DEVELOPMENT OF PREDICTION REGRESSION EQUATIONS FOR BIOMASS ESTIMATION IN POPLAR MONOCULTURE PLANTATIONS IN THE PUNJAB (INDIA)

India is one of the countries where Populus genes with all 6 species namely P. Ciliata, P. laurifolia, P. gamblei, P. euphratica, P.alba, P. Jaquemontiana var.glauca, are growing well. While considered the economic importance of exotic poplar clones fast growth and ability to provide substantial production as commercial wood on a short rotation basis, their hybrids / clones were tried in various agro-climatic conditions in Punjab. Having realized that P. deltoides and P. xeuramericana are the two species/hybrids, which have succeeded well. These were tried on large scale in the Tarai and plains of Punjab, Haryana, Himachal Pradesh, U. P. etc. (Tewari 1992 & 93) Poplar is a large tree reaching over 25 m in height and 100 to 130 cm in girth (GBH) in the short period of 10-12 years only. It is shallow rooted and spreads widely. The tree tops develop a tail straight bole. The main branches forms conical crown. It is deciduous, and the leafless period remains upto 3 - 5 months in winter season. They prefer deep, well drained, nutrient rich soil. They are susceptible to even light fires.Poplars are grown in Agro-forestry along with cash crops in Punjab. The growth of poplars in this Agro-forestry system is very encouraging. The methodology adopted for all the experiments conducted and studies undertaken were the same for all monoculture and mixed plantation sites in Poplar species. During estimation of Diameter and height correlation and selection of sample trees for harvesting, there is always a high correlation between DBH, height and weight of tree, that's why measurement of diameter and height has been universally recognised to be a reliable measure for growth of trees. Thus, it becomes essential to measure all the DBH (diameter at breast height 1.37m) and height of some of the trees in a sample plot. Regression of height and diameter can be used to estimate the height of the remaining trees, a free hand curve may also serve the purpose. The data obtained using stratified tree technique method of Art and Marks (1971) by harvesting the sample trees, within sample plots of different sizes (10 x 10m, 15 x 15m, 20 x 20m, 25 x 25m, 30 x 30m and 50 x 50m) laid out according to the size of the land area in Poplar plantations. The DBH and heights of 15 representative sample trees covering the entire diameter range of each plot were recorded in sample plots and correlation (diameter & height) was established by having regression coefficient (R2) values. The entire diameter range was then divided into different diameter classes. Three sample trees from each diameter class (close to the mean DBH of that class) were harvested, in each plantation for biomass estimation and development of best suitable prediction regression equations for biomass estimation in Poplar forest plantations in the Punjab state of India