Lecture 11FORE 3218
Forest Mensuration IIForest Mensuration II
Lectures 11Lectures 11
Stocking and Stand DensityStocking and Stand Density
Avery and Burkhart,Avery and Burkhart,
Chapter 15Chapter 15
Lecture 11FORE 3218
Definitions Definitions
Stand Density Stand Density –is a quantitatively term describing –is a quantitatively term describing the degree of stem crowding within a stocked areathe degree of stem crowding within a stocked area– Absolute or relative Absolute or relative
StockingStocking –refers to the adequacy of a given stand –refers to the adequacy of a given stand density to meet some density to meet some management objectivemanagement objective– Understocked, fully stocked, or overstockedUnderstocked, fully stocked, or overstocked
Stand density and stocking are often applied Stand density and stocking are often applied interchangeably interchangeably
A stand that is “overstocked” for one management objective could be “understocked” for another
Lecture 11FORE 3218
Measures of Stand DensityMeasures of Stand Density
Stand density – measures how thickly trees grow Stand density – measures how thickly trees grow in a standin a stand– Stems per unit areaStems per unit area
– Basal areaBasal area
– VolumeVolume
– IndicesIndices
Lecture 11FORE 3218
Measures of Stand DensityMeasures of Stand Density
Stems per unit areaStems per unit area Basal areaBasal area Relative stand densityRelative stand density Crown competition factorCrown competition factor
Black spruce
0
2000
4000
6000
8000
10000
0 20 40 60 80 100
Stand age (years)
Ste
ms
per
ha
Subject stand
Fully stocked
Lecture 11FORE 3218
Stems per unit areaStems per unit area Basal areaBasal area Relative stand densityRelative stand density Crown competition factorCrown competition factor Black spruce
0
10
20
30
40
0 20 40 60 80 100
Stand age (years)
Ba
sa
l a
rea
(m
2 /ha
)
Fully stocked
Measures of Stand Density (Measures of Stand Density (cont.cont.))
N
iibBA
1
2)2
( ii
db
Subject stand
Lecture 11FORE 3218
Ontario’s Jack Pine DMD (Archibald & Bowling. 1995. OMNR NEST TN-005)
Zone of Imm
inent Com
petition Mortality
Zone of crown closure
RSD=1
=0.55
=0.15
Measures of Stand Density (Measures of Stand Density (cont.cont.))
Stems per unit areaStems per unit area Basal areaBasal area Relative stand densityRelative stand density Crown competition factorCrown competition factor
RSD =Density of the subject stand
Maximum density attainable with the same as the subject standV
3/2 law of self thinning
aNV log2/3log
Lecture 11FORE 3218
Measures of Stand Density (Measures of Stand Density (cont.cont.))
Stems per unit areaStems per unit area Basal areaBasal area Relative stand densityRelative stand density Crown competition factorCrown competition factor
– reflects the area available to the average tree in a stand in relation to the maximum area it could use if it were open-grown
2)2
(CW
MCA
DBHbb 10
100(%) 1 a
MCA
CCF
N
ii
Lecture 11FORE 3218
Measures of Point DensityMeasures of Point Density
n
jj
ii aA
CI1
1
Quantify the competition level at a Quantify the competition level at a given point or a tree in a standgiven point or a tree in a stand
rcompetitioth theof overlap of area
rscompetitio ofnumber
eesubject trfor circlen competitio of area
eesubjext trfor index n competitio
ja
n
iA
iCI
j
i
i
Area overlap indexArea overlap index
Lecture 11FORE 3218
Measures of Point DensityMeasures of Point Density
n
j ij
iji DIST
DDCI
1
/
Distance-weighted size ratiosDistance-weighted size ratios
competitorth and treeebetween th distanceDIST
eesubject trth theofdbh
competitorth theofdbh
scompetitor ofnumber
eesubjext trfor index n competitio
ji
iD
jD
n
iCI
ij
i
j
i
Lecture 11FORE 3218
StockingStocking
A ratio of comparison of A ratio of comparison of the density of a subject the density of a subject stand to that of a “ideal” stand to that of a “ideal” or reference stand or reference stand – VolumeVolume– Basal areaBasal area
Lecture 11FORE 3218
Measures of StockingMeasures of Stocking
What should constitute full stocking of a What should constitute full stocking of a particular species on a given site?particular species on a given site? – NormalNormal or fully stocked stand: or fully stocked stand: in such a hypothetical in such a hypothetical
stand, tree crowns are fitted together so that no stand, tree crowns are fitted together so that no sunlight is wasted and each crown is matched with a sunlight is wasted and each crown is matched with a root system that fully utilizes the soilroot system that fully utilizes the soil
Normal stands are “Normal stands are “average bestaverage best” -- closed ” -- closed canopy stands canopy stands
Lecture 11FORE 3218
MeasuresMeasures– Mature standsMature stands– Stands at Stands at
regeneration stageregeneration stage
Stocking (Stocking (cont.cont.))
Lecture 11FORE 3218
Stocking GuidesStocking Guides
Depicts the relationship between basal area, Depicts the relationship between basal area, trees per ha, and quadratic diameter at breast-trees per ha, and quadratic diameter at breast-heightheight
Trees per ha
Bas
al a
rea
per
ha
Mean DBH (cm)
A
B
10
1520
25
30
Top Related