Tree planting: Preventing Erosion

Brief Description : Students learn about the role of trees in preventing erosion and plant a tree by the creek.

Objectives :

Students discuss what lives in a creek and how detrimental sedimentation can be to habitat
Students discover the importance of having trees on creek banks through a kinesthetic game
Students have the opportunity to work together to proactively prevent erosion through tree planting

Materials : Tree seedlings (contact your County Soil and Water Conservation District), shovels, buckets for mulch and water.

Getting Started / Procedure -

Begin by asking students what lives in a creek. If students do not come up with “insects” as an answer ask them what fish eat. Why are insects important? Discuss the food chain. Sedimentation of soil is the number one pollutant of Western North Carolina creeks and rivers. Discuss how soils can erode from farms, construction sites, creek banks without trees and the soil settles down stream, blanketing rocks and other habitat for small critters in the creek. After discussing the problem ask students what we can do about it. If or when planting trees is brought up discuss how tree roots help to stabilize creek banks and hold soil in place.

Outside game - Explain to students that there is a creek here at school (use a rope or other materials to designate where the fictional creek is) and we are going to try to protect it from pollutants (review what that might be – eroding soil, lawn chemicals, oil from parking lot, etc). “Plant” to students as trees in front of the fictional creek. Explain that once trees are planted they can not move, these students have to stay in one place and can only spread out their roots (arms). Designate boundaries on each side of the trees, about 25 feet apart. The rest of the students in class are water droplets. There has been a huge thunderstorm and these water droplets have run across exposed soil and lawns and parking lots. Picking up soil particles, chemicals and oil on their way to the creek. The goal is for the water droplets to get to the creek without being tagged by the trees. If anyone is tagged they have to freeze where they are. Count to three and have the water droplets rush to the creek. Ask students if two trees were able to protect the stream from erosion (no, water droplets got to the creek easily). Plant several more kids between the boundaries and have the water droplets try to get though again. Plant more kids each round until there is not any space for water droplets to get through to the creek. Talk to students about how this illustrates how a creek needs a lot of trees to project it from erosion.

Have flags or markers of some sort to designate where students should plant their trees. Walk students through basic tree planting – dig a hole (providing extra space for roots to grow), put tree in and bury roots with soil (stress the point that only the roots should be under ground – if the stem of the tree is buried it will rot), mulch all around the tree a few inches thick (but not up close to the stem), and water the tree.

It is best to plant trees in the fall, but if that is not possible make sure they are watered regularly (at least once a week for the first month or two).

Extensions:

Students write about what they did and why
Students make posters to encourage others to plant trees – including how trees help prevent erosion
Students write a story about a conversation between a creek and the trees on its bank
Math extension – have students measure an area of creek and figure out how many trees it would take to cover the whole length of the stream if they were planted 3 feet apart.