Pattern, Process, and Productivity in Hypermaritime Forests of Coastal B.C:    The HyP3 Project

Keywords:  western redcedar, yellow-cedar, low productivity forests, British Columbia north coast, silvicultural systems, hydrology, forest ecology, operational harvesting trials, forest inventory, ecological mapping, site productivity, soil ecology, peat formation, management guidelines, hypermaritime.

Introduction
 

HyP3 (pronounced “hip cubed”) is an integrated forest research project initiated in the North Coast Forest District in 1997. This project is aimed at developing ecologically based guidelines for the management of cedar-dominated forests that are mostly outside the current operable land base of north coastal B.C. Poor- and low-site cedar - hemlock forests dominate much of the outer coastal landscape.  They contain significant amounts of fibre as well as high value redcedar (Thuja plicata) and yellow-cedar or cypress (Chamaecyparis nootkatensis), for value added and specialty markets. Currently there is much uncertainty surrounding the feasibility and sustainability of harvesting these wet, slow growing forests. Using a combination of basic studies of structure and function as well as manipulative studies, four overall project goals are being addressed:

• To assess the feasibility of managing poor- and low-site cedar – hemlock forests on the outer coast of B.C. for timber/fibre production.
• To define the extent of these sites and to be able to readily identify the potentially operable portion.
• To develop ecologically based management guidelines for these forests.
• To document the ecology of the blanket bog – upland forest complex of north coastal B.C.

The Issue

The North Coast Timber Supply Area (TSA), within the Coast Forest Region, encompasses 1.95 million hectares (ha) along the B.C. coast, extending from Princess Royal Island to S.E. Alaska.  While 39% of the total area within the TSA is considered productive forest land, environmental, accessibility and timber size and quality limitations result in only six percent (119,130 ha) of the area being currently included within the operable (timber harvesting) landbase.
 

From the hand logging and A-frame operations that began at the turn of the century, to the larger industrial operations of today, the footprint of the logging industry is readily apparent along the north coast. A closer look reveals that harvesting, for the most part, has been restricted to the highly productive steep slopes (often adjacent to tidewater) and alluvial valley bottoms. These locations have yielded the highest volumes per ha and the greatest return on investment for the relatively costly coastal timber harvesting operations.  Harvesting of some species such as Sitka spruce (Picea sitchensis) and balsam  (Abies amabilis) has been disproportionately high, compared with their percentage of the standing volume.

Very little harvesting has occurred in the lower productivity, height class 2 and 3 (less than 30m tall) cedar – hemlock stands, typical of the gentler north coast terrain. These stands make up an additional 12 percent of the TSA (roughly 235,000 ha) and contain significant quantities of both redcedar and yellow-cedar. The cedars typically grow together with low-quality western (and mountain) hemlock  (Tsuga heterophylla and T. mertensiana) as well as lesser amounts of shore pine (Pinus contorta var. contorta). As the market value of cedar and cypress fluctuates, so does the attractiveness of these stands for logging. Currently most of these stands are excluded from the operable landbase but some are now being considered for inclusion in the operable area. Any increase to the six percent operable area, however, could occur only after questions regarding the location and extent of potentially operable wood, the appropriate harvesting system, and the capability of the selected areas to successfully regenerate, have been addressed.

In response to the Chief Forester’s request for further research (Pederson 1995), Ministry of Forests research staff commissioned a problem analysis (Kayahara and Klinka 1997), then submitted a proposal to Forest Renewal BC to carry out research and develop operational guidelines for timber harvesting in the cedar – hemlock forests on the outer coast.  Funding for the project was approved by Forest Renewal B.C. in May of 1997.

The sites of interest for this research appear to be low in productivity because of their wet soils and thick surface organic layers (forest floors). Ecologically, these areas are classified mainly within the very wet, hypermaritime subzone of the Coastal Western Hemlock Zone (CWHvh2 – central variant).  Research in the CWHvh2 in British Columbia and adjacent areas in Southeast Alaska suggests that productive forests, through a process of soil organic matter accumulation (paludification), can develop into bogs (Banner et al. 1983, Kayahara and Klinka 1997).  Understanding the effect of timber harvesting in promoting or combating this process and thus impacting on second growth productivity is one of the subjects of the HyP³ research.

HyP³ is linked to the Salal – Cedar – Hemlock Integrated Research Program (SCHIRP) being carried out on northern Vancouver Island (Prescott and Wheetman 1994).  While many of the SCHIRP results are undoubtedly applicable to more northern ecosystems, ecological differences between the two areas (CWHvm1 and vh1 vs CWHvh2) appear significant enough that directly extrapolating harvesting and regeneration experience from the south the north coast would not be appropriate. HyP³ is thus building on existing information from SCHIRP and establishing additional studies on the north coast, where to date we have had relatively little experience with second-growth management of lower productivity forests.