Can the cultivation of industrial hemp spare forested habitat for wildlife in Canada?

Michelle Campbell

Department of Zoology, University of Guelph
Guelph, ON, Canada N1G 2W1, e-mail: mcampbel@uoguelph.ca

        Campbell, Michelle 1999. Can the cultivation of industrial hemp spare forested habitat for wildlife in Canada? Journal of the International Hemp Association 6(1): 10-13. The Canadian forestry industry is responsible for cutting approximately 1 million hectares of forests annually, and this level of harvest is affecting the integrity of wildlife habitat. A significant percentage of the annual harvest is directed to the pulp and paper industry and Canadians are becoming increasingly critical of forestry's old-growth policies and clearcutting practices, and are demanding alternatives to wood pulp. Hemp is an annual, sustainable, source of fibre and could replace the use of wood fibre for pulp and paper. Annual productivity of hemp stems surpass that of spruce-dominated forests in the Boreal region of the province of Ontario, on average, by a factor of 4.9:1. The fibre obtained from the entire pulpwood harvest in Ontario in 1996 could have been met by cultivating approximately 11 500 ha of hemp. The use of hemp fibre for pulp and paper could present an opportunity to conserve forested habitat for wildlife. In Canada, the current lack of infrastructure and low market demand for hemp products are the main limiting factors.

     The quality and quantity of forested habitat for Canadian wildlife has become a serious concern in this decade. Between 1975 and 1996 the number of hectares of forest harvested annually has increased by a factor of 1.5 (CPPA 1998b), so that in 1996, 4.1% of the total productive forested land in the country was harvested. Of this, 86% nationally was clearcut, with 91% in Ontario and 100% in Manitoba (CPPA 1998b; NFD 1998). Of the 211,829 ha harvested in Ontario in 1996, only 93,910 ha (or 44%) were re-planted or seeded, and in Manitoba this figure is only 39% (NFD 1998). Re-planting does not necessarily mean replenishing quality habitat for wildlife because these areas are generally mono-species stands with low biodiversity, tended through the use of herbicides and pesticides, and involve high management costs. These stand-tended areas rarely represent the habitat characteristics of the area prior to logging and thus support different species (Thompson and Walsh 1993). Due to this, and because there is not enough autoecological research conducted on the potential effects of these practices on the quality of habitat for wildlife, the management practices of the country's forested regions raise questions of sustainability. The Committee on the Status of Endangered Wildlife in Canada lists 42 forest-dependent mammals, birds and reptiles currently at risk in Canadian forests (COSEWIC 1998).

Pulpwood harvest
     It is estimated that 60% of the virgin wood extracted in 1996 was directed to the pulp and paper industry in Canada (Rosmarin 1997). However, approximately two-thirds of this contribution is in the form of 'waste' (e.g., wood chips, shavings and sawdust) from sawmills (CPPA 1998a). Statistics for direct pulpwood harvesting are not available in Canada, however, figures for the volume of pulpwood sent to mills is published (NFD 1998). In this evaluation, it would be useful in to know how these figures relate to the percentage of total harvest and number of hectares cut annually for pulpwood. Calculations were made based on the available data (i.e., may not correlate precisely with the actual number of hectares cut for pulpwood) and it was determined that in Ontario approximately 27% (57,000 ha) of the total harvest in 1996 was used directly for pulpwood. In Manitoba this figure is as high as 64%, or just under 10,000 ha.
        Canada is currently the second largest producer (behind the US) of wood pulp (24.85 million tons in 1997) in the world (CPPA 1998a), and world-wide demand for pulp and paper products is increasing; it has more than doubled (from 128.8 to 277.4 million t) since 1975, and is projected to double again by 2010 (CPPA 1998b). Currently, one way to ameliorate this has been to use recovered paper, a method which has increased greatly (550%) in Canada over the past 22 years (CPPA 1998b). However, this approach does not represent a long-term solution, because the fibres lose strength and length each time they are re-pulped and therefore cannot be recycled indefinitely.
        Canadians are increasingly becoming concerned about the apparent non-sustainability of the forestry sector and are beginning to demand alternatives to wood pulp (Rosmarin 1997). As of 1991, non-wood sources of fibre (including straw, bamboo, kenaf, and hemp) represented 10.7% (16.5 million t) of the total virgin fibre used for paper pulp in the world (CPPA 1998a). World production of hemp pulp in 1994 was estimated at 120,000 tonnes, or 0.05% of total pulp production (van Roekel 1994), and none was cultivated in Canada because of the legal status of hemp at the time. Now that hemp can legally be cultivated in Canada (Health Canada 1998) for commercial processing (as of March 1998), there could be a considerable opportunity to decrease the total amount of wood fibre used in pulp mills in this country and thus the amount of trees harvested directly for the pulp and paper industry. If this were to occur, the size and quality of certain forested wildlife habitat areas in Canada could potentially be increased, especially in provinces where hemp can be grown successfully and a significant percentage of the timber harvest is for pulpwood. The focus in this paper is on Ontario and Manitoba because most of the reports on hemp cultivation in these early stages are from these provinces.

