Download - NASP IMDS Stand Density THE BIG THREE: Absolute stand density Quadratic Mean Diameter Basal Area
NASP IMDS
Stand Density
THE BIG THREE:• Absolute stand density• Quadratic Mean Diameter• Basal Area
Graphical Guides
Size-Density Relationship
The predictable relationship between mean size of trees and their associated density in crowded (i.e., stem exclusion) populationsD
en
sity
Age
Boundary Line Examples (AKA: “-3/2 Power Law”)
Log-logScale
Growth Trajectories Wiley 1976
Stand Density Index
Stand Density Index (SDI) – Woodard paper
Reineke (1933) Species-specific upper limit Density when the stand has a standardized QMD Calculated as:
605.1
Imperial 10TPASDI
QMD 605.1
Metric 4.25TPHSDI
QMD
Stand Density Index Values
Maximum SDI Maximum SDI(English) (metric)
White fir 830 2050 Reineke, 1933Red fir 1000 2470 Reineke, 1933Mixed conifer for CA 750 1850 Reineke, 1933Douglas-fir for WA-OR 595 1470 Reineke, 1933Douglas-fir for CA 600 1480 Reineke, 1933Eucalyptus 490 1210 Reineke, 1933Redwood 1000 2470 Reineke, 1933Ponderosa Pine 800 1980 Reineke, 1933Loblolly Pine 450 1110 Reineke, 1933Longleaf Pine 400 990 Reineke, 1933Slash Pine 400 990 Reineke, 1933Shortleaf Pine 400 990 Reineke, 1933Upland Oak 230 570 Schnur, 1937Ponderosa Pine 830 2050 Long, 1985Lodgepole pine 690 1700 Long, 1985Douglas-fir 587 1450 Long, 1985Western Hemlock 790 1950 Long, 1985
Species Source
Suggested Maximum SDI by species and source. English units are number of10-inch trees per acre. Metric units are number of 25.4cm trees per hectare.
Long, J. N. 1985. A pratical approach to density management. Forest Chronicle 61:23-37. Reineke, L. H. 1933. Perfecting a stand density index for even-aged forests. Journal of Agricultural Research 46(7):627-638. Schnur, G. L. 1937. Yield, stand, and volume tables for even-aged upland oak forests. USDA Technical Bulletin No. 560, 87p.
StockingCharts & Guides
Size vs. Density Log-Log scale SDI on the “third axis” SDImax = 1000
Taylor WoodsLevel-of-Growing-Stock
Study
Flagstaff, AZ
Relative Density Index
Relative Density Index (RDI) Basically the percent of maximum SDI Communication across species (species have
maximums) Intuitive feel Magic thresholds for stand dynamics
0.15 - 0.30 for crown closure 0.40 for scheduling of growing space thinnings 0.55 for entering “the zone of imminent competition” 0.80 for certain mortality agents
DensityGuides
Density Management Diagrams
Packaging the concepts together
Simple management tool Old GSL “boat” diagrams Additional information on
the diagrams
INTERPRETING CHANGES
150
(800 TPA, 5.1”)
653 TPA
4”
340 TPA
6”
DensityGuides
Density Effects on Growth
Density Effects on GrowthTaylor Woods: Four decades of TREE DIAMETER growth; 1962 - 2002
y = -1.3146Ln(x) + 7.106
R2 = 0.97y = -1.415Ln(x) + 7.6447
R2 = 0.9793
y = -1.4821Ln(x) + 8.2557
R2 = 0.9873
y = -1.1867Ln(x) + 6.8112
R2 = 0.9767
0
1
2
3
4
0 20 40 60 80 100 120 140 160
basal area (sf/ac) at decade's beginning
DB
H g
row
th (
inch
es/d
ecad
e)
GSL40 1962-1972
GSL60 1962-1972
GSL80 1962-1972
GSL100 1962-1972
GSL120 1962-1972
GSL150 1962-1972
1962-1972
1972-1982
1982-1992
1992-2002
Log. (1962-1972)
Log. (1972-1982)
Log. (1982-1992)
Log. (1992-2002)
Density Effects on GrowthTaylor Woods: Four decades of TREE HEIGHT growth; 1962 - 2002
