Bronydd Mawr Agroforestry Site

Silvopastoral Network

The site is was established by the Institute for Grassland and Environmental Research (IGER) and Forest Research.  IGER merged with the Institutes of Rural Sciences and Biological Sciences at Aberystwyth University, to form the Institute of Biological, Environmental and Rural Sciences, in 2008.

Bronydd Mawr Research StationSite Details:

  • Bronydd Mawr (51o37'N 03o38'W) is an upland site at 330m a.s.l. situated near Brecon, Powys.
  • Average annual rainfall is 1500mm
  • Mean screen temperature is 8oC
  • The soils overlie Old Red Sandstone and are predominantly well-drained acid brown earths

Bronydd Mawr Research Station


  • There are two tree species, Sycamore (Acer pseudoplatanus) and Hybrid larch (Larix eurolepis) planted at 3 densities; 100, 400 and 2500 stems ha-1.
  • The 2500 trees ha-1 treatments are Farm Woodland Controls with no grazing.
  • There is a sheep-grazed Agricultural Control which has no trees.
  • The silvopastoral treatments are sheep grazed, trees are individually protected.
  • Grazed plots are 0.6 ha in area and receive nitrogen at 160kg N ha-1 yr-1.
  • Farm Woodland Controls are a minimum of 0.1 ha
  • In addition there are sycamore and ash (Fraxinus excelsior ) planted at 400 stems ha-1 in plots that were sown with clover and receive zero N.
  • On this site, trees are planted in rows oriented North-South on all plots.
  • There are three replicates of all treatments and controls.

Stocking details

  • Beulah ewes are mated to Texel rams (Suffolk prior to 1998)
  • The Beulah has an average prolificacy of 1.3 lambs born per ewe.
  • Mating commences in mid-October when ewes are removed from the experimental plots.
  • Ewes are off-wintered on silage with the addition of concentrates in late pregnancy.
  • Twins are lambed indoors, singles outside
  • Grazing on the experimental plots starts after lambing in early April.
  • Lambs are weaned in late July and removed from the plots.
  • Site management conforms to National Network protocols.

Data collection

  • Data collection conforms to National Network standards.
  • Annually recorded measurements include:-
    • tree dimensions and survival,
    • stock carrying capacity,
    • lamb production,
    • ewe condition,
    • climate data (daily),
    • soil nutrient status and foliage nutrients.
  • Other studies conducted at Bronydd Mawr include:-
    • bird and insect surveys,
    • microclimate studies to evaluate light levels under canopies,
    • monitoring of herbage production (quantity and quality),
    • soil compaction,
    • evaluation of tree protection systems,
    • detailed botanical assessments, root studies.

Exclusion cages under hybrid larch
Exclusion cages under hybrid larch (400 stems ha-1) to monitor herbage production

For more information on the Bronydd Mawr Agroforestry Experiment, contact Chris Duller or Max Hislop

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