Update of Short Rotation Intensive Culture in Canada

Marie Louise Tardif, NRCan, Alternative Energy Division, 580 Booth Street, Ottawa, Ontario K1A 0E4

ABSTRACT

Canada is a large country with abundant quantities of biomass in many diverse forms. Forest industries and related operations alone annually produce 39 million oven dry tonnes. But in the past fifteen years, bioenergy has contributed only 7 percent of Canada total energy supply. Many provinces of Canada are fortunate in having affordable natural gas and hydro-electric power. As a result, the demand for wood fuel energy sources has risen very slowly.

In this context, what is the status of Short Rotation Intensive Culture (SRIC) for energy purposes? Is there any possibility for this type of cultivation to be commercially competitive as a source of energy?

INTRODUCTION

Canada is a large country where diversified forms of biomass are found in abundant quantities. However, bioenergy contributes only 7 percent of the total energy supply and the demand for wood fuel energy sources has risen very slowly because many parts of Canada have access to affordable natural gas and hydro-electric power.

This paper will review the status of Short Rotation Intensive Culture (SRIC). Emphasis will be on new developments which have occurred in some regions of the country and discussion of the feasibility for this type of cultivation to compete economically as an energy feedstock.

Canadian Land And Canadian Resources

Canada has varied and abundant biomass resources. There are over 453 million ha of Canadian forest of which practically half (46 percent) is classified as commercial forest.

There are vast quantities of wood residues stacked in the forests and mill yards of this country. Bush logging residues, composed of tree tops, branches and foliage, are estimated at 30.6 million oven dry tonnes per year (M o.d.t./yr) (Simons, 1994) and across Canada, discarded wood mill residues are evaluated at 8.4 M o.d.t./yr. This total of 39 M o.d.t./yr of wood residues does not include urban wood waste which is estimated to be a further 14.2 M o.d.t./yr. This total of wood residues represents a potential of 750 PJoule/yr, which is equal to 12 percent of all of Canada's annual energy requirements.

Other important sources, including agricultural residues, municipal and industrial process wastes and peat resources, are a potential source for large quantities of feedstock for bioenergy.

However, even though great quantities of biomass exist in Canada, bioenergy contributes only 7 percent of the total energy supply. (EMR Canada) This is equivalent to the energy supplied by nuclear sources, and approximately half of that obtained from coal. In the last fifteen years, the demand for fossil fuel energy sources has risen slowly. Consumption has only increased an average of one-third of one percent annually.

Canada is also fortunate in having competitively priced hydro-electric power and affordable natural gas.

Therefore short rotation intensive culture (SRIC) for energy purposes has not been commercially developed. If only the economic aspect of these cultures is considered, and without a drastic change in the world's energy situation, it is unlikely SRIC. will achieve competitive pricing. However, public concern with environmental issues is driving the search for more products and methods, which are environmentally friendly, including those used to produce energy.

What Is The Status Of The Fast Growing Trees?

Canada has 67.8 M ha of agricultural lands of which more than 21 M ha (Simons, 1994) of marginal land are considered usable for energy crop production.

Close to 80 percent of the total area of these lands is located in British Columbia and Alberta, the western provinces.

After examining the constraints of short intensive culture energy competitiveness, the potential and the ecological benefits accompanying the use of these cultures as clean feedstocks must be considered.

Because the exploitation of short rotation tree plantations for pulp, veneer, oriented strand board and energy is relatively new, there are few commercial plantations in Canada.

Provinces Affected

The diversity of the Canadian landscape is such that it is impossible to make general conclusions for the country as a whole. The situation varies from province to province and even from site to site. There is presently no fully operational energy plantation in Canada.

In British Columbia

In the province of British Columbia (B.C.) a pulp and paper fibre gap is predicted in about twenty years. Because poplar is an abundant native species, pulp and paper companies such as MacMillan Bloedel and Scott Paper Limited have been involved in testing of hybrid poplar and tree planting for pulpwood purposes, since 1984.

One thousand (1,000) ha of land in B.C. are under short rotation intensive culture. Scott Paper is currently harvesting 30 year old plantations in the Fraser Valley and replacing the trees by Populus Interamericana, a poplar hybrid to be grown on a fifteen year crop cycle. Scott Paper's oldest short rotation poplar plantation is now eleven years old and produces a yield of 30 m³/ha/yr mean annual increment.