Hemp's comeback in Canada
     In 1998, over 2100 hectares of hemp were planted (Gardner and White 1998), mostly in South-Western Ontario and Manitoba, where research trials between 1994 and 1998 had proven that hemp cultivation was successful (Schiefele et al. 1996; Manitoba Agriculture 1998). Small numbers of hectares were licensed for cultivation in every other province, except Prince Edward Island and Newfoundland, and small plots were in place in a few northern locations, such as Dawson's Creek, British Columbia and Peace River, Alberta. However, the commercial success of hemp in the northerly locations is not yet known. Because hemp is being cultivated mainly on previous corn or soybean fields in Manitoba and Ontario there is currently no clearing of additional land for hemp. This is an important point because habitat sparing will not be as significant if marginal farmlands (in varying stages of successional growth), or other forested regions are cleared for the cultivation of hemp in the long-term. The cultivation of alternative, reliable crops is needed in Canada because of the recent world-wide decline in the prices of grains which has led to marked instability in the agricultural sector.
        After cultivation, issues in Canada concerning the feasibility of using hemp for pulp and paper include how to store the unprocessed fibre and how to separate the bast fibre from the inner hurd. Storage represents a problem because a moisture content of less than approximately 12% is required to prevent rotting and the baled fibre needs to be available year-round even though harvested in late summer. The bales are large and bulky and it has been suggested that it is currently not economically feasible to ship the baled hemp stems more than 60 km (100 miles) within Canada (Roy 1998). Kynaston (1997), has suggested that mini-mills located close to cultivation areas, processing 50-300 t fibre/day, would be the most reasonable option (compare this with an average wood pulp mill that processes over 1000 t/day). Separation can be achieved by field retting, but for this technique to be effective in the majority of areas in Ontario and Manitoba, harvesting would have to occur in late July or early August to ensure adequate weather conditions. Because a significant portion of the growing season would then be lost, fibre yield would decrease. Separation can also be achieved by mechanical decortication, but this is extremely expensive and could cost up to CA$100/t (Marcus 1998). Other techniques being researched in Europe include ensiling (de Maeyer et al. 1994) and steam explosion (Nebel 1995). In British Columbia, Accell Technology is developing, on a laboratory scale, a thermo-mechanical process which could be used to separate the hurd and bast fibre (Kynaston 1997). However, given the expense of developing or adopting these techniques, field retting may be the best current option for the separation of hemp stems in Canada.
        Problems in separating the fibre, and efficiently utilizing the inner hurd, are not just Canadian concerns. Research is being carried out in Europe to determine the feasibility of pulping the hurd (de Groot 1995; Krotov 1994b) or the whole stem (Krotov 1996). In situations where the bast fibres are being directed for non-paper uses (such as textiles, geotextiles, hemp plastics or metals), it may be economical and value-adding to use the hurds for printing and writing paper, tissue, packaging materials, newsprint or as an input for fibreboard. Using the whole stem may be advantageous where separation of the bast and hurd would not be economical or efficient.

     The main factor limiting the use of hemp for pulp and paper in Canada is the lack of a processing infrastructure. The existing mills are set up for wood pulping, and current technologies would need adjusting to accommodate hemp fibre efficiently. There are no mills in Canada that can produce pulp from hemp fibre, and no primary plants that can prepare the bast fibre for pulping. However, a new 112,000 sq ft, CD$6 million plant, is to be built in Manitoba by summer 1999 to produce bast fibre for insulation and paper-making (Kuxhaus 1998). Since there are currently no secondary processing plants, the fibre will have to be exported to be made into pulp and end products. Three to four more plants may be built in the next few years, which may branch out into secondary processing and manufacturing value-added products. These value-added products could be high strength items such as coffee filters, tea bags, science and technical filter paper, and specialty art papers. Whether or not an infrastructure will be developed in Canada for pulp and paper really depends on whether hemp productivity is comparable to that of forests.

Annual productivity
     A US Department of Agriculture (1916) bulletin states that hemp inner hurd can out-produce wood in terms of the area required for sustained supply by a factor of 4:1. This is a bold statement and the researchers do not specify the latitude and types of forest studied, or explain their methodology. The applicability of these dated findings may be in question because of modern technological advances in forest management, measurement of annual growth increments and improved hemp cultivars. However, a potential 4:1 production factor certainly warrants updated research. A recent Ukranian study found that, using an average annual yield of 8-10 t dry stems/ha, hemp fibre production approaches that of a fast growing poplar plantation (annual increment of 30m3/ha, wood density of 420 kg/m3) which yields 12.6 t wood fibre/ha/yr (Krotov 1994a). With more research and advanced cultivars, the Ukranian Institute of Bast Crops (UIBC) expects that a hemp fibre yield of 12-14 t dry stems/ha can be achieved, equaling or even surpassing that of a fast growing poplar stand.
        Annual growth increment data for Canadian forests are difficult to obtain. However, they are available for four sites of spruce-dominated forest in the Boreal region of Ontario (45o N. latitude), and ranged from 1.02 to 5.26 t of wood (bark removed) per year for the overstory (DeAngelis et al. 1981). The average age of the stands in the four sites ranged from 84 to 246 years, and the highest growth increments were found in the two sites over 200 years of age. No data are currently compiled in Canada (Luck 1998) for the average age of stands harvested for pulpwood (important to know because productivity depends on this), or the species distribution (important to know because different species grow at different rates).

