Agroforestry systems and architecture

Agroforestry, Subsystems of
Agrisilviculture - Shifting
cultivation, Taungya and
Intercropping, Tree architecture
© Vivek Srivastava

Agroforestry is an integrated
dynamic system

Agro forestry as an enterprise

AGROFORESTRY
• An efficient and integrated land use
management system by raising of certain
agricultural crops, forest tree species and or
animals simultaneously or sequentially on the
same unit of land with appropriate management
practices which result in overall increase in the
production, under a particular set of climatic
and edaphic conditions and socio-economic
status of local people.

TYPES OF AGROFORESTRY
SYSTEMS
Functional basis -- production to protection
Socioeconomic basis - commercial to
substance
Structural basis

AGROFORESTRY SYSTEMS
 i) Agri-silviculture
 ii)Silvipastoral system
 iii) Agrisilvipastoral system
 iv) Horti-silviculture system
 v) Agri-horticulture system
 vi) Agrihortisilviculture system
 vii) Multipurpose forest tree production(other specialized
agroforestry systems).
 viii) Apiculture with trees
 ix) Aquasilviculture or Aquaforestry
 x) Agrisilviaquaculture

Agri-silviculture
 When agricultural crops are grown in
combination with forest tree species, the system
is known as" Agrisilviculture "
 For instance, when groundnut and arhar are
grown as intercrop with Leucaena leucocephala
and Sesbania aegyptica.
 This crop combination with forest trees results in
an increase in both grain as well as fodder
yields.

Agri-silviculture system provides
• Food,
• fuel,
• fodder,
• manure,
• paper pulp and
• packaging materials for the
rural people.

Ways to grow tree crops with
agricultural crops
Tree species on the border of crop field or
orchard.
Tree species and agricultural crops in
alternate rows.
alternate strips.
mixed form

Based on the nature of the
components
 Improved fallow species in shifting cultivation
 The Taungya system
 Multispecies tree gardens
 Alley cropping (Hedgerow intercropping)
 Multipurpose trees and shrubs on farmlands
 Crop combinations with plantation crops
 Agroforestry fuelwood production
 Shelterbelts
 Windbreaks
 Soil Conservation hedges

SHIFTING CULTIVATION
 Forest land is cleared by cutting down all the
trees, shrubs, herbs and climbers near the
ground level;
 Felled material is allowed to dry and then set
on fire;
 Sowing is followed in cleared area
 The cropping is done a few years on the same
unit of land and then left for the regeneration of
the bush (fallow period).
 Clearing and burning of vegetation leads to a
disruption of the closed nutrients cycle on the
forested land.

Consequences
 However, burning causes raising in soil
temperature temporarily, more solar radiation is
received on the bare soil surface resulting in
higher,soil and air temperatures
 This change in the temperature regime causes
changes in the biological activity in the soil.
 The addition of ash to the soil through burning
causes important changes in soil chemical
properties and organic matter content

 After clearing and burning, a sharp increase of
available nutrients may benefit the first crop but
later on the soil becomes less and less productive
and crop yields decline.
 When raising of crops become non remunera-tive,
the cultivators abandon the site and move into
other sites.
 After a lapse of a few years again the same site is
used for cultivation.
 By that period cut tree regenerates and soil also
regains in its fertility and productivity.
 However, the next return has low productivity
than the previous turn.

In India, shifting cultivation is
practiced in
The north eastern hill region
(Assam, Meghalaya, Manipur, Nagaland and Tripura) and
Andhra Pradesh,
Bihar,
Madhya Pradesh,
Orissa and Karnataka.
Shifting cultivation is called "Jhum" in north eastern hill region and "Podu"
in AndhraPradesh and Orissa states.
The size of the plot varies from 1.0 to 2.5 hectares per family having
members 3 to 5.

Demerits of shifting cultivation:
 Shifting cultivation is a faulty land use. It
enhances soil degradation by way of soil
erosion.
 It is a primitive method of cultivation in which
crop yields are less and requires hardwork.
 Due to complete cutting and burning of
vegetation there is an abrupt changes in soil
microbial population.
 It causes environmental degradation.
 There is loss of nutrients from the soil through
run off, leaching and percolation.

