abteilung waldnutzung wood properties of sawn timber of norway spruce (picea abies (l.) karst.)...
TRANSCRIPT
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
??