Hypothetical situation
     The medium-term yields for hemp grown in Canada for fibre are estimated at 10 t dry matter (DM/ha/yr) by an overview of the economics of hemp cultivation in Canada (Marcus 1998). This season, yields in Ontario for hemp grown for fibre were 3-12 t DM/ha (Roy 1998). In Manitoba, where hemp is usually grown for both seed and fibre, average yields are estimated to be 4.5-8 t DM/ha (Manitoba Agriculture 1998). In both provinces, yields were lower that expected due to administratively delayed planting, lack of cultivation experience and regulatory restrictions on cultivar choice. Assuming that on average, 84% of dry matter yield is stem (van der Werf et al. 1996), and using the estimated medium-term Ontario yields, this equals 8.4 t stems/ha/yr. In this model then, productivity of hemp (whole) stems would be 1.6 to 8.2 times greater than that of spruce forests at 45o N. latitude, averaging out at a factor of 4.9:1. Using this average, approximately 11,500 ha of hemp would have to be planted annually in Canada for fibre, to produce as much raw fibre as was obtained from the total number of hectares cut (57,000 ha) in Ontario in 1996 directly for pulpwood. Dutch studies have also determined that the inner hurd comprises approximately 65% of the stem (van der Werf et al. 1996]. Thus, a yield of 5.5 t hurd/ha/yr could be realized in Canada, which translates to a 1.04 to 5.4 times increase in productivity over the forests used in this model, and is similar to the findings presented in the 1916 US Department of Agriculture bulletin mentioned above. If only the bast fibre were being used for paper-making (2.9 t/ha/yr), it would not be more productive than cutting down the spruce forests in this model for pulpwood, except at the least productive site (1.02 t wood/ha/yr). Clearly, there is potential for hemp productivity to surpass that of wood in Canada, but more research needs to be done to determine precisely what this will be at different locations.

Habitat Sparing
     The greatest potential for sparing habitat will be realized if hemp fibres are used to produce newsprint or newsprint quality pulp. The reason for this is that the majority of wood pulp produced in Canada (61% in 1996) is used for newsprint production (CPPA 1998b]. Furthermore, 65% of paper export shipments in 1996 (of which over two-thirds were shipped to the U.S.) were newsprint (CPPA 1998b). The limitation here is in convincing foreign importers that hemp pulp and paper products are as high in quality as wood pulp and paper products. Also, there may be serious political obstacles in that many of the major logging companies have long-standing contracts with many of the newsprint and paper manufacturers, both in Canada and the US, and these manufacturers may be unable, if not unwilling, to switch to non-wood pulp. However, this may change if logging companies foresee the capacity for market shifts, and put investment dollars into hemp and other non-wood pulping technologies. Already, forest companies like Domtar are realizing the potential markets and are developing technologies to pulp many non-wood fibres including hemp (Twomey 1995; Kynaston 1997).
        In order for the use of hemp to have a significant effect on sparing forested wildlife habitat, it will have to replace much of the use of virgin wood fibre for the manufacturing of pulp and paper products. This would require a complete change in the pulp and paper industry in Canada, which would be most effectively driven by changes in consumer demand and market forces. In the interim, the use of hemp fibre mixed with recycled wood fibre and sawmill waste products (sawdust, wood chips and shavings) may be a good starting point.

Further Research
     There are still many unanswered questions, and this evaluation would be more complete if the following information were known in the Canadian context:
        Annual productivity data for other types of forest (both softwood and hardwood) at varying latitudes across the country.
        More complete data on hemp yields at various latitudes and longitudes, percentage of stem in the dry matter, and bark/hurd in the stem, for cultivars approved for use in Canada.
        Pulp yields that can be attained for hemp stem/hurd/ bast and how these compare to pulp yields from raw softwood/hardwood fibres. Meijer et al. (1996) suggest that about 80% of the raw bast fibre can be recovered after extrusion pulping.
        Amount of hemp pulp required to produce a given amount of end- product, and how this ratio compares to the amount of end-product (packaging materials, newsprint, printing and writing paper) that can be produced from wood pulp.
        Age class and species distributions for current pulpwood harvesting in each individual province, as well as the total number of hectares cut (and in what areas) annually for pulpwood.
        Market analysis for hemp pulp and paper products, including short- term, medium-term, and long-term projections.

     I would like to thank Dr. Vernon Thomas for his helpful comments regarding the manuscript.