Demerits
 The carbon, nitrogen ratio reduces due shifting
cultivation.
 The excessive runoff in the shifting cultivated
areas causes floods in the adjoining plains.
 Denudation of hill slopes takes place.
 Wild life in the shifting cultivated areas is badly
affected. It disturbs the fauna.
 Forest flora become weak and grow sparsely.

Ways for improving degraded areas
 Efficient land use management including
provison for horticultural crops, forestry crops
preferably legume species and livestock like
cattle, sheep and goats
 Preventing loss of soil fertility by making contour
bunds, graded".bunds, half moon teraces,
levelling, drainage system and water utilization
technology,
 Soil management by growing cover crop, strip
and mixed cropping, erosion checking crops,
relay cropping, green manuring and use of
organic amendments and fertilizers.

 Adoption of production based crop management
by raising high yielding varieties, suitable crop
planning, weed and water management, timely
plant protection measures, application of
fertilizers for restoring soil fertility and use of
implements.
 Adoption of soil enriching hedgerow
intercropping, or 'alley cropping' aims at
eliminating the fallow period altogether by
combining tree species with agricultural crops.
 The problems created by shifting cultivation can
easily be overcome by adoption of suitable
agroforestry models

TAUNGYA SYSTEM
 The 'Taungya' is a Burmese word, consisting of
'Taung' means hill and 'ya' means cultivation i.e.
cultivation in the hills
 Taungya is also a shifting cultivation in which
cultivators are allowed to plant forest 'tree
species and to raise agricultural crops in
between rows of forest tree species
simultaneously, and cared for about 3 to 5
years.
 Thereafter, cultivators are required to shift to
another patch of land.

Origin of Taungya
The aim of Taungya system is both wood
and food production
Taungya was reported to have started first
in Burma in the year 1850 for replanting
vast areas under teak plantation, and in
Java in 1856.
Taungya was introduced to India by
Brandis, in 1856. The first plantations
were raised in 1863 in North Bengal

Places of practice
It is practiced in Kerala, West Bengal,
Uttar Pradesh, Tamil Nadu, Andhra
Pradesh, Orissa, Karnataka, and North
eastern hill regions.
This system provides employment
opportunities to unemployed rural people.
It is also suitable in the area where land
shortage is very acute.

Crops and trees
a)Trees
 Tectona grandis
 Bamboo
 Santalum album
 Tamarindus indica
 Acacia nilotica
 Acacia mearnsii
 Ceiba pentandra
 Cashew, Rubber
b) Crops
 Millet, pulses, groundnut,cotton

Types of Taungya
 Departmental Taungya
 Leased Taungya
 Village Taungya

Main crops of Taungya
Jowar, bajra, paddy, maize, lentil, wheat,
mustard, rapeseed. gram.
arhar, urad, soybean, castor, sunhemp,
barley. potato, sweet popato tapioca. til,
groudnut, turmeric, ginger etc.

State Tree crop Associated agricultural crops
Uttar Pradesh - Shorea robusta, T ectona Maize, paddy, sorghum,pi-
grandis, Acacia catechu, geon pea, soybean, wheat,
Dalbergia sissoo, Eucaly- barley,chickpea,rape seed
ptus spp.,Populus spp. and miscellaneous
Kerala - Tectona grandis, Bombax - Paddy, tapioca, ginger,
ceiba, Eucalyptu spp. turmeric
Assam - Shorea robusta paddy
TamilNadu - Tectona grandis, Bamboo, - Millets, pulses,groundnut,
Santalum album, Tamarin- cotton, tapioca, potato
dus indica, Acacia meamsii,
Ceiba pentandra, Cashew,
Rubber

Merits of Taungya
Weed and climbers growth is suppressed.
Employment opportunities to unskilled
unemployed rural people
Regeneration of forest species is cheap.
There is full utilization of available land for
the production of food crops.
This is an important way to integrate rural
development programmes.
Increases forest wealth of the country

Demerits of Taungya
 Exposure of land leads to erosion and loss of
soil fertility.
 There is an exploitation of human labour.
 Danger of epidemics is expected due to raising
of agricultural crops.
 Forest trees are not adequately cared by
cultivators once they are settled.
 Cultivators may claim for legal right on land
 Insecure land tenure.

