Variable Retention Strikes a Balance

As Published in the Summer 1999 Edition of the Truck Logger Magazine

When MacMillan Bloedel announced a five-year phase-out of clearcutting in coastal old growth forests you could hear both cheers and jeers from a great distance. No one will say it didn’t make an impression, what with CNN and all the big networks paying attention. Greenpeace told them to.

And MB isn’t the only forest company to join the growing interest in the new system called variable retention harvesting. Both Timberwest and Interfor have announced plans to adopt this approach and the Northern Forest Products Association states that its member companies in the Interior have been practicing what amounts to variable retention for over ten years.

The high degree of controversy around MB’s announcement is both healthy and confusing. It’s healthy because the subject of forest practices needs an ongoing lively debate to encourage continuous improvement. It’s confusing because the word “clearcut” is anything but clearcut in its meaning.

Clearcut has come to mean something like “total destruction of the environment for corporate greed” to many people while to foresters it just means cutting down trees in groups, sometimes rather large ones. Understanding variable retention harvesting requires getting beyond these differences in definition.

Variable retention, like clearcutting, involves cutting down groups of trees, sometimes over fairly large areas. These are called “openings” and they are surrounded by “edges”, again very similar to clearcutting. So what is the difference?

To put it simply, the difference is science. Whereas clearcutting is a very general term that involves building roads and cutting large swaths of timber, variable retention is based on detailed knowledge of the species and habitats in the forest and careful planning to ensure their survival. Clearcutting is totally focused on removing timber while variable retention is balanced between removing timber and retaining timber in the landscape.

The variable retention harvesting system began with the work of the Clayoquot Sound Scientific Panel. MacMillan Bloedel was central to that process so they learned a lot from it. Even though the recommendations for Clayoquot Sound were too extreme for application to the entire coast there was a lot of good work done by the Science Panel. MB eventually decided to work with the co-Chair of the Panel, Professor Fred Bunnell of UBC, who heads the Centre for Applied Conservation Biology in the Faculty of Forestry. Fred’s team produced a document titled “An Ecological Rationale for Changing Forest Management on MacMillan Bloedel’s Forest Tenure”. I believe it is a brilliant document.

Variable retention is based on the idea that the most important value in the forest is biodiversity, the many species of plants, animals, birds, insects and invertebrates living there. In order to make sure that all the species can survive in a managed forest it is necessary to understand their habitat requirements for breeding, feeding, hibernating, etc. So long as sufficient habitat is retained in the landscape it should be possible to maintain viable populations of each species. Coincidentally, many species are perfectly happy in landscapes where the trees have been recently cleared. Birds that nest in shrubs will usually find more available shrubs where the forest cover is removed. Other species, such as cavity nesting birds, need standing dead trees in the landscape, and still others, such as woodland caribou, need fairly large blocks of older forest. Variable retention is about planning timber harvesting over time so that all the necessary features for species survival are always present somewhere in the landscape.

In the case of MacMillan Bloedel’s 1.1 million hectares of public and private forest land, 205 species of vertebrates known to live there. Variable retention theory makes the assumption that vertebrate biodiversity is a good indicator of overall biodiversity. In other words, if all the vertebrates are looked after, the other species will survive as well. These 205 species of mammals, birds, reptiles, amphibians and fish are all catalogued as to their requirements. This information is used to design the pattern of harvesting over time.

In order to provide a limit on the amount of timber removed from a landscape, it has been agreed that no opening (cleared area) may have more than 50% of its area beyond the influence of the trees on the edge of the opening. The area under the influence of the edge is defined as within one tree-length of the edge. This definition allows for openings that are no more than four tree-lengths across. While this is relatively small compared to the way clearcutting was practiced in the past, it still allows for openings that are large enough for the practical purpose of logging.

MacMillan Bloedel made it very clear in announcing the adoption of variable retention that it did not mean single-tree selection harvesting. This kind of harvesting is not suitable for the ecology of coastal forests and in most cases it cannot be done safely. In coastal forests, variable retention means a landscape with a fair amount of openings of various sizes, contoured with the land and with mandatory buffers around all fish streams. It also means a network of corridors, patches of trees and single trees for wildlife protection and conservation. It will look a great deal different from the old square cut-blocks that were based on laying out straight lines with a compass rather than on the biology of woodpeckers and coho salmon.

You might say its all smoke and mirrors anyway. Well, there’s a little of that in it because we are trying to talk to a huge urban public that thinks stumps are ugly at the best of times. It’s called “communications” and it often involves simplifying things that are actually very complicated. I believe it is legitimate to adopt a new term for the type of harvesting proposed by Fred Bunnell and his team at UBC. The word “clearcut” has too much negative emotional baggage, partly due to its association with some pretty bad practices. So long as those bad practices are no longer part of forestry it is reasonable to give timber harvesting a new name, and variable retention is as good a description as any. I’m on board, and I encourage other companies to look at their operations in terms of this new approach. I think they will find they are moving in this direction, anyway, and they may actually be there already but just calling it something else, such as “clearcuts with reserves”.

Words are a powerful tool, far more powerful than the biggest yarder or logging truck.

May the Forest be With You

Patrick Moore, Ph.D.