Forest Ecosystem Topics

Harvest

Is it sustainable? Both the health of our forests and the health of our forest industries depend on the answers to this question. "Sustainable" means you can do it forever without compromising the options for future generations. For forestry, this comes down to two questions: (1) is the rate of harvest consistent with the rate of regrowth of new trees, and (2) will the kind of forestry practiced alter forest ecosystems so that other forest values may be lost to future generations? The rate and kind of harvest are critical to biodiversity. A more rapid harvest transforms the forest into one with more younger stands across the landscape, favouring the kinds of plants and wildlife that thrive in young forests, but putting those that require stable, older forests at a disadvantage. Unfortunately, the issue of biodiversity is not about having the most species; it is about conserving those that are most at risk. In a complex of ecosystems characterized by an increase in disturbance regimes - these include settlement, agriculture, creation of reservoirs, fires, insect infestations and timber harvest - the plants and animals that need stable, old and undisturbed ecosystems are those most at risk of extinction. That is why the rate and kind of timber harvest is important for conservation of biodiversity. Information about the rate of harvest and the kind of harvest is given below.

Rate of Harvest

From the early years of industrial forestry in British Columbia until about 1990, the rate of harvest increased exponentially (Harding, 1994). It was always known that this rate of harvest could not go on forever, because second growth can not produce the volume or quality as are present in the province's natural forests. The year 1990 was the point of diminishing returns, when the annual cut would have to begin to drop to a level that is sustainable in the long term. In addition to this "fall-down effect," as people argued for preservation of some remaining old growth and other natural forests near their communities, some forest land was withdrawn from the harvestable land base. Also, beginning in about 1994, a new forest practices code was introduced (see below) to ensure that the kind of logging we do protects biodiversity and does not damage other, non-timber values. This resulted in constraints on where trees could be harvested, and in some case on how they are harvested, further reducing the amount of timber available annually. In 1996 a new timber inventory review was completed, and new annual allowable cuts determined. Those for the Kootenays are shown in the accompanying graphs for Timber Forest Licenses and Timber Supply Areas.

These graphs show that in all timber supply areas and all Timber Forest Licenses in the Columbia Basin, the current annual allowable cut is higher than the Ministry of Forest's estimate of the Long Term Harvest Level - in some cases, considerably higher. These levels are unsustainable. New forests are growing rapidly throughout the region, however, as a result of intensive reforestation during the 1980s and 1990s, and will begin to reach harvest age about the middle of the next century. Therefore, while the current rate of harvest is unsustainable, commercial forestry can continue indefinitely, albeit at a lower level of harvest.

Harvest by Species

Important tree species contributing to the harvest volume are shown at left. Throughout the Nelson Forest Region, lodgepole pine contributes the most by volume, with spruce a close second. "Balsam" is a catch-all term including all true firs, which in the Nelson Region is mainly sub-alpine fir. This graph shows (a) the high contribution of high elevation Englemann spruce,sub-alpine fir and lodgepole pine forests to the current harvest, and (b) the extent to which lower elevation, moist forests of western red cedar, white pine and western hemlock, and lowland dry forests of Douglas-fir and ponderosa pine, have declined in importance because of past harvesting in the more productive and accessible valley bottoms. Compare the volumes harvested with the area and volumes of tree species present in the region.

Kind of Harvest

In 1994 the B.C. government introduced two new initiatives, which are still being implemented: A Forest Practices Code is designed to ensure compatibility with wildlife, biodiversity, and other resource values, while Forest Renewal B.C., a separate agency, funds on-the-ground work designed to improve the productivity and health of forests, including repairing some past damage to watersheds.

One of the most contentious practices is clearcut logging. This method is unquestionably damaging to the timber stands cut, and the non-timber values they support, but across a landscape of varying forest types and other disturbances, clearcuts must be seen as part of the process of renewal. They fit more easily into forest types where stand-replacing disturbances are common - such as dry forest types that normally experience frequent wildfires - and less so into forest types that are normally more stable over time. The right hand graph shows that, prior to implementation of the Code, about 90% of harvest in Tree Farm Licenses, 70% in Timber Supply Areas and half in private lands was by clear cutting. In 1996/97, the last year for which data are published, as shown in the left-hand graph, a higher proportion of the harvest was by partial cutting on Timber Forest Licenses (where volume was much lower), and more in Timber Supply Areas and on private land. The new Code requires, on average, smaller clearcut patch sizes, and mandates partial cutting methods in certain environmentally and visually sensitive locations. As well, the Code sets out detailed guidelines for protection of such environmental values as biodiversity, endangered species, specifically identified wildlife, streamside and lakeshore habitats, terrain stability and water quality.

References

Ministry of Forests, 1995. Annual Report 1993/94.
Ministry of Forests, 1998. Annual Report 1996/97.

More Information

http://www.gov.bc.ca/for/
Follow links to Forest Practices Code summaries and document lists, Biodiversity and other Guidebooks; or go to http://www.for.gov.bc.ca/hfd/ and Search for these documents.

Follow links from luco.gov.bc.ca to find this site containing Resource Inventory Committee standards for collection of biological data in B.C.

Treebook - classifying the natural world is downloadable.

The Ministry of Forests, Forestry Division, Services Branch page allows you to search for specific documents. Enter the exact title or author of the forest tree genetic references listed above. You can read the abstract on-line and download the full documents to read offline. They are in *.PDF format, and you need Adobe Acrobat Reader to read them, which you can also download by linking from the same site.

Forest Ecosystem Topics