(Source : Stipanicic, A. 1999)
The first tests of provenance with larch in Quebec were in 1960, under the direction of the National Forestry Institute in Petawawa and in collaboration with the forestry company, CIP. Within the Quebec government, the program of genetic improvement with larches was initiated in 1970 by Gilles Vallée, with the goal of providing information and necessary recommendations for the use of different exotic and indigenous species of larch for the Quebec tree planting program. Numerous comparative studies of plantations using diverse species, indigenous and introduced, were established in a number of different regions in Quebec.
The broad genetic variability within each species as well as between larch species provides the possibility of improving a number of important characteristics : growth, form, resistance to disease and insects, adaptability to different sites as well as the mechanical and chemical properties of the wood. The hybrid species interspecifiques often surpass the parent species, opening the way to some particularly interesting genetic improvements.
Since the beginning of the genetic improvement program, 127 schedule including about 25 tests of provenances and 43 tests of descendances have been set up throughout Quebec, using the network of arboretums or in collaboration with forestry companies. The program includes larches from Europe and Japan as well as the tamarack larch and their hybrids. These three species and their hybrids are presently used on an operational scale for tree planting. In 1980 the Ministry of Natural Resources became a good source of improved seeds. The annual production has been evaluated at 4.3 million trees for exotic larches and 24 million trees for the tamarack larches.
Results from thirty years of work by the DFR in Quebec have shed light on the potential of larches, especially from comparative studies. In effect, sites of average yield vary from 5 to 10 m³\ha\year depending on the region and the site. To date, the program of genetic improvement has also enabled the identification of the best sources of larch for different regions of Quebec, as well as the best gene sources for the production of new hybrid varieties (Martin Perron, personal communication).
The most attractive feature of the larch is its productivity. The European and Japanese larches are the most productive softwood in the province. On the best sites, these species have shown that they can produce up to 310 m³\ha in thirty years, giving an average annual growth of more than 10 m³\ha\year. The tamarack, although less productive as a result of smaller diametre growth, can produce 194 m³\ha in thirty years. The increased productivity of the larch is characterized by rapid growth in the early years making it particularly desirable for short rotation tree plantations.
At the present time, the program of genetic improvement of larches is focussed on the development of hybrids using the European and Japanese larches. Although the program using the the tamarack is less developped, tree selection in natural stands and the establishment of seed orchard have been achieved as this species can be used for planting on less rich and less productive sites where other rapid-growth species cannot be planted.
The larch provides a very good quality wood useful for a wide variety of products : construction, furniture, carpentry, panelling, paper and cardboard. As a result, the Direction of Forestry Research has attracted interest from numerous forestry companies which depend on the rapid-growth larches to assure the future supply of wood for their mills. Smurfit-Stone, Forex Saint-Michel and Tembec have collaborated with the DFR and have already begun programs which focus on the use of hybrid larches in their production of cardboard, particle board and sawn lumber.
Based on results from operational and experimental plantations, larches are becoming more important in the tree planting program in Quebec. In 1997, 195,000 exotic larch trees were planted, 471,000 in 1998 and 950,000 in 1999. Recently, work has been undertaken to develop larch varieties which are better adapted to the northern regions of the Quebec forest (summary of a presentation by Mr. Perron at ACFAS).