Intercropping
spatial arrangement of crops.
the annual and perennial crop
components are simultaneously present
on site but are spaced in such a manner
that they became mutually supportive
rather than competing.
Under such circumstances, they may
jointly yield higher outputs per hectare per
year.

Four subsystems of Intercropping
Border tree planting
Alternate rows
alternate strips
Random mix

Border tree planting
 lines of trees specifically
as boundary markers, live
fences, windbreaks or
firebreaks.
 protecting or stabilizing
the site
 producing green manure
as organic fertilizer
 producing fuelwood.

Alternate rows
 "alley", "avenue",
"corridor", "zonal", or
"hedgerow" cropping
 found most effective
for erosion control
and slope
stabilization.

Alternate strips
A "strip" differs from a row in that it is composed of two or more rows

Random mix
 displays no specific or
orderly placement of
the component crops
 the plants actually
occupy their own
special ecological
niches and are able to
coexist very well.
 Home gardens of
Indonesia and the
Philippines

Acacia (Acacia confusa) - Tea
(Camellia sinensis)

Agroforestry System (Forestry-Fishery-
Agronomy) with water canal

Wheat Intercropped in Paulownia
Nursery

Poplar (Populus euramericana 1 - 214) -
Wheat Intercropping

LOPPING AND PRUNING
• Q. Is Tree Pruning The Same As Tree
Lopping And Tree Topping?
A. The short answer is ‘No’ but this needs
some explanation because of the
widespread belief that they are the same.

• The Standard defines lopping and topping as:
lopping is ‘the practice of cutting branches or stems between branch unions
or internodes’
Topping is ‘reducing the height of a tree through the practice of lopping’
• The Standard says lopping and topping are unacceptable because:
• They increase the rate of shoot production and elongation.
• The resulting regrowth is weakly attached and becomes prone to failure or
collapse.
• The natural habit of the tree destroyed.
• They may reduce the lifespan of the tree.
• ·They predispose trees to fungal infections and insect attack.

• When lopping cuts are made in order to
reduce the height of a tree, the overall
process is referred to as tree topping.
• Topping is a world wide tree mutilation
practice that must stop! Topping not only
destroys a tree’s dignity, but it weakens
the tree and makes it a high hazard risk. If
a tree must be topped it is time for a new
tree.

What Happens To A Tree
After It Has Been Lopped?
Lopping and topping inevitably removes the leaves. Without leaves the
tree cannot capture sunlight and manufacture sugars for transport to
the roots. Without leaves, the cooling effect of water transpiration
ceases and the tree can no longer move water and nutrients
upwards from the soil. In essence the entire physiology of the tree is
disrupted. Some tree species respond to topping and lopping by
growing ‘emergency’ shoots (epicormic shoots) whilst others
including many Eucalyptus species are killed outright.

A short time after the lopping, new shoots will emerge from below the lopping
cuts. Known as epicormic shoots, they arise from suppressed buds retained
just under the bark cambium. Removing the uppermost branches stops the
downward flow of bud suppressing chemicals. With no suppression from
above, the dormant buds burst through the bark skin to act as emergency
light receptors as the tree attempts to establish a new canopy using energy
stored in its woody parts and especially in its roots.

Short rotation energy
plantations
Fast-growing tree crops grown in carefully tended plantations for rotations
shorter than 15 years have an important role to play, because of their
numerous ecological benefits. This special type of forestry is concerned with
maximization of wood biomass output per hectare for energy production.
Highly productive pioneer species are willow and poplar species as a short
rotation coppice (SRC) system.
It involves the establishment of plantations using genetically improved, clonally
propagated, plant materials (i.e. willow and poplar species) at a density of
~15000 plants ha−1, which are coppiced at the end of the first year and then
managed on a three-year rotation (Th arakan et al., 2003). The biomass
produced from short rotation coppice (SRC), such as willow and poplar, may
have a number of uses: as a fuel for electricity generation plants; for the
production of charcoal; as a soil amendment for clay caps; or simply as a
carbon sink for atmospheric CO2.

