The State of BC’s Forests The Indicators Ecosystem diversity — PDF print version

Indicator 1 – Ecosystem diversity

click graphic to enlarge

Why is this important?

Diverse, well-functioning ecosystems are essential for environmental, economic and social sustainability. Many British Columbians are concerned about land use and preservation of old growth forests.

Overview

• Ecosystem diversity refers to the variety of ecosystems, their organisms and the interactions of those with their environment.
• British Columbia is the most biologically diverse province in Canada, and includes parts of 6 of the world’s 30 terrestrial ecoregions.
• Most of this diversity still exists 150 years after the start of European settlement, but development is critically threatening some ecosystems such as wetlands, grasslands and Garry oak meadows.

STATE

good

TREND

mixed

INFORMATION

partial

Questions about ecosystem diversity

1-1	How varied and extensive are B.C.’s ecosystems?
1-2	What are the areas, types and ages of B.C.’s forest ecosystems?
1-3	How have B.C.’s forests changed over the last century?
1-4	How much older forest does B.C. have?
	Ministry of Forests and Range’s assessment

Related indicators

• Agricultural and urban development, fires and logging (see Ecosystem dynamics, Timber harvest, Silviculture) have modified the province’s ecosystem diversity to date. Climate change (see Greenhouse gases) may cause extensive further changes.
• Forest ecosystem conditions affect wildlife habitats (see Species diversity), may ameliorate climate change (see Greenhouse gases) and support economic activity (see Forest products, Jobs and communities).
• Management responses include protected areas (see Protected forests) and ecosystem restoration.

Indicator 1-1

How varied and extensive are B.C.’s ecosystems?

larger versions – HTML | PDF | Excel — Biogeoclimatic zone descriptions

Why is this important?

Human settlement and resource development change the diversity and extent of ecosystems.

State and Trend

• B.C.’s maritime and continental climates, combined with its mountainous terrain, have resulted in a wide variety of ecosystems, from desert to alpine tundra. They are often grouped under 14 biogeoclimatic zones.
• Forests occur in all 14 zones, dominating in most of them. Varied conditions within each zone have led to diverse forest types.
• Since 1850, ecosystem conversion to agriculture, reservoirs, urban areas and other land uses has occurred on 2% of the province.
• About 3% of former forests have been converted to other land uses. Only the three smallest, warmest biogeoclimatic zones have had more than 10% of their former forests converted. The Coastal Douglas-fir (CDF) zone has been most affected, with 46% of its former forests now converted.
• Conversion impacts on former grasslands and some former wetlands are greater than those on most former forests, and are endangering some of these ecosystems and the species dependent on them.
• Fire exclusion has resulted in forest encroachment onto former grasslands and in-growth of more trees in formerly open forests.
• Maps: Biogeoclimatic Zones (PDF), Land Use Conversion (PDF)

Information

• Recent satellite imagery provides reasonably accurate information on the location and extent of major ecosystems and converted ecosystems.
• Estimates of forest encroachment and in-growth are incomplete.
• Various inventories are available or planned for different purposes.
• References: MFR’s BEC, NFI, VRI; MoE’s BEI, CDC, SEI; MAL’s BTM
• Related international and national indicators: MP 3.a; CCFM 2.2

Indicator 1-2

What are the areas, types and ages of B.C.’s forest ecosystems?

larger versions – HTML | PDF | Excel

Why is this important?

Different forest types and ages provide specialized habitats for plants, animals and fungi, and support a variety of human activities and livelihoods.

State and Trend

• Forests cover 59 million ha, or about two-thirds of B.C.’s 95 million ha. A further 4 million ha are other wooded land with woody shrubs, stunted trees or scattered trees.
• About 83% of the forests are predominantly coniferous, 6% are mixed, 6% are broadleaved, and the remaining 5% are regenerating forests with no species assigned. Lodgepole pine, spruces and true firs are the most widespread predominant trees.
• About 6% of the forests are less than 20 years old.
• Many of B.C.’s forests are old: 62% are over 100 years old, 41% are over 140 years old, and 14% are over 250 years old.
• Some forest types have trees over 1,500 years old.
• Maps: Forest Land (PDF), Predominant Tree Species (PDF)

Information

• Detailed forest cover inventories exist for 96% of the province, but many are not current. Updates are current for logging, but not for mountain pine beetle and fire impacts. Current inventories for tree farm licences and private land are mostly not available to government and the public.
• The 1950s inventory and satellite imagery are the only public sources of data for some parks and private land, about 4% of B.C.’s area.
• References: MFR’s VRI; MAL’s LRDW
• Related international and national indicators: MP 1.1.a, 1.1.b; CCFM 1.1.1

Indicator 1-3

How have B.C.’s forests changed over the last century?

larger versions – HTML | PDF | Excel

Why is this important?

Natural disturbances, logging, and land use conversion affect ecosystem processes.

