Sci-Comm: Holt Research Forest S-10 Lines

Our S-l0 transects are l0m-wide strips that run the length of the "E" and "I" blocks (Fig. 1). On the S-10s, researchers have collected sapling and crown measurement data. Mapping and measuring tree heights and crowns on the S-10s allows us to better understand tree growth, including the role of regeneration trees within the system, particularly in response to timber harvests.

Figure 1. Map of the S-10 transects at Holt Research Forest study grid.

All saplings (trees 2-10cm in height) are tagged and recorded for species, DBH, condition, and location along the S-10s. Past inventories have been completed in 1986, 1989, 1995, 2003, and 2010. Our sapling mapping datasets include S-10 sapling data in long format, with one line per observation, and in wide format, with one line per sapling. 

Researchers surrounded by regeneration at Holt Research Forest.

Tree height and tree crown radii were also measured on all trees with DBH > 9.5cm within the S-10s. The measurements include crown radius distances in four directions, crown height, and live crown ratio, which can be correlated with shigometer readings from the same trees to assess tree vigor (Fig. 2). A shigometer is a portable device that measures electrical resistance. Trees with higher electrical resistance typically indicate reduced vigor or tree health.

Combining these measurements allows researchers to document the general size and shape of the tree crown and can provide insight into temporal and spatial changes in tree crowns. This information is particularly useful in harvested areas, where a response to harvesting by the remaining trees would be expected. 

Figure 2. Examples of tree crown and height measurements.

To learn more about these methods and to download the data, please visit https://www.uvm.edu/femc/CI4/holt.