UNB Faculty of Forestry and Environmental Management
State of the Greater Fundy Ecosystem
Forest Management Guidelines to Protect Native Biodiversity in the Fundy Model Forest
Greater Fundy Ecosystem Research Group
S. Woodley and G. Forbes (eds.)
GFE Research Project
Faculty of Forestry and Environmental Management
University of New Brunswick, Fredericton, N.B.
Studies in and around Fundy National Park
In 1996, the Greater Fundy Ecosystem Research Group (GFERG) submitted a series of guidelines to the Fundy Model Forest partnership for use in planning for the wise harvest of forested lands to conserve biodiversity. The guidelines were developed after much on-sire research - much of which is summarized in this report - and the review of similar efforts elsewhere. The guidelines took as their primary focus a series of broad, landscape-level considerations which have been absent from most sets of forest guidelines. The emphasis of the guidelines was on activities occurring on Crown and freehold licenses.
Planning for Biodiversity
Biodiversity is simply the variety of life and the processes that support it. Scientists usually characterize biodiversity at different scales: the gene, the species, the community and the landscape. All these scales interact to produce what we know as the diversity of life or biodiversity.
The area of the Fundy Model Forest has a characteristic native biodiversity. At the genetic level, for example, stands of Red Spruce trees have different characteristics from neighbouring stands only a few kilometres away. The species level - which is best known - is characterised by 42 species of mammals, about 250 species of birds, about 1000 species of vascular plants and an unknown number of insects and other life forms. These species naturally form communities which we refer to by such terms as "Upland Sugar Maple forest" or "Lowland Spruce Forest". In turn, communities are a product of bedrock, topography, slope, climate and disturbance history. The landscape patterns are delineated at different scales such as "ecoregions" or "ecodistricts".
It is impossible to plan for the conservation of biodiversity on a species-by-species basis. There are simply too many species and we have information on only a small percentage. Thus, to conserve native biodiversity, we have taken a combined top-down (coarse-filter) and bottom-up (fine-filter) approach. The coarse-filter approach allows for planning of larger-scale arrangements of communities, including their composition, size, adjacency and age class distribution. The needs of the vast majority of native species may be accommodated by a coarse-filter approach. However, to ensure that species don't fall through or are missed by the coarse-filter approach, we have also examined the specific requirements of species or species guilds that are likely to become vulnerable given the significant stand- and landscape-level changes resulting from modern forest management and a growing human population.
COARSE-FILTER AND MANAGEMENT PLANNING LEVEL GUIDELINES
Patch sizes and disturbance regimes - Forests should be managed as either gap or stand-replacing disturbance regimes. This duplicates the historical disturbance pattern and recognizes that tree species regenerate under certain conditions or opening size and canopy thickness. The division into disturbance regimes should be done first at the ecodistrict level, which accounts for climate differences and enduring landscape features. Secondly, the forest should be subdivided into ecological units with an aim to maintain forest types that exist because of gap-type disturbance. In all gap-type stands, the aim should be to maintain a predominantly closed-canopy cover, a mixed-age distribution of overstory trees and sufficient regeneration to restock the forest. This can be accomplished by selection cuts. For forests managed under a stand-replacing disturbance regime, the operating patch size should be between a range of sizes and include some that are 375 to 500 ha. However, this should not mean that yearly cuts of that size be conducted. To approximate natural patchiness, the 375-500 ha blocks should be cut over a period of 10-15 years, which would allow working cuts in the range 25-50 ha.
Guidelines for the amount of tree removal on a watershed are being developed. It has been shown that the hydrology and nutrient quantity of a watershed changes with disturbance and we hope to present this relationship in the future.
Connectivity - A network of forested connections needs to be maintained across the Model Forest landscape, with a minimum corridor width of 300 meters and maximum corridor length of 3 km. The forested connections should have a closed canopy forest (minimum 35% crown closure) of any species, with a minimum canopy height of 12 meters. From preliminary research, it appears that selection harvesting will meet the requirements of connectivity.
Water quality and habitat conservation should be
practiced through riparian zone guidelines
(Photo: G. Forbes)
Stream side buffers - The GFE research group supports the direction and content of the Watercourse Buffer Zone Guidelines for Crown Land. However, the steep river valley slopes of the FMF present an additional concern for water quality in the area. We recommend that these steep valley slope areas represent unique and sensitive conditions that should be specifically identified in buffer zone guidelines. A general rule should maintain the current buffer setback of 60 m but beginning at the top of the valley (instead of the shoreline), at a point where the slope is less than 20%. Forest harvest activity would follow the guidelines established within the 60 m buffer, except that no cutting or very controlled cutting should occur within 5 m of shorelines.
Mature-Overmature forest classes - A minimum of 12% of each fire-origin stand replacing community type (except regenerating and non-forest communities) should be maintained in a mature-overmature age class; 4% should be in the overmature age class. In Red Spruce dominated stands, there should be 17% in a mature-overmature state. In gap-replacing communities a minimum 30% should be maintained in mature-overmature condition. On an ecodistrict level the mature component should exceed the minimum patch size of 375-500 ha. For selection cut forests, mature forests should have a minimum canopy crown closure of 60 %.
