The effect of former land use and vegetation management on survival and growth of fast growing tree species

Abstract

Influences of vegetation management (control, mowing, competitive replacement) on the survival and growth of fast growing tree species were studied in newly planted stands on former arable land and grassland. The study site is located in Northwest Germany and characterized by acid, nutrient poor podsols and brown soil podsols. The assessment of the species composition and biomass of the ground vegetation showed that the vegetation produced less biomass on crop land than on grassland (Fig. 1). The higher biomass of the natural vegetation on grassland, especially of the monocotyledons, lowered the survival and growth of the young trees. After the first vegetation period the survival (Tab. 3) and growth rates (Tab. 4) of the young trees were significantly higher on crop land than on grassland. Both methods of vegetation management reduced the biomass of the natural ground vegetation significantly. Salix viminalis ("Turbo") and Robinia pseudoacacia showed satisfying results of survival and growth on the control plots, so that no further vegetation management neither on crop- nor grassland was necessary. Mowing influenced the survival rates of the poplar cuttings "NE 42" (P maximowiczii x P trichocarpa) and "Max 4" (P nigra x P maximowiczii) positively. Mowing also can be recommended for Populus tremula, especially on grassland. The survival rates of the poplars showed a significant negative correlation with the biomass accumulation of the competing monocotyledons (Fig. 2). Sowing of buckwheat and clover as competitive species changed the weed composition significantly, but not the survival and growth of the young plants.