Logging industry harvesting practices to counter impacts of clearcutting – Williams Lake Tribune
A recent article published in Ecological Process by lead author William Beese is a good source to see what the industry has been doing over the past two decades on using variable retention harvesting to counter some of the impacts of clear cut.
One of the goals of the study was to produce future forest stands that more closely resemble the conditions that develop after natural disturbances, thereby maintaining a greater diversity of habitats for a variety of organisms.
“For example, higher species abundance in pre-harvest forest has been documented for vegetation, birds, beetles, gastropods, ectomycorrhizal fungi, and soil fauna in retention cutblocks. compared to clearcuts. There are, however, negative consequences for timber production, such as wind damage to retained trees and reduced growth rates of tree regeneration compared to clearcutting.
Some of the findings of the study were:
“1. The landscape context determines what is necessary or appropriate for stand-scale conservation in relation to biodiversity conservation objectives.
2. It is neither practical, nor likely even possible, to accurately mimic natural disturbance patterns.
3. Retention patterns around streams and lakes should be considered first because of their requirements and high value habitat characteristics.
4. Wind damage is a significant challenge for most stand-level retentions, making aggregate retention or clearcutting with allowances the most viable options for some sites in windy landscapes. I didn’t see any discussion of how the size of the clear cut blocks may have influenced the impact of the wind.
5. Retention provides habitat that allows some forest-associated organisms to persist after harvest (i.e. lifeboat), with a positive correlation between the amount of retention and species persistence. My interpretation is that the few scattered trees had little positive impact on diversity, with numbers 6 and 7 repeating the same observation.
6. Growth impacts on forest regeneration increase with percentage canopy retention and greater dispersal of isolated trees or small aggregates.
7. Typical retention levels (less than 25% does little to distinguish variable retention from clearcutting in the public eye, unless trees are distributed as scattered individuals or small aggregates .”
The authors suggest that after decades of experience in applying variable retention harvesting to industrial-scale management of forest lands in British Columbia, it is possible to balance timber production with conservation. of biodiversity.
While this is a laudable goal, the data presented in Figure 2 is not so optimistic. Compared to clearcutting, partial cutting and variable retention were about 20% (my estimate) from 1998 to 2006, but less than 10% for the following 10 years. The majority of the harvest came from clearcuts and clearcuts with reserves. Some companies have done much better than others in trying to implement alternative harvesting practices.
For example, Wyerhaeuser’s British Columbia Coastal Group attempted the variable retention approach for all harvests in 2003 after over 75% in 2001. For readers wishing to follow the discussion, you will need to familiarize yourself with the types of cuts partial such as: patch cutting, shelterwood cutting, selection systems and intermediate cuts (e.g. thinning)
I’ll be the first to admit that I’m getting lost in some of the lingo and so I would recommend readers go to the provincial government site and see a tour of 12 types of harvesting practices involving some type of retention.
If you google “Tour Stop 8. clear cut with reserves Gov.bc.ca” you will find good pictures and explanations of the different types of retention.
Jim Hilton is a professional agronomist and forester who has lived and worked in Cariboo Chilcotin for 40 years. Now retired, Hilton still lends her skills to local community forestry organizations.