• Technically speaking, energy
plantation means growing select species
of trees and shrubs which are harvestable
in a comparably shorter time and are
specifically meant for fuel. The fuel wood
may be used either directly in wood
burning stoves and boilers or processed
into methanol, ethanol and producer gas.

Tree architecture
Pollarding
• Pollarding is a pruning system in which
the upper branches of a tree are removed,
promoting a dense head of foliage and
branches. It has been common in Asia
and Europe since medieval times and is
practiced today in urban areas worldwide,
primarily to maintain trees at a
predetermined height.

Suitable for...
Pollarding is a pruning technique used for many reasons, including:
• Preventing trees and shrubs outgrowing their allotted space
• Pollarding can reduce the shade cast by a tree
• May be necessary on street trees to prevent electric wires and
streetlights being obstructed
Pollarding a tree is usually done annually, and would need to be
carried out every few years to avoid potential problems.

• The best time for pollarding many trees and shrubs is in
late winter or early spring. However, bear in mind the
following:
• Summer can be a suitable time to pollard. However, the
new growth may be poor as a result of the scorch,
drought or heavy shade cast by neighboring trees
• The least favourable time for pollarding is the autumn,
as decay fungi may enter the pruning cuts

• Once young trees or shrubs have reached the desired height, you
can begin to pollard them. This involves choosing a framework:
• On a shrub, this might be one stem cut to a metre high – a mass of
stems will grow from the top
• With a tree, it is more typical to leave a trunk supporting three or five
branches – these branches are cut back to a desirable length and
the twiggy growth appears at these ends
• Initially, the new branches are held weakly in place as they grow
rapidly from underneath the bark, rather than from within the tree.
As the wood lays down annual growth rings, the union strengthens,
often forming a thickened base where the shoot meets the trunk.
Over a number of years, a swollen 'pollard head' forms where new
shoots grow each year.

• A hedge or hedgerow is a line of closely
spaced shrubs and tree species, planted
and trained to form a barrier or to mark the
boundary of an area. Hedges used to
separate a road from adjoining fields or
one field from another, and of sufficient
age to incorporate larger trees, are known
as hedgerows. It is also a simple form
of topiary.

OVERSTORY LAYER
• Also called emergent
layer.
• Consists of giant
emergent trees that
tower above the
surrounding canopy.
• The air is much drier
and moderately
strong winds blow
through their
branches.

CHARACTERISTICS
• Trees are huge
• A height of 213 feet (65 m) with horizontal limbs that
stretch over 100 feet (30 m).
• Often covered with epiphytes (non-parasitic plants
which take no nutrients from the host plant but use it
for support)
• Example lichens, mosses, liverworts, and algae.
• The most successful and most plentiful predators of
vertebrates in the canopy are the birds of prey, such as
eagles.

CANOPY LAYER
• Found directly beneath
the overstory layer
(emergent layer).
• The primary life
sustaining layer with an
abundance of food and
forms a natural roof
over the remaining two
layers beneath.

CHARACTERISTICS
• Canopy rising to 150 feet above ground .
• Trees elevations, creates a highly reflective
shield that protects them from the higher
levels of intense sunlight.
• This almost shield filters out 80% of the light,
preventing light from penetrating the forest.
• Consists of a thick layering branch system of
limbs and vines that create natural vistas and
form a natural umbrella.

• Absorbs ultra-violet rays from the sun
protecting the plant and animals species
beneath the canopy layer from UV rays.
• Retains moisture and makes a natural shield to
prevent “wash-outs” during the flooding caused
by heavy rain from the tropical rainy seasons.
• Many Epiphytic Plants, commonly called “air
plants” like Bromeliads and Orchids grow in the
canopy Layer.

