"Windbreaks are planned and managed as part of a crop and/or livestock operation to enhance production, protect livestock, and control soil erosion. Field windbreaks protect a variety of wind- sensitive row, cereal, vegetable, orchard and vine crops, control wind erosion, and increase bee pollination and pesticide effectiveness.
Livestock windbreaks help reduce animal stress and mortality, reduce feed consumption, and help reduce visual impacts and odors. Living snowfences keep roads clean of drifting snow and increase driving safety. They can also spread snow evenly across a field, increasing spring soil moisture. " -- U. Missouri Center for Agroforestry
The video above provides a good overview of the impact of windbreaks in food production in Western countries, like the United States. In tropical countries, like the Philippines, the devastating impact of wind comes during the rainy season (between July to November), the season when typhoons and tropical atmospheric depressions develop. With climate change however, there were recent years when tropical atmospheric depressions develop as early as January and all the way December. Regions of the country that were frequently visited by typhoons have been ravaged by typhoons the past few years.
Typhoon Megi (Juan). Apart from the catastrophic of impact excessive rain pouring within a very short period (as much as 500-600 mm in 24 hours), a typhoon barrels through its path with wind speeds exceeding 100km/h. On 18 October 2010, the supertyphoon Megi (Juan) hit the province of Isabela directly with one of the highest wind forces associated with a supertyphoon. At its strongest, the highest wind speed was estimated at about 295km/h (for 1 minute) and 230km/h (for 10 minute) before landfall. While the wind speed generally slows a bit at landfall, Typhoon Megi (Juan) was still quite strong, with enough wind speed to destroyed so many houses, infrastructures, trees, crops, other vegetations through its path. It brought as much as 500mm of rain along the path of the typhoon. However, because the people along the projected path of the typhoon heeded the early warning and massive evacuation advisory from critical areas, there were only a few human fatalities in the country. An estimated 600,000 tons of palay (rice) was lost in the Philippines. The lost for other crops and livestocks were not indicated.
The economic cost of Typhoon Megi (Juan) destruction along the path of the typhoon was estimated at about US$709million (2010); US$255 million in the Philippines. The estimate of damages in the Philippines seemed rather low and this may be due in part because the regions directly hit were mainly rural communities. Had Typhoon Megi (Juan) hit Metro Manila and the adjacent densely populated and urbanized regions, the cost of damages in the Philippines would have been in the tens of billions of dollars (even more costly than Typhoon Haiyan (Yolanda) and significant numbers of casualties.
Typhoon Megi (Juan) drastically changed the perspective of the people in Isabela. Since then, most (even the many of the poor) had their houses rebuilt with concrete (cement), iron bars and galvanized iron. Ironically, while the houses protect people from strong wind force during the succeeding typhoons since Typhoon Megi (Juan), the rebuilt houses are essentially hot oven habitats, in the region with very high relative humidity (75-90%) and very high temperatures; in 2014, a temperature as high as 40oC) was recorded in Cagayan Valley, where Isabela is located.
On a more personal level, one of the Cadu farms that we propose to restore in our EcoCulture projects, once had about a thousand fruit bearing rambutan trees before Typhoon Megi (Juan); less than a hundred of the rambutan fruit trees survived the typhoon. The extent of such damages (in remote rural areas may not have been included in the estimated economic cost of damages brought about by Typhoon Megi (Juan).
Windbreaks - Design and Construction Considerations
Windbreaks and Forest Zones (WFR). The impact of supertyphoon Megi (Juan), with its double punches of excessive wind forces and massive rain (500-600mm in 24 hours) was highlighted here to emphasize that the windbreaks for tropical countries, like the Philippines must be built with the perspective to address the more unique conditions encountered in wet tropical countries, like the Philippines.
The predominantly long rainy reason (June to November; longer in certain regions or year round in a number of regions) is then followed by at least four (4) months of dry season. However, because of the high temperatures during later stages of the dry season, evapo-transpiration rate exceeds the total rainfall during the first rains of May and even June. The rainy season is also the season for the arrival of a number of typhoons that hit different regions of the Philippines. A longer or more intense rainy reason occurs during the onset of La Niña, while a longer dry occurs during the onset of El Niño. These conditions lead to flash flood, landslides, soil and water erosion during the rainy season, more severely during the onset of La Niña while the potential for drought is quite common during the dry season especially during the onset of El Niño.
