BOGFOR V
2005-2006
Effects of mechanical site preparation techniques on soil properties and tree growth in cutaway peatlands
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For further information contact: Florence.Renou@ucd.ie
Site preparation is a prerequisite for successful afforestation of cutaway peatlands. A wide range of site preparation practices have already been tested and new methods have yet to be looked at. It is important to analyse which growth factors will be affected by different preparation methods. Optimum soil temperature is important to the success of seedlings and it is well known that the temperature of soil is strongly influenced by site preparation methods. Comparisons of soil temperature sums often indicate considerable differences between site preparation methods. These variations are greatest during the summer months when solar radiation is high. Availability of soil water is also closely linked to the successful establishment of seedlings: either too little or too much water can limit physiological processes during establishment. On wet sites, excesses of water can be avoided by creating an elevated planting spot (e.g. mounding). Oxygen is also required for root growth and oxygen deficiency is often the result of over-wet conditions. The natural density of peat soil may be higher than optimum for seedling establishment, and loosened soil may therefore be preferable for seedling growth. On the other hand, too much loosening may dry out the soil too quickly and disturb plant water uptake by interfering with root-soil contact. The ideal soil preparation technique should increase the degree of soil aeration by removing excess water, provide an improved rooting medium for root proliferation and reduce the impact of vegetation, thus allowing a fast establishment of the seedlings.
The investigation will endeavour to identify various growth factors that may be affected by site preparation techniques and which in turn will affect seedling growth and the successful establishment of plantations on cutaway peatlands. The study will examine factors such as water-table depth, soil temperature, moisture and aeration within the range of existing BOGFOR cultivation trials (c. 45ha planted in 1996, 1999 and 2000). Older cutaway peatland plantations will also be examined as most did not undergo any cultivation. In addition, new cultivation trials will be established to test the suitability and the effect on soil properties of specific cultivation techniques such as spot mounding and scarification. The physical state of the planting medium should be monitored over the winter and spring period in order to identify seasonal variations. It is envisaged that expertise will be gained from site preparation used abroad (a ‘bedding’ plough is currently being used for forest site preparation in wetlands in Savannah, USA). If deemed suitable, such machinery may be leased to test it on different Irish cutaway peatlands.
Bord na Móna has agreed to make available several areas of cutaway bogs across the midlands in order to establish the new trials.
BOGFOR Research Team: Florence Renou (FERG, Project Manager), Prof. E. P. Farrell (FERG, Project Leader), Dr. Michael Keane (Coillte), Mr. Gerry McNally (Bord na Mona) and Mr. John O'Sullivan (Coillte).
