber 2007. According to Bond (2006) and Gruber (2007), the following important implications for the t/R requirement can be made:

The ‘one-third rule’ is neither scientifically valid nor practicable and therefore should not be used for tree hazard assessment.

The t/R ratio can not be used as an index of trunk failure potential.

Trees can tolerate extremely large amounts of internal decay without necessarily being rendered hazardous. Invasive diagnostic devices

As the t/R ratio has no practicable implications for tree assessment, it has to be greatly questioned whether damage to trees inflicted by invasive diagnostic techniques for measuring the residual thickness is in any way justified. Module 1

Microscopy

Anatomy

Water conducting system

Wood as substrate for decay fungi Organisation levels of the water conducting system in trees

IIIIII IV

Tracheid- Fibre- Limited Vessel type type tracheid- fibre-tracheid- vessel type vessel type

Materials Sci ence & Technolog y Dry weight losses of balsa wood incubated with brown and white rot fungi (n=10)

6weeks

40 12weeks

10 W e ig h t lo s s (% )

0 Trametes versicolor Poria placenta Laetiporus sulphureus Gloeophyllum trabeum Coniophora puteana

-5

-10

Materials Sci ence & Technolog y Module 2

Biology

Tree pathogens

Symptoms

Infection courts

Biological control Mycoparasitism

Einführung

Material & Methoden

Ergebnisse & Diskussion

Schlussfolgerungen

Ausblick

Schubert et al. 2008. Biocontrol 45, 111-123.

Materials Sci ence & Technolog y Evaluation of antagonistic activity in wood

Mean weight losses of inoculated wood blocks Wood decay fungus Trichoderma 14.00 a 12.00

10.00

8.00 a

6.00 a b weight losses (%) losses weight 4.00 b b 2.00

0.00 6 weeks 12 weeks 18 weeks Incubation period

Symbols with different letters indicate significant (p≤0,05) differences in weight losses according to Ryan-Einot-Gabriel-Welsch-Test (REWGQ).

Materials Sci ence & Technolog y The carbon cycle

Materials Sci ence & Technolog y Sources of CO2 emissions

GtC02/y means gigatons (billions of metric tons) carbon dioxide per year

Materials Sci ence & Technolog y Using wood to tackle climate change

Biological control

Ely Cathederal Materials Sci ence & Technolog y Module 3

Construction of the wood cell wall

Lignin monomer composition

Degradation patterns

Impact on mechanical properties Beef steak fungus (Fistulina hepatica)

Heartwood

Discoloured heartwood Module 4

Compartmentalization of decay

Penetration of boundaries

Invasiveness of decay fungi

Prognosis of decay Reaction zones and barrier zones

Module 5

Visual assessment of crown structure

Application of diagnostic devices

Risks of invasive diagnostic devices

Assessment of tree vitality Reproduced from Jahn (2005) The absence of compensation growth may indicate a high tree risk for potential targets. Fungal ID Research

Seminars Expertise

Materials Sci ence & Technolog y WoodWood decaydecay fungifungi asas analyticanalytic toolstools forfor researchresearch

Lignin monomer Construction of Tree ring composition the cell wall analysis

Schwarze et al. (2000) Schwarze & Engels (1998) DeFlorio et al. (2005). Mycol. Res. 104,1126-1132. Holzforschung 52, 117-123. Dendrochronologia 22, 123- 130.

Materials Sci ence & Technolog y Detection of tree rings - Acer pseudoplatanus

Dry weight loss 11,85% 1 cm

Control Varnish 6 weeks Douglas fir Laetiporus sulphureus DeFlorio & Schwarze, F.W.M.R. (2004). Dendrochronologia.

Materials Sci ence & Technolog y Biotechnological application of wood decay fungi

Increase in wood Acceleration of Improvement of permeability wood decomposition acoustic properties

Schwarze et al. (2006) Schwarze & Ferner (2006) Schwarze et al. (2008) Holzforschung. New Phytol.

Materials Sci ence & Technolog y Are stem wounds potential infection courts for wood decay fungi?

? % ? % ? %

Tilia platyphyllos Are stem wounds potential infection courts for wood decay fungi?

