Only 56% of managed lodgepole pine in British Columbia's Lakes TSA still healthy after 24 years - new study used drone photogrammetry to validate growth model accuracy across 30 plots
A study just published in The Forestry Chronicle revisited 30 one-hectare plots in the Lakes Timber Supply Area that were originally established in 1997. The researchers (led by Alex Woods from BC Ministry of Forests) wanted to check whether managed lodgepole pine stands were actually growing the way the province's models predicted.
Short answer is not really.
Healthy tree proportion dropped from 74% to 56%. Comandra blister rust was the single biggest killer (42% of all mortality), but the combined impact of western gall rust, snow damage, stem defects, MPB, and competition actually did more total damage. And the province's standard growth model (TASS III) only came close to matching observed volumes when they updated both Site Index values and added disease mortality adjustments. Using the original 1997 inputs, the model significantly overestimated what was actually standing.
The methodology is interesting too. They used a consumer drone (Mavic 2 Pro) with terrain-following flight planning software (UgCS, made by our company) to capture imagery across all 30 plots, then built canopy height models to estimate volumes. The drone estimates correlated at 0.92 with hand-measured ground verification plots. It's a scalable approach for monitoring programs that need to cover a lot of area without doing full ground cruises at every site.
The bigger takeaway for anyone in BC forestry: growth and yield forecasts built on pre-beetle, pre-Dothistroma assumptions need serious recalibration if they're being used for timber supply planning.
Full case study: https://www.sphengineering.com/news/ugcs-terrain-following-uav-forest-inventory-british-columbia
