Comments by Peter Bush (Provincial Landscape Ecologist, Forest Research and Planning; Acting Manager of Forest Research and Planning, Nova Scotia Department of Natural Resources and Renewables)
On Nov 23, 2021, I sent an e-mail to Peter Bush at NSNRR: “Hi Peter, perhaps I missed it but I can’t seem to find this no anywhere in the proposed Old Growth policy. So by current criteria (>125 years), can you say how much we have, documented of course, in hectares?
I didn’t hear from him and wrote again Mar 12, 2022, & received a detailed reply the next day.
Said Peter Bush (bolding mine):
Old-growth forest is primarily determined on the ground through field assessment. That is why the department has developed a rigorous scientific method to measure and determine old-growth forest in the field. An important part of the Old-growth forest policy is the clear statement that all old-growth forest is policy protected, whether it is currently known or is found in the future as a result of field assessments prior to forest harvesting.
Remote-based technologies do not allow us to accurately identify forest age, and therefore make it difficult to determine the precise amount of old-growth forest in Nova Scotia.
Currently, our Old Forest Policy layer has restoration old forest that is either known or believed to be old-growth (but not assessed) and has old growth that is not known. For example, Hemlock trail in Kejimkujik National Park is known old-growth forest but has not been assessed through our scientific method. The original old-growth restoration opportunities on Crown were chosen based on local expert knowledge of regional biologists and foresters as sites that were very likely to be old-growth.
Because all of these best restoration opportunities are protected under the policy, it hasn’t been necessary for the department to determine which areas have fully developed to the old growth stage, since the restoration forests develop to old growth over time. Resources have been spent on identifying any forest not under protection (legal or policy protected) that might be old growth. This effort supports the Review of Forestry Practices recommendation to “Accelerate and improve data collection on the existence of old forests across all unprotected Crown lands”.
Having said that, it will be important for the new policy to identify the layer that is old-growth vs restoration. We are making the effort to visit as many stands as possible. We now have identified, through field-based assessments, over 4,000 ha of forests (mostly on crown land) that meets the old-growth definition. Again, based on the paragraph above, this does not mean there is only this amount of old-growth forest, just what has been assessed to date (i.e. the minimum, especially considering very little assessed in legally protected areas). When we consider all of the restoration opportunities forest areas (in and outside protected areas) and known old-growth forest there is over 8% of the total forest area in Nova Scotia (or over 20% of crown forest).
The department is also exploring some advance remote sensing and GIS methods to better estimate the amount of old-growth forest in the province with our academic partners.
So I figured if the Triad total landbase is 1,824,000 ha (from HPF Discussion Paper), 4000 ha is 0.22%; the no is evidently lower on private land, prob higher on federal land… so it is something in the area of 0.2%; perhaps substantially lower depending on how the sampling was done (re Crown versus private land).
I asked Peter Bush about my estimate. He replied:
In part this is why it is a difficult question to answer.
I don’t feel that is appropriate to divide those numbers for several reasons
We have not sampled the population in any statistical way (no stratified random sample).
The 4,000 ha was based on a ballpark sample of maybe 20,000 ha (so similarly it would be wrong to suggest there is 20% old-growth in Nova Scotia)
Many of protected areas (~600,000 ha) were selected for protection because they had OGF (so not just a little bit more, for over 35% of provincial land).
1,824,000 is not the correct denominator (includes naturally non-forest areas).
We really haven’t been sampling in some of v-types listed in the new policy coastal, wet forests, etc.
4,000 ha is really just the amount of forest outside of protected areas that is known OGF (i.e., sampled OGF). We are fairly confident there is much more OGF on crown alone (why many original OF policy areas were selected), again we have not sampled most of these because they are already protected under the policy.
Mosseler, J.A. Lynds, and J.E. Major. 2003. reports an estimate range of 1-5% for OGF in Acadian Forest for NS. Until further research at the broad-scale has been concluded, we have no reason (or data) to support that this range is wrong. The old-growth policy acknowledges that OGF in NS has had significant decline and important to protect all remaining old-growth, no matter whether there is 1%, 3%, 5% or 9%.
‘Grateful to PB for the clarifications