Growth response of hybrid poplars to different types and levels of vegetation control

Poplar plantations established on agricultural or forest land can be adversely affected by abundant competing vegetation already present or that grows after planting. In this paper, we investigate how different intensities of manual vegetation control and mulching with polypropylene plastic effect poplar growth during the first two years after planting. Field data revealed that, during the first year, mulching with polypropylene plastic increased seedling growth more than manual vegetation control when performed over the same area. However, during the second year, these differences diminished and poplar seedlings continued to grow at the same rate irrespective of vegetation control. The difference in growth between treatments seems to be related to the fact that mulching positively influences water and nutrient availability to a greater extent that manual vegetation control during the early phase of establishment. Vegetation control also affected biomass allocation, with a relative increase in leaf biomass and decrease in stem biomass. The increase in leaf biomass associated with vegetation control was a result of both an increase in leaf number and increased leaf size.