NR 326 Lecture 3 Describing Forest Stands

What is a stand?• Stand = site + vegetation • Stand is a silvicultural management unit A contiguous group of trees sufficiently uniform in age-class distribution, composition, and stru

What is a stand?

• Stand = site + vegetation

• Stand is a silvicultural

management unit

A contiguous group of trees sufficiently uniform in age-class distribution, composition, and structure, and growing on a site of sufficiently uniform quality, to be a distinguishable unit (SAF 2008)

Stand Descriptors

• Location

• Site

• Stand development phases

Stand Initiation Stage

Stem Exclusion Stage

Understory Reinitiation Stage

Old Growth Stage

Stand Descriptors

• Location

• Site

• Stand development phases

• Stand age

IIB

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10

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80

6 9 12 15 18 21 24 27 30 33 36 39 42 45

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D1.3

Stand Descriptors

• Location

• Site

• Stand development phase

• Stand age

• Even-aged Vs two-aged Vs uneven-aged

Even-aged stand

A forest stand or forest type in which relatively small (10-20 year) age differences exist between individual trees

A stand of trees composed of a

single age class in which the

range of tree ages is usually

±20 percent of rotation (SAF,

2008)

A stand with trees of two

distinct age classes

• Balanced Vs Irregular

• Pure or mixed species

• Single tree or group-wise

regeneration gaps

A stand with trees of three or more

distinct age classes, either

intimately mixed or in small groups

Stand Descriptors

• Location

• Site

• Stand development phase

• Stand age

• Even-aged Vs two-aged Vs uneven-aged

• Composition

– Pure Vs Mixed

 Pure stand

 Mixed stand

Natural forest in Ba Be

Stand Structure

the horizontal and vertical distribution of components of a forest stand including the height, diameter, crown layers, and stems of trees, shrubs, herbaceous understory, snags, and down woody debris (SAF, 2008)

Stand Descriptors (cont.)

• Horizontal structure

• Vertical structure

Stand Descriptors (cont.)

• Horizontal and vertical structure

• Basal area, tree density and stocking

Basal area

The cross section area of the

stem or stems of a plant or of

all plants in a stand, generally

expressed as square units

per unit area

Bitterlich sampling

The principle of Bitterlich sampling

Illustration of calculation of the radius of the virtual circular

sub-plot for a tree with diameter d i

(Kleinn 2007)

Stand Descriptors (cont.)

• Horizontal and vertical structure

• Basal area and Tree density

• Size class distributions

Size class distributions

Number of

trees

Stand Descriptors (cont.)

• Horizontal and vertical

structure

• Basal area and Tree density

• Size class distributions

• Stem quality

Today’s Goals

• What is a stand?

• What are the components of site?

• How do we describe stands?