Windbreaks in South Patagonia- Growh models, windspeed reduction and effects of shelter on crops

PERI P.L.; BLOOMBERG M.

AGROFORESTRY SYSTEMS

SPRINGER

Año: 2002 vol. 56 p. 129 - 144

0167-4366

In Patagonia, where strong winds are a constrain to agricultural production, live windbreaks are often planted in agricultural fields to protect crops, livestock, and soils from wind hazards. The major factors that determine the efficacy of windbreaks are its height, porosity, orientation, length, and location in the landscape. A review of the research on the effect of live windbreaks during 1993 through 2000 is presented in the paper. Porosity and distance from windbreak were found to have major effects on relative windspeed reduction. The greatest degree of protection was for dense windbreaks ( windspeed reduction of 85%) at 1H (1H= a distance of one tree height, leeward of the windbreak). Different crops showed a differential yield response to wind stress. The production of garlic (Allium sativum) was not significantly affected by wind. Tulip (Tulipa sp.) bulb yield decreased on average by 25% between 2H and 17H. The production of lucerne (Medicago sativa) at 1H was 40% higher than lucerne grown in open conditions. In contrast, strawberry (Fragaria sp.) and cherry (Prunus avium) were more sensitive to the effect of the wind. Dendrometric models (diameter, site index, volume and crown dynamics) were developed to define the wood potential productivity that could be expected from different site qualities. The prediction of height growth as a function of age, allows the estimation of the area protected by the windbreak. An economic assessment based on realistic estimates of shelter benefits is required to encourage the development of windbreak systems that could also offer other benefits, including erosion control and timber production.