Relation between biomass and height in open pollinated families and selected clones of black locust

Black locust (Robinia pseudoacacia L.) is a fast growing, nitrogen-fixing leguminous tree, exhibiting an outstanding adaptability in a wide range of pedoclimatic conditions. It is native to southeastern North America, but it was also extensively naturalized in the temperate regions of Europe and Asia, while in Greece it was introduced 150 years ago. Widely used as multi-purpose species, black locust is ideally suited for forage production of high quality and quantity. The biomass produced, however, is not stable from one year to next and is also influenced by genetic factors. In this paper, aboveground biomass was harvested and measured from 9 open pollinated families and 13 selected clones of the monophylla variety at the end of the growing season for 6 consecutive years. Subsequently, this biomass was correlated with annual height by means of a regression analysis, involving four types of equations: linear, quadratic, exponential and power. It was found that annual biomass can be predicted with relatively high accuracy by using the easily measured annual height for both open pollinated families and clones of the monophylla variety and employing an exponential or, preferably, a power equation.