I had a question regarding using InVEST in calculating the net present value of carbon sequestration being stored in a Coastal Alaska Forest near Haines, AK that has not changed land cover that much.
Essentially what my Master’s Thesis team and I are trying to accomplish is finding the modeled net present value of carbon sequestration that a logging company can consider before harvesting their old-growth and old secondary-growth timber. The Haines area is an old forest where trees (Sitka Spruce and Western Hemlock) grow exceptionally slowly.
When using two LULC land cover files (2010 & 2015) the land has not changed that much, only 500 hectares have changed in the last five years!
I know the other 2000+ hectares are sequestering carbon at some rate. How could I account for this? Would I need to reclassify land cover classes to barren for current and input that raster with the other remaining the same? Would I need to use USDA’s FIA to find a sequestration rate and apply it to the InVEST user guide equation?
What I really want to do is apply different LULC tree ages to account for this (as stated in the user guide) how would I do this with different LULC codes?
This is a VERY data poor region in SE Alaska so any help would be greatly appreciated!
A very stressed UCSB Graduate Student
P.S. I am a visual learner so any visuals would be AMAZING
It’s not unusual that the landsat data doesn’t capture enough detail to model your scenario accurately. You’ll need to make your own LULC classes to represent categories that are both relevant to your study, and have data available. For example, your biophysical table might look like
The spatial distribution of your LULC classes (i.e., a map of tree ages in the area of interest)
If this data isn’t already available, you may have to piece it together and make your own map.
The biophysical parameters for those classes (carbon in each pool for each tree age group) Note that it’s rare that separate data are available for all four carbon pools - just use the one(s) you can and set the others to 0.
You might also be interested in the other InVEST carbon models, though they aren’t directly applicable to your study:
Emily! Thank you so much! I was able to find annual sequestration rates in the USFS’s Forest Inventory Analysis (FIA) Database. They were located under “custom report” in the carbon change category (FIA you sneaky buggers). Using your example, I was able to reclassify the future raster and update the LULC carbon pool table by adding these values to the stored values and using everything else for an NPV of sequestered carbon. Emily, you are the GOAT.