Structure Condition Services Stressors
While assessments of mature trees provides information about the current condition of Vermont’s forests, densities of sapling give details about the likely softwood composition in the future. Softwood regeneration is a measured as the density of seedlings per acre, inventoried annually on Forest Inventory and Analysis (FIA) plot data. Per FIA protocol, plots are reassessed every 5 years until 2014, and then every 7 years since then. A softwood seedling is classified as a small tree less than 1" in diameter1. Here, a dominant component of the Montane Spruce-Fir Forest, and an ecologically and economically important species, red spruce (Picea rubens), was used as a proxy for all softwood species regeneration. These red spruce regeneration estimates are from Spruce-Fir Forests where we would expect to find red spruce seedlings. The current year is scored for where it falls between zero and the target, scaled to be between 1 and 5.
The score is calculated using a target value and the historical range of the the entire long-term dataset. The higher the score, the closer this year's value is to the target.
Once the score is computed for each year, the trend in scores over time is calculated. If the trend is significantly positive or negative, the long-term trend is marked as increasing or decreasing respectively.
Distance between 0 and the data maximum (scaled 1-5)
Data maximum + 10% of the range
|Directionality of scores||
Higher values in the data are better
|Minimum value used in scoring||
|Maximum value used in scoring||
Data maximum + 10% of the range
We collected counts of red spruce (Picea rubens) seedlings per subplot in the Forest Inventory and Analysis Phase 2 plots via the FIA EVALIDator1. The first year of available data is 2003. A softwood seedling is classified as a small tree less than 1" in diameter and greater than 6" in height2. We averaged seedling counts over all sampled subplots of spruce-fir forests per year and scaled this number to the acreage of a subplot (0.25 ac.) to compute a density value (seedlings per acre). Per FIA protocol, plots are reassessed every 5 years until 2014, and every 7 years after that. To compute the annual score, we used 5-year leading edge moving window (i.e., data reported for 2007 used 2003, 2004, 2005, 2006 and 2007) until 2014 when we switched to a 7-year leading edge moving window per FIA protcol2. The target for this dataset was set to the maximum value plus 10% of the range. The current year is scored for where it falls between zero and the target, scaled to be between 1 and 5
Forest cover is the percent of the state of Vermont with tree cover.
Regeneration of sugar maple seedlings provides information about the future of Vermont's hardwood forests.
Regeneration of red spruce seedlings provides information about the future of Vermont's softwood forests.
Forests with greater stand complexity have trees in a range of sizes and as a result, may be more productive and resilient to stress.
Forest patch sizes provides information on the average size of contiguous forest blocks.
Forest connectivity is a measure of the linkages among Vermont's forests.
With greater diversity in tree species, forests can support more biodiversity, exhibit higher resilience to stress, and store more carbon.
Across the landscape, having a range of forest stand ages provides diversity, varied habitat conditions, and resilience to stressors.