Branch and leaf biomass of Lebanon oak (Quercus libani Oliv.) and gall oak (Q. infectoria Oliv.) trees in different years after pollarding

Abstract

This study was carried out to estimate the branch and leaves (crown) biomass of Lebanon oak (Quercus libani Oliv.) and gall oak (Q. infectoria Oliv.) trees at single and stands level in different ages after Galazani (pollarding). We selected three oak stands which have been pollarded one, two and three years ago and an undisturbed (untouched) stand as a control. In order to estimate the amount of biomass produced from tree crown partial harvesting method and allometric equations were used. We selected 36 Lebanon and 36 gall oak trees in the various diameter classes with an average and almost uniform crowns. In the middle of tree crowns, four branches were cut from four cardinal directions randomly, and then fresh weight of leaves and twigs were measured in each branch to estimate crown biomass. Power regression model was performed as the best predictor model and relative bias and RMSE % were calculated at branch level. The results showed that there is no significant difference between measured and estimated biomass in branch level. Also, partial harvest method is unbiased procedure in biomass estimation. According to the results, amount of crown biomass at tree and stand level, in the untouched stands (9.21 tons ha-1) were more than the crown biomass in one, two and three years after pollarding (1.26, 2.32 and 3.16 tons ha-1 respectively). These results can be used to do a better management and monitoring of oak forests which affected by pollarded.

Keywords

• Allometry
• oak stands
• partial harvest
• tree fodder
• wet leaf weight