? % ? % ? %

Aesculus hippocastanum Wood structure and construction of the cell wall

Early-wood tracheids

Materials Sci ence & Technolog y Cell wall constituents and their distribution within the

cell wall

l l

l Secondary

a e

w wall

a e

l Cellulose

P M

Pectin

Hemicellulose

Lignin

T.S. Materials Sci ence & Technolog y Brown rot fungi

Materials Sci ence & Technolog y Birefringence of cellulose when viewed under polarised light

T.S.

Under polarised light cellulose has a birefringence and appears bright, whereas strong lignified cell wall regions appear dark.

Materials Sci ence & Technolog y Dry weight losses of balsa wood incubated with brown and white rot fungi (n=10)

6weeks

40 12weeks

10 Weight loss(%) Weight

0 Trametes versicolor Poria placenta Laetiporus sulphureus Gloeophyllum trabeum Coniophora puteana

-5

-10

Materials Sci ence & Technolog y Detection of tree rings with brown rot fungi

6 Gewichtsverlustweeks 11,85%

Dry weight loss 11,85% 1 cm

Control Varnish Laetiporus Douglas fir sulphureus

DeFlorio & Schwarze (2005). Dendrochronologia 22, 123-130. Materials Sci ence & Technolog y UV-absorption measurements in Pinus sylvestris- wood

Absorption of UV-light by lignin is measured at wave lengths 250 – 300 nm. T.S.

Materials Sci ence & Technolog y Lignin monomers in trees

Guaiacyl-units Syringyl-units

Softwoods Hardwoods Syringyl units show a maximum absorption of uv-light at 272-274 nm, guaiacyl units at 278-280 nm.

Materials Sci ence & Technolog y Organisation levels of the water conducting system in trees

IIIIII IV

Tracheid- Fibre- Limited Vessel type type tracheid- fibre-tracheid- vessel type vessel type

Materials Sci ence & Technolog y Norway spruce and Fir

Excellent strength properties Nondurable in contact with soil

Difficult-to-treat (refractory)

wood species Quer Limited use of wood in service

Ta n g e l n dia tia a l R

Materials Sci ence & Technolog y Organisation level I

Tracheid-type

• Tracheids • e.g. conifers

Materials Sci ence & Technolog y Organisation of the water conducting system Level I

Tracheid type Strengthening tissue consisting of tracheids All conifers

Materials Sci ence & Technolog y Organisation level II

Fibre-tracheid-vessel type

• Fibre-tracheids • Vessels • e.g. Beech, London plane

Materials Sci ence & Technolog y Organisation of the water conducting system Level II Fibre-tracheid-vessel type Strengthening tissue consisting of fibre-tracheids Buxus sempervirens Rhododendron laetum Prunus padus

Fagus sylvatica Viburnum lantana Sobus aria Fagus orientalis Viburnum opulus Sorbus aucuparia Cercidiphyllum Alnus glutinosa Tilia cordata japonicum Crataegus monogyna Alnus incana Tilia platyphyllos Cratageus oxycantha Alnus viridis Castanea sativa Ilex aquifolium Betula pendula Castanea crenata Liquidambar styraciflua Betula pubescens Hippophae rhamnoides Malus sylvestris Carpinus betulus Rosa canina Mespilius germanica Corylus avellana Eucalyptus creba Platanus acerifolia Corylus colurna Eucalyptus globulus Platanus occidentalis Laurus nobilis Juglans regia Prunus avium Liriodendron tulipifera Juglans nigra Pyrus communis Magnolia tripetala

Materials Sci ence & Technolog y Organisation level III

Limited fibre-tracheid- vessel type

• Fibre-tracheids • Wood fibres • Vessels • e.g. Oak

Materials Sci ence & Technolog y Organisation of the water conducting system Level III Restricted tracheid-vessel-level Strengthening tissue consisting of fibre-tracheids and wood fibre regions Quercus borealis Ulmus carpinifolia

