|AN INTRODUCTION TO SUSTAINED YIELD
The 150 year old prescriptive planning technology of sustained yield remains the unacknowledged fundamental problem with forestry globally. This land rent approach to forestry, where forests are rearranged in an attempt to achieve timber sustainability, is the basic philosophical and methodological tenet of every professional forester's education and the basis for industrial forestry world wide.
Sustained yield, where human use is limited to harvesting only the annual increment of what have been mislabeled renewable resources without depleting the resource, is a noble ideal goal.Unfortunately, because it is impossible to harvest this annual growth from each tree, sustained yield in forestry means scheduling a particular area of forest so that harvesting follows a segmenting pattern. When the last segment of the original forest area is cut the first segment of forest has regrown into a rotation ready to cut. This planning for a flow of commodities, timber sustainability, remains the basis for forestry world wide.
Simplified, consider an area of forest: if in the professional forester's opinion the maximum volume of wood can be captured by harvesting trees when they are a hundred years old (at this particular stand), divide the forest area into 100 units and harvest one segment each year and plant a future crop of trees.. When the one hundredth segment is harvested, the first cut segment will be ready to harvest and each successive segment as they mature constitutes a flow of commodities ensuring timber sustainability.
The planning area may be a small woodlot, or as in B.C., in my neck of the woods, every reachable forested area in the whole province. Furthermore, in B.C. as in the U.S. Pacific North-West, the Progressive union of government and industry , using the Hanzlic formula, sought to systematically convert "decadent and over-mature" old growth forests into thrifty rotations of high stem volume second growth.
In B.C. this liquidation - conversion timber sustainability schedule remains the basis for forestry even though this approach to forestry is totally discredited ecologically, and even though the raw commodity industry created is economically unsustainable. Clear cutting remains the liquidation method. Age classes that we're historically + 200 years are radically redesigned to under 100 year rotations. Historic disturbance patterns are suppressed .
" (T)hose who see forests primarily as sources of fiber and are committed to the commercial development of the resource remain on the policy track laid down after the Second World War. The forest industry and the ministry continue to implement what can be called the liquidation - conversion project, a set of policies aimed at achieving a controlled liquidation of old growth forests and their conversion into managed second-growth plantations. Despite two decades of intense debate over forest policy, both harvest levels and the proportion of the harvest that is clearcut have increased dramatically since the 1970s. The busy air of policy innovation may simply mark the final stages of the elimination - conversion project, amounting to nothing more than a sophisticated symbolic politics that serves to contain environmental opposition."
Ken Lertzman (ecologist), and Jeremy Wilson and Jeremy Rayner (historians)
There have been two failed revolutions against sustained yield forestry: multiple use and Integrated Resource Management (IRM). Neither was compatible with sustained yield planning and both were marginalized into boundary constraints (parks, set asides) on continued timber scheduling. In B.C. the NDP government's attempted reform of forestry failed to recognize and acknowledge the impropriety of continuing sustained yield and instead implemented cosmetic changes to continuing liquidation - conversion of B.C. forests.
International conventions including the Montreal Process for determining a sustainable forest management are not confronting the profoundly unecological problem of flow of commodities redesign of forests.
Ecosystem-based forest management,. where the continued health, integrity and function of forests is the primary goal, must begin with a complete refutation of timber sustainability planning. The Clayoquot Scientific Panel reports and recommendations are a template for ecologically sustainable forest management. The first CSP report documented existing constrained flow of commodities forestry. Renouncing this approach to forestry, subsequent CSP recommendations turned traditional forestry on its head by concentrating not on outputs but on leaving healthy forests .
Managing man to protect and restore ecological sustainability begins with a full recognition of man's attempts to redesign nature.
(You can watch the SY pathogen - brought to North America from Central Europe by Bernard Fermow and Gifford Pinchot at the turn of the century - cross the continent to the Pacific North-West and B.C. by reading HR, Ken Drushka's biography of timber (and salmon) baron H.R. MacMillan and Nancy Langston's fine FOREST DREAMS, FOREST NIGHTMARES. Follow the pathogen's progress in stereoscope if you read them together.
THE REAL WORLD OF TECHNOLOGY is a very wise little book about prescriptive planning. It was the 1989 CBC Massey lecture by distinguished Canadian scientist Dr. Ursula Franklin.)
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