Daniel Larson

Dr. Michael Wulder presented what seemed to me a quite hopeful message.  His presentation focused on how we can use satellite data to quantify the return of forests following wildfire/harvest.  To begin, Dr. Wulder talked about how he had used LiDar data to complete a project, and one of the reviewers asked why he didn’t just use LandSat data, which is free.  For the type of work he was doing, LandSat data offered enough resolution.

Dr. Wulder then went on to the topic of change detection.  With forests, up-to-date information is needed.  He explained that people often make the mistake of assessing forests as they were several years ago.  Forests will regenerate and change over time and the process is not black and white.  For example, you cannot classify a forest as “recovered/not recovered” because there is a continuum.

I liked Dr. Wulder’s point about changing the way we classify forests.  In some regions, trees are not able to grow taller than 5 meters.  Instead of classifying the trees as less than/greater than five meters, they will assess the capacity of the trees in the area to grow taller than five meters and then assess the area.  I also found it a strikingly short time before forests were “recovered.”  In some regions, he said it took only five to ten years.

I also found his Composite2Change (C2C) and Years to Recovery (Y2R) applications intriguing.  We learned that recovery rates were higher in the south where trees grow faster, and trees are harvested more down south.

I don’t claim to know much about forestry, but I wonder how “recovered” these forests really are.  I assume forests return to their natural state after a wildfire.  But when humans clear cut a section of forest and replant, it seems difficult to reproduce the variety of plants that were originally on the landscape.  I wonder how well Dr. Wulder’s LandSat imagery can pick up on the diversity of plants, especially smaller plants.  I can agree these GIS programs can work well for assessing how well the canopy layer has rebounded.  But, I would argue that you cannot assess a forest completely until you have the “ground truth.”

However, I think this dataset can be used for a variety of applications, including climate change models assessing global carbon storage of our forests.  It is also helpful to assess change in the landscape.  His change detection models from the 1980’s until today were very interesting and could have a variety of applications.  Overall, I would agree this satellite data could be used for an overall picture of trends and regional analysis.  However, assessing a single forest’s health needs greater detail.