GREATER FUNDY ECOSYSTEM RESEARCH PROJECT

UNB Faculty of Forestry and Environmental Management


Forest Management Guidelines to Protect
Native Biodiversity in the Fundy Model Forest

Landscape Level Considerations

Water Course Buffers


A waterfall in Fundy National Park
(Photo: G. Forbes)
 It has long been recognised that forest harvest activities have the potential to significantly affect the quality and quantity of freshwater systems. The proximity and extent of harvests near waterways can alter the amount of coarse woody debris, water temperature, siltation levels, nutrient availability, and stream hydrology. In turn, these abiotic factors have been shown to effect the abundance and functions of fish, amphibians, invertebrates, and vegetation (see overview by O'Laughlin and Belt, 1995). In response, managers have implemented a series of buffer zone guidelines that limit the amount and type of harvest within a prescribed distance from the waterway. The following are some considerations from the existing New Brunswick buffer zone guidelines and some additional recommendations for use in the Greater Fundy Ecosystem.

Existing Buffer Zone Guidelines:

Buffer zone guidelines have generally been proposed based on their value as;
1. filters - the ability of a band of shoreline vegetation to absorb nutrients before they enter a waterway;
2. shelters - the amount of canopy needed to keep water temperature from surpassing the tolerances of fish species requiring cool water;
3. stabilisers - preventing erosion on steep slopes and the siltation of waterways, and;
4. detritus suppliers - provide input of coarse woody debris.

At a landscape level, the creation of a relatively uncut, older-aged buffer system network also has value in that it creates corridors that are important for wildlife movement. In New Brunswick, these buffer guidelines are set under the Watercourse Buffer Zone Guidelines for Crown Land Forestry Activities (NBDNRE, 1996) and the Clean Water Act. The Clean Water Act requires a minimum 30 m buffer zone on all watercourses. On small watersheds (less than 600 ha) located on crown land, exceptions may be authorized by DNRE.

The GFE Research Group endorses the application of the buffer guidelines used on crown land. These guidelines include objective-based rules on identification of waterways, mapping and reporting procedures, forestry activities within buffers, and various special situations needing buffers such as recreation routes, moose calving areas, snags, wildlife corridors, and waterfowl production areas. The following text and Table 6 outline the guidelines we see as most relevant to ecosystem management:

Identification

A waterway or watercourse is any natural drainage feature with a discernible channel. In terms of vegetation make-up, the edge of the watercourse begins with Alder or Willow zones rather than grasses and ericaceous shrubs.


Activities Within Buffer

Selection harvest within the buffer is allowed in watersheds less than 600 ha based on an approved harvest prescription, with permits needed for areas greater than 600 ha. A maximum cut of 30% of merchantable basal area is allowed every 10 yrs. As well, the site must retain a Basal Area >18m2/ha, Canopy Cover >50%, and Canopy Height >10 m. Maximum removal of 30% dead and dying trees every 10 yrs., within 15 m on any watercourse >15 m wide, is advised. Harvest operations will not create openings >10 m wide. Tree tops or slash are to be kept out of the water.

Best Management Guidelines:

The GFE research group supports the direction and content of these revised guidelines. The guidelines reflect the importance of naturally functioning aquatic environments, and are based upon a combination of empirical research and established guidelines developed by forest managers throughout North America.

We recommend the following additions to the provincial guidelines:

1. Special effort is required to identify a range of diameter class trees to ensure large trees are retained in the buffer strips.

2. Woody debris is an essential component to the diversity of habitat along watercourses. Removal of this debris has negative effects on fish abundance. Fish abundance can be increased by input of woody debris back into the system. In order to achieve a sustained input of woody debris, riparian zones should include sufficient numbers of large mature trees immediately adjacent to the stream or river bank. To achieve this goal it is recommended that a 5 m no cut zone be put in place along all watercourses.

3. The steep river valley slopes of the FMF present an additional concern for water quality in the area. The high slopes of the Point Wolfe, Goose, and Big Salmon Rivers, for example, often extend several hundred meters away from the shoreline, well beyond the prescribed 60 m maximum buffer width on steep slopes. In some areas, small plateaus exist part way up slopes. These steep slopes are considered inoperable due to present harvesting technology and costs. We believe that these steep valley slope areas represent unique and sensitive conditions that should be specifically identified in buffer zone guidelines. A general rule should be to maintain the current buffer setback of 60 m but begin it at the top of the valley (instead of at 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 no cutting would occur within 5 km of the shoreline.







 

 

Go to Guidelines for:
Patch Size
Connectivity
Stand Age - Provisions for Mature Forest Stands
Incorporating Maturity into Forest Harvest Schedules
Guidelines for Mature/Overmature Coniferous Forest
Plantations
Stand Conversion
Roads
Protected Areas

Habitat Considerations for Specific Species
Special Status Tree Species
Coarse Woody Debris
Snag and Cavity Tree Retention


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Information provided by:
Dr. Graham Forbes
Faculty of Forestry and Environmental Management at UNB
Last Update: Dec 17, 1997
This document: http://www.unb.ca/web/forestry/centers/cwru/water.htm