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Multiple-purpose silviculture in British Columbia

H. Benskin and L. Bedford

An analysis of changing demands on silviculture in British Columbia in response to new multiple objectives of forest management.

Henry Benskin and Lorne Bedford are, respectively, Director and Forest Establishment Officer of the Silviculture Branch. British Columbia Forest Service, Victoria. Canada.
Note: This article is excerpted, with permission, from a paper presented at The Silviculture Conference, 12-15 September 1993, Toronto, Canada, and published in the Forestry Chronicle, 70(3), May/June 1994.

In the "good ol' days" silviculture in British Columbia (and most other places) was relatively straightforward. There were two simple facts of life for foresters: one, silviculture was almost exclusively concerned with obtaining successful regeneration after logging; and, two, either it was not working or there was not enough of it going on. Today, in the 1990s, life for the forester is not nearly so simple.

The public has many loudly voiced opinions about how forests should be managed and for what purpose. Forestry must now serve "many masters". While it is the job of politicians to determine the major uses to which the land will be devoted, it is up to foresters to provide the scientific expertise, to help maximize the benefits that come from a finite resource and to respond to public concerns about forestry practices. Both the economy and the environment are of vital importance to British Columbia and its citizens. The major issues on the environmental side appear to be global health, gentler forest practices and the management of forests for multiple values. On the economic side they are sustained management of timber supply, other forest-dependent industries and benefits, for example tourism, and employment opportunities.

Global health

Among other global health issues, people are worried about carbon dioxide concentrations and global warming. The jury is still out but the potential consequences are frightening rising ocean levels, forest fires, movement in tree species ranges, and so forth. It has been proposed that forests have a role to play as "carbon sinks" by absorbing atmospheric carbon dioxide. The forests of British Columbia constitute 7 percent of the world's softwood growing stock and so they are very significant in the matter of global health.

Gentler forest practices

The anti-clear-felling movement, visual quality concerns and protests about the use of chemicals in forests are linked to a greater awareness of and concern for the environment. Groups and individuals espousing environmental concerns want forest managers to be gentler with "mother earth" by being less invasive in forest practices.

To many people not familiar with forestry science, a clear-cut is nothing other than brutal treatment of the land. Selection harvesting is seen as being gentler and, in some people's eyes, creating less change. Certainly, it is better visually.

The proportion of area that is clear-cut in British Columbia has risen over the last decade from less than 85 percent to more than 90 percent of the total area harvested. As discussed below, the Ministry of Forests is now attempting to reverse this trend through the Silviculture Systems Programme. In fact, the proportion of area clear-cut in 1991 was slightly less than what it was in 1990.

Managing for all values

At least in principle, silviculture used to be a simple task - grow trees for the next crop. Not any more! Now there is the challenge of managing for many more values, not only traditional ones such as fish and wildlife but others that have only recently come into the public eye, including biodiversity and old-growth forests.

In the past, the basic question in forest planning was: How do we get the logs out without harming the other resources? Today, the question is evolving into something more like: How can we get the logs out in concert with good management of the other resources or resource values? In part, this is happening now, but the complexity of putting it into practice is enormous in the context of managing with an appropriate emphasis for ten or even 15 values all on the same piece of land. In the future, silviculture will become an ever larger player in achieving such a result.

Timber supply

The forest industry is by far the largest economic engine of British Columbia and it will remain so for the foreseeable future. However, annual allowable cuts (AACs) are falling and are anticipated to fall further. AACs are also decreasing significantly in the Pacific Northwest of the United States. Can the surge in timber prices that occurred in 1993 be taken as an indication of future prices? Will there be a supply shortage that pushes up prices? Will sustained higher prices for timber justify previously uneconomical silvicultural activities?

Without a doubt, silviculture has a significant potential role to play not only in timber supply but also in timber value. Recent strategic planning initiatives by the Silviculture Branch of the British Columbia Forest Service have been attempting to define this role.

Other forest-dependent industries

Although the forest industry will remain in the economic forefront for the foreseeable future, other forest-dependent industries are growing in importance. Tourism, for example, is founded on the theme "Beautiful British Columbia" and tourists expect British Columbia to live up to that image. There is a whole new tourism industry, ecotourism, springing up out of the environmental movement. In 1991, tourism revenue was a significant Can $5 500 million (US$4 400 million) (approximately 20 percent of which was business-related expenditure) compared with Can $10 200 million (US$8 100 million) in forest products shipments.

A recent study undertaken by the Ministry of Forests identified 175 non-wood products, including such items as medicinal plants, fruits and berries, landscaping plants and craft products. While these may not compare economically with industries such as forestry and tourism, a great many of them can be influenced by silvicultural regimes. Will we be conducting silvicultural techniques to benefit the growth of mushrooms in the forest? This is a US$35 million industry in Oregon, United States, and is already a multimillion-dollar industry in British Columbia.


