Une Forêt Unique


Il existe au Nouveau-Brunswick des forêts rares d’arbres à feuilles caduques, qu’on appelle les « Appalachian Hardwood Forests » (AHF), trouvés dans les comptés de Carleton et de Victoria. Malheureusement, ces forêts disparaissent vite.

La valeur actuelle des arbres à feuilles caduques va peut-être convaincre les propriétaires de vendre leurs forêts. Ce n’est pas une bonne chose ! Mais, en plus d’avoir une valeur monétaire, ces forêts ont de grandes valeurs environnementales. Les 65 sites au N.-B. varient en grandeur, d’un seul hectare jusqu’à plus de 100 hectares, distribués entre à peu près 200 propriétaires privés.

Le Nature Trust a mis en place une campagne pour protéger ces forêts. La plupart des sites ont déjà été coupés sélectivement. Mais, le gros problème, c’est la coupe à blanc. Les propriétaires peuvent prendre des précautions pour protéger les forêts AHF. Ou bien, ils peuvent vendre leur terre à une organisation de conservation, comme le Nature Trust.

La protection des forêts rares comme celles-ci commence par la compréhension du problème. Si on ne sait pas ce qui est là, on ne sait pas ce qu’on détruit.

A Unique Hardwood Forest


George Peabody
Nature Trust of New Brunswick
June 1998

t.gif (259 bytes)he central St. John River valley is home to a type of hardwood forest found nowhere else in Atlantic Canada. Sometimes known as Appalachian Hardwood Forest (AHF) for its similarity to the forests of central New England and southwestern Quebec, it contains tree and other plant species uncommon or rare in New Brunswick.

Unfortunately, there's not much left.

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Mature Basswood rises to form the canopy of an AHF stand
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ahf3.jpg (4365 bytes)
(photo: George Peabody)

The rich calcareous soils on which the hardwoods and their understorey grow are prime agricultural land. Today, less than one percent of the land suitable for AHF actually contains mature forest of this type. These remnants of a woodland ecology, which once covered nearly 150,000 hectares in Carleton and Victoria counties, are vanishing at an alarming rate. A 1997 survey by the Nature Trust of New Brunswick found that nearly half of the sites classified as mature AHF when forest cover data was last assembled in 1981, had since been partially or entirely clearcut

The sixty-five remaining sites, which the Nature Trust considers to have significance for conservation, may all be under threat. Even if they are well managed by their present owners - as many of them are - there is constant and increasing pressure on landowners to take advantage of the present high market value of hardwood lumber. And even where current owners are resistant to clear-cutting, there are no guarantees of future protection if and as the land ownership changes.

 

Seeing the Forest and the Trees

Many of the mature hardwoods which form the canopy of AHF stands - butternut, basswood, sugar maple, yellow birch - are commercially valuable trees. Of less commercial value, but still ecologically significant, are such other AHF tree species as ironwood, elm, silver maple and beech. Some of these species - butternut, basswood and silver maple, in particular - are at or near their northern growth limits in New Brunswick's remnant AHF sites.

Protected by the shade of the canopy are numerous woodland flowers, ferns, grasses and bryophytes. These understorey species include several which are rare or uncommon in New Brunswick. More than 80 percent of AHF sites catalogued by the Nature Trust in 1997 contained at least one rare species. Among them was desmodium glutinosum, which had been listed as provincially extirpated, not having been recorded in New Brunswick for nearly a century.

ahf2.jpg (5015 bytes)
(photo: George Peabody)
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Rich understory growth characterizes mature AHF
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Other rare species included populations of Clinton's shield-fern, which is very rare in New Brunswick, and two of its hybrid forms which had not before been seen in the province and are rare throughout most of North America. Perhaps the most significant species discovered was Entodon brevisetus, a moss known from only one other location in Canada.

Together, the trees and understorey form a forest type capable of great richness and diversity. AHF sites also provide crucial habitat to numerous bird species, particularly migratory songbirds, and cavity nesting species which find homes in the large mature trees, such as wood duck.

Now What?

The sixty-five remnant mature AHF sites in Carleton and Victoria counties are, with one exception, all on privately owned land. The sites range in size from smaller than a hectare to over 100 hectares, averaging just over ten hectares. Very few of the sites have a single owner; most of them have five or more owners. In total, more than 200 landowners possess portions of mature AHF woodland in the region.

Following up on the survey, the Nature Trust has begun a landowner contact and public awareness program in the region. The objectives of this program, which is planned to run until the Spring of 2000, are to seek the highest level of protection possible for each site.

The exact meaning of "highest level of protection", of course, will differ depending on the wishes and needs of individual landowners. Many of the sites - more than 80 percent - show evidence of some selective harvesting. It would be unrealistic to expect all site owners to stop all forms of harvesting. Nor would this be necessary, in most cases, to protect rare species and maintain the present ecological value of the site.

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Desmodium glutinosum - A species of tick-trefoil had not been recorded in NB for nearly a century before the Nature Trust survey.
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ahf1.jpg (2996 bytes)
(photo: George Peabody)

Careful selective harvesting can be consistent with an ecologically diverse and rich forest: avoiding certain areas when the understorey species are most vulnerable; retaining certain mature trees; maintaining the vital canopy. As part of the landowner contact program, the Nature Trust will be collaborating with the Carleton-Victoria Wood Producers Association to develop, for some sites, management plans which meet the harvest objectives of the owners as well as the ecological needs of the site.

Other owners may wish to explore higher degrees of protection, and the Nature Trust has several options to suggest. These include Conservation Easements - legally binding management agreements which can be placed on a deed in perpetuity. Among other options for landowners to consider are donation or sale to a conservation organization such as the Nature Trust.

Protecting the remaining Appalachian Hardwood Forest sites in Carleton and Victoria counties is, really, up to the owners of the sites. Protection begins with understanding what is on the site: seeing the forest, not only the trees. It continues when landowners follow good conservation stewardship practices, caring for their valuable woodland.

For many landowners, protecting the habitat of rare species is a good enough reason for becoming conservation stewards of their forest land. Other landowners will look for practical reasons. As a single sample of what they might find: Canada yew is an AHF understorey species; it was not considered to have commercial value until recently when scientists discovered that an important anti-cancer drug could be extracted from it.

Who knows what other rare or uncommon species, with yet-to-be-discovered commercial value, may exist in our remaining Appalachian Hardwood Forests?

The only certainty is that if we fail to protect this woodland now, we may never discover what we have lost.