A less intensive management occurs on the B.C. coast. Natural regeneration of Populus trichocarpa is augmented with planting of hybrid poplar or native cottonwood whips (P. balsamifera L. spp. trichocarpa) and grown on a 25 to 35 year rotation. Over 10,000 ha of land are committed to the extensive culture of poplars in B.C. (growth rates range from 10 to 20 m³/ha/yr; Scott Paper Ltd, Skeena Cellulose, B.C. Ministry of Forests and the Department of Indian Affairs are involved.) These numbers reveal that most of the fast growing tree plantations and the highest yield in Canada are in B.C.

Recent outbreaks of disease on hybrid poplars, in the States of Washington and Oregon, underscore the need to test disease resistant clones and avoid the establishment of large monoclonal block plantations. B.C. native Populus trichocarpa will be used in future breeding efforts.

In Alberta

In the province of Alberta, Alberta Pacific, a pulp and paper company, is in the process of starting an entire program of Poplar culture, including genetic breeding. These trees will be used primarily for Oriented Strand Board and Pulp and Paper.

In Ontario

In the spring of 1993, in the province of Ontario, the faculty of Forestry of the University of Toronto established two 2 ha prototype willow plantations using 12 different clones. This research is to verify the yields of clones previously grown only on small plots, to provide figures on the survival and growth of the selected clones, to test prototype planters and harvesters, to produce large quantities of biomass and to assess the economics of biomass production. The used clones are not available for distribution yet because they are still experimental.

However, the Ontario Ministry of Natural Resources listed ten selected hybrid poplar fast growing clones that are regularly planted. Some horticultural centers are also selling improved uncertified fast growing material.

Also, Resource Efficient Agricultural Production, (REAP) a cooperative of Quebec and Ontario farmers, has been involved in short rotation intensive culture, in Ontario, for the past four years. The farmers are trying different type of plantations with different tree species, such as establishing monoculture plantations with willows and establishing windbreaks with poplars, willows, black locus and Norway spruce in mixed systems.

This is a three years old Salix miyabeana (Austree) windbreak plantation growing on swine manure fertilized soil in south western Ontario.

According to the economist Girouard, working for REAP Canada, it appears that the windbreaks have significant advantages over the monoculture production systems. The preliminary economic assessments indicate that the average net increase in crop yield from a windbreak will cover all production costs associated with the short rotation windbreak and that the sale of the biomass crop will enable profitability.

In southern Ontario, in the near future, a large research project will begin to evaluate the use of mixed primary and secondary paper sludge in forest biomass production. This will occur on 1,400 ha of clay mineral soils. Pulp and paper sludge will be used as an organic soil amendment to improve soil qualities and to increase the yield of fast growing tree species and indigenous species. The effects of pulp and paper sludge on trees never have been evaluated in Canada. A large amount of data is available related to agricultural cultures but not to forestry.

The pulp and paper company Domtar Inc. owns a 12 year-old hybrid poplar plantation for pulp purposes of more than 2,100 ha.

In Quebec

In the province of Quebec, a genetic improvement program for poplars has been underway since 1968. Some 2211 clones have been evaluated. Of these, 53 were selected for testing in different regions of Quebec to verify resistance to frost, canker and leaf rust. Generally, hybrids with Populus balsamifera such as P. Balsamifera x deltoides, x nigra, x euramericana, and P. balsamifera with (P.deltoides and trichocarpa) are the most used.

These poplars will be used primarily for management of natural forest stands and fibre production and secondarily for energy purposes. The idea is to recuperate the logging and mill residues for energy use. The province now has 350 ha of land under monoculture poplar plantation.

Concerning willow, the city of Montreal has the largest urban nursery in North America, and is conducting extensive work with fast growing Salix plantations. Mr. M. Labrecque, a botanist at the Vegetal Biology Research Institute, is the leader of this field research. His team reforested abandoned landfill sites beside the municipal waste water plant. Wet or dry treated municipal waste waters have been used to successfully irrigate plantations. The objectives were to evaluate effects on yield and to determine whether the chemical components contained in the soil dispersed into groundwater or translocated along the roots, the stems or the leaves. This project began in 1992, and after two years, initial conclusions were that the most soluble metals, such as nickel, cadmium and zinc, are accumulated in the plants. 50 percent stay in the roots and the stems; the other 50 percent is returned to the soil by leaves. There are no significant effects the first year of the application but by the second year the willow yields increase considerably. The amount of waste water applied is always proportional to the nitrogen available in the soil.

