Disturbance-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: http://www.for.gov.bc.ca/hre/becweb/bec-view.htm 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.

In this module, you will learn about disturbance-maintained ecosystems — what they are, where they occur in British Columbia, how they relate to BEC zones, and some of the non-timber forest products that commonly grow in them.

Disturbance-maintained ecosystems are multi-aged, savannah-like forests and grasslands in dry climates. The structure of these forests is maintained by regular (< 10 year return period) ground fires.

The main characteristics of disturbance-maintained forests include:

  • Uneven-aged forests interspersed with grassy and shrubby openings.
  • Periodic surface fires consume woody fuels and rejuvenate herb and shrub layers.
  • Fire maintains species composition, stand structure and regulates fuel loading.
  • The timing of fires is critical: too frequent seriously affects tree regeneration; too infrequent increases understory growth and fuel loadings, which may ultimately result in a catastrophic fire.
  • These forests are generally comparatively low in biodiversity, though often have very high endemism, which means it contains a lot of species that are naturally confined to those areas and those areas only. Large ungulates and associated predators are usually a significant component of biodiversity in these ecosystems.
  • Diversity is very closely related to stream courses, springs and moist depressions, and small wetlands.

Disturbance-maintained ecosystems comprise the following BEC zones: Dry Coastal Douglas-fir (CDF-d), Dry Interior Douglas-fir (IDF-d), Ponderosa pine-bunchgrass (PP), and Bunchgrass (BG). They occur at low elevations on the dry, leeward side of major mountain ranges — in the Georgia Depression and in major river valleys of the southern interior. On the coast the CDF-d zone includes Garry oak-meadow communities, one of the most endangered ecosystems in Canada and the subject of a major restoration program. In the interior valleys similarly endangered dryland ecological communities (PP and BG) are continuous southward with similar communities in Washington, Idaho and Montana states.

Some commercially- and culturally-important plants characteristic of disturbance-maintained ecological communities in B.C. and their uses are shown in the following table.

Click on the English name to see a photo of the plant species and click on Map to see the species’ distribution map. The photo and map will open in a new browser window. Click the Close button at the bottom of the image before clicking on another species or map.

English Name

Scientific Name


Chocolate lily

Yellow bell


Fritillarea lanceolata

F. pudica

Important food plants for Aboriginal Peoples.

Highly-prized garden ornamentals.

Arrow-leafed balsam-root


Balsamorrhiza sagitatta

Important food plant for Aboriginal Peoples.

Important deer, elk and bighorn sheep food.

Attractive ornamental for the dry garden.


Columbia bitter-root


Lewisia rediviva

L. columbiana

Important food plant for Aboriginal Peoples.

Potential showy garden ornamentals.

Desert parsley
Desert parsley
Desert parsley


Lomatium dissectum
L. nudicaule
L. macrocarpum
L. geyeri
L. triternatum
L. ambiguum

Important food plants for Aboriginal Peoples (seeds and roots).

Valuable ornamentals for rock gardens and xeroscaping.

Common camas

Great camas


Camasia quamash

C. leichtinii

Important food plants for Aboriginal Peoples.

Highly-prized garden ornamentals.

Note: Some plant species have a limited occurrence outside of the disturbance regime in which they generally occur. This is because any mapping exercise is, by nature, a generalization. Thus the conditions of a particular disturbance regime may exist in small pockets in adjacent regimes (e.g. small areas of dry disturbance-maintained communities may exist on dry southerly aspects within the general area of moister disturbance-driven communities).

All of these species occur on warm, dry, mineral soils. All are light-demanding to mildly shade-tolerant. Regular fire appears to significantly increase the abundance of several species, such as balsam-root and desert parsley. Many species have significant biomass stored in underground structures such as bulbs, rhyzomes and fleshy tap-roots — a common characteristic of fire-adapted plants which accounts for their importance to Aboriginal Peoples as food plants.

Management strategies for these threatened ecosystems and the NTFPs they support will focus on protection and rehabilitation of the remaining intact ecological communities, strict regulation of the type and intensity of NTFP harvest, control of human disturbance and invasive exotic species, and selective re-introduction of ground fire. Eco-cultural tourism and education are potentially valuable tools for heightening public awareness of the status and values of these threatened ecosystems and as a potential fund-raising source for ecosystem protection and restoration.


John Dick

Production Team

Peggy Faulds, Project ManagerKate Seaborne, Production ManagerJudy Somers, Audio-Visual ProductionKaty Chan, Instructional/Technical Design & Graphic DesignMarc Furney, Marc Furney IllustrationJeff Ralph, Research Assistant

Many thanks to Dal Meidinger and John Parminter, British Columbia Ministry of Forests, for providing slides and advice on this project. Our thanks also to Nancy Turner, School of Environmental Studies, and Wendy Cocksedge, Royal Roads University for their advice and support.

Landscape photos were taken by John Dick, John Parminter and University of Victoria staff. Plant photos are from Nancy Turner’s collection or were taken by University of Victoria staff.

The content of this learning object was developed in 2004/05 by the University of Victoria and Royal Roads University and created as a media rich learning resource by Distance Education Services at the University of Victoria. Funding was provided by the Ministry of Advanced Education, Province of British Columbia through the BCcampus Online Development Fund. Please direct enquiries to distance@uvcs.uvic.ca