The contribution of plantations to mature habitat objectives is possible if they :
Network of protected areas - We recommend that a network of protected areas be established in the model forest to protect rare, unique and representative species and features. These protected areas should be off limits to any development except:
Sustainable, non-motorised recreational hunting and fishing, which may be allowed in areas where they are currently being practised (e.g. Fundy coastal ravines [allow sporadic fishing, except for Atlantic Salmon] and Fundy upland bogs [allow Moose hunting])
2. In some of the forested sites, some form of limited extraction may be acceptable as long as it:
Fundy National Park (Photo: G. Forbes)
a) excludes the harvest of Hemlock
b) reflects existing natural disturbance regimes (e.g. selection harvesting in tolerant hardwood stands)
c) maintains late seral forest in areas where it presently exists
d) respects stream buffer zones, and avoids areas hosting rare or uncommon plants. Management plans for timber extraction and road design within the watersheds encompassing the protected areas will be necessary to integrate the protected area into the working landscape, and to improve the role of the protected area as an "eco-bank".
FINE-FILTER AND OPERATIONAL LEVEL GUIDELINES
Coarse woody debris - Intensive forest management practices tend to eliminate large pieces of decaying wood from the forest. Tree limbs and tops should be left on site after harvest. On all conifer dominated or mixed-wood managed sites or stands, there should be a minimum of 200 pieces/ha of coarse woody debris (average piece diameter greater than or equal to 10 cm) and a minimum total of 10m3/ha throughout the rotation of the stand.
|Retention of snags - In intensively managed forests, a lack of suitable numbers and types of large decaying or preferred nesting trees often limits species that need cavities. Forests can be best managed for cavity nesting species of birds by selection harvesting techniques. After commercial timber is removed during the first intervention, the best management option for cavity nesters is to leave a minimum of 12-15 snags (defined as standing dead trees, preferably greater than 20 cm dbh (diameter breast height)) per hectare for feeding, plus 10-12 live, or partially dead, mature Aspen or Beech (in the absence of Aspen or Beech, Maple and Yellow Birch may be substituted) with minimum dbh of 25 cm to be used for nesting. Subsequent interventions should maintain those numbers and ratio and consideration must be given to regenerating young trees as well.
Single snags or live trees in clearcuts less than 4 ha. in size may be useful as feeding and nesting trees for certain species of cavity nesters. Live Aspen, Beech, Maple or Birch are preferred over conifer species. Trees should be mature, with a minimum dbh of 25 cm. Clumps of trees are preferable over single trees. The minimum number remaining should be no less than 12-15 single trees per hectare and, in any situation, more is always better than less.
Snags provide nesting and feeding habitat for many wildlife species such as mushrooms, beetles and woodpeckers. (Photo: G. Forbes)
In larger clearcuts (> 4 hectares), managers should pay special attention to leaving scattered clumps of live trees - both mixed deciduous and mixed coniferous. Large clumps are always better than small clumps but a minimum clump size should be 25 m2. In forest clear-cut operations, managers should have knowledge of what there is in terms of potential nest trees (i.e. live Aspen and Beech with 25 cm dbh) and snags (i.e. dead trees with 20 cm dbh) as well as the amount of commercial timber.
In cuts less than 4 hectares, 10-12 potential nest trees and 12-15 snags should be left per hectare. Managers should pay special attention to leaving clumps of trees rather than single trees. Where dead, leaning and down trees do not present a hazard or otherwise interfere with selective timber removal, they should be left undisturbed as an important component of the forest ecosystem.
Improvements to plantations:
Options for existing plantations:
For new or planned plantations:
Habitat needs for threatened species - Population and habitat objectives will be developed for these species in the near future.
Special status tree species -Tree species that are uncommon or rare due to human activity should be retained in forests by limiting their harvest and creating the conditions needed for regeneration. The identified species are Eastern White-cedar, Eastern Hemlock, Bur Oak, Red Oak, Basswood, Butternut, Ironwood, Black Cherry, and Black Ash. Red Spruce and American Beech are common but require selection harvest to promote regeneration. The identification and regeneration of disease-resistant trees for American Beech is also critical.
Roads - An unplanned consequence of forestry is a dramatic change in access through road networks. Roads allow increased legal and illegal hunting, fishing and other harvest. They also fragment habitat and allow the spread of disease and exotic species. Road networks should be at a low density, avoid crossing water and be positioned so as to limit access to unique sites. We recommend a target road density of less than 0.58 km of road per km2 of land. As many roads as possible that are not required for ongoing silviculture should be temporarily closed using embankments and boulders which eliminate or decrease vehicle access. Road networks should avoid loop roads and promote cul-de-sac roads.
Department of Natural Resources and Energy. 1995. Management of Forest Habitat in New Brunswick. Fish and Wildlife Branch. Dept. of Natural Resources and Energy. Fredericton, NB.
Department of Natural Resources and Energy. 1996. Watercourse Buffer Zone Guidelines for Crown Land Forestry Activities. New Brunswick Natural Resources and Energy. Fredericton, N.B.
Woodley, S. and G. Forbes (eds.). 1997. Forest management guidelines to protect native biodiversity in the Fundy Model Forest. New Brunswick Co-operative Fish and Wildlife Research Unit, University of New Brunswick. Fredericton, N.B.
Information provided by:
Dr. Graham Forbes
Faculty of Forestry and Environmental Management at UNB
Last Update: May 7, 1998
This document: http://www.unb.ca/web/forestry/centers/cwru/soe/chapter7.htm