If you recall in my last column, I estimated what I thought was a conservative amount of biomass (i.e. 10 per cent of the annual allowable cut) left as residual material.
I would like to discuss a more comprehensive approach using the forest inventory maps and data base.
The Ministry of Forests has made some major technical advances since my career started in the early 1970s.
When I started with the inventory section in the 1980s we were just starting to digitize the first forest cover maps.
It took about 10 years to finally get all of the provincial maps in digital form.
Prior to the digital format any map requests were produced one at a time from a hand drafted master.
Last year (at no charge) I got the updated inventory maps for the entire province all in one file downloaded over the internet.
Someone in the government had anticipated the need for biomass data so they now included the weight of stems, branches, foliage and bark as well as the volume of the saw logs.
What I did was convert the biomass to cubic meters per hectare so I could approximate what was left after the sawlogs were removed.
When I used the whole stems and subtracted the sawlogs, I got 23 per cent residual left behind and when I include the bark and branches I estimated more than 30 per cent residual.
The data is on maps and in a data base so we can better predict the kind, amount and location of the cull material.
I want to caution the readers that the use of the inventory biomass data is a very new concept and to my knowledge has not gone through a rigorous field confirmation.
I am also assuming there could be a wide variation throughout the province, especially the more productive areas.
Before the discussion on cull piles is complete there should be some mention of the provincial waste assessment program, which deals with the amount of sawlogs allowed on the block following logging.
This is not an area I am familiar with, so I will discuss this material later after I have had a chance to see how relevant it is to this topic.
I did find one reference to large burn piles in the Okanagan.
The estimate there was from 20 to 30 per cent of the pre-logging stand in the pile.
My vision of Forest Ink is to stimulate a conversation with the Tribune/Weekend Advisor readers which will lead to better forest management.
In my opinion some of the most valuable input and practical ideas will come from the people who work in the forest industry.
The road builders, chain saw operators, people running the processors and skidders and of course, the truck drivers.
These people are in the woods every day and I trust have opinions regarding some of my estimates of what is out there and how we could best put it to use.
It would be extremely valuable to have their input and discussion.
Jim Hilton is a professional agrologist and forester who has lived and worked in the Cariboo Chilcotin for the past 40 years. Now retired, Hilton still volunteers his skills with local community forests organizations.
