Unfortunately British Colombia isn't deforesting at a rate of 9 square miles per year, it's been deforesting at an average rate of ~1579 square miles/year for the past 21 years. [0] At that rate it'd take about 145 years to finish the job.

Depite the seemingly limitless bounty of British Colombia's forests modern technology will let us wipe them out in a fraction of the time it took pre-modern Europeans to do it to their own continent.

There are definitely more pressing concerns around the world with regards to deforestation than BC - at least BC are making some efforts to preserve their forests and replant, unlike many equatorial countries with arguably more precious rainforest ecosystems. But a net loss is still a net loss, and tree farms are not a one-for-one replacement for old-growth forest.

As an aside: the 15% forest cover Britain of 1086 wasn't its pre-human state - it was aleady heavily deforested by humans. Prehistoric and ancient humans were very effective at deforestation, since the most popular method of early agriculture in Europe involved burning swathes of land, farming the nutritious soil left in the fire's wake, and then moving and burning more forest when the soil became useless.

By the beginning of recorded history Europe had already achieved most of the deforestation it ever would.

[0]: https://www.globalforestwatch.org/dashboards/country/CAN/2/?...