October 6th, 2014

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Monitoring Protocols

Green City Monitoring Protocol

In order to evaluate progress, Green City Partnerships have established a set of forest monitoring protocols to be used in Green City restoration sites (Green City Partnerships, 2012).

This protocol establishes a 1/10 acre circle in an area just before restoration begins. The location of the plot is recorded by the GPS coordinates of the center of the circle, walking directions from the entrance to the park or a nearby major landmark, and the bearing of at least two reference objects from the middle of the circle.

The circle is split into four quadrants, and the following data are collected:

  • Height, DBH (diameter at breast height), species, and health of trees.
  • Percent cover of all shrub and undergrowth plants, native or invasive.
  • Snags and coarse woody debris, grouped into three decay classes.
  • Basic site characteristics, such as slope, aspect, soil compaction and moistness, canopy cover, general habitat type.
  • Photographs of the monitoring site are taken at the cardinal directions (Green City Partnerships, 2012).

Percent cover is usually decided by consensus of the people working on the plot, and is reported in broad categories (i.e., “1-5%,” “6-15%”) to standardize data recording across the city.

The first report establishes a pre-restoration baseline. Ideally, the plot would be visited once a year for three years during the same month of that the baseline was taken. Budget and logistical constraints make that infeasible. After the fourth visit, monitoring drops to once every five years.

Green City forest monitoring is a citizen science project. The volunteers are knowledgeable about native plants, or taking the opportunity to learn more. Many of the volunteers are forest stewards themselves.

A practical minimum for this monitoring protocol is three people: two observers and one recorder. A good number is five, which has one observer in each quadrant and one recorder. Larger groups don’t make the process happen faster, but do make the observations more complete.

The data is entered into a web form, and at the end of the summer, summary reports are sent to the monitoring team and the forest steward. GSP uses this data to assess restoration progress and to assign restoration phases to a restoration site (which is generally a subset of a Habitat Management Unit).

North Beach Park has three official forest monitoring plots, one each in the South Plateau, the Headwaters Bowl, and the Central Valley. These plots were initially established in 2012 and revisited in 2013. Two more plots, each 1/2 the standard, in the Central Valley and the 92nd St. Wetlands, were established as training exercises for an Edmonds Community College class in 2013.

The data from these reports is discussed in the “South Plateau,” “Headwaters Bowl,” “Central Valley,” and “92nd St. Wetlands” sections.

Belt Transect


In June, 2014, forest stewards and volunteers performed a cross-gradient belt transect of North Beach Park, following the 90th St. right of way (see below). This area for the transect was selected because it crosses every gradient of the park, from highest to lowest, and three habitat management units: the West Slope, the Central Valley, and the North Slope. It is also the only cross-gradient transect route that stays completely on public property.

On the West Slope, 4’ square plots were established; in the Central Valley and the North Slope, the plots were 4’x16’. The plots were established every 40’ on alternate sides of the transect line, and situated 2’ off the transect line to avoid trampling. For each plot, we listed species found and percent cover. Per cent cover included mature canopy trees leaning over the plot. The transect provided data for comparing the unrestored state of the areas transected to their target forest types and target ecosystems. Although we were unable to take accurate GPS readings, the transect is still replicable given the definition of its space.

The green lines indicate park boundaries. The 90th St. Right-of-Way is the gap between the southern and northern halves of the park. Red lines indicate habitat management unit boundaries. (Source Green Seattle Partnership Reference Map on arcgis.com.)

The green lines indicate park boundaries. The 90th St. Right-of-Way is the gap between the southern and northern halves of the park. Red lines indicate habitat management unit boundaries. (Source Green Seattle Partnership Reference Map on arcgis.com.)


In advance of the main survey, a transect line was established by two volunteers. Waypoints were established at intervals dictated by visibility and varied from 105’ to 16’. The line was maintained using a compass.

The transect itself was done by seven volunteers. Three worked in advance of the sampling, setting up the plots. On the West Slope, because of its steepness and dense herbaceous cover, two plots, four square feet each, were set up. In the Central Valley, nine 4×16’ plots were set up. On the North Slope, eight 4×16’ plots were set up. Each plot alternated sides, and was two feet away from, the transect line. The plots were spaced 40 feet apart.

Two people did the plant identification, with one person making the decision about per cent cover for efficiency and consistency. A third person recorded all the details.

The last person recorded GSP data using the smartphone app GPS Test, version 1.2.9, by Chartcross Ltd. However, the nature of working in a ravine and the inaccuracy of the phone made this data unreliable. Despite this, given the definite boundaries of the route, we think we can replicate the transect.

The belt transect provided a wealth of data in comparison to the circle method of forest monitoring. We were able to compare results across eight plots in the Central Valley and nine on the North Slope. These results suggested methods for invasive removal and further monitoring based on the status of the areas transected. However, the logistics involved in preparing for the transect, and the size of crew necessary to implement it, make it much more difficult to execute than the circle method.

The data from the belt transect is discussed in detail in the “West Slope,” and “North Slope,” and the “Central Valley” sections.


Green City Partnerships. 2012. “Monitoring Data Collection Methods.” Green City Partnerships, Seattle.

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