In Quebec, REAP Canada is also involved. In Quebec as in Ontario, its major activity in the spring and summer of 1993 was the establishment of three (side by side treatments with 6 replications) field scale experiments, each of approximately 5 ha in size, cultivated with trees and grasses. This design will provide effective comparable estimates of production costs and productivity assessments between short rotation forestry systems and warm season grasses systems of biomass production.

Currently, there is controversy between researchers. Some are pro-grasses while others are in favor of more fast growing trees. According to Labrecque and others, trees are more adapted to wet nordic lands and grasses to dryer and warmer sites. But, even if grass has the advantage of a harvest each year, it has been proven that this type of cultivation depletes the soil more rapidly than tree culture. I think both cultures could have applications on appropriate sites. Respect for the ecological zones for the planting of specific native tree species is very important. While genetic selection is a major factor, the species must be planted in their native zones for best performance.

In addition, the potential of mycorrhizal fungi to improve nutrient cycling and the evaluation of diversified technologies to reduce the production costs are studied by REAP Canada.

Expected Yields And Costs

In Canada, yields of SRIC biomass plantations and windbreaks vary widely with species, region, and management strategy.

At present, all energy plantation yield data come from small research plots. In some cases, yields as high as 28 odMg/ha/yr (Labrecque M., 1994) and as low as 2 odMg/ha/yr have been obtained. Nevertheless, it is not known what scaling up the experiment to commercial size plots would do to yields. Results will be available in the next two to three years, through mid-commercial size plots (2 to 3 ha) established in central Canada, in the spring of 1993 (Montreal City, REAP, U. of Toronto).

It is therefore very difficult to be certain which of the cost figures given by researchers are the most accurate. Variance between different cost calculations is enormous. With a revolution of 20 years and a rotation period of 4 years, average Short Rotation Tree yields range from 7 to 15 odMg/ha/yr, producing annual biomass costs between $63 (U.S.) and $11 (U.S.) (See Table 1). These numbers do not include the cut- back cost of the first year and the chipping and transporting costs. Gambles and Kenney (1991) estimated the chipping and the transporting costs respectively at $7.46 U.S./odMg and $0.15 U.S./ odMg/km. These are the most accurate figures available.

According to Mr. P. Foody (1993), regarding ethanol production, if biomass (both woody and herbaceous) could be bought at $22.5/odMg, these feedstocks would be competitive with other sources of energy. This scenario would be achieved on a no rental cost land with low harvest cost ($450 U.S.) and high yields (20 odMg/ha/yr). At the present time, Short Rotation Forestry is not a viable feedstock for ethanol production. However, one of the ways to reduce SRF biomass cost is to use it on-site and to avoid transportation costs.

Harvesting And Processing

Many studies estimate that harvesting and delivery costs account for over 45 percent of the cost per MJ of energy produced per ha (Strauss and others, 1988), and can range from 35 percent (Ranney and others, 1985) to 73 percent of the total biomass production costs (Zsuffa and Gambles, 1992). The equipment alone is responsible for the greatest part of the costs. Logically, decreased harvesting costs would also greatly contribute to reduced operational costs and overall biomass cost.

The National Research Council of Canada, in the mid-1980's, developed a few single-row prototype machines. Only one, the FB7 used to harvest medium sized trees, (18 cm), was tried in the field and provided a basic understanding of field difficulties. FB7 harvested an average of 850 trees per productive machine hour while harvesting single trees from rows. Unfortunately, this research program was discontinued. After these trials, no specific machine has been developed for short rotation intensive culture.

In Canada, because of the new interest in short rotation intensive culture, no machine has been developed for this specific application. Harvesting is done manually with a brush saw and this simple method seems to be the most appropriate for small plots. The average productivity per person is estimated at 0.4 ha/day. On the other hand, it appears to be relatively easy to harvest the fast growing grasses with existing agricultural machines followed field bailing.

However, even though the country is well endowed with many diversified forest machines, their design is suitable only for conventional forestry and not for S.R.F. For example: Domtar Inc. in Ontario cuts its 12 year-old poplar plantation with a Timbco T435 feller-buncher. The entire tree lengths are removed from the site by a grapple skidder. Because the chips are produced for pulp, the trees are chipped with a Morbark flail delimber/debarker/chipper. Chips for energy purpose do not require such processing.

