The productivity of a site for tree growth is usually evaluated on a stand basis. Considered in this way, site quality expresses the average productivity of a designated land area for growing forest trees. A common way of expressing relative site quality is to set up from three to five classes, or ordinal ranks, such as site I, II and III. The characteristics of each class must be defined to enable any area to be classified.

Site is complex of physical and biological factors of an area that determine what forest or other vegetation it may carry

• Site quality is measure of relative productive capacity of a site fora particular species
• Different site gives different growth response to different spps.
• This help to evaluate the vegetation characteristics and site factors

Site Quality can be evaluated by following factors:

1. Site factors

It is effective climatic, edaphicand biotic factors which influencethe growth and development of forest or other vegetation in locality.

So, CVP= (Tr/Ta)*(P8G/12)*(F/100)

Where, CVP index= climate, vegetation and productivity index, Tr & and Ta are maximum and minimum temperature, P is precipitation in mm , G is growing period in months and E is a measure of evapo-transpiration

2. Vegetative characteristics

Site qualities can be described and differentiated either by the types of plants occurring naturally in the area or basal areas, volume, diameter or heights of trees which form the dominant part of the vegetation in the area.

3. Plant indicators

One possible way to evaluate site quality is to use the composition of the vegetation and search for some characteristics of plants which may be correlated with site qualities. This approach is based on the theory that certain species of lower vegetation, i.e. herbs and shrubs are clear indicators of the suitability of the site for a particular tree species or forest type. As such they can be used to describe and differentiate site qualities.

4. Tree characteristics

The most important characteristics of tree which reflect the productivity of site are its volume, basal area, diaand ht. As the primary object of site quality differentiation is to assess its productivity, the quantity of wood produced per unit area should therefore be the ideal measure of site quality, but as this method requires prior calculation of volume, it is difficult to apply in practice.The site classes are delimited by one of the following methods:

• Strip-height method based on Baur’s method
• British Forestry Commission (BFC) method
• FRI Method

Site Quality Graph