Quercus castaneifolia Ulmus glabra

Quercus ilex Ulmus laevis

Quercus petraea Koelreuteria paniculata

Quercus pubescens Laburnum anagyroides

Quercus robur

Wisteria sinensis

Materials Sci ence & Technolog y Organisation level IV

Vessel type

• Living wood fibres • Dead wood fibres • Vessels • e.g. Sycamore, Horse chesnut

Materials Sci ence & Technolog y S:G ratio of SW 88:12 Organisation of the water conducting system Level IV S:G ratio of CML 12:88 Vessel-wood fibre type Vessels Strengthening tissue consisting of dead or living wood fibre regions Acer campestre Fraxinus angustifolia Albizzia odoratissimia Acer ginnala Fraxinus excelsior Afzelia pachyloba Acer japonicum Fraxinus ornus Dipterocarpus indicus Acer negundo Gleditisia triacanthos Ficus carica Acer platanoides Gymnocladus dioicus Hura crepitans Acer pseudoplatanus Morus alba Lophira alata Acer saccharum Morus nigra Shorea talura Acer tataricum Paulownia tomentosa Sterculia oblonga Aesculus Rhus vermiciflua Terminalia superba hippocastanum Aesculus carnea Robinia pseudoacacia Triplochiton Lagerstroemia indica Sophora japonica Virola surinamensis Nothofagus dombeyi Tectonia grandis Khaya senegalensis Salix caprea Acucoumnea Peltophorum pterocarpum Samanea saman

Materials Sci ence & Technolog y Sycamore wood naturally infected with Armillaria mellea

Schwarze et al. 2000. Mycol Res. 104, 126-132. Sycamore wood viewed under the UV-microscope at a wavelength of 280 nm

The darker the appearance of the cell wall, the stronger the absorption of UV-light by lignin.

Schwarze et al. 2000. Mycol Res. 104, 126-132.

Materials Sci ence & Technolog y UV-spectra of sycamore wood cells

0,3 Absolut values are highest in vessels 0,25 and parenchyma 0,2

cells, lowest in fibres 0,15 without and with intercellular spaces 0,1

UV-maximum of Relative UV-Absorption 0,05

vessels = 280 nm 0 250 260 270 280 290 300 UV-maximum of Wavelength in nm fibres = 276 nm

Schwarze et al. 2000. Mycol Res. 104, 126-132. Materials Sci ence & Technolog y Annual ring border White rot

Simultaneous rot Selective delignification

Materials Sci ence & Technolog y Selective delignification by Phanerochatae chrysosporium

Phanerochatae chrysosporium

Materials Sci ence & Technolog y Norway spruce and Fir

Excellent strength properties Nondurable in contact with soil

Difficult-to-treat (refractory)

wood species Quer Limited use of wood in service

Ta n g e l n dia tia a l R

Materials Sci ence & Technolog y Aspiration of bordered pits

Margo

Torus

Sapwood

Heartwood Materials Sci ence & Technolog y Incising of conifer wood

Control

Incised wood

Materials Sci ence & Technolog y Water sprinkling and wet storage of wood

Water sprinkling of logs

Degradation of pit membranes by bacteria Materials Sci ence & Technolog y Lignolytic enzymes of white rot fungi + Laccase (α-naphthol)

-KOH

+ Peroxidase (Pyrogallol &

H2O2)

+ Tyrosinase (p-cresol)

Materials Sci ence & Technolog y Selective degradation of calicium pectate by Physisporinus vitreus

Schwarze & Fink (1998). New Phytologist, 139, 721-731.

Schwarze & Landmesser (2000). Holzforschung 54, 461- 464.

Materials Sci ence & Technolog y Pretreatment of wood with Physisporinus vitreus to enhance its permeability

Schwarze et al. (2006) Holzforschung 60, 450-454. Materials Sci ence & Technolog y Selective degradation of tori by Physisporinus vitreus

Polygalacturonase Oxalic acid

Schwarze et al. (2006) Holzforschung 60, 450-454. Materials Sci ence & Technolog y Bioincising of conifer wood with Physisporinus vitreus

Properties under evaluation: Reduction of water uptake (Hydrophobisation) Fire protection UV-light protection Hardness

Materials Sci ence & Technolog y Fungal enzymes for biotechnology

Laboratory for Wood 115 – Laboratory for Biomaterials 275 wood protection group Know-how: Know-how: • Genetic engineering (cloning and modification of • Isolation and cultivation of wood-degrading fungi genes in microbial expression systems) • Mechanisms of biological wood degradation • Protein expression and purification • Strain collection of white rot fungi • Bioprocess engineering (high cell density culture for efficient production of recombinant enzymes) • Biotechnological modification of wood • Chemical and biochemical analytics

