<h3>Tree Spacing</h3> <i>Yield is not all that sensitive to spacing. It should be about 1 to 4 metres depending on whether you want biomass or logs.</i> <p>For the tightest possible packing, trees are planted to form triangles (blue lines in the following diagram).</p> <p align="center"><img src="sp.gif" width="319" height="296"></p> <p>Each tree can be then considered to have a hexagonal hinterland (green area). This provides each tree with a hinterland closest in shape to a circle, thus providing even space and lighting all round the tree. The perpendicular from the mid point of any of the 6 sides of this hexagonal hinterland to its centre is half the spacing between trees.</p> <dl><dt>Therefore if</dt> <dd>sp = spacing in metres</dd> <dt>each tree's hinterland area:</dt> <dd>a = 0.8660254037844 * sp&sup2; square metres</dd> <dt>0.8660254037844 = half the square root of 3.</dt> </dl> <dl><dt>The total number of trees required in the plantation</dt> <dd>N = A / a</dd> <dd>N = A / (0.8660254037844 * sp&sup2;)</dd> </dl> <p> Total annual wood yield of a plantation is not very sensitive to spacing. It should be about 1 to 4 metres depending on whether you want biomass or logs. For the ratio of just under 1.3 logs to biomass I need for heating and engine fuel production, I would go for a spacing of 3 metres with a mix of willow, poplar and sycamore and then learn from the results. The mix of tree types is to help in some way towards their biological protection.</p> <p> A 3 metre spacing makes the area occupied by each tree 0.8660254037844 * 9 = 7.79422863406 m&sup2;. A plantation of 1 hectare (10,000 m&sup2;) therefore requires 10000 / 7.79422863406 = 1283 trees.</p> <p> I would also try to divide up the plantation into separate areas. This may be a little inconvenient from the point of view of maintenance, but it makes the whole less vulnerable to fire, disease and pests. <hr /> &copy; January 2001 - Robert John Morton