The significance of the loss of old growth - By Gord Miller

When one walks in the majestic old pine forests of Temagami, you realize that there is a strong case to be made that the surviving forest communities that meet the ecological description of ‘old growth’ deserve to be protected from extraction by legislation. There are two facets to the argument in favour of special protection of old growth, both derive their significance from the immense age of the features.

Ecologically and genetically old growth is a bequest to the present age given to the forest landscape from the evolutionary experience of past millennia. Within that bequest is embedded not only the dominant large living trees emerging from surrounding, younger mixed species forest, but also the dead standing snags, the downed coarse woody debris and the vast array of very specialized lifeforms colonizing the complex mat of the forest floor. The genetic characteristics of the surviving giant trees encode the survival information from conditions 400years ago when those trees were germinated but, also, the genes gathered in the whole forest biological community over the 10,000 years since the land emerged from glaciation. This is significant because, if such an ecological feature is cut by modern forestry techniques, it will never be seen again. The silviculturally managed replacement stand will grow logs for harvest within a single century. The land will never again achieve the ecological structure and function of the ancient forest. The genetic legacy will be lost forever. Int his sense, old growth is in need of protection in the same manner as species at risk listed in the Endangered Species Act have been recognized to need.

But the other significant facet of the importance of old growth must also be recognized. We live in times of alteration of the atmospheric composition of the planet such that the Earth is accumulating heat and climate systems are becoming radically altered. Although the developing impacts of this are too complex to predict with precision, we know that there is an urgent need in the next few decades to reduce the emissions of carbon dioxide and methane being released into the atmosphere from deposits of carbon sequestered from the air and held these many centuries. We focus on the reduction in the use of fossil fuels in this regard, but we should not ignore that old growth ecosystems are also reservoirs of sequestered carbon. This carbon may not be millions of years old like petroleum but it is not carbon from this or any recent century. Destruction of these ecological communities by forestry result in a carbon emission into current times which is equivalent to burning coal for electricity. We know we must keep coal in the ground. For the same reasons we need to keep our old growth forests in the ground, intact and continuing to sequester carbon into the next centuries.

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