Habitat Management Units

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Green Seattle Partnership splits each park into different zones called “habitat management units” (HMUs). This allows GSP to assign different target forest types and reference ecosystems to the different HMUs, and the forest stewards to use techniques and approaches best suited to each HMU.

North Beach Park is split into 11 HMUs; nine of these are discussed in this document. The other two are only accessible by crossing private property lines.

The HMUs were delineated by Nelson Salisbury and Ella Elman when they mapped North Beach Park for EarthCorps in late summer of 2011. The names of the HMUs were decided by the forest stewards. All of the names are descriptive in some way.

The HMUs in North Beach Park are based on two basic characteristics: slopes and uplands, and wetlands. There is some mixture in that all the wetland areas contain some upland slopes, and the upland areas frequently contain some seeps or wet areas in their lower regions.

Within these two divisions, slopes and uplands are assigned their name based on nearby property (ie, Fletcher’s Slope is below Fletcher’s Village; 91st St. Slope is below 91st St.; 92nd St. Wetlands is below 92nd St.), characteristics (the South Plateau is the largest flat area of the park and 80 feet above the rest of the park), or aspect (South Slope, West Slope, North Slope). The Headwaters Bowl is where the groundwater enters the park and begins to form the stream; the Central Valley is in the middle of the park.

Each of these HMUs received a reference ecosystem at the time of mapping, based on broad category of the plant species seen. There are two reference ecosystems for NBP: “mesic-moist conifer and conifer-deciduous mixed forest” and “riparian forest and shrubland.” These are based on NatureServe classifications.

The table below shows the nine HMUs discussed in this book sorted by size, and listed with their target forest type and reference ecosystem. The target forest types are explained in “Target Forest Types,” next week.

Name	Size	Target Forest Type	Reference ecosystem
Central Valley	1.97	ALRU/RUSP/CAOB-LYAM	Riparian forest and shrubland
Headwaters Bowl	1.39	ALRU/RUSP/CAOB-LYAM	Riparian forest and shrubland
North Slope	1.14	TSHE-PSME/POMU/DREX	Mesic-moist conifer and conifer-deciduous mixed forest
West Slope	0.84	TSHE-PSME/POMU/DREX	Mesic-moist conifer and conifer-deciduous mixed forest
South Slope	0.76	TSHE-PSME/POMU/DREX	Mesic-moist conifer and conifer-deciduous mixed forest
92nd St. Wetlands	0.69	THPL-TSHE/OPHO/POMU	Mesic-moist conifer and conifer-deciduous mixed forest
South Plateau	0.57	TSHE-PSME/POMU/DREX	Mesic-moist conifer and conifer-deciduous mixed forest
91st St. Slope	0.54	TSHE-PSME/POMU/DREX	Mesic-moist conifer and conifer-deciduous mixed forest
Fletcher’s Slope	0.53	TSHE-THPL-ACMA/ACCI/LYAM	Riparian forest and shrubland

The Central Valley, Headwaters Bowl, and 92nd St. Wetlands are all primarily wetlands and are discussed first. The other six HMUs are primarily uplands and slopes and are discussed after the wetlands. Within each category, the HMUs are discussed in the order of greatest amount of restoration effort they have received.

Mirrored from Nature Intrudes. Please comment over there.