Gap-Driven Ecosystems and NTFPs

British Columbia is the most ecologically diverse province in Canada; a diversity that is primarily determined by its unique macro-climate and topography. This biodiversity has been the basis for a rich array of subsistence, spiritual, recreational and economic non-timber forest products. Non-Timber Forest Products (NTFPs) are all of the botanical (plant) and mycological (mushroom & fungus) resources and associated services of the forest other than timber, pulpwood, shakes, or other conventional wood products.

Human activities have modified natural ecological processes with varying impacts on these resources. To manage NTFPs effectively, we need to understand the ecosystems within which they occur. There are two important keys to this understanding.

The first key is ecological zonation, of which the most widely used system in B.C. is the Biogeoclimatic Ecosystem Classification (BEC). Here is the website for a BEC map that will show you the current ecological zonation for British Columbia: BEC incorporates climate, soil, topography and vegetation data to produce an integrated, hierarchical classification consisting of:

  • zonal units based on climatic climax vegetation;
  • sub-zone units based on moisture; and
  • site/ecosystem units describing how the composition of ecological communities changes over time on specific areas.

BEC supports predictions of what plants will occur on undisturbed landscapes across zones and subzones, and judgements on site productivity, vegetation succession after disturbance, species for ecosystem recovery, and wildlife habitat capability.

The second key is the concept of Natural Disturbance Regimes (NDRs). The NDR in any area largely determines species composition, vertical canopy architecture and spatial structure of ecological communities over time. BEC zones and sub-zones are the end result of the prevailing disturbance regimes. NDRs help us understand the manner in which ecosystems have changed when human activities, often associated with single-purpose management, have modified the nature, intensity and frequency of disturbance. NDRs also give us some hints about the measures that might be used to re-introduce more natural, multi-purpose ecosystem management practices.

There are three general categories of NDRs:

  1. gap-driven ecosystems resulting from rare stand-initiating events,
  2. disturbance-driven ecosystems resulting from frequent stand-initiating events, and
  3. disturbance-maintained ecosystems resulting from frequent stand-maintaining events.