Silviculture - 1

 Silviculture

-Branch of forestry which deals with the establishment, development, care and reproduction of stands of timber (Toumey and Korstian).

-Art and science of cultivating forest crops (FRI)

-In English, it refers to certain aspects of the theory and practices of raising forest crops (Champion and Seth).

Silviculture= Silvics+culture i.e. Applied silvics

Silvics- study of the life history and general characteristics of forest trees and crop with particular reference to environment factors, as the basis for the practice of silviculture.

Objectives

·         Production of species of economic value

·         Production of larger volume per unit area

·         Production of quality timber

·         Reduction of rotation

·         Raising forests in blank areas/unprotected areas

·         Creation of man-made forests in place of natural forests

·         Introduction of exotics.

Virgin forest- Natural forest uninfluenced by human activity, it may or may not be climax forest.

Rotation- The planned number of years between the formation or regeneration of a crop and its final felling.

Natural Regeneration- The renewal of a forest crop by self-sown seed or by coppice or root-suckers.

Exotic- Not native to area

Indigenous- Native to a specified area or region.

Forest Protection- branch of the forestry which is concerned with the activities directed towards the prevention and control of damage to forests by man, animals, fire, insects, disease or other injurious and destructive agencies.

Forest mensuration- branch of forestry which deals with the determination of dimensions, form, age, volume, increment of logs, single trees, stands or whole woods, either standing or after felling.

Forest utilization- the branch of forestry concerned with the harvesting, conversion, disposal and use of the forest products.

Forest Economics- branch of forestry concerned with those aspects of forestry that deals with forest as a productive asset, subject to economic laws.

Forest management- defined as the practical application of the scientific, technical and economic principles of forestry.

Forestry- is defined as the theory and practices of all that constitutes the creation, conservation and scientific management of forests and utilization of their resources.

Intensive forestry- the practice of forestry with the object of obtaining the maximum in volume  

Tree maybe classified into 1) Herb 2) Shrub 3) Tree

1. Herbs: are plants whose

ü  Stem is always green and tender

ü  Height is usually not more than 1 meter

ü  According to the span of life, herb classified into annual, biennial and perennial

2. Shrub: are woody perennial plants

ü differing from a perennial herb in its persistent and woody stem

ü Less definitely from a tree in its low stature and its habit of branching from the base. 

ü Height is usually not more than 6 meter

Both herbs and shrubs are very small in size to produce wood, so they are economically used for Non timber forest produce (NTFPs) but shrubs can be used as fire wood material.

3. Tree:  are large woody perennial plants having

ü a single well-defined stem

ü and a more or less definite crown

ü A tree is usually more than 6 m in height.

World	India
Largest trees (Height)
Pseudosuga taxifolia (Columbia)- 127.1m Sequoia sempervirens(California)- 112.1 m	Conifer - Cedrus deodara - 73.2 m Broadleaved - Tectona grandis – 58.5 m                         Shorea robusta  -  51.2 m
Largest trees (Girth)
S. sempervirens (California)- 3574 cm Eucalyptus (Australia) – 2438 cm	Conifer – C. deodara (Kullu, HP) – 1646 cm Broadleaved - Shorea robusta  -  782 cm                         Tectona grandis – 625 cm
Largest trees (Age) (years)
S. sempervirens (California)- 4000 years	Conifer – C. deodara (Kullu, HP) - 704 yrs Broadleaved – Dalbergia latifolia – 600 yrs                         Tectona grandis – 500 yrs

Trees have three major parts; i) Crown ii) Root iii) Stem

i) Crown: are the upper branchy parts of a tree above the bole.

ü  Formed from branches springing from tree bole

ü  Shape and size of the crown of tree varies with species and environmental Condition.                                                                      

Crown Type	Example
Large leave crown of cylindrical branched stem	Phoenix, Cocos, Borassus
Conical	Pine, Cedrus deodara
Spherical	Mangifera indica, Azadirachta indica , Tamarindus indica, Madhuca indica
Broad & Flat topped	Albizzia stipulata
Cylindrical	Abies pindrow

Crown Development: the expansion of crown measured as crown length and crown width.

Mode of branching & Angle: mode of branching varies with species but sometime it is characteristic of genus or family.

ü  Mostly tree make branching angle of 60 – 70 degree

ü  But some species make angle up to 20 - 30 degree: Populus nigra, Cupressus sempervirens

ü  Horizontal branches: Old Cedrus deodara, Duabanga Sonneratiodes

ü  Drooping downwards: Anogeissus pendula, Terminalia myriocarpa

Leaf colour, size & texture: Colour of mature leaves is normally green due to presence of chlorophyll. The shade of two surfaces of leaf is often different, lower being paler than upper.

