Grant: Discovery Grants Program - Individual

Natural root grafting has been seldom studied since the 1960's in North America. It was however observed to occur in a lot of tree species, and possibly in all species for which roots have been specifically examined. Root grafting is often viewed as a natural oddity, and its implication in forest ecology and management has been generally disregarded, although most will agree that root connections have great eco-physiological significance. Root grafts can act as infection networks for the transmission of diseases such as the dutch elm disease. They can transfer, to untreated trees, herbicides and fertilizers ('backflash' phenomenon). Root grafts can also confer more wind resistance to a forest stand, and can affect responses to thinning operations. Because they allow trees to share water, minerals, assimilates and diseases, root grafts most probably play a major role in tree biology and thus should be better understood. In this research project, I propose to 1) evaluate the occurrence of root grafts among common boreal tree species (jack pine, black spruce and balsam fir), 2) examine factors enhancing root grafting and dendrochronologically determine the timing of root graft formation, 3) characterize processes involved in translocation of water, nutrients and assimilates through root grafts, and 4) evaluate the impact of silvicultural treatments on tree biology and stand dynamics in relation to root grafting.