Not only do the forests directly employ 6.5 percent of the British Columbian workforce in the logging and processing industries, these are also among the highest-paying jobs in the province, second only to those of the mining industry. When indirect employment is included, the forest industries are the source of livelihood for almost 20 percent of the province's labour force.

The Forest Resources Commission found that over 200 communities in British Columbia are primarily dependent on the forest industry. Another study found that one in five jobs in Greater Vancouver could be directly or indirectly attributable to the forest industry. Silviculture is very labor-intensive and has high potential for employment creation.

Serving the masters: silviculture for multiple purposes

Now that we know who the masters are, how do we go about serving them? Contrary to the images of monocultures, biological deserts and deforestation which some would like to portray, there is an incredible amount of change occurring in British Columbian forest management and silviculture is central to many of these. The following British Columbian initiatives are grouped under three basic objectives for silviculture: basic stewardship of all values; investments to improve volume and value; and employment.

Basic stewardship of all values

In order to improve stewardship of all values, the Ministry of Forests has developed new guidelines in a number of areas and is experimenting with and implementing new silvicultural and harvesting techniques while undertaking research and demonstrations to address the challenge presented by silvicultural systems.

Biodiversity guidelines for all of British Columbia were targeted for adoption by December 1994. The forthcoming Forest Practices Code will reinforce some aspects of these guidelines which address biodiversity at both the landscape and the stand level. Stand management guidelines cover silvicultural systems, harvesting, regeneration, stand tending and pest management.

Soil conservation guidelines for harvesting in the interior were released in May 1993. These guidelines define what constitutes detrimental soil disturbance and places limits on acceptable amounts. Interim guidelines for mechanical site preparation are in place and are expected to be finalized in 1994. These guidelines place restrictions on detrimental and total site disturbance.

In 1992, the Ministry of Forests signed a memorandum of understanding with the Ministry of Environment, Lands and Parks as well as the Worker's Compensation Board concerning wildlife and dangerous trees (i.e. snags). This memorandum ensures that forestry operations provide for the retention of trees that play an important role in the maintenance of habitats for species dependent on them, while at the same time ensuring that worker safety will not be compromised.

New silvicultural techniques

New silvicultural techniques are being implemented in the areas of vegetation management, spacing and mechanical site preparation. In vegetation management, the use of chemicals in the forest is being minimized through better site preparation, better planting stock, controlled sheep browsing and the improvement of forage and seedling management. Chemically treated area dropped from 58 000 ha in 1990 to 35 000 ha in 1991. In 1991, 4 000 ha of brushing and site preparation was done by sheep. Sheep browsing is expected to continue to increase over the next few years and the indications are that, in 1993, it may have surpassed 10 000 ha. The sheep solution cannot be universally applied, however. Concern is growing about the potential effect on domestic water supplies and about the interactions between sheep and other wildlife species.

It was noted earlier that the biodiversity guidelines cover stand tending. The spacing component promotes, among other things: the retention of snags and some dying green trees that are likely to become snags; variable stand density; and mixed-species stands. Overstocking is considered as equally detrimental as understocking is to the achievement of an acceptable free-growing crop of trees. Consequently, the silvicultural regulation provides for the setting of maximum density guidelines. Provincially correlated standards were issued in 1990 for lodgepole pine and in 1993 for drybelt fir.

One of the main reasons behind the dramatic improvement in survival is greatly improved site preparation. There is now a good understanding of how to overcome soil temperature and moisture problems through site preparation. The Ministry of Forests has done extensive work in researching and developing site preparation equipment, particularly related to soil mounding.

The silvicultural systems challenge

Historically, the standard prescription has been: clear-fell, burn, plant. However. much less area is now being burnt and there are significant changes in species and stock types being planted. This necessitates a hard look at clear-felling practices. This is being done through the Silvicultural Systems Programme. From its inception in 1990 until 1992, approximately Can $4.6 million (US$3.7 million) had been spent across British Columbia on research and demonstration for partial cutting systems. Another Can $1.7 million (US$ 1.3 million) was to be spent in 1993. As of March 1993, more than 75 projects were under way or had been completed. Following is a description of several of these initiatives.

Advanced regeneration. One modification is to take a closer look at protecting and utilizing the advanced regeneration in many stands. In the province's interior, spruce often comes up under pine on the slightly wetter sites and, on the coast, balsam will often come up under other species.

Selection systems. The range of the effects of alternative silvicultural systems is enormous. Current studies are examining the many aspects of selection systems: for example, related to wildlife there are studies under way on diversity, breeding habitats and caribou and grizzly bear habitats. For forest management, there are studies on visual quality, seedling shade tolerance root rot incidence, pine beetle hazard reduction, dry sites, wind throw, biodiversity and steep slopes. On the economic side, studies are looking at impacts on wood supply, growth and yield and costs. And this is just a partial list!

