The use of living fences in the Central American region is prolific. Although installation techniques and application style of living fences varies across borders and climates, in Costa Rica the fences generally serve to delineate property and keep livestock within a boundary. Aside from their obvious uses, living fences generate far more benefits, both ecological and economic, than are typically noticed at first glance. Through careful selection of species and well planned maintenance, living fences can assist in boosting crop yields, generating animal forage, increasing soil fertility, producing food, stabilizing slopes and establishing microclimates, among myriad other benefits. This article seeks to focus on the methods used at a specific Costa Rican site, CIRENAS (Centro de Investigaciones de Recursos Naturales y Sociales), to establish living fences.
CIRENAS is a Costa Rican educational and research institute that focuses on generating models for living that can be replicated on a local and regional scale. To these ends, CIRENAS focuses on permaculture and appropriate land and structure design for the region. The area surrounding the site is highly influenced by the cattle culture typical of much of Central America, and has been for many generations. Because of the pattern of large animal movement over broad, sloping terrain in a region that has a heavy rainy season, much of the land has been unintentionally abused. Problems such as erosion, loss of nutrients, poorly managed water resources, and more are easily visible across the landscape. In an effort to repair the damaged landscape of the CIRENAS site, which is located on generations old sloping cattle pasture, living fences have been installed as a base line model for regional use. Other regenerative methods are actively being used but will be covered in a future article. Although living fences are already a known quantity, the CIRENAS fences have been planned in such a way that their benefits go beyond simply controlling animal movements. Constructed using techniques identical to those practiced by the local populace, CIRENAS was able to maintain the local skill set and amplify the benefits using a few basic changes.
Living fences are installed in Costa Rica using live cuttings of locally available species. Cuttings are typically taken from trees at a size of 3cm-8cm in diameter, and cut to roughly 2m in length. Depending on the area where the fence will be installed, timing of planting cuttings can be influenced by the season. Dry season plantings can struggle to survive if not close to a water source.
(1) Timing and placement of species is heavily dependent on characteristics of species and the local resources available.
(2) Cuttings are planted to a depth of roughly 20 cm. Spacing or placement of the cuttings can vary based on the desired use of the fence or the existence of already placed posts. Spacing can be as little as .5m or as much as 4 or 5m.
Often times posts that have been milled, or “dead” posts, are used as stabilizing posts between living cuttings. Although more costly, many farmers prefer these posts because they are guaranteed to hold. If a live stake does not take, a farmer can be left with a gap in his fence, potentially allowing for livestock to roam freely. Costa Rican living fences typically employ barbed wire to connect posts and live stakes, insuring that animals cannot move through the fence while stakes are establishing. Readily available and inexpensive, barbed wire is well known to the local populace and ubiquitous in cattle regions. Application of already popular materials, albeit in a slightly different manner, is key in gaining the understanding of local populace. This trend can be seen across the spectrum of sustainable development efforts.
At the CIRENAS site, four species were predominantly used. The goals of the fences were many, and placement of stakes reflected the desired outcomes for the fence. Like most others, the fence was primarily made to keep livestock out. Additionally, the CIRENAS fence needed to stabilize slopes, fix nitrogen, offer shade, provide fodder, provide more fence material, produce fruit, attract local bird and animal species, and generate biomass. With these parameters in mind, the following species were selected: Gliricidia sepium, Spondeas mombin, Bursera simaruba and Pachira quinata.
Planted at 1m intervals, the stakes were alternated to spread the benefits of each species across a large distance. Nitrogen fixing Madero Negro was the most prominent species used as it is most readily available and grows the most quickly with the most success (2). Planted towards the end of the rainy season, the goal was for live stakes to establish themselves prior to the dry season. Over the course of several months, growth was monitored visually. After ten weeks, visible growth was recorded on 87% of live stakes planted. Living fences provide habitat for over 160 (2) types of local and migrating birds, insects, and animals, and serve as a major boon to the local ecosystem. In the months and years to come, all of these species will provide additional fencing material at some interval. Many of the new trees will take a coppice pruning technique, creating green mulch, putting significant nitrogen(3) back into the soil and offering a varied profile of tree heights (wind breaks etc…) depending on the location of the tree. Food and fodder production will be enhanced as soils improve, and fruit and nut trees within the CIRENAS campus will benefit from the pollinators that are drawn and housed within the living fence. Lastly, the fence will keep cattle from neighboring properties from grazing on lands that are out of rotation.
Although most local farmers employ methods very similar to those used by CIRENAS to create fences, slight variation in the spacing or selection of species could potentially yield significantly more positive effects for both farmer and landscape. Unknowingly, farmers installing living fences have often times lend a significant hand to reforestation and soil improvement efforts, not to mention creation of habitat. For more information on CIRENAS, please visit cirenas.org or contact Sam Kenworthy at firstname.lastname@example.org
- Zahawi, R.A. Establishment and Growth of Living Fence Species: An Overlooked Tool for the Restoration of Degraded Areas in the Tropics.
- Binkley, D. and Giardina, C. Nitrogen Fixation in Tropical Forest Plantations.
- Dreyfus, B.L., Diem, H.G., Friere, J., Keya, O., Dommergues, Y.R. Nitrogen fixation in tropical
By Sam Kenworthy
(Source: The Permaculture Research Institute; February 6, 2015; http://tinyurl.com/qjca2y8)