• Roots of these plant do not reach the ground
or live in soil.
• Instead they thrive by absorbing moisture and
nutrients through an aerial root system by
attaching themselves to a host.
• A home to many species, including birds,
butterflies, monkeys, parrots, the slow
moving sloth, tree frogs,
toucans, jaguars and leopards.

UNDERSTORY LAYER
• Directly underneath the
canopy layer and on top
of the forest floor.
• Growth here is very
dense.
• This layer is a dark,
sometimes almost
impenetrable natural
habitat like vines, shrub
and broadleaf trees.

CHARACTERISTICS
• Provides superior camouflage and many of the
species who live here crossover between this
layer and the canopy layer.
• Average 12’-15’ feet in height and have
exceptionally large leaves to compensate for
the lack of sunlight.
• The leaves are so large in fact, just one single
leaf could be used for an umbrella.
• Many species living in this layer like darkness.
(nocturnal)

• Several animal species such as tree frogs, bats,
owls, and an amazing array of insect species
like the famous team working “Leaf Cutter
Ants” can be found.
• Intermingling between layers is done by many
species but especially by the many varieties of
Monkeys, Sloths, Jaguars and Leopards.

FOREST FLOOR
• The Forest Floor is the
ground layer.
• No sunlight reaches
the Forest Floor cause
it is very dark.
• Quality of the soil is
extremely poor and
very few plants are
found growing in this
area.

• Examples of the plants: moss, ferns and some low
growth plants and vine roots.
• It is rich in microorganism and this environment
makes quick work of decomposition making a
natural compost that is exceeding rich.
• Beetles, Frogs, Lizards, Snakes, Termites, and
insects of every kind thrive by the millions in the
moist, dark climate of the Forest Floor.

INTRODUCTION
• The light penetration level varies by each
layer.
• Maintains under storey vegetation and
determines the degree of suppression or vigour
of its growth.
• Each canopy layer consist of different types of
plants and have their own specific
characteristic and structure that can help in
the light competition.
• All plants must compete to get sunlight for
photosynthesis.

PHYSIOGRAPHIC LOCATION TO
LEAF POSITION
• Light incident on a leaf varies with leaf angle and
canopy position
• Plants can change the amount of energy they
absorb by changing their effective “physiographic
location”
• Heliotropic leaf movements: Some plants follow
the sun by moving leaves to maximize absorption
(diaheliotropism) or minimize by moving parallel
to the sun (paraheliotropism)

CANOPY COMPOSITION AND
DISTRIBUTION
• This affects both light quantity and light quality
• Light quantity diminishes through the canopy
but all canopies are not equal.
• Incident light (PAR) at the forest floor may be
different between types of forest in this world.

WHY WOULD THE PAR IS
DIFFERENT BETWEEN THE
FOREST??
1. Species – leaf optical properties
2. Density – how much is there, LAI, LAD, etc
*Leaf Angle Distribution refers to the
angular orientation of the leaves in the vegetation
*Leaf area index refers to leaf area per unit
ground area
3. Architecture – Canopy structure, shape,
orientation and heliotropic leaf movements give
each plant its own characteristic light absorption
characteristics

PHOTOSYNTHETICALLY ACTIVE
RADIATION (PAR)
• PAR is the amount of light available for
photosynthesis, which is light in the 400 nm to
700 nm wavelength range.
• Light is a waveform which can be measured
in terms of wavelength.
• The range of human vision(400 to 700 nm) in
term of wavelength is called the visible
spectrum.

Conclusion
When being well managed agroforestry can
support food production, increase the total
efficiency and stability of the system, provide
a diversity of outputs, enhance the natural
resource base, and overall is likely to be a
better option than a solely crop based
system, particularly in lower potential areas.

REFERENCE
 www.fao.org
 www.centerforagroforestry.org
 www.answers.com/topic
 www.agroforestry.co.uk/silvoar.html
 www.aftaweb.org
 www.ncrs.usda.gov
 www.unl.edu/nac/agroforestrynotes
 www.sustainableharvest.org/m
 www.ncga.com
 Text book of Agro forestry –Chundavat..

Agroforestry systems and architecture

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