Mature Hybrid Poplar Riparian Buffers along Farm Streams Produce High Yields in Response to Soil Fertility Assessed Using Three Methods

Abstract

This study had three main objectives: (1) to evaluate the aboveground biomass and volume yield of three unrelated hybrid poplar clones in 9 year-old riparian buffer strips located on four farms of southern Québec, Canada; (2) to compare yield data at 9 years with previous data (at 6 years); (3) to evaluate how soil fertility, measured using three different soil testing methods (soil nutrient stocks, soil nutrient concentrations, soil nutrient supply rates), is related to yield. Across the four sites, hybrid poplar productivity after 9 years ranged from 116 to 450 m ) were observed at all sites, but the productivity gap between the less fertile site and the three other sites was widened. Clone MxB-915311 was the most productive across the four sites, while clone DxN-3570 was the least productive. However, at the most productive site, clone MxB-915311 experienced severe stem and branch breakages. Independently of the soil testing method used, available soil P was always the first soil factor explaining volume yield. OPEN ACCESSSustainability 2013, 5 1894

Biomass and Volume Yield in Mature Hybrid Poplar Plantations on Temperate Abandoned Farmland

“…Our results also confirm previous observations done in poplar agroforestry systems of the studied region (southern Québec, Canada). In 9 year-old poplar buffer strips, allometric relationships between DBH and branch biomass were similar for clones MxB-915311 and DNxM-915508, while clone DxN-3570 had much lower branch biomass at a given DBH [34]. Yet, 7 year-old poplar clones of different parentages (D, DxB and DxN) showed little variation in allometry of woody biomass compartments [50].…”

“…This is because different poplar hybrids may have different biomass allocation patterns or architecture [34]. Important variation in allometry have also been shown for different Salix clones grown in short rotation coppices [35].…”

“…As in our previous yield studies [11,21,34], we used a model-based sampling approach [46], by developing new allometric relationships for each hybrid poplar clone to assess yields. The choice of this sampling approach was motivated by the fact that hypothesis testing (Clone and Site effects, and Site × Clone interactions) in short-rotation forestry often requires that object-specific allometric relationship have to be developed and destructive sampling cannot be avoided [35].…”

Plastic Allometry in Coarse Root Biomass of Mature Hybrid Poplar Plantations

“…The PRS-probes consist of an ion exchange membrane encapsulated in a thin plastic probe, which is inserted into the ground with little disturbance of soil structure. Nutrient availability predicted with this method is generally significantly correlated with conventional soil extraction methods over a wide range of soil types [53], and which has also been corroborated in poplar riparian agroforestry systems of the study region [54,55]. In August 2012, four pairs of probes (an anion and a cation probe in each pair) were buried in the A horizon of each plot for a 35-day period.…”

Potential policy reforms for a “more exotic” Canadian forest sector: Comparing Canada's plantation policies with those in Australia, New Zealand and the United States

“…But such estimates are heavily dependent on assumptions regarding growth rates of plantations. Compared to indigenous tree growth rates of around 2 to 5 m 3 /ha/yr, studies in Quebec have shown hybrid poplar growth rates can range from 22 m 3 /ha/yr (Truax et al 2012) to 50 m 3 /ha/yr (Fortier et al 2013), though these growth trials occurred under conditions that are likely much more favourable than would occur operationally. More conservative growth rates were suggested by Anderson and Luckert (2007) Low returns on private land may also arise from the spatial organization of the forest industry.…”