Intensively managed forest plantations are used to produce large quantities of wood on limited land areas. In 2010, the total area of planted forests was only 7% of natural forest areas worldwide, while their contribution was about 40% of global fiber needs (FAO 2010). Although there is increasing evidence that mixed-species plantations should be favoured over tree monocultures, monoculture plantations are still more common than mixtures of species or clones because they are more convenient to manage. In 2006, plantations with more than one genotype represented less than 0.1% of the total area of industrial plantations worldwide.
When compared to natural forest stands, tree monocultures decrease biodiversity across the landscape and affect a wide spectrum of other plant and animal species, ranging from soil microorganisms to macrofauna. For this reason, monocultures have been described by some as “biodiversity deserts”. In addition, exhaustion of soil nutrients, deterioration of soil physical and chemical properties are often associated to monocultures. Current studies have shown that mixing cultivars or species may positively affect biotic and abiotic environments through optimal use of nutrients according to niche differentiation theory and in this way, enhance specific and functional biodiversity relative to monospecific plantations. For instance, in young plantations that we established in northwestern Quebec, mixing hybrid poplar clones resulted in slightly greater aboveground growth, lower root:shoot ratios, and different spatial root distributions, when compared to monocultures. We also recently found that collembola abundance and litter decomposition rates increased in mixed plantations of poplar and spruce, and that herbaceous species present in old fields helped litter decomposition and nutrient cycling and hence strongly influenced carbon (C) sequestration in these plantations. Nonetheless, some plantations can have a highly diverse understory of indigenous plants species; this is likely the case of Quebec’s plantations where the use of herbicides is prohibited and weed maintenance is mainly done mechanically over only a few years after plantation.
The objective of this project is to evaluate the effect of clonal/species mixtures in intensively managed fast-growing plantations on species composition and functional diversity of understory plants compared to hybrid poplar monocultures.
Start date: September 2019
Location: The student will be based at a forest research institute (IRF, http://www.uqat.ca/programmes/irf/) at the UQAT campus in Amos. In addition, the student will be member of the Sustainable Forest Management research chair (http://chaireafd.uqat.ca/) and the Center for Forest Research (http://www.cef-cfr.ca). The IRF team is dynamic and offers ideal working conditions for students, while the region is very active culturally and offers a high quality of life thanks to its many outdoor activities.
Funding: $ 21,000 / year scholarship for 3 years.
To apply: Email your resume, a letter of motivation and transcripts to Annie DesRochers (firstname.lastname@example.org) and Nicole Fenton (email@example.com).
Annie DesRochers professeure/professor UQAT (http://www.cef-cfr.ca/index.php?n=Membres.Anniedesrochers) Nicole Fenton, professeure/professor UQAT (http://www.cef-cfr.ca/index.php?n=Membres.NicoleFenton)