The program of genetic improvement of poplars began in Quebec in 1969. The program was initiated by Gilles Vallée of the tree improvement service within the Quebec Ministry of Energy and Resources. In the beginning, the project introduced species and hybrids obtained from elsewhere as well as a selection of local trees or natural hybrids. The research consisted of comparative tests of provenance, descendances and clones which were carried out at numerous research centres across Quebec. The goal of these tests was to find clones and lines of rapid-growth poplars having a certain resistance to pathogens and insects which were adapted to different ecological conditions of Quebec (Vallée, 1985).
The first programs of hybridisation quickly produced genetic material which performed better and was much better adapted to local conditions. These programs have continued to develop and they now include numerous aspects of the growth of poplars. It is relatively easy to obtain poplar hybrids and particularly easy to achieve multiplication in propagation by cuttings, which makes it an ideal tree species for genetic improvement, cloning, molecular genetics and biotechnology (Périnet, 1999).
In Quebec, the poplar is now a species valued by the forest industry and represents a new source of wood supply. The forest industry uses poplar wood to make pulp and paper, particle board, laminated beam , plywood and lumber for a variety of uses. Poplar stands are increasingly common and it is very probable that within the near future the industry will find increased uses. Wood from plantations of hybrid poplar will complete the production from natural stands (Vallée et al., 1997).
The program of genetic improvement of poplars is run by a team under the Direction of Forestry Research (DFR) of Forest Quebec. This program has produced improved populations from five principal parent species :
Throughout the years DFR researchers have created an important system of experimental plantations. These plantations are dispersed throughout numerous ecological sub-regions of Quebec. To date the DFR has produced an increased number of hybrid poplar clones which are recommended for more than 40 ecological sub-regions in Quebec. As well, this list of 44 clones covers bioclimate zones 1 to 5, from maple stands to fir to white birch (Périnet et al. 2001). These clones are being produced in greenhouses of Forest Quebec where current production could reach 2.5 million plants per year.
Briefly, the genetic improvement of poplars is usually carried out in the following steps (Périnet, 1999) :
Over the last 30 years, more than 3,700 clones have been evaluated in Quebec. The wood produced in tree plantations has been more uniform and has contained much less rotten wood while the wood density in the hybrid poplar plantations seem ideal for the production of oriented strandboard (osb). Annual growth from 1 m to 1.8 m in height and 1.0 to 2.5 cm in diametre are common depending on the region, the quality of the soil and the intensity of the cultivation (Vallée et al., 1997). On average, the poplar hybrid yields are from 8 to 12 m³\ha\yr (160 to 240 m³\ha in merchantable volume over 20 years) (Périnet, 1999). On the most fertile sites, situated in the more southern regions of the province, the growth could reach 12 to 15 m³\ha\yr (240 to 300 m³\ha over 20 years). In the best regions, and under exceptional growth conditions, the yield could reach 20 m³\ha\yr (300 m³\ha over 15 years) following strict silviculture guidelines (Pierre Périnet, personal communication). The rotation of poplar hybrid plantations is two to three times less than the rotations observed in natural poplar stands. The cultivation of hybrid poplars would seem a viable choice within the context of diverse zones of forest use while increasing the yield from Quebec forests (Périnet, 1999).
Other very promising hybrids are being considered by the DFR and continue to be tested in plantations to better understand the limitations of the clones, particularly in ecological regions 4 and 5. Numerous other aspects relative to the genetic improvement of poplars are being studied including phytopathology and molecular genetics. In effect, the poplar, as a result of its characterisics and the size of its genome, is a model tree for studies in molecular genetics. Due to the genetic material currently available to the DFR, future prospects look good for the continuation of studies in genetic improvement of hybrid poplars. (Périnet, 1999).
Researchers and Innovative and Dynamic Forest Companies in Quebec
For a number of years the DFR has collaborated with numerous users of the forest resource, the forest companies who plant thousands of hybrid poplars each year. The table below presents the principal forest companies using hybrid poplars as well as the land area planted annually.
This list exludes land areas within private forests which have been reforested. A couple of demonstration forests established in 2002 in the Gaspé region by Tembec could also be added to the list.
In 1998 the production of hybrid poplar seedlings in Quebec numbered 200,000. In 1999 and 2000 500,000 plants were produced in Quebec greenhouses, whereas in 2001 and 2002 the production reached 1.5 million plants (Note : in 2002 the demand for hybrid poplar plants was 2 million but the Direction of seedling and plant production (DSPP) could not meet this demand due to budget cuts). Finally, in 2003, even though demand may be greater, 2.5 million hybrid poplar plants will be produced.