1 Introduction to Silviculture • Objectives – Overview of silviculture – Structural measures used to characterize forest stands and resources – First: questions, take-home points, things you learned, etc. from reading assignment Silviculture is to forestry as agronomy is to agriculture in that it is concerned with the technology [i.e., science] of growing vegetation. Like the rest of forestry itself, silviculture is an applied science that rests on the more fundamental natural and social sciences.
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Introduction to Silviculture
• Objectives – Overview of silviculture – Structural measures used to characterize
forest stands and resources
– First: questions, take-home points, things you learned, etc. from reading assignment
Silviculture is to forestry as agronomy is to agriculture in that it is concerned with the technology [i.e., science] of growing vegetation. Like the rest of forestry itself, silviculture is an applied science that rests on the more fundamental natural and social sciences.
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• Silviculture - Applied Forest Ecology
Introduction to Silviculture
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• Silviculture - Applied Forest Ecology – Ecological forestry (Franklin et al. 2007)
• Emulation of natural disturbances and resulting stand development processes as a model for silvicultural practices
• 3-legged stool of ecological forestry – Retention of biological legacies at harvest – Intermediate treatments to enhance stand heterogeneity
(structural & compositional) – Allowance of appropriate recovery periods between
harvests
Introduction to Silviculture
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• Silviculture - Applied Forest Ecology – Ecological forestry (Franklin et al. 2007)
Introduction to Silviculture
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• Silviculture - Applied Forest Ecology
Introduction to Silviculture
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• Silviculture - Applied Forest Ecology
Introduction to Silviculture
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• Silviculture - Applied Forest Ecology – Silvicultural practices / treatments
Introduction to Silviculture
Thinning Pruning
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Introduction to Silviculture
• Silviculture - Applied Forest Ecology – Silvicultural practices
• Control of stand structure & processes • Control of composition • Control of stand density • Control of rotation length • Facilitating harvest • Restocking/renewing next cohort • Protection • Conservation of site productivity
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Introduction to Silviculture
• Forest Structure - Stand Density 10 m
10 m
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Introduction to Silviculture
• Forest Structure - DBH
10 m
10 m
# inside circle is DBH (cm) 60
15 20
30
35
45
1.37 m diameter
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Introduction to Silviculture
• Forest Structure – Diameter Distribution
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Introduction to Silviculture
• Forest Structure - Basal Area (Ind. Tree) – Cross-sectional area of an individual tree at
breast height (cm2 or m2) – BA = (π*dbh2) / 4
• For dbh in cm and BA in cm2 – BA = (π*dbh2) / (4 * 10,000)
• For dbh in cm and BA in m2
DBH = 20 cm
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Introduction to Silviculture
• Forest Structure - Basal Area (Stand) – Typically expressed as square units of BA (m2) per
unit of land area (ha); m2/ha (or cm2/m2)
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10 m
# inside circle is DBH (cm) 60
15 20
30
35
45
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Introduction to Silviculture
• Forest Structure - Quadratic Mean Diameter – For QMD (cm) from Mean BA (m2)
10
10 m
# inside circle is DBH (cm) 60
15 20
30
35
45
)0000785.0/()( MeanBAcmQMD =
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Introduction to Silviculture
• Forest Structure - Annual Increment – MAI = Mean Annual Increment
• Volume or mass per unit area / Age – CAI = Current Annual Increment
• Volume or mass at the end of the current year - Volume or mass at the beginning of the current year
– PAI = Periodic Annual Increment • (Volume or mass at the end of a period - Volume or
mass at the beginning of the period) / length of the period
• If length of the period is 1 year, then PAI = CAI
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Introduction to Silviculture
• Forest Structure - Annual Increment
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Introduction to Silviculture
• Forest Structure - Allometry
• Biomass – Y = aXb
– Y = 0.88*X1.86
dbh (cm)
0 10 20 30To
tal B
iom
ass
(kg)
0
150
300
450
600
CR2=0.95
Metrosideros polymorpha
Litton & Kauffman (2008)
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Introduction to Silviculture
• Forest Structure – Site Index
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Introduction to Silviculture
• Forest Structure – Site Index & Volume Douglas-Fir
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Introduction to Silviculture
• Forest Characterization Exercise – Purpose: (a) experience calculating some of
the more commonly used metrics of forest resources; and (b) to prep you for Mid-term II
– Assigned 3/7/16 via email – Due 3/17/16 in class via hardcopy print
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