In this regard, a few months ago, I began an inventory of small diameter tree harvesters and chippers available on the Canadian market. I contacted most of the Canadian manufacturers of forest equipment requesting as much detail as possible on these types of machines. Most of them were unaware of fast growing tree plantations for energy and did not have any interest in harvesting such small diameter trees. Many of them sent me information on chippers. There are hundreds of different chippers on the market. Brucks, Comact, Hakmet, John Deere, Morbark, Nicholson, Rodrigue Metal, Timberjack...etc. sent me folders on their equipment, saying, of course, that they have the most efficient ones. But in fact, none of this equipment met my requirements for a machine which would cut and chip trees simultaneously. Because of the constraints mentioned at the beginning of my paper, for trees with diameters less than 7.6 cm, the most effective process is to harvest and chip in one operation thereby reducing labor costs (Johnson and Erickson, 1987) and becoming competitive with other energy sources.

However, it permitted me to reduce my list to include only those companies offering machines which were of some interest. None of them is perfectly suited to my requirements, but there is great potential for them to be adapted to our needs.

I would like to describe two of these machines:

I call this unnamed multi function head: "The Material Circuit Chipper". It has been designed and built by a gentleman who was involved in road construction and roadside brush clearing. He developed two different machine sizes for his purposes. One is 1.8 m wide and the other is 1.4 m wide with cutting openings of 1.2 and 0.9 m and 12 and 8 cutting blades respectively. The total weight of the two mobile chippers is, respectively, 499 and 363 kg. The motor R.P.M. is around 2,000.

These machines, which are very effective for the purpose for which they were designed are not yet in commercial production and have never been tried in S.R. Plantations. I have not seen them in operation, but, will attempt to explain how they operate.

A woodbrush cutting machine is comprised of two horizontal and adjacent cutting units, which rotate in opposing directions. The units consist of cylindrical surfaces to which longitudinal wood brush cutting blades are mounted.

In the region between the two cylinders, the blades of one cutting unit fit between the cutting blades of the other unit. The blade of unit A passes in the space between the cylinders followed by the blade of the unit B, in sequence.

The angular position of the blades of unit A is 90 degrees apart from the angular position of the blades of unit B, about the axis of rotation.

In action, opposite rotation of the cutting units forces the woody stems to pass between the cylinders where they are cut by the blades. Then the blades throw the woodchips upward. A tunnel like channel with a wide lower opening surrounds the cutting units to efficiently receive the wood chips. They are then directed toward the discharge opening. This opening is provided with a spout to discharge the chips into a container. When the container is full, (capacity is about 1 cubic meter) the boom-and-arm assembly is articulated to tilt the container and pour its contents. I believe this machine could be quite easily adapted to the harvesting of small, fast growing trees. I intend to further examine the possibilities of this multi-function head.

Midiforst and Forst built by Seppi M., an Italian company, have been tried in many diversified forest stand conditions including a project on small trees on a private woodlot. The objective of this study was to evaluate machine performance in cutting and chipping various types of woody material. It is a really efficient machine in brush cutting andherbaceous control. The major impediment to use of this machine in SRIC is that it will cut and chip but does not harvest the chips. The cutting system consists of at least 20 hammers of 1.6 kg each.

These machines are perfectly suited for site preparation of abandoned brushy fields. There are also positive effects in stopping the herbaceous and ligneous competition because they blow away and spread the chips covering the soil and return nutrients to it.

CONCLUSION

Given the immense availability of marginal, abandoned farmland in Canada, plantation for bioenergy is an attractive possibility. The sustainable use of these lands as an alternative energy source would result in CO2 absorption, land conservation, and a reduction in greenhouse gas emissions.

However, as when research began, the challenge is:

• to improve the technology and thereby reduce production costs,
• to develop a market for the final products, and
• to generate more interest among potential growers, buyers and policy makers.

There is some positive news. It is very encouraging that large hydro-electric utilities, such as Hydro Québec and Ontario Hydro are increasingly receptive of technologies and have indicated an interest in being involved in field trials in the near future.

Also, H. A. Simons, a private consulting engineering firm, working for the Canadian Electrical Association and Natural Resources Canada, is currently doing national research on the prospects for biomass for future electrical generation plants.

Natural Resources Canada also wishes to complete an analysis of policies to create opportunities to increase the contribution of forest biomass to energy production in Canada. To this end, it will award a contract to develop a national technical-economic database for forest biomass to support its policy analysis. I believe that these initiatives, will have significant impact on the use of biomass for energy and will result in enlightened and effective new policies.

*1. Includes: herbicide application, plowing, discing, harrowing, planting

*2. Includes: herbicides, fertilizers, spraying, land lease

*3. Estimated costs from literature review

*4. Real costs on small plots in Montreal, Quebec

File posted on March 5, 1996; Date Modified: February 21, 1999