Degradation of tori (= lignified gates between wood cells) in spruce Recombinant Escherichia coli Purification of hexa-histidine-tagged wood by Physiporinus vitreus after six weeks of incubation expressing intracellular green GFP by Ni-affinity chromatography: fluorescent protein (GFP) White rot fungus P. vitreus 1 total cell protein cultivated on malt agar plate 2 soluble proteins after cell lysis 3 purified protein (expected size 29.2 kDa)

GFP-6His

(SDS-PAGE gel, Coomassie-stained)

Picea abies (spruce) Automated high pressure bioreactor at Empa St. Gallen 100

80 Increased uptake of water- based dyes after wood Abies alba (fir) 60 600

colonization by P. vitreus OD (numbers = specific water 40 uptake in kg m-3), arrows 20 indicate the direction of

hyphal growth 0 0 5 10 15 20 25 30 process time (h)

Laccase Manganese peroxidase

Materials Sci ence & Technolog y Laccase antibacterial surface process (LASP)

Laccase catalyzed grafting of bioactive molecules on the wood surface

Materials Sci ence & Technolog y Spruce wood blocks after 80 weeks incubation with Heterobasidion annosum

Materials Sci ence & Technolog y Impact of selective delignification on the mechanical properties of wood

Materials Sci ence & Technolog y Simultaneous rot by Fomes fomentarius

Materials Sci ence & Technolog y Simultaneous rot in a stem of beech

Materials Sci ence & Technolog y Soft rot

T.S.

Materials Sci ence & Technolog y Soft rot caused by Kretzschmaria deusta within the stem of a living tree

S:G ratio of SW 88:12 S:G ratio of CML 12:88

Schwarze et al. (1995). Eur. Journal For. Path. Materials Sci ence & Technolog y Soft rot within the stem of a living tree

Speed of sound:

√ = E/ρ

E = Modulus of elasticity ρ = Density

Steel: 5000 m/s Aluminium: 5300 m/s St res s w av es Carbon fibre 11600-21200 m/s Wood: 800 -1800 m/s

Schwarze et al. (1995). Eur. Journal For. Path. Materials Sci ence & Technolog y Factors that influence the sound of a violin

Maintenance of the Instrument instrument Concert hall Art of violin making

Material Solist •Bow Interpretation • Strings • Wood Wood quality only partly •Varnish influences the sound of a violin

Materials Sci ence & Technolog y Function and requirements of violin components

Top plate: Norway spruce (Picea abies) Sound radiation Loudness

High ratio EL/ER

Bottom plate: „Curly maple“ (Acer pseudoplatanus) Aesthetics Damping Colour and „personality“

Low ratio EL/ER

Materials Sci ence & Technolog y Tonewood

Properties Very low density (maple 55- 65 g/cm3, Norway spruce 35 - 45 g/cm3) Minimum of 75 - 80% early wood Homogeneous annual rings Geographic origin Special drying and conditioning requirements

Wood with a low density, high velocity of sound and modulus of elasticity has superior properties i.e. its resonance characteristics and sound radiation is improved.

Materials Sci ence & Technolog y Violins of Antonio Stradivari (1644-1737)

Stradivari's earliest extant label is dated 1666 and his last 1737. His finest instruments were made after 1700. He produced some 1,100 instruments, of which about 540 violins, 12 violas and 50 cellos are known. His workmanship brought the violin to perfection.

Stradivari Violin Goes for $2.7M Christie's auction house

Materials Sci ence & Technolog y Maunder Minimum

During the coldest part of the Little Ice Age, from 1645 to 1715, there is believed to have been a decrease in the total energy output from the Sun, as indicated by little or no sunspot activity. Known as the Maunder Minimum, astronomers of the time observed only about 50 sunspots for a 30- year period as opposed to a more typical 40-50,000 spots.

Materials Sci ence & Technolog y Wood decay fungi as a substitute for cold climate

Structure of „normal“ wood Early wood tracheids grow in the spring and summer and have a wide lumina and thin walls. Their function is to conduct water and dissolved minerals. Latewood tracheids posses thick cell walls and are responsible for the mechanical stability of the tree. Structure of tone-wood Latewood content is reduced (<20%), resulting in a low wood density.

(A) Structure of decayed wood Hyphae produce cavities in the thick-walled tracheids. During incipient stages (left) mechanical properties are not altered significantly.

