Georgian Court University

Home Up Dune importance Permits Dune Preparation Trees and Fences What to plant where Assessing Plant Quality When and how What not to plant Amendments Planting to harvest Vendors Funding DuneItRightPresentation More Information

Trees, Fences and Geotubes

Christmas trees, dune fences and cedar shims are generally effective ways to promote dune growth. The idea with all of these is to provide a mechanism for slowing the wind to encourage sediment deposition, which mimicking the role of natural dune vegetation.  Dune fencing, cedar shims and Christmas trees can be effective ways to jumpstart dune formation in seasons where planting vegetation isn't possible or during the time where the vegetation is still getting established.  Fences can also be a useful way to prevent sand from blowing into the street.  (Photo credit: Friends of Island Beach State Park via facebook)

When installing dune fencing, its important that the fence not be used to restrict legal access to the beach.  Installation of dune fencing is permitted when it is used to control sand but is not allowable when used for defining boundaries.  With fences you can also control the geometry of the dune to some degree by encouraging either vertical or horizontal growth. Some great information on how to best use sand fencing to build dunes is available here.

Christmas tree dune restoration at Island Beach State Park during the Waves Of Action clean upThe Christmas trees should be placed at the base of the dune, and commonly are placed with the tip facing the ocean and trunk landward to maximize surface area for sand collection. However, laying them in a shallow trench parallel to the shore is also a common practice. Whatever you do, though, please don't put the trees on top of vegetation!  They should be placed in front of the vegetated part of the dune to grow the dune forward from its current position. The trees usually gather sand relatively rapidly resulting in their burial.  However, they should be monitored in case later erosion exposes them once again.  One of the reasons that use of Christmas trees went out of favor in the past was over concerns that the exposed dead trees and brush might prove to be fire hazards. (Photo Credit Clean Ocean Action via facebook)

Another strategy that is is sometimes employed to help make dunes more stable is installation of geotubes or similar structures at the base of the dune. Geotubes are typically filled with a water and sand mixture (slurry) typically on sight. The mixture is pumped into the tube or casing and the water is expelled through the porous fabric, while the sand remains. When filled, the tubes are very solid. The fabric is designed to withstand puncture so they generally stand up well to debris impact and vandals. This can work well if dunes continue to collect sand and grow.  However, care needs to be taken that if the tube is exposed it doesn't roll out of place. Also, if the geotube becomes exposed routinely, it essentially acts like a seawall and can increase erosion. As a last line of defense or a jump start to a large dune, such structures may be a useful tool for dune managers, but maintenance of the beach in front of the dune is important if they are to be effective on the longer term. (Photo credit Brick Patch)


Content for these pages was contributed by Chris Miller, Jon Miller, Michael Peek, Ray Bukowski, and Louise Wootton.  Edited by Louise Wootton.