NorthCoast Rainforests 11-98

NorthCoast Rain Forests 11-98

SUMMARY: Narrowing focus from Hemlock rainforest to Hecate Lowland's "very humid" sub-zone. Which, surprisingly, has some red listed ecosystems (the rich, easily accessed sites). Then a wider look at NorthCoast forests uniqueness: rain, and muck

CWH wet, mild and humid --

Coastal Western Hemlock ecosystems (CWH) thrive in proximity to the Pacific Ocean's mild climate to produce spectacular old growth forests. "Ancient" because fires are infrequent and, before modern logging, there was little to do but outgrow your neighbors. Thus huge trees, where the soils allowed, dominated these temperate rainforest, The profligate lushness created a reputation for fertility.

The Skeena River and Kitimat fjord systems allow moist, warm Pacific air to carry its benign influence well inland. The figure also makes it apparent the Kitimat, Skeena and Nass Rivers have, at higher sea levels, been one river system.

CWHvh2 Hecate Lowland

The coastal sub-zone (MOF's CWHvh22 -pink left, grey right) pretty well equals the geographers' "Hecate Lowland".
Foresters' emphasize the rain, other's the low relief as explanation for this ecosystems unique features. (3 other sub-zones can be seen on figure)

See table below for Hecate Lowlands

Wet, Mild and Vulnerable to logging

As elaborated on elsewhere the Hecate lowlands is a study in contrasts between steep sided fjords and subdued lowlands. Between lavish productivity and vulnerability. Huge rainforest spruce and cedar trees contrast with scrub coastal bog forests. It is hard to believe whole ecosystems are endangered, but that is the case. As the table below shows it is mostly the timbered, easily accessed sites that are threatened. The coastal shore forests (site units 14-16) have been vulnerable to loggers for over a century. The more localized landforms like sloughs, and estuaries were not common to begin with. More alarming is the red listed stream/ river bottom lands which were easy, rich and subject to erosion from poor logging practices.

Rains' Fecundity

How can anything be vulnerable, here? Every possible piece of support (land, rocks, tree trunks, etc.) is soon "colonized" by plant life.

That richness comes from "liquid sunshine". That elixir allows trees to grow in a handful of soil perched on some cliff face
Rain acts as an equalizer, carrying nutrients from the sources to sinks. Survivors have to counter that by making their sugars secure.
(On left , three different species of juvenile trees growing on a cliff side along streets of Prince Rupert.)

.Is this muck soil?

The rainforest owes its fertility and biologic uniqueness to the muck (organic layer) that accumulates over the centuries. At right it is perhaps 24 inches thick. (Here is a playful previously published "muck article) There is an apocryphal story that Rupert kids visiting Terrace on the first trains were dumb struck at the sight of dirt. Of soil that was "solid".
Think of the muck as congealed rain. It releases nutrient only to those plants that know its secrets. And they are usually symbiotic fungii that live in rainforest plant's roots.

The Drowned outer coast- where's the soil?

There are 2 variants: outer coast lowlands and steeper uplands.

A good working hypothesis as to why there is so little real soil on the outer coast was that it was washed away when the sea level was higher. Meanwhile the illustration above right has little soil and is typical. The flat lowland makes one think it has been scraped off by the glaciers. The Prince Rupert town site can be viewed as intermediate between the two variants. The Port Simpson - Big Bay area are good lowland types.

Next Week: Lowland CWH page for closer look at coastal ecosystems

Ecosystem Hecate Lowland	Total
Source Protected Areas Strategy document	Hectares
Alpine Tundra - AT	4,200
Coastal Western Hemlock very wet hypermaritime subzone - CWHvh	1,398,200
Coastal Western Hemlock very wet maritime subzone - CWHvm	10,500
Mountain Hemlock wet hypermaritime subzone - MHwh	112,300
Total	1,525,200

This table uses MOF site units. These will be elaborated on in next weeks pages dealing with lowland and more mountainous parts of Hecate Lowland separately. Data source CDC (Conservation Data Center)

CWHvh2/02	ridge	S3	BLUE
CWHvh2/05	rare	S2S3	BLUE
CWHvh2/07	rich	S3	BLUE
CWHvh2/08	fluvial	S2	RED
CWHvh2/09	fluvial	S1	RED
CWHvh2/10	fluvial	S3	BLUE
CWHvh2/14	shore	S3	BLUE
CWHvh2/15	shore	S2S3	BLUE
CWHvh2/16	shore	S2S3	BLUE
CWHvh2/17	rare	S3	BLUE
CWHvh2/18	slough	S3	BLUE
CWHvh2/19	estuary	S2S3	BLUE

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