Thus, for our EcoCulture projects, the windbreaks zones will be designed beyond what windbreaks are meant for, as outlined in the video. Apart from serving as windbreaks, they will be developed as micro-forest zones (akin to the tropical rainforest ecosystem) within the farm, as well as integral component of our rainwater harvesting and groundwater recharge strategies. These added functions are part of our long term goal to address the question:
How can the excess rainwater during the rainy season be harvested, stored, treated; and, then used during the long dry season for domestic purposes, farm irrigation, livestock husbandry and aquaculture?
Biodiversity. The proposed Windbreaks and Forest Zones (WFR) will be zones of biodiversity, unlike traditional windbreaks, there will be multiple rows and columns of trees with multiple and varying stories of tree canopies. Ecosystem intensification will include tall trees with under storeys of shade trees, shrubs and vines while the outer rows or columns with be plants of partial shade to sun loving plants, perennials and annuals. Deep rooted trees, shrubs and other plants will help anchor the WFR with thicker leaf plants protecting taller trees from high wind forces at the lower levels. Nitrogen fixing trees and plants will be integrated in the array to help provide nitrogen fertilizer.
Fast growing trees and shrubs will be integrated at the initial stages of the development of the WFR to accelerate its role as a windbreak zone. These fast growing trees will include coppice plants to allow regular and drastic pruning and avoid shading of the slow growing trees that will serve as the anchor (tall) trees in the mature WFR.
Flowering (Fruit bearing) Plants and Trees will provide the nectar and pollen to attract bees, other insects and animals, as well as provide source of food for many birds and animals. In turn, the harvested fruits will provide another source of diversified income for the EcoCultule farm.
Biopesticide resources. Trees like the Neem tree will be integrated in the WFR to serve as source of biopesticide. The leaves of the Neem tree are included in storage containers to mitigate postharvest damage from insect and microorganisms that attack or infest stored rice and corn. The leaves are ground and soak in water to extract a biopesticide juice used to spray in plant. Unfortunately.the biopesticide component is light sensitive so the spraying must consider this limitation when used.
Biological Pest Control. The biodiversity of the WFR will attract biodiverse groups of insects, birds and other animals and organisms as well as their own predators that will allow more biological control of pests that are part of any living ecosystem. The relatively undisturbed subsoil of the WFR will serve also as ecosystem for growth of soil and subsoil organisms and microorganism to improve soil health and help in biological control of pests.
The addition of water ecosystems, e.g., ponds, canals, swales, as well as riparian zones, will add another layer of ecodiversity in the EcoCulture farms, in turn introducing additional groups or organisms and microorganisms for more ecosystem approach to checks and balances of organisms and microorganisms that would otherwise become pests.
As much as possible, indigenous plants and organisms will be integrated in the development of the Windbreaks and Forest Zone (WFR). However, deep-rooted plants from reliable sources will be included to help anchor the WFR zones.
Beekeeping. When the windbreaks and forest zones are extensive enough, it may be possible to culture bees within the EcoCulture farms. The bees will be critical for pollination of many fruit bearing crops and trees, and have the added benefit as additional source of income (honey, wax, etc.)
Kahon-kahon. The term kahon-kahon is a Filipino term that may be considered to mean "to place in boxes". I encountered the term first use in water sequestration, akin to the ability of rice terraces to serve as thousands and thousands of micro-dams holding water from the top of the mountain all the base. When it rains therefore each "terraced box" has the capacity to hold more water up to the top of the packed bund or the height of the "micro-spillways" designed to let water flow from the upper terraces to lower levels -- the process repeated until the collected rainwater reaches the lowest terraced land before it spills over to the adjacent stream at the base of the terraced mountains.
While the rice terraces technology has been perfected thousands of years back, the rice terraces intricate and integrated (holistic) structure is one of the most efficient in rainwater storage at the surface as well as in water percolation to re-charge the underground water reservoir.
A similar "kahon-kahon" design will be adapted for our proposed windbreaks and forest zones (WFR) with some gaps to allow access to/from each segment of the EcoCulture farms. Unlike large area farms in the US (ranging from hundreds to tens of thousands of acres of land), the average farm in the Philippines may average in size of about 1-3 hectares or less.