Materials Sci ence & Technolog y Metriguard-Impulshammer (stress-wave timer)

Velocity of sound:

√ = E/ρ

E = Modulus of elasticity ρ = Density

Steel: 5000 m/s Aluminium: 5300 m/s Carbon fibre 11600-21200 m/s Wood: 800 -1800 m/s Irregularities in the wood structure!

ISA Inaugural Asia Pacific Conference, Brisbane, Australia Materials Sci ence & Technolog y Metriguard stress-wave-timer

Measures the time taken for a stress wave to pass between a start probe and a stop probe. High readings = reduction in the velocity of sound.

ISA Inaugural Asia Pacific Conference, Brisbane, Australia Materials Sci ence & Technolog y Metriguard Laboratory Clamp Set

Measurements are made in wood blocks with a defined and reproducible stress-wave inserted via a pendulum hammer.

Schwarze et al. (1995). Eur. Journal For. Path.

ISA Inaugural Asia Pacific Conference, Brisbane, Australia Materials Sci ence & Technolog y Reduction in speed of sound in decayed wood blocks

Fungi Host Weight loss Control Decayed

F. pinicola Spruce 31,6 % 1048 m/s 281 m/s (73%)

F. fomentarius Beech 21,2 % 1300 m/s 672 m/s (52%)

I. hispidus Plane 13,7 % 1134 m/s 903 m/s (20%)

H. annosum Spruce 1,4 % 1048 m/s 222 m/s (77%)

K. deusta Lime 8,3 % 822 m/s 794 m/s (3,4%)

Schwarze et al. (1995). Eur. Journal For. Path.

ISA Inaugural Asia Pacific Conference, Brisbane, Australia Materials Sci ence & Technolog y Kretzschmaria deusta

√ = E/ρ

Schwarze et al. (1995). Eur. Journal For. Path. ISA Inaugural Asia Pacific Conference, Brisbane, Australia Materials Sci ence & Technolog y Soft rot within the stem of a living tree

St res s w av es

Schwarze et al. (1995). Eur. Journal For. Path.

ISA Inaugural Asia Pacific Conference, Brisbane, Australia Materials Sci ence & Technolog y Incubation method

With feeder blocks or malt solution Wood is incubated on vermiculite with buffered solution Wood strips (A): 2 - 50 weeks Quarter cuts (B): 6 - 9 months

Schwarze et al. (2008). New Phytol. Materials Sci ence & Technolog y Schematic drawing of the device used for measuring resonance frequency

Oscilloscope Figures of Lissajous Excitation and response Sinus wave generator Voltmeter

Pre-amplifier for Power amplifier 2 to 4 Watts the microphone Excitation or sound leve meter

Coil with Response Microphone resistance 4 WMagnet x

y 2/9 5/9 2/9

Axial wood strip : 150 mm x 25 mm x 3 to 4 mm

Transverse wood strip : 100 mm x 25 mm x 3 to 4 mm

Spycher et al. (2007). Wood Science & Technology Materials Sci ence & Technolog y Principal acoustic properties used for the assessment of tone wood quality of axial (L) and radial (R) samples

Schwarze et al. (2008). New Phytol. Materials Sci ence & Technolog y Norway spruce wood incubated with Xylaria cubensis

T.S. / 20 weeks T.L.S. / 20 weeks

Soft rot Type 1 Cavities in the S2 layer of the secondary wall

Materials Sci ence & Technolog y Norway spruce wood incubated with Xylaria cubensis

Density E modulus Sound velocity Radiation ratio Damping factor 10 100 Axial direction Radial direction 5 * **50

0 0 * -5 * -50 * * * * * * Change [%] Change * * -10 * -100

-15 -150 * * [%] factor of damping Change

-20 -200 Control 8 12 16 Control 8 12 16 weeks weeks weeks weeks weeks weeks (n=5) (n=5) (n=5) (n=5) (n=5) (n=5) Incubation time Schwarze et al. (2008). New Phytol. Materials Sci ence & Technolog y Norway spruce wood incubated with Physisporinus vitreus

T.S. / 12 weeks T.S. / 20 weeks

Selective delignification without degradation of the middle lamella and separation of cells from each other After 20 weeks incubation the compound middle lamella shows signs of degradation

Materials Sci ence & Technolog y Norway spruce wood incubated with Physisporinus vitreus

Density40 E modulus Sound velocity Radiation ratio Damping factor400

30 Axial direction Radial direction 300

20 * 200

* * 100 10 * 0 0

-10 -100

Change [%] * ** ** * * * -20 -200 * -30 * -300 Change of damping factor [%]

-40 Control 6 12 20 Control 6 12 20 -400 weeks weeks weeks weeks weeks weeks (n=10) (n=10) (n=10) (n=10) (n=10) (n=10)

Incubation time Schwarze et al. (2008). New Phytol. Materials Sci ence & Technolog y Sycamore wood incubated with Xylaria longipes

Schwarze et al. (2008). New Phytol.