y = -2.1886Ln(x) + 14.675
R2 = 0.6736
y = -1.4543Ln(x) + 11.654
R2 = 0.3773
y = -2.3839Ln(x) + 16.391
R2 = 0.6455
y = -1.8418Ln(x) + 13.568
R2 = 0.6672
0
2
4
6
8
10
0 20 40 60 80 100 120 140 160
basal area (sf/ac) at decade's beginning
hei
gh
t g
row
th (
feet
/dec
ade)
GSL40 1962-1972
GSL60 1962-1972
GSL80 1962-1972
GSL100 1962-1972
GSL120 1962-1972
GSL150 1962-1972
1962-1972
1972-1982
1982-1992
1992-2002
Log. (1962-1972)
Log. (1972-1982)
Log. (1982-1992)
Log. (1992-2002)
Density Effects on GrowthTaylor Woods: Four decades of CUBIC FOOT VOLUME growth; 1962 - 2002
y = 209.37Ln(x) - 241.19
R2 = 0.8082
y = 240.24Ln(x) - 387.18
R2 = 0.8335
y = 278.49Ln(x) - 516.98
R2 = 0.7585
y = 444.4Ln(x) - 1246.2
R2 = 0.8503
0
200
400
600
800
1000
1200
0 20 40 60 80 100 120 140 160
basal area (sf/ac) at decade's beginning
MC
F V
olu
me
gro
wth
(cf
/ac/
dec
ade)
GSL40 1962-1972
GSL60 1962-1972
GSL80 1962-1972
GSL100 1962-1972
GSL120 1962-1972
GSL150 1962-1972
1962-1972
1972-1982
1982-1992
1992-2002
Log. (1962-1972)
Log. (1972-1982)
Log. (1982-1992)
Log. (1992-2002)
PER ACRE
Density Effects on GrowthPER ACRETaylor Woods: Three decades of BOARD-FOOT VOLUME growth; 1972 - 2002
y = -0.2407x2 + 33.39x + 1134.4
R2 = 0.31
y = -0.3955x2 + 56.14x + 847.11
R2 = 0.6366
y = -0.2786x2 + 71.106x - 626.9
R2 = 0.8283
0
1000
2000
3000
4000
5000
0 20 40 60 80 100 120 140 160
basal area (sf/ac) at decade's beginning
Scr
ibn
er B
oar
d-F
oo
t V
olu
me
gro
wth
(b
f/ac
/dec
ade)
GSL40 1972-1982
GSL60 1972-1982
GSL80 1972-1982
GSL100 1972-1982
GSL120 1972-1982
GSL150 1972-1982
1972-1982
1982-1992
1992-2002
Poly. (1972-1982)
Poly. (1982-1992)
Poly. (1992-2002)
DENSITY EFFECTS ON GROWTH
Tree vigor and mortality rates Plasticity of the trees – think about this at
“Hoskins” LOGS study (chapter 7) Live Crown Ratio and “canopy depth” Crown Radius (branch length/size) and crown closure Height:Diameter and “stability” (e.g., in wind and snow) Wood utilization products; size and quality
Understory richness, diversity and abundance Net Primary Productivity distribution Ecosystem “stuff”
OTHER DENSITY MEASURES
CURTIS’ “RELATIVE DENSITY” RD = BA √QMD
RELATIVE or “AVERAGE SPACING”: (can be relative to heights, as well)
TREE-AREA RATIO: area occupied by tree crowns per unit land area; TA can be estimated from D or D2
CROWN COMPETITION FACTOR; TA relative to open grown trees
Spacing impacts Example calculations - Douglas-fir (SDImax = 600)
QMD TPA BA SDI RDI CRD Description
6 50 9.8 22 0.04 4 low-density young plantation
6 200 39.3 88 0.15 16 crown closure
6 400 78.5 176 0.29 32 well-stocked
10 50 27.3 50 0.08 9 low density, but great tree growth
10 200 109.1 200 0.33 34 well-stocked
10 400 218.2 400 0.67 69 moved into "the zone"
15 50 61.4 96 0.16 16 crown closure
15 200 245.4 383 0.64 63 moved into "the zone"
15 400 491 767 1.28 127 impossible, would have self thinned
24 50 157.1 204 0.34 32 well-stocked
24 200 628 815 1.36 128 impossible, would have self thinned
24 400 1257 1630 2.72 257 completely crazy idea
UNEVEN-AGED structures?
SDI calculated by diameter class from a stand table
BUT don’t stretch too far…why?
TPA BAPA SDI
2 50 1 4
6 10 2 4
10 0 0 0
14 60 64 103
18 80 141 205
22 20 53 71
220 261 388