Autumn tint: In some species, leaves undergo a striking change in colour before falling from the trees such colour are called autumn tint.

Species	Leaf colour during the autumn tint
Lannea coromandelica	Yellow
Anogeissus latifolia	Dark red
Sapium sebiferum	Red, Purple and orange

ü  Some species have characteristic attractive colour in their young leaves

Quercus incana	Pinkish or purplish
Acer caesium	Bright Red
Schleichera oleosa	Bright Red
Mangifera indica	Brown
Cassia fistula	Dark Red Brown

Leaf size: depends upon rainfall

ü  Species leaf size is smaller in lesser in low rainfall area and bigger in heavy rainfall area.

Leaf texture:

ü  Soft & membranous leaf: decompose easily & hasten decomposition of hard & coraceous leaf. e.g. Grewia, Ougeinia, Anogeissus

ü  Hard & Coraceous Leaf: decompose very slowly & create the problem for natural regeneration. e.g. Shorea robusta, conifers

Leaf shredding:

ü  Deciduous: A tree normally remains leafless for some time during the year.

ü  Evergreen: A tree which is never entirely leafed less and the old leaves persist until a new set has appeared.

Deciduous	Acacia catechu, Adina cardifolia, Ailanthus excelsa, Bombax ceiba, Garuga pinnata, Halloptelia integrifolia, Lannea coromeandellica, Melia azedarach, Schleichera oleosa, Terminalia tomentosa
Evergreen	Abies pindrow, Cedrus deodara, Cupressus torulosa, Hopea parviflora, Mallotus philippinensis, Mangifera indica, Michelia champaca, Picea smithiana, Pinus wallichiana, Pterospermum acerifolium.

ü  Santalum album is exception to above general rule it become deciduous or evergreen according to the habit of its host plant.

ii) Stem: the principal axis of plant from which buds & shoots are developed.

ü  In trees, stem, bole & trunk are synonymous but bole is sometime referred to only lower part of the stem up to a point where main branches are given off.

Taper: The decrease in diameter of the stem of a tree or of a log from base to upwards.

ü  As a result of wind pressure, trees growing in open plains &/ or on ridge in hills have generally shorter and

ü  The trees growing in dense forest have relatively longer & more or less cylindrical stem.

Defects of stem:

a)      Epicormic Branches: Branches originating in clusters from dormant or adventitious buds n the trunk of a tree or on older branch when exposed to adverse influence such as excessive light fire / suppression.

ü  When this is caused due to drought is called Stag headed tree.

ü  Stage headed – a condition of the tree with dead upper branches projecting above green portion of the crown.

b)      Forked tree: Trees with more than 1 leader. Timber below forking point is wasted or produces small sized timber.

c)      Buttressed tree:  out-growths formed usually vertically above the lateral root & thus connect the base of stems to root.

ü  e.g.: Acrocarpus fraxinifolius, Bombax ceiba, Pterocarpus dalbergiodes, Terminalia myriocarpa, etc.

d)      Fluting: irregular involutions & swelling on the bole just above the basal level. e.g. Tectona grandis.

iii)  Root: portion of plant which develop inside the soil & away from light.

ü  Generally, comprise of taproot & lateral roots.

ü  The taproot & lateral roots including their branches up to root hairs, forms the root system of the tree.

ü  On the basis of tap root system trees are classified as shallow and deep-rooted trees.

Ø  Shallow Rooted trees: root system does not extend far enough into the soil to save them from relatively easy wind throw.

Ø  Deep- Rooted trees: root system goes very deep in to the soil, & trees are not easily uprooted by wind & are called wind firm.

Adventitious roots: produced from parts of the plant other than the radical or its subdivision.

ü  Usually thin & undivided.

ü  Don’t show secondary thickening & are replaced by new roots when old one die.

Adventitious root type	Meaning and example
Prop root	Produced from branches and remain suspended in the air till they reach the ground. On reaching ground they get fixed in soil. e.g. Ficus bengalensis
Stilt root	Emerge from the butt of a tree above ground level so that the tree appears as if supported on flying buttresses. e.g. Mangroves of genus Rhizophora
Pneumatophore	A knee-shaped or spike like projection of the roots of swamp tree. e.g. Heretiera, Bruguiera