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AbteilungWaldnutzung
Wood properties of sawn timber
of Norway spruce (Picea abies (L.)
Karst.) grown under wide spacing
Franka Brüchert, Florian Frisch, Udo H.
Sauter
IUFRO All Division 5 Conference, Taipei
AbteilungWaldnutzung
“ If we regard future-crop trees
rather as tamed solitaries than
as partially unshackled captives,
then science must also more
intensly address research on
solitary trees.“
ABETZ 1987
Introduction
AbteilungWaldnutzung
Silvicultural alternatives
2 trees per site
alternative
A
350 / ha
age 28-29
alternative
B
700 / ha
age 27-29
alternative
FA
1600 / ha
age 42
isolation at age ~ 15 years
AbteilungWaldnutzung
Test material
stem
dis
c at
1
.30
m
stem
dis
c at
5 m
4 m log, split to 2x2m
2 short logs (1.37 – 2.06 m)
44 cants
5 x 10 cm²
78 laths
3 x 6 cm²
AbteilungWaldnutzung
Results “Roundwood“
AbteilungWaldnutzung
Roundwood quality
0 %
25 %
50 %
75 %
100 %
A B C D A B C D
BW grading rules ENV 1927-1: 1998
grade
pro
po
rtio
n o
f lo
gs
in
gra
de
cla
ss
[%
]
alternative A
alternative B
alternative FA
down-grading reasons: knots, ring width, compression wood
AbteilungWaldnutzung
Branchiness of roundwood
alternative A & B: ca. 80% sound knotsalternative FA : 7.5% sound knots
22.3
34.4
38.7
0
20
40
A B FA
alternative
larg
est
bra
nch
[m
m] threshold
between grade B and C
AbteilungWaldnutzung
Ring width of roundwood
7.37.9
4.0
0
2
4
6
8
10
A B FA
alternative
rin
g w
idth
wit
ho
ut
juven
ile w
oo
d
[mm
]
threshold between
A & B
threshold between
grade B & C
threshold S 7/ S 10
AbteilungWaldnutzung
Results “Sawn timber“
AbteilungWaldnutzung
threshold S 13/ S 10: wide side: 20mm narrow side: 10mm
threshold S 10/ S 7 : wide side: 40mm narrow side: 20mm
26,722,6
17,8
0
10
20
30
A B FA
alternative
mea
n d
iam
eter
of
thic
kest
bra
nch
[m
m]
Knot dimension of sawn timber
AbteilungWaldnutzung
Knottiness of sawn timber
0
25
50
75
100
S 13 S 10 S 7 S 0 S 13 S 10 S 7 S 0
cant lath
grade
pe
rce
nta
ge
of
pie
ce
s i
n
gra
din
g c
las
s [
%]
A
B
FA
S 0 = reject
AbteilungWaldnutzung
Ring width of sawn timber (cants)
7,2 7,2
3,7
0
2
4
6
8
A B FAalternative
rin
g w
idth
[m
m]
threshold between
S13 & S10
treshold between S10 & S7
AbteilungWaldnutzung
Ring width of sawn timber
0
25
50
75
100
S 13 S 10 S 7 S 0 S 13 S 10 S 7 S 0
cant lath
grade
pe
rce
nta
ge
of
pie
ce
s i
n
gra
din
g c
las
s [
%]
A
B
FA
S 0 = reject
AbteilungWaldnutzung
Twist of sawn timber
0
25
50
75
100
S 13 S 10 S 7 S 0 S 13 S 10 S 7 S 0
cant lath
grade
pe
rce
nta
ge
of
pie
ce
s i
n
gra
din
g c
las
s [
%]
A
B
FA
S 0 = reject
AbteilungWaldnutzung
Wood density, MOE & MOR of sawn timber
AbteilungWaldnutzung
Quality trend for future?
branches
ringwidth
density
juvenile core
??
