Silviculture and management in relation to risk of windthrow in Northern Ireland.

  • R.F. Mackenzie Forestry Division, Department of Agriculture, Belfast.
Keywords: Wind, gley soil, damage, geology, exposure.


In producing a windthrow risk assessment chart the object has been to provide a rational means of deciding what management principles are best suited to any particular site. The degree of risk predicted refers to damage of the kind that can occur under ordinary circumstances. There are many factors involved in the assessment of wind risk, only some of which are included, and changes in the value of one may alter its relative status with regard to others. Those used are broadly assessed and capable of substantial refinement. For example the gley soil group includes humic gley which is more windthrow prone than gley with a well developed eluviated horizon. Some of the effects are indirect, for example 'geology' combines the effect of land form and exposure, and is also related, by chance, to changing wind speeds over the country. Of the wind itself, its speed, gustiness and turbulence, very little is known, although there are indications that storms may follow a cyclical pattern with 4 or 5 years of high winds being followed by 6 or 7 quieter years, within an 11-year cycle. The guide must be used with this background in mind and results interpreted and applied in the light of local knowledge and experience.
How to Cite
Mackenzie , R. (1976) “Silviculture and management in relation to risk of windthrow in Northern Ireland.”, Irish Forestry. Available at: (Accessed: 29May2024).