Another month in the bush and I’m starting to get the hang of this ribbon-hanging business. In the past few days I have officially had my first experience of a solo black bear encounter. A somewhat terrifying but exhilarating experience which I’m glad to be able to tell the tale. More surprisingly, I managed to encounter porcupines on two consecutive days which I’m told is a much rarer experience.
(Left: Porcupine evading the British invasion of the pine flats at War Lake. Right: Testing the structural integrity of beetle kill sprue logs.)
Block access and road design
Recently I was involved in designing a particularly challenging mainline for accessing a previously untouched valley. The famously punny Tutu block was a 10-day intensive heli-shift battling through challenging ground conditions and smoke drift. Not to mention the sighting of a grizzly bear on the first day to remind us we are not alone in the wilderness.
(Designing a double adverse switchback to access harvesting area).
The Tutu block required an extensive amount of mainline and additional spur roads to access this untouched timber resource. Prior to commencing fieldwork of this scale, the block is assessed for proposed block boundaries and road lines, using a mixture of orthophotographs and LiDAR slope analysis. This give the field operative an informed approach to tackling such large projects. These projections however useful, are just to be used as a guide, as local ground conditions can restrict even the best laid plan.
Slope is particularly limiting depending on the harvesting method to be utilised. Conventional harvesting using feller bunchers and skidders do not operate safely above slopes of 45%. Therefore, ground exceeding these parameters is excluded to produce a sustainable block for harvesting. Greater flexibility of harvesting can be achieved using cable systems, but local contractor availability limits the use of this practice.
Ideally roadbuilding should adhere to parameters deemed appropriate for timber haulage. This translates as a maximum favourable gradient (Loaded haulage vehicle heading downhill) of 12% and adverse gradient (Loaded vehicle traveling uphill) of 8%, for interior British Columbia. This can be very challenging especially on complex terrain such as the Tutu valley. Starting the over 6km stretch of mainline from the closest accessible built road, towards the proposed point of access 400m upslope, the road was forced an additional 50m upslope (See above). This change in road projection consequently limited the future usability of all projected roadlines within the block area. To remedy this situation, the options were to rip out a substantial length of designed road in the hopes of entering the block closer to the proposed location. Or engineer a potentially difficult double adverse switchback to drop down to the appropriate elevation. The switchback option was approved, and I was part of the team ensuring the road would be drivable by fully loaded haulage trucks. Using an adverse switchback is generally discouraged and only used as a last resort.
Designing a road that is safe and cost effective is among the most important and challenging aspects of harvesting layout and can make or break the decision for harvesting. It is entirely possible that consultant companies such as Strategic Natural Resource Consultants, can recommend a block not be harvestable as part of the financial appraisal process.
Hydrology (Streams, streams and more streams)
Protecting hydrology is a high priority for planning harvesting operations. Any area identified for harvesting must be thoroughly surveyed for stream features big and small. Any hydrological feature that has a defined channel greater than 100m is designated a stream classification (See below). Smaller features are also identified but do not require as greater protection. Each stream is hung and traversed, meaning a series of coloured ribbons (Blue for Conifex and red for Canfor sites) are tied to the centre line of the stream frequently enough to follow, and recorded using GPS. To distinguish between each stream, each is named following a numerical sequence. Information is also gathered on the stream profile including width gradient and substrate.
Information gathered during this process also assists in planning road lines and selecting an appropriate size of culvert. Streams found to be fish bearing will also require bridging to prevent creating a barrier in the stream. To determine if a stream is fish bearing, the stream must be connected to a fish baring stream and not have any permanent barriers impassable to fish. Potential fish barriers are listed below:
- >25% stream slope for 25m
- >22% stream slope for 100m
- Permanent vertical drop that exceeds the average channel width and residual pool depth
- Absence of a defined channel bed
(Example of hydrology features within a typical harvesting block in the Tutu Valley).
In a forest suffering heavily from beetle kill mortality, and large woody debris, it can be very challenging to collect this information. But the satisfaction of correctly classifying each stream so it is allocated the correct level of protection justifies the process. Measuring each stream allows for the correct size bridge/culvert to be allocated for each road crossing. To small and the volume of water risks washing out the road, to large and the cost of the road increases. Surveying each stream provides a balance of both factors in the name of sustainability.
Living for the weekend
(P125 showing of her rugged Ford charm along the Icefield Parkway).
During my time in Jasper, I made the trip SE towards the Columbia Icefield Glacier complex and stopped to admire the Athasbasca glacier. Initial impressions blew me away at the ancient ice and vast beauty. However, beyond initial impressions a far sinister story was at play. Since 1844, the glacier has retreated approximately 2km, by 10-25m per summer. A stark reminder of our rapidly changing climate, and our potentially anthropogenic influences on the world we live. This phenomenon reinforced the importance of sustainable land use and the role forestry plays in the world ecological stage.
(View of the Athabasca Glacier from the Columbia Icefield Discovery Centre).
I spent my second weekend in Vancouver and experienced a dramatic change of pace from the rural life. The hustle and bustle of the city was very refreshing and it was more enjoyably spent with good company. Stanley Park, Canada’s west coast equivalent to Central Park, was a great place to visit with skyline views and sea planes on the horizon. The Vancouver Aquarium was pleasant with much aquatic life to see and learn about- I newly discovered an interest in jellyfish.
(Looking back towards Downtown Vancouver from Stanley Island).
Not much time is left for me in The True North, but I look forward to what is yet to come.