Bronydd Mawr Agroforestry Site

Silvopastoral Network

The site is run by the Institute of Grassland and Environmental Research and Forest Research.

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 pseudoplatanu)s 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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