Monthly Archives: December 2015

Garden archeology

Past garden manager, Carola, is quoted in Alcatraz’s Discovery film as saying the gardening is like ‘garden archeology’. Her words perfectly described the work of clearing vegetation and finding artifacts and landscape features that had lay hidden underneath ivy and blackberries for decades.

Her words are still very true today. The garden crew has been in over their heads clearing ivy from trees and uncovering terrace walls.

Volunteers clearing ivy from terraces. Photo by Shelagh Fritz

Volunteers clearing ivy from terraces. Photo by Shelagh Fritz

Using the Cultural Landscape Report for Alcatraz Island as a guide, permission was granted by the Park Service to clear overgrowth from known garden areas that no one had worked in since the prison closed in 1963. As part of the approval, garden volunteers and staff attended a lecture by National Park Service Archeologists, Leo and Peter.

Leo giving his presentation to garden volunteers. Photo by Shelagh Fritz

Leo giving his presentation to garden volunteers. Photo by Shelagh Fritz

With broad reaching strokes, Leo and Peter described their work across the park. San Francisco has a rich history with native settlements, missions, military history. Every time significant ground disturbance is done in the Park, this duo is on the scene. Some finds are accidents whereas others are known sites of interest. Leo described what to do in case items were found –

-take a photo with a point of reference in the background, not to zoom in on the object but give an easy way to find where the object had been found.

-fill out the paperwork that marks on a map where the object was found, and describe the item and the circumstances under which it was found

A key point was to distinguish between a single item found and a ‘feature’. A feature, as we now know, is considered a group of artifacts. In the case of finding a feature, the objects should be left in place and give Leo a call.

Barbara finding an intact bottle. Photo by Shelagh Fritz

Barbara finding an intact bottle and spoon. Photo by Shelagh Fritz

All of the objects found are taken to the Presidio archives where they are cleaned, recorded, and added to the collection. For garden artifacts, Leo has been marking the locations of the items on an overall map. Overtime, the pinpoint locations of objects give a big picture of significant areas, slow archeology in a sense.

Most people think of Alcatraz as only a federal prison, but the island has layers of history that equals the city of San Francisco, where the story of the gardens is woven throughout. Seeing the island through Leo’s eyes was really, well, eye-opening. Landscape features that we always walk by, were given an explanation, or at least a theory that made us all think – ah, that makes sense. For example, many parts of the island had a whitewash over the bricks, stone and concrete. The whitewash façade has fallen away in many areas, but the anchor holes of the façade remain.

Bolts holding whitewash facade in place along the Main Roadway. Photo by Shelagh Fritz

Bolts holding whitewash facade in place along the Main Roadway. Photo by Shelagh Fritz

Today, the holes look like planting pockets. We had always wondered about the evenly spaced shallow holes. They obviously weren’t big enough for a large plant with roots, or even to hold moisture during the dry summer. With Leo giving his theory of the holes being the anchor points, the holes suddenly made sense. By chance, the cliff below the Warden’s house is being stabilized with the addition of fake rock being anchored with long bolts – just like was done long ago.

Holes left behind by anchor posts for whitewash? Perhaps... Photo by Shelagh Fritz

Holes left behind by anchor posts for whitewash? Perhaps… Photo by Shelagh Fritz

 

One of the coolest objects found was an arrowhead several years ago, and another arrowhead showed up a few months ago. Leo explained that the arrowheads can be dated by using the fact that glass absorbs water at a specific rate for locations.

 

Other features of the island, are fun to speculate over – the bluestone found on the island is only found in a few locations around the Bay Area, Angel Island and Corte Madera. Not only did significant labour went into gathering the bluestone and hauling it to Alcatraz, but seeing it used for building reflects a known time period and a recycling of building material as well. Leo’s passion was evident as he said ‘some we will never learn but there is meaning in it all’.

 

Our take away lesson from Leo’s talk was to “overly thoughtful and nerdy about everything you find”.

Bluestone and bricks used to create a wall below the main roadway in Officers' Row. Photo by Shelagh Fritz

Bluestone and bricks used to create a wall below the main roadway in Officers’ Row. Photo by Shelagh Fritz

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Wrongfully Convicted – Life of a Banana Slug

Most gardeners hear the word slug and immediately have a negative thought about them being destroyers of their beautiful plants and I was guilty of this assumption too when I first heard banana slug.  In most cases they are a nuisance, but the Pacific banana slug (Ariolimax columbianus), along with its other two relatives, the California banana slug (A. californicus), and the slender banana slug, (A. dolichophallus), have a different role in the environment. Banana slugs are detritivores (decomposers) and thrive on dead plant material, mushrooms, animal droppings, moss, and leaves. They recycle these materials and help with the dispersing of seeds and spores as well as take part in creating nitrogen rich fertilizer. The dead organic matter they consume supports decomposition on the forest floors and aids in nutrient cycles.

Banana slug party on Alcatraz after the first rain. Photo by Caity Chandler
Banana slug party on Alcatraz after the first rain. Photo by Caity Chandler

Banana slugs are primarily found in the Pacific Northwest, ranging from southern California up to Alaska and are home to moist, temperate, forest floors.  They are the second largest slug in the world, reaching up to 10 inches (25 cm) in length and can live to be seven years old. They get their name because of their yellow coloring, resembling a banana, but can also take on dark spots or even become a little greenish. This is caused by a number of things such as their food consumption or the light or moisture levels they are exposed to and even the health of the slug. They have two sets of antennae that serve different purposes. The shorter set is used for sensory while the longer pair is used for sight.

Just a handshake today, no licking. Photo by: Shelagh Fritz

Just a handshake today, no licking. Photo by: Shelagh Fritz

One of banana slug’s unique characteristics is their slime.  Banana slugs are prey to raccoons, garter snakes, ducks, and geese, but their slime serves as an anesthetic to predators causing their mouth to go numb if they dare take a bite. The slime isn’t toxic to humans and people have been known to lick them to test the theory of the numbing sensation. I personally haven’t tried it, but know people that can attest to its factuality. Another benefit of the slime is its ability to help them retain moisture. Banana slugs are mostly water and are prone to desiccation. The slime actually helps attract water and has the potential to absorb up to 100 times the slugs water weight.  Slime also supports the banana slug’s mobility in navigating through the forest, gliding over dirt, leaves, and other debris.

Love at first sight. Photo by: Shelagh Fritz

Love at first sight. Photo by: Shelagh Fritz

Being new to the West Coast, I was unfamiliar with the banana slug’s positive influence on the forest floor and contribution to the soil. I thought they were a nuisance to the garden and plant life similar to other slugs, but in fact they are an important aspect of the ecosystem assisting in decomposition. The banana slugs still remain happy, innocent, inhabitants of the island. I was very excited the first time I spotted one and after I saw one, I must have seen 30 that day. Keep your eye out for these cute little guys on moist days and appreciate their positive impact in our beautiful forests. Hugs for slugs!

 

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