Trends in Silviculture in B.C. (1987-2016)
Managing and conserving the province’s Crown forest and range resources provides environmental, social and economic benefits to all British Columbians. Silviculture—one of the primary means to enhance the social and economic benefits from our forest resource—entails the manipulation of forest and woodland vegetation in stands and on landscapes to meet the diverse needs and values of landowners and society on a sustainable basis. This indicator investigates the trends in four measures of silviculture from 1987 to 2016.
- What silvicultural systems are used? A variety of silvicultural systems are used in B.C. and can be grouped into three general categories: clearcutting, partial cutting, and clearcutting with reserves. Each name reflects the type of forest structure remaining after the initial harvest. The area of Crown forest harvested annually averages 209,000 hectares. Clearcutting with reserves was the most common silvicultural system applied over the last 15 years.
- How much is reforested after disturbance? The area of Crown land reforested annually is approximately the same as the area harvested two to five years earlier. Additional natural disturbance areas are reforested through government funded programs. For example, the Forests for Tomorrow program has funded 110,000 hectares of rehabilitation planting since 2005.
- What incremental silvicultural treatments have been done? Investments in incremental silviculture to improve the growth and quality of future crop trees included fertilizing, pruning, spacing and using select seed (usually from seed orchards) for planting. Since 1987, incremental silvicultural treatments totalled approximately 2.7 million hectares.
- What volume gains will incremental silvicultural treatments yield? Cumulative volume gains 65 years after making investments in incremental silviculture since 1987 are estimated at 92 million cubic metres (m3).
What is Silviculture?
Silviculture is the art and science of controlling the establishment, growth, composition, health and quality of forests and woodlands.
Visit the Silviculture Program Page to learn more about silviculture strategies in British Columbia.
What Silvicultural Systems Are Used?
- A Silvicultural system is a planned program of treatments during the whole life of a stand designed to achieve specific stand structural objectives. The three general categories of silvicultural systems used in B.C. are clearcutting, partial cutting, and clearcutting with reserves. Selection of a silvicultural system depends on the ecological traits of the tree species, and on balancing the objectives of the landowner.
- Since 1987, the area of Crown forest harvested annually has ranged from 150,000 hectares to 250,000 hectares, with an average of approximately 209,000 hectares.
- From 1987-1996, a clearcutting silvicultural system was applied on 88% of the area harvested. By 2012, clearcutting with reserves accounted for 85% of the area harvested on public forest land. While both systems remove the majority of the trees, clearcutting with reserves saves some trees within or outside the cutting boundary for other purposes such as wildlife habitat, water quality and visual landscapes.
How Much is Reforested After Disturbance?
- Forests disturbed by timber harvests and other natural causes reforest naturally over time. Silviculture investments accelerate reforestation, increase timber supplies and restore ecological services sooner.
- In 1987, explicit reforestation obligations on public land were introduced requiring holders of harvesting rights to reforest the areas they harvest. This led to planting a greater proportion of harvested areas.
- In the early 1990’s, increased investments in site preparation, research that led to better planting methods, planting, rehabilitation planting and brushing ensured prompt restocking and the growth of desired trees.
- Recent catastrophic wildfires and the mountain pine beetle epidemic have added large areas with below acceptable stocking. Since 2005, the Forests for Tomorrow program has funded the reforestation of mountain pine beetle and wildfire impacted land not currently under legal reforestation obligations.
- Forests disturbed by timber harvest can take 7 years or more to regenerate, an average of 1.9 years when planted and an average of 5.5 years when left to reforest naturally. This is referred to as regeneration delay and accounts for a large amount of the gap between disturbance and reforestation area in the last 7 years.
What Incremental Silvicultural Treatments Have Been Done?
- Incremental silviculture is an investment in future timber production and environmental benefits from forests. Incremental silviculture only includes treatments that are not part of basic silviculture, where natural unimproved seed sources are used. Incremental silviculture can increase timber quantity and quality, manage forest health and fire risks, and improve specific habitats, water quality and visual landscapes. Incremental silviculture also creates employment opportunities for communities.
- Since 1987, investments in incremental silviculture to improve the growth and quality of future crop trees included fertilizing (302,000 hectares), pruning (47,000 hectares), spacing (403,000 hectares) and using select seed—usually from seed orchards— for planting (1,856,000 hectares). Over this period, silvicultural treatments totalled approximately 2.7 million hectares.
- The use of select seed increases the rate of tree growth, increasing future timber volume, reducing constraints on harvesting adjacent areas and reducing the need for costly brushing treatments.
- Fertilization has seen significant increases since the inception of the Forests for Tomorrow program in 2005.
- The Forests for Tomorrow program was established to respond to catastrophic wildfires and the mountain pine beetle epidemic. Since 2005, the program has funded planting on approximately 110,000 hectares of mountain pine beetle and wildfire impacted land not currently under legal reforestation obligations.
What Volume Gains Will Incremental Silvicultural Treatments Yield?
- Timber volume gains from incremental silviculture are the estimated volume gains—based on yield modeling predictions—in 65 years when compared to basic silviculture using natural unimproved seed sources.
- Gains from incremental silviculture include increased short- and mid-term timber supply through spacing and fertilization, accelerated development of mature or old growth forest characteristics where needed for wildlife or biodiversity, higher wood quality through pruning, more pleasing visual landscapes and planting to make up the long-term timber supply.
- In general, compared with natural regeneration, planting increases harvestable volume by about 15% without the use of select seed and by about 31% with the use of select seed.
- Cumulative volume gains 65 years after making investments in incremental silviculture since 1987 are estimated at 92 million cubic metres (m3), based on fertilization (4.2 million m3), Spacing (6.5 million m3), select seed (60.1 million m3) and reforestation through the Forests for Tomorrow program (20.9 million m3).
View the methods used to develop these measures (PDF). The R code for creating the graphs presented on this page is available on GitHub.
For more information on this indicator or on Silviculture in British Columbia contact the Resource Practices Branch at Forests.ForestPracticesBranchOffice@gov.bc.ca.
References and Other Useful Links
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Updated May 2018
Suggested Citation: Environmental Reporting BC. 2018. Trends in Silviculture in B.C. (1987-2016). Ministry of Forests, Lands, Natural Resource Operations and Rural Development, British Columbia, Canada.