Development and productivity of young scots pine stands by regulating density

Abstract

Hie key to the control of ihc produclivily ol" Scots pine {Pinus sylvesiris L.) is the regulation of stand density, [lie growth of two Scots pine viands of the forest type Vaccinio-myriillosa has been observed in the course of id years. ] he initial age varied from 4 lo H years, while the initial density was in the range of 5,400-8,100 trees/ha. Both stands are planted, one on former agricultural land and ihe second on former forest land. Ten plots with two replications ol 5 treatments were established in each stand at the beginning of the experiment. Starting with 600 trees/ha, the initial density was increasing at each subsequent treatment with 50(1-1,000 trees/ha, ending with the control stand. The density was regulaied to provide different conditions for competition (Hiring (he time of the experiment, liacli treatment was re-measured 4 to S times during the period of 1.1 to 16 years. Growing of stands with 2,000-3,000 (4,000) trees per ha over the period of 7-19 years has a positive influence on the height growth of trees. The mean diameter increment of trees growing in Ihe most intensively thinned stands (600 trees per ha) exceeds the mean diameter increment of trees in the control stand by I.K-2.8 times. The ratio of the mean tree volume increment of intensively thinned stand to Ihe control stand comprises 3.1-3.7 at the age of 17-24 years. Early and intensive thinning of pine stands resulted essentially decreased competition, increased growth and higher level of accumulated wood increment per stand. The study outlines the conditions enabling to achieve intensive growth of tree diameter and a higher level of yield.