State and Trend

• Ecosystem processes in forests are largely dependent on the area and distribution of forests, tree species composition and age.
• The area of forests recorded in forest inventories increased from 1957 to 2000, but it is not known how much of this is due to changes in inventory methods and how much is due to changes in actual forests.
• Similarly, apparent changes in predominant species may be due to methods more than changes in the forests.
• The area of forests 1 to 80 years old decreased provincially from 38% to 23% of the forest land base, despite extensive logging. The Interior area decreased, while the Coast region area increased from 19% to 24%.
• The area of forests over 80 years old increased provincially from 48% to 61%, primarily due to the increase in the Interior (from 45% to 61%). Railways and settlements led to large areas of forest being burned by accidental fires in the late 1800s. By the 1950s, many of these areas had regrown to become forests under 80 years old and, with effective fire suppression over the past 50 years, are now over 80 years old.
• Maps: Forest Age (PDF), Old Growth (PDF)

Information

• Differences between the forest inventories of 1918, 1937 and 1957 are largely due to changes in inventory methods, and do not provide reliable trends of changes in forest area, species or age in the early 1900s.
• The 1957 and 2000 inventories permit reasonably reliable analysis of changes in age distribution, but do not support reliable analysis of changes in forest area or species composition².
• References: MFR’s NFI, VRI
• Related international and national indicators: MP 1.1.b; CCFM 1.1.1

Indicator 1-4

How much older forest does B.C. have?

larger versions – HTML | PDF | Excel— Biogeoclimatic zone descriptions

Why is this important?

Older forests provide specialized habitats not found in younger forests.

State and Trend

• The dry temperate and boreal ecosystems in the Interior have frequent, natural wildfires that limit the proportion of older forests. The wetter ecosystems in the Coast region and along the Interior mountain ranges have fewer wildfires and higher proportions of older forests.
• Forests over 140 years old exist in all 14 biogeoclimatic zones and cover 24 million ha (41% of B.C.’s forests). These include forests over 250 years old that cover 8 million ha (14% of B.C.’s forests).
• Substantial proportions of older forests exist in most biogeoclimatic zones that naturally develop them, with the exception of the Coastal Douglas-fir and Interior Douglas-fir zones. Relatively small areas, 3% or less, of the forests in these two zones are over 250 years old, a result of logging and the development of agriculture and settlements.
• Tree height is often ecologically, economically and culturally important. Trees are over 20 m tall in about 70% of forests over 140 years old and 80% of forests over 250 years old.
• About 25 million ha (42%) of B.C.’s forests are considered old growth. These forests tend to have more large trees and standing dead trees, multi-layered canopies with gaps resulting from the deaths of individual trees, and coarse woody debris on the forest floor.
• Maps: Forest Age (PDF), Old Growth (PDF), Biogeoclimatic Zones (PDF)

Information

• Information on older forests is incomplete in a few biogeoclimatic zones.
• The age of forests over 250 years old is often inaccurate in the inventory.
• References: MFR’s VRI, Forest Science
• Related international and national indicators: MP 1.1.b; CCFM 1.1.1

 

Indicator 1 – Ecosystem diversity Ministry of Forests and Range’s assessment State good B.C.’s varied climates and mountainous terrain have led to expansive forest cover of diverse types and ages – for example, oak parklands, temperate rainforests, dry pine forests and boreal black spruce muskegs. Most of this diversity still exists 150 years after the start of European settlement. Permanent conversion to agriculture, reservoirs, urban and other development has changed 2% of the land base and 3% of former forests. Trend mixed Further permanent conversion of forest land will be limited by terrain and climate, but will be mainly in the ecosystems already stressed by development. Fire suppression over the past 50 years has allowed the area of older forests to increase in parts of the Interior. Forest encroachment into grasslands and in-growth of more trees in formerly open forests has also occurred. This partly offsets the conversion of forest land to other uses, but threatens the ecological integrity of grasslands and some forest types. Continuation of these trends will strain the ability of several ecosystems to support B.C.’s rich biological heritage. Information partial The diversity of forest ecosystems in B.C. requires diverse management approaches, which in turn require an extensive knowledge base. Biogeoclimatic ecosystem classification data and 1:250,000 maps are used for forest and range management throughout the province, and larger scale maps of site series are available for almost half the province. A broad ecosystem inventory with 1:250,000 maps is used to assess habitat potential. Threatened plant communities and sensitive ecosystems, including forests, are not well documented. A national forest inventory will provide broad overview and trend information on forest cover. Detailed forest cover inventories on 1:20,000 maps exist for 96% of the province, but many are not current. Current inventories for tree farm licences and private land are mostly not available to government and the public. Forest cover inventories available in B.C. do not enable reliable analysis of trends in forest area and species composition. Forest cover information is incomplete in areas where the highest proportions of former older forests have been converted.