Materials Sci ence & Technolog y Sycamore wood incubated with Xylaria longipes

Density E modulus Sound veolcity Radiation ratio Damping factor 20 200 Axial direction Radial direction 15 150 10 * * 100 * * * 5 * 50 0 0 -5 * * * * -50 -10 * * -100 Change [%] * * * -15 * * * * -150 -20 * -200 Change of damping factor [%] factor damping Change of -25 -250

-30 -300 Control 6 12 20 Control 6 12 20 weeks weeks weeks weeks weeks weeks (n=5) (n=5) (n=5) (n=5) (n=5) (n=5) Incubation time

Schwarze et al. (2008). New Phytol. Materials Sci ence & Technolog y Rot offers fresh sound for violin makers

Sounds like a Strad? Must be the mushrooms

Michael Rhonheimer, CH Dank Pilzen wird jede Geige zur Stradivari

Pilze lassen Geige wie echte Stradivari klingen

Pilze verhelfen Geige zu Stradivari-Klang

Materials Sci ence & Technolog y Beech – Meripilus giganteus Magnitudes of vitality

Roloff (2001) Beech – Meripilus giganteus Magnitude of vitality

Roloff (2001) Inonotus dryadeus -Oak

Early stage

Advanced stage Assessment of vitality via the crown architecture Magnitudes of vitality

Reproduced from Jahn (2005) The absence of compensation growth may indicate a high tree risk for potential targets. Reproduced from Jahn (2005) Symptoms Risk Aa No damage or visible symptoms, stem and bark intact, good increment growth…………………. 0 Ab Symptoms (damage to bark, cracks, decay, growth sunken bark, inclusions, fruit bodies) present B Ba Damage superficial, bark symptoms or decay that affect the stem from the outside……………… 1a Bb Damage not only superficial (decay also in deeper regions of the stem, cracks, inclusions, C reduction in increment growth …………………………………...... Ca Size of symptom or damage approx. 25 % of stem circumference, sharply demarcated by wound 1b wood, bark otherwise healthy and vigorous, compensation growth present……………………… Cb Region of damage larger and/or not sharply demarcated by wound wood……………………….. D

Da Stem or roots in areas of damage showing no or only weak compensation growth………………. 3 Db Stem or roots with compensation growth in close proximity to damage symptom……………….. E Ea Strong compensation growth of the stem or roots, bark intact and vigorous, sound wood sharply 2 demarcated from damaged regions……………………………………………………………… Eb Compensation growth not demarcated from damaged regions. Stem or roots showing severe 3 bark and decay symptoms…...... Classification of potential risk 0 Good condition No damage discernable 1a Satisfactory condition Superficial damage that can may affect the water conducting sapwood. Typical crown symptoms develop and dead branches may fail and cause damage t people and property 1b Satisfactory condition Damage compartmentalized and compensated by the tree 2 Adequate condition Larger amount of damage, which is compensated by the tree. Problems arise, when decay develops into the formerly sound compensation wood and cambial activity i.e. secondary thickening declines 3 Advanced damage Tree poses a risk to people and property. Reproduced from Jahn (2005) Forest tree Urban tree

Monetary value = low Monetary value = high - very high

Trees grow collectively Trees grow as in an ecosystem individuals

Weak abiotic stress Strong abiotic stress

Seldom stem and root Excessive stem and root damage damage

High strength and Low strength and stability stability Priority I Priority II

Condemn (total of Retain, prune and eight trees) inspect with Picus in two years (total of nine trees) Priority III Priority IV

Retain and inspect with Retain and inspect with Picus in five years (total of Picus in ten years (total 15 trees) of 20 trees) Biological control of wood decay fungi with Trichoderma spp.

32 x 1800 Euro = 57.600 €

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Sporulation period