Mixed hardwood/softwood stands. In the northeastern corner of British Columbia, on the eastern side of the Rocky Mountains, lies the Peace River region where hardwoods grow as well as softwoods. In the past, these mixed forests were not a problem to manage because nobody really wanted them. Now, with aspen becoming an economically valued species, there are some real regeneration challenges, not the least of which is deciding which type of regenerated forest is desired. Do we target separate hardwood and softwood stands or do we allow nature to take its course and manage for mixed stands? Is partial cutting a viable silvicultural regime in these stands?

New forestry. In 1991 the Old Growth Strategy Project commissioned a guide for British Columbians on the Principles and Practices of New Forestry. In new forestry, timber is seen as a by-product of forests which have sustained biodiversity and long-term ecosystem health as their primary functions. A research and demonstration project is being carried out in an effort to explore some of these new concepts.

Commercial thinning. Silviculture is also expanding in the area of enhancing and protecting short-term wood supply. In 1993, commercial thinning took place on approximately I 000 ha. While this programme is relatively small at present, its importance is increasing.

Improving volume and value

Efforts are being directed towards improving the volume and value of British Columbia's forests along several fronts.

Strategic planning. The emphasis on strategic planning is increasing. Through a consulting contract, the Ministry of Forests recently completed a review of strategic silvicultural planning processes worldwide for their potential application to British Columbia. What the consultants found was that strategic planning processes in many other jurisdictions were pointing to an increasing emphasis on growing quality sawlogs; that quality will command premium prices in the future. But they also noted that British Columbia should not put all its eggs in one basket. With the same consulting firm, the ministry has been taking the first steps towards developing a decision support system to evaluate the implications of alternative silvicultural strategies for timber supply at the forest level.

Forest health. significant strategic organizational move has been the recent transfer of the Forest Health Section from the Protection Branch to the Silviculture Branch. This move recognizes that the management of insects and disease is integral to silvicultural systems. The ministry spent about Can $10.5 million (US$8.3 million) on forest health treatments in 1993.

Incremental silviculture. Strategic planning points to value added timber. In keeping with this, the trend has been towards more spacing, fertilization and pruning. The big question now is how much and where? There is now quite a lot of knowledge about spacing for maximum density and about which stands respond to fertilization. However, there is still much to learn about pruning and commercial thinning. There does not yet appear to be any definitive answer to the question of how to get more volume from our forests to offset the further harvest reduction expected.

Incentives for investment. Ways need to be found to encourage industry to invest in the forest as the methods adopted to date have not worked. There is also a need to consider whether such investments will be at cross-purposes with other possible objectives such as biodiversity and "new forestry".


As a relatively young component of forest industry, silviculture offers many new employment opportunities. There is a constant demand for skilled workers which the government is helping to fill through special employment programmes. At present, silvicultural work generates an estimated 4 000 to 6 000 person-years of direct employment annually in British Columbia. The province is working with indigenous peoples to encourage and develop silvicultural contracting expertise and to provide employment. In 1991, the ministry began a pilot project to award silvicultural contracts of up to Can $50000 (US$39 600) directly to indigenous peoples. The goal is to develop sufficient expertise to enable indigenous contractors to become competitive participants in the silvicultural industry.

British Columbia has a long history of worker development efforts under different names. In 1993, through the Forest Worker Development Programme, a total of Can $39 million (US$31 million) was being invested to: create employment and assist employment-disadvantaged groups; promote economic recovery in non-metropolitan areas where the recession has had a significant effect on employment; and encourage a localized forest contracting industry.


There have been major shifts in silvicultural trends over the past few years, primarily resulting from the "privatization" of basic silviculture in 1987 but also in response to social objectives. British Columbia is moving to meet the silvicultural challenges in many ways. The total number of trees planted annually is decreasing as a result of reducing demand and there are significant changes in species and stock types being used. There is substantially less broadcast burning and more mechanical site preparation taking place. The use of chemicals in brushing is giving way to alternative techniques such as manual treatments and sheep browsing while better prescriptions are preventing the necessity for brushing altogether.

Stand tending and incremental silviculture are increasing.

In terms of basic silviculture, seedling survival has increased dramatically, the area being reforested has been greater than the area harvested since 1987. Audits indicate that we can expect a high degree of success in achieving free-growing crops after timber harvesting.

There is a growing demand to use silviculture for meeting social objectives for values other than timber. The public is concerned about global health and wants different forest practices; with 7 percent of the world's softwood growing stock, British Columbia has an important role to play in this respect.

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