Strong winds can result in tree uprooting (windthrow, the most common one) and/or breakage (windsnap) causing considerable damage and leading to major financial losses for forest owners. The annual loss to the forest industry due to windthrow is estimated at approximately €1.3 million. Damage to timber is one of the main consequences of storm damage. Fitzpatrick determined that during the period 1971 to 1998 15.1% of the total volume of timber sold was windthrow timber. One key issue is that after major storms the price of timber often falls arising from an oversupply of timber onto the market and/or a reduction in the quality of the timber salvaged.
The current approach to understanding and managing these factors in Ireland follows a two-pronged approach. Firstly, attention is focused on the management of tree stability through cultivation techniques aimed at promoting tree stability, and secondly, via an empirical model which relates tree stability to site factors and wind induced forces to predict the probability or occurrence of windthrow. Whilst much success and progress has been achieved through these approaches, these methods have limitations in that they have been developed based on general wind conditions and represent endemic windthrow in forest stands. Therefore, their usefulness to quantify the effects of severe winds and storms (i.e. catastrophic windthrow) is more limited. Hence, considerable uncertainty exists within climate change scenarios of increased frequency and severity of winter storms and their likely effects on Irish forest and whether new/different management approaches are required and the influence of forest design to mitigate windthrow (e.g. minimising brown edges, direction of cultivation, etc.). New methods and technology now exist in which to incorporate the characteristics of wind and root anchorage in response to soils characteristics which allows a greater understanding of the potential effects of catastrophic windthrow.
The research will combine the expertise of biologists, arboriculturist, foresters and engineers in order to investigate windthrow/windsnap in trees. An idealised numerical model of the tree will be developed covering both the stem and root system. Previous work on crops has shown that it is the latter which is key to understanding the issue and as such, a physical model will also be developed which will enable calibration of the numerical model. The research aims to use innovative methods to include wind as including physical testing in a wind tunnel to simulate different windspeeds and directions and a variety of turbulent conditions with tree models in order to predicted realistic windthrow/windsnap velocities for different soils and as a function of tree height. Combined with the numerical modelling, the aim is to provide insight on the terminal height of trees in response to wind loading and the influence of forest design on the vulnerability of forests to windthrow.
Funding is available through a Walsh Fellowship funded by Teagasc in Ireland. Funding covers UK and EU Home fees and stipend. International students are welcome to apply as long as they can cover the overseas fees.
Apply directly online here.