Over the years, farmers have been integrating  tree+crop+animal  components for sustenance.  With the passage of time the agricultural component received priority over woody elements for sustaining self-sufficiency in foodgrains.  The population pressure resulted in small holdings and consequently lesser number of trees of the farms providing food, fodder, fibre, fuel, fertilizer, fruit, etc.  The introduction of high yielding crops has no doubt resulted in self-sufficiency in foodgrains but its role in degrading top-soil by increasing salinization due to faulty irrigation, loss of fertility and deposition of non-biodegradable agricultural chemicals in soil can not be overlooked.  In order to bring a balance between food sufficiency and ecological stability it is paramount to copy the nature by integrating different biota of life i.e trees, shrubs and bushes, high value cash crops and/or animal husbandry.  Unfortunately, these three pursuits, namely agriculture, forestry, and animal husbandry have grown independently  but at the grass-root level they are inseparable because of being land based. Delinking these either at the village level, or in the governmental functioning would prove to be counter productive.  The traditional systems which have been evolved by trial and error by our villagers, are to be preserved and improved by adding scientific input  of tree+crop+animal modeling and by introducing superior genetic base in these polycultural systems.

Agroforestry is defined by some as a dynamic, ecologically-based natural farm management system that, along with agriculture and the integration of trees on farms, has many environmental benefits. Put simply, agroforestry is using trees on farms. Trees can provide many products such as timber, fodder, fuelwood, medicines, and oils. It also helps to conserve soil, enhance soil fertility, and provide shelter belts for crops and fruit trees.

Agroforestry systems with their element of intercropping are in essence ecological models similar to natural systems and have, therefore, an element of sustainability associated with them.  These systems have lasting production, as they help in recycling of organic residues, biological nitrogen fixation, and mineral fertilization.  This happens all the time in an intercropping system involving nitrogen fixing trees.  Their litterfall improves nitrogen level and organic matter in soil and consequently its overall fertility.  Essentially, the element of sustainability that agroforestry afford, stems from the fact the system is based on the ecological consideration. The need for such a system is to reduce the risk of crop failure due to uncertainty of weather conditions, erosion hazards as well as to meet most of the demands of society without depending on reserve forest.

Agroforestry systems are the practice of mixed farming developed over centuries. Most of them are the long-term land management systems having a life cycle of more than one year. Moreover, these systems are the complex form of land management both ecologically and economically than other agricultural or forestry systems. Based on the components used in a given land management unit, a number of agroforestry systems are prevalent in India. The most common of which are used in northern India are:

Agrisilviculture : Agriculture+ forestry, Slivipastoral : Forestry+ livestock, Agrisilvipastoral : Agriculture + forest+ livestock, Agrihorticultural : Agriculture + fruit trees. Agrisilvihorticultural : Agriculture + forestry + fruit trees. Hortipastoral : Fruit trees + forestry.

As per climate conditions of Punjab the trees like Poplar, Eucalyptus(safeda), dek(dhrek), Subabul, Kikar etc. can be successfully grown with the main crops Poplar is considered to be the best agroforestry species for intercropping, having high rate of growth, short rotation, good economic returns and has less effect on intercrops. Farmers can plant this species on their cropland and within 6-7 years harvest and market it to the industry. During the Kharif season soybean, maize and grain legume can be grown while during the Rabi season wheat, potato, peas, etc., can grow successfully. The Punjab Agricultural University has released seven clones of poplar for growing in Punjab. These are PL-l, PL-2, PL-4, PL-5 (for the central plain region), PL-6, PL-7 (for semi-arid region) and PL-3 (both for central plain and semi-arid region).

Along with financial benefits to farmers , Agroforestry can play a vital role in balancing our ecology. Pollution can be mitigated by planting good biomass producing tree like Arjun, Jamun, karanj , Neem, Guava, Siris, Aonla , Babool, Sheesham , Ironwood, Bamboo, and khamer etc. in Punjab .

In addition to general uses of forests, Agroforestry systems have the following advantages: 

— Maintain soil fertility (leguminous trees) through recycling of nutrients, prevent soil erosion and loss of nutrients through leaching and runoff. Poplar is the widely used tree in Haryana, Punjab and the Terai area of Uttar Pradesh.

— Certain tree species stimulate the growth and production of a particular crop through allelopathic reactions.

— These systems make available to people the required quantity of timber, fruit, firewood, fodder, etc for which they traditionally depend on forests. Thus the system helps in reducing the pressure on reserve forests and helps in their conservation and development.

— They optimise the physical conditions (permeability, water holding capacity and acidity or alkalinity) of soil to a level which is supportive for the growth and production of the standing crops. The tree species grown along with the crops in waterlogged areas helps maintain water-table up to a certain extent.

—In situ stabilization of high sand dunes by planting species like Sarkanda (Saccharum munja), Ber (Zizyphus nummularia), Pahari Kikar (Prosopis juliflora), Jand (Prosopis cineraria), Subabul (Leucaena leucocephala), Kikar (Acacia nilotica) along the periphery of fields to check the movement of sand by wind action.

—Reclamation of salt affected cum waterlogged area and bring them under plantation with species such as Safeda (Eucalyptus spp.), Pahari Kikar (Prosopis juliflora), Kikar (Acacia nilotica) and Neem (Azadirachta indica), which act as biopumps.

— In alluvial plain areas with brackish ground waters, Eucalyptus and Dek can also be grown, however, if there is assured availability of canal water, agriculture can be the best practice

— Since the systems are labour intensive, they generate employment opportunities for the rural people. Hence, they also help in rural development.

Agroforestry  has come up as an important and economical  component in land use technologies which must be incorporated in the land management system of productive and unproductive land by the farmers of Punjab. Vast Potential of agroforestry in different parts of the state needs to be exploited to meet the the basic and growing demands of food, fodder, fuel and timber one hand and to conserve the much endangered ecological balance, deforestation and soil erosion.