In an earlier post I had remarked on the apparently low wood volumes harvested from Crown land compared to private land in Nova Scotia, and that I had submitted a request to NSDNR for an explanation.
I received this explanation from Bruce Stewart, RPF, Acting Director, Forestry Division Manager, Forest Research & Planning, Nova Scotia Department of Natural Resources on July 27:
In response to your question of July 17, “why is the volume of wood harvested per hectare so much lower on Crown land than on industrial and private lands?” as observed in your correspondence (below)*:
The footnote at the bottom of the table in the National Forestry database provides insight into how the data is derived:
Private land: Clearcut area on private land is an estimate. It is determined by converting volume to area using a volume conversion factor of 130 m3/ha. The volume is attributed to clearcutting unless otherwise is known.
Crown: Clearcut areas reported on crown are the actual figures reported by DNR Crown land officials.
On private lands (both industrial and non-industrial), the volume of wood is tracked through the Registry of Buyers but the actual harvest area is not known. The wood volume associated with any area of partial harvesting on private land that is recorded under silviculture treatments (Woodlands Acquisition Plan through the Registry of Buyers and Association for Sustainable Forestry) is estimated and the remaining volume from private lands is assumed to be from clearcut harvesting and the area is estimated based on a factor of 130 m3/ha. For 2015, there was only a small amount of partial harvesting recorded under silviculture treatments on both industrial and non-industrial private lands which results in the factors of 120.6 and 123.2 that you calculated.
On Crown land, the actual harvest area by harvest methods is tracked (DNR staff) as is the volume of wood from Crown lands (Registry of Buyers). In 2015, 33% of Crown land harvests were by partial harvest methods which can be expected to yield lower volume per unit area than clearcut harvest methods. An average harvest of 76.8 m3/ha is consistent with the level of partial harvesting taking place.
Thanks for the explanation, NSDNR
*From: Nunn, Bruce
Sent: Tuesday, July 18, 2017 11:14 AM
To: David Patriquin
Subject: Re: Question about Crown land harvest stats
I am forwarding this inquiry to our forestry staff to advise.
Dept. Natural Resources
1701 Hollis St., Halifax
Nova Scotia, Canada
On Jul 17, 2017, at 5:29 PM, David Patriquin wrote:
Looking at 2015 stats reported on the National Forestry Database at http://nfdp.ccfm.org/data/detailed/html/detailed_6100_p_NS.html for area harvested and at the Registry of Buyers of Primary Forest Products 2015 Calendar Year / June 20 at https://novascotia.ca/natr/forestry/registry/annual/2016/2015AnnualReport.pdf for volumes I arrived at these numbers:
Crown 11342 ha, 870755 m3 = 76.8 m3/ha
Industrial 3881 ha, 467860 m3 = 120.6 m3/ha
Private 19554 ha, 2409881 m3 = 123.2 m3/ha
My question: why is the volume of wood harvested per hectare so much lower on Crown land than on industrial and private lands?
I guess part of my misconception was that (as an ecologist), I was looking at wood volumes as a proxy for forest productivity. They can be, but then you would want to combine the volumes for both cuts in a 2-stage clearcut. From that perspective it would be helpful if volumes were reported separately for single stage and multi-stage clearcuts.