Tuesday, October 18, 2016

Senescense: Why leaves change color

Here at Sierra Outdoor School we have few large trees that provide the bulk of our autumn color: black oak, big leaf maple, and Pacific dogwood. All of these trees are deciduous - meaning that each year they shed all of their leaves, remain leafless for a period of time, and then grow all new leaves. The process where the leaves prepare to fall from the tree, or the cells gradually deteriorate as they age, can be referred to as senescense. During this process of senescense, the pigment levels in the leaves change producing the much awaited fall colors.

Pacific dogwood leaves changing along the ditch trail at S.O.S.
The change in day length and temperature signals deciduous trees to begin the process of senescense by first sending any nutrients available in the leaf to other parts of the tree. The next step is to breakdown chlorophyll, the pigment that gives leaves their green color and allows for photosynthesis to occur. As the dominant green pigment slowly disappears, other colors are revealed: yellow, orange, red, and purple. After the chlorophyll is gone, the other pigments will breakdown. At the same time, the cells of the leaf stem are changing so that the leaf will eventually fall off the tree and leave a sealed, leaf scar behind.

Unusually colorful black oak leaves at S.O.S.
In addition to light and temperature, water availability also helps to determine the intensity and duration of the fall colors. If you live in an area with maple, dogwood, and sumac trees they are known for their bright red and orange leaves. These colors are at their peak when temperatures are low, yet above freezing, and also after an early frost. While less intense colors are created from rainy and overcast weather. These photos were all taken along the ditch trail here at S.O.S. Wherever you are, we hope you take the time to enjoy these beautiful changes around you!

Big leaf maple leaves in various shades of yellow

If you'd like to learn more about autumn colors, check out these reference pages:




Wednesday, October 5, 2016

Where are they now...2015-2016 SOS Naturalist Interns?

Every year SOS says hello and goodbye to some great Naturalist Interns. This post is dedicated to the amazing people from the 2015-2016 school year. Let's see where they are now!


Andrew Martin (Summit)

Andrew is enjoying teaching children in the outdoors at Sierra Outdoor School as a Naturalist. He loves living and working in the mountains and SOS is the perfect place for him. He is excited about his new roommate, Juno, his puppy, and about learning and working with the SOS raptors.  


Beth Thompson (Owl)

Beth is working at Glen Helen Outdoor Education Center in Yellow Springs, Ohio, as the Program Coordinator Administrative Intern. She is communicating with the schools prior to their arrival to gather information for their visit to the OEC. She also develops the schedule rotations for the naturalists. As one of three administrative interns, she mentors a third of the naturalists and provides input and advice on their lesson plans and teaching techniques. While her position does not require that she works with any of the birds from the Raptor Center, she is putting in the time to handle an Eastern Screech Owl right now!

Emma Ervolina (Glacier)


Emma is working as a Naturalist at Greenkill Outdoor Education Center. Greenkill is a branch of the New York City's YMCA. She teaches anyone from elementary to college folks about the diverse flora and fauna on their 1,150 acre forest.

Karl Koehler (Jellyfish)

Karl is working at Catalina Environmental Leadership Program on Catalina Island. He gets to go sea kayaking and snorkeling all the time with kids and loves every minute of it.


Laurel Marks (Peregrine)

Laurel is working as a Naturalist in the beautiful coastal redwoods at Mendocino Outdoor Science School. She lives in a yurt among the giant trees and takes kids hiking in an old growth redwood forest that's 1,400 years old, to explore the tide pools, and on a fun challenge course. In November she is off to Australia, New Zealand, and Bali to teach Outdoor Education

Lizzie Hoerauf (Salamander)

After leaving SOS, Lizzie had a wonderful road trip back to Virginia. The highlight of it was hiking the Grand Canyon from the rim to the river and back in one day - 18 miles and totally worth it. She spent the summer working for Friends of the National Zoo at the Smithsonian Conservation Biology Institute as an educator at their residential Nature Camps. She had a blast hiking along parts of the Appalachian Trail with the campers while learning about the Smithsonian's breeding efforts for highly endangered species. After a great summer, she made her way out to Minnesota to begin her Naturalist Fellowship at Eagle Bluff Environmental Learning Center.

Madeleine Burke (Trillium)

Madeleine is working in the beautiful Yosemite National Park as a Field Instructor for Nature Bridge - Yosemite. She is having a great time exploring the park and surrounding areas while taking kids on all sorts of adventures. 

Stephen Ligtenberg (Monkey)

Stephen is in the middle of a three month European tour. He started in the Netherlands and since then has traveled through Germany, Denmark, Sweden, Finland, and is currently exploring Estonia. His photo is from Nimis, Ladonia. Ladonia, an independent micro-nation on the west coast of Sweden, known for its life sized drip castles and driftwood structures. In the next couple of months he will travel through Germany and Poland and then various countries in southeastern Europe. He is currently participating in the Adidas Sickline Whitewater Kayaking World championship in Austria.