Weed‐poplar competition dynamics and yield loss in Italian short‐rotation forestry

Abstract

In recent years there has been increasing interest in short-rotation poplar plantations for biomass production and cropping techniques and weed control strategies are being developed. Slow initial poplar growth can favour weed infestation and so there is a need for appropriate timing of weed control, based on an understanding of the competitive relationship and dynamics between poplar and weeds. A field experiment with annual and biennial crop cycles was conducted over two years. A 35 cm wide within-row weedy strip was allowed to develop as the basis for competition. Yield data were fitted with sigmoidal equations, in order to find the critical point (CP) and critical period of weed control (CPWC), using thermal time as the independent variable. Results showed that poplar is very sensitive to weed competition, especially in the first growing season after planting or cutting, and that competition can cause important yield losses. In the annual cycle, the CP corresponds to a yield loss of 26% and 8% in the first and second growing season respectively; in the biennial cycle the CP corresponds to a yield loss of 29%. Furthermore, the CPWC is long. For example, in the first year, based on a 5% yield loss, it lasts from 30 to 84 days after planting. This makes effective weed control difficult to achieve only using a pre-emergence herbicide, and thus necessitates a post-emergence treatment, either with herbicides or inter-row cultivation. These results, together with the inability of the crop to recover from damage, mean that resources must be invested in weed control soon after the beginning of the cropping cycl

Biomass Production with Willow and Poplar Short Rotation Coppices on Sensitive Areas—the Impact on Nitrate Leaching and Groundwater Recharge in a Drinking Water Catchment near Hanover, Germany

“…However, as the area requirements for bioenergy feedstock production increases, the pressure on marginal sites or fallow grounds with unfavorable site conditions may increase and SRC systems applied here may also have negative environmental impacts. Most importantly, it seems that SRC plots have to be optimally prepared by plowing to guarantee weed control during crop establishment [8][9][10]. Especially on fallow grounds, this may lead to an extra emission of CO 2 and N 2 0.…”

Influence of Cutting Type and Fertilization in Production of Containerized Poplar Plants

“…Therefore, establishment of poplar should be performed at this time as poplar is sensitive to competing vegetation [7,10,12]. A newly transplanted plant needs time to recover from the stress of handling and moving and establish roots to uptake soil water and nutrients.…”

“…However, poplar plantings on forest land are not always successful. Poplar plantations may fail due to poor vegetation control or soil management as young poplars are sensitive to competing vegetation [7,10,12]. Poplars are fast growing, with a rotation period of 10 to 25 years depending on planting density and location [11,13].…”

Relationships between understory vegetation and hybrid poplar growth and size in an operational plantation

“…Previous studies have found that hybrid poplar shows considerable sensitivity to competition from herbaceous species, with disproportionately large effects on trees less than four years of age (Buhler et al 1998, Shock et al 2002, Pinno and Belanger 2009, Otto et al 2010. Competition effects also vary depending on the identity and abundance of competitors, and generally results in a loss of tree biomass and altered crown morphology (Marino andGross 1998, Kabba et al 2007).…”