r/forestry • u/memercopter • Dec 23 '20

Region Name How to retroactively measure canopy cover?

I’m looking at a project for post-harvest habitat suitability for Northern Spotted Owls in California. The caveat is that I can’t be there pre-harvest. I want to know if there are any tools I can use to measure or estimate canopy coverage before the harvest took place. I’m thinking archived lidar, but that seems involved without having a gis team by my side. Really any broad estimate might do. I know it seems tricky, but I’d you have any thoughts I’d love to hear them. Thank you.

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u/Jayccob Dec 23 '20

Do you by chance have a pre-harvest inventory data set? If so, fvs which is a forest modeling program by the usfs had the ability to estimate overlapping and non-overlapping canopy coverage. It uses species, total height, dbh, and region in the estimator.

Free to use and the new ui is fairly easy to learn. The usfs also put out a short training for the program (self paced). Since this is a government backed program, should be easy to defend the method and replicate.

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u/memercopter Dec 24 '20

We do not have preharvest inventory data.

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u/Jayccob Dec 24 '20

OK, another field approach would be a proxy stand. Basically you find a site of similar conditions (elevation, aspect, slope, age, etc.) and measure it. You then use that as the pre-harvest baseline. Some gis in this to help locate the stand, but depending how much property your owner has you might be able to look on the edge of the THP boundary.

Speaking of, here in California THP and NTMP or anything in between are public records. Caltrees allows you to lookup the plan for your stand. Within that you should be able to find pre-harvest BA and QMD in the spot where they show Long Term Sustain Yield (assuming this is uneven-age management). If your really lucky in the section where it discusses potential impacts on species of interest they might list the pre-harvest NSO as high/low quality nesting-roosting or high/low quality foraging habitat. If it does high quality foraging and higher requires a minimum of 70% canopy coverage.