WNPS Native Plant Steward

Friday, August 28, 2015

August 19th Work Party

Another month and another work party.  Thanks to all the volunteers that showed up to pull himalayan blackberry (R. armeniacus) from the site.  Also I great big thanks to the City of SeaTac Parks Department for giving us a head start by mowing a large part of the site!


The mowing allowed us to get right to digging out the root balls, and laying some cardboard and mulch.  Stewards were also onsite doing some herbicide treatments on the English holly, Cherry laurel, and Black locust stumps.  Frilling was done on the stumps of these species to prevent further new growth from spawning from the stump and near by soil.

Two volunteers clearing root balls

All told we were able to treat over twenty stumps and clear/mulch 400 square feet.

Cleared and mulched area

Hoping for even more volunteers to help finish up the last of the clearing so that we can get to the fun part and begin planting this October.  If you, or anyone you know, wants to volunteer your time please contact the Stewards at seatacstewards@gmail.com. We will be having another work party on September 20th at 9 AM.

Picking Plants for Restoration Part 3: History

Ever wonder why certain plants are used in restoration work and not others?

Many factors are looked at when picking plants for any project; what kind of soil, how wet the soil stays during the year, and what plants are already thriving on the site.

This post will cover how what is already at a restoration site, or what historically was there, can help determine what plants will be included in a restoration plan.

When taking inventory of a restoration site a site map will be compiled to inventory what plants are already present on the site.  Much like the one below that was composed when work first began at North SeaTac Park.

Site Map for Current Conditions.jpg

By looking at this inventory we can see what kind of mature plants are growing on the site and if any of them are natives.  If there are natives plants growing on the site we can identify other natives plants that are known to grow with those already on the site, or are known to like similar growing conditions.  The image above lists native plants already found on the site: Western Red Cedar, Douglas Fir, Snowberry, Indian Plum, and Sword fern.  These species give us clues that will allow us to pick other species that might do well on the site.  

When a site has no plants, or where native are not present, planners can research what historically grew on the site.  By using historic documents from Native American interviews or settler accounts planners can reconstruct the native plant community that previously existed.

Thursday, August 13, 2015

Picking Plants for Restoration Part 2: Wetness

Ever wonder why certain plants are used in restoration work and not others?

Many factors are looked at when picking plants for any project; what kind of soil, how wet the soil stays during the year, and what plants are already thriving on the site.

This post will look at how the wetness of a site helps determine what plants are used in restoration.

It is one thing to know how well soil will hold or drain water around a plant, it is another thing to know when to expect the water and how much will come.  In the Pacific Northwest we receive a large quantity of our water from the Fall through Spring.  Summer can be downright parched.  For this reason it is good to know what a restoration site looks like all year round before determining what plants to include.

Some restoration sites may retain water year round and others, like North SeaTac Park, may be moist during the winter but dry during the summer.  These differing levels of moisture through the year are caused by a combination of rainfall and soil composition.  Knowing the moisture profile of the site allows planners to determine if they need drought resistant or aquatic plants for their restoration.  In some cases a mixture of both may be needed.

Another factor to consider is how the tree canopy might affect the amount of rainfall actually hitting the ground. A dense canopy could mean little to no rain reaches the understory. We soon realized this might be the case at some portions of our site at North Seatac Park because even in rain some areas could stay relatively dry. If this is a really big concern, manually watering plantings should be considered. Fortunately, for us in the Pacific Northwest even in the dry years we still get downpours in the winter that get passed the canopy and give our plants a good drink!
Knowing the moisture level of a site all year round also determines the best times to plant.  Planting in late Autumn and early Winter, when plants are hibernating and will be exposed to large amounts water, is the best way to give plants the best start at a new location.  This keeps the plants from being too damaged from transplanting and also exposes the roots to water for a long time allowing them to establish before the Summer heat arrives.  Ideally the plants would be watered through the first, and possibly second, Summer to help further establish the roots and increase the likelihood of survival However sometimes it is not possible to manually water a restoration due to size,location, or resources.  This means choosing plants that are best suited to the sites conditions is extremely important to the success of the restoration project.