The 2019 the provincial government asked foresters Gary Merkel and Al Gorley to undertake a strategic review of the state of BC’s old-growth forests. Their report led the BC government to seek First Nations’ approval for temporary logging deferrals on 2.6 million hectares of forest that government databases have identified as old forest.
One page of this report that is particularly relevant to the Discovery Islands Forest Conservation Project is the description of the risk to biodiversity in areas that now have low levels of old forest compared to their original state, and the list of biogeoclimatic zones where that risk is high. The list includes the three main biogeoclimatic zone variants that occur in the Discovery Islands. Below is the text from page 31 of the report:
"Knowing how much to maintain as forest with old trees is guided by the notion that mimicking nature is the approach that presents the least risk to biodiversity. The concept used to measure this is called 'natural range of variability' (NRV). This is typically based on a description of ecosystems as they existed before major changes brought about by extensive industrial or agricultural activity. Conservation science provides us with a general risk rating, telling us that if we retain 70% or more of the natural abundance of forest with old trees the risk of species loss, compromised ecosystem services, and losing ecosystem resilience is low. If we retain below 30%, the risk is high. At between 30% and 70%, the risk varies by ecosystem.
"Consistent with what we heard from several provincial government staff, a recent report submitted to the panel by a group of independent scientists illustrates that we are in situations of high risk to biodiversity in many areas in the province, particularly in high-productivity, low elevation ecosystems. More troubling is the future projection where almost all of the province will be in high biodiversity risk once our current management approach harvests most of the available old forest. The time to complete this transition depends on the available old forest and various industry and economic factors in each region.
"Their research also provided the following list of BEC zones that contain less than 10% of their original old forests:
CDFmm (all CDF),
CHxw, mk3,4, mw1,2,3,4,
IDFxc, xh1,2,4, xk, xm, xs, xx2, dc, dk1,2,3,4,5, dm1,2, mw1,2,
PPxh1,2,3 (all PP),
and possibly: ESSFxv2, dc1, mh, mv1,2,3,4, wc3,4, wh3, wk1 and wm1,2,3,4.
"They note that there is some uncertainty because of potential misclassification of age in some of these units, and also recommend that these areas be deferred from further development until we have brought them back enough to meet current legislated targets.
"Several practitioners also raised the issue of our current management system combining old forests and using their aggregated data when making assessments for managing biodiversity risk and planning for old forest retention. One example was parks and protected areas, where an initial net down estimate is removed at the landscape level and then netted out again at the detailed operations level, resulting in double counting. A related concern is that many parks and protected areas contain low-productivity old forests, which are deducted from total old growth aggregate targets without identifying which ecosystem they represent. These types of aggregation calculations overlook distribution and spatial considerations that are crucial in managing for effective ecosystem health."
The main biogeoclimatic zone variants in the Discovery Islands are CWHxm1, CWHxm2, and CWHdm, all estimated to have less than 10 percent of the natural level of old forest remaining, thus putting each of these variants at high risk of biodiversity loss.