B.C.’s forests are doing better than many areas but there is always room for improvement.
Tony Kryzanowski (June/July 2014 issue of the Logging and Sawmilling Journal) reported some interesting findings about forest biodiversity.
A recent report from the United Nations Food and Agriculture Organization was warning about monoculture reforestation in China, India and Vietnam.
Many of the forests in these areas are planted with single species for commercial purposes, mainly palm oil and rubber plantations.
This practice has been blamed for a four-year drought in this traditionally rain-rich area because these species use much more water than the native species.
There are similar practices in New Zealand, Sweden, Brazil and some parts of the USA. Most of the privately held forest lands plant intensively managed monocultures like radiate pine, yellow pine and eucalyptus.
Tony’s article ends with this warning: “We have to be extremely careful in the management of our crown forest resources to ensure that biodiversity is maintained and that we are not turning what would naturally have been a mixed forest into coniferous monocultures strictly for financial gain.”
As part of the ongoing discussions on the Williams Lake Timber Supply Area (TSA) it would appear that our silviculture practices will lead to a greater biodiversity than the monocultures mentioned above.
Figure one of the Williams Lake TSA discussion paper shows the parks in and surrounding the TSA along with the following summary.
The TSA covers about 4.93 million hectares, of which approximately 66 per cent — 3,238,188 hectares — is Crown forest land base (CFLB).
About 1,408,272 hectares of the TSA are in reserves for old growth, wildlife habitat, wildlife tree patches or riparian areas, in areas of environmental sensitivity or low productivity, non-merchantable forest types, or for other reasons are unavailable for timber harvesting.
About 56 per cent of the CFLB, or 37 per cent of the total TSA area, comprise the current timber harvesting land base (THLB) of 1,829,922 hectares.
Figure two shows the main commercial forest species consist of 64 per cent pine, 15 per cent Douglas fir, nine per cent spruce and minor amounts of balsam, cedar and hemlock.
Biodiversity should be maintained since a good portion of our forests are not in the THLB and therefore not destined for harvesting and any associated manipulation of the natural stand structure.
For example, the reduction of the deciduous hardwoods in favour of the more marketable softwoods like pine, fir and spruce sawlogs for lumber.
Our silviculure practices also recognize the diverse ecological sites and attempt to plant trees that replicate the original species.
Past and present silviculture practices will have some impact on the commercial species on some sites within the THLB.
For example, we have traditionally favored lodgepole pine trees in many areas and planted a disproportionate amount in some areas.
We have also tried to reduce competition from deciduous species using herbicides, mechanical control and in some cases use of animals which will give the conifers an advantage at establishment.
The greatest impact of our management practices on the THLB will likely be the change in age class structure resulting in a much greater percentage of younger trees after our first rotation.
This has a number of people concerned since some of the oldest and largest trees have been growing on the better sites that are mostly found in the THLB.
This can have an influence on biodiversity in that many plant and animal species change as the age of a stand becomes much older.
In conclusion, our forest practices are much different from monoculture practices mentioned above. While our practices are not likely to result in anything that resembles a monoculture we may be over treating some stands to reduce hardwood competition.
It is always a good idea to continually examine our forest practices in light of new research and potential markets and keep in mind the original stand structure may be the most logical choice in the long run.
Jim Hilton is a professional agrologist and forester who has lived and worked in the Cariboo Chilcotin for the past 40 years. Now retired, Hilton still volunteers his skills with local community forests organizations.