Silvicultural advice for reducing the risk of wind damage

Two scenarios can be tested:

The Forestry Commission Yield models for Sitka spruce with a maximum mean annual increment of 14 m3/ha/yr, initially planted at 1.7m spacing provides the following data for average trees within the crop.

Non-thin

Age Height (m) spacing (m) dbh (cm) vol (m3) Windspeed to overturn (m/s) Windspeed to break stem (m/s)
23 10.3 1.96 13 0.06 11.9 13.5
33 15.8 2.21 18 0.16 13.6 14.3
43 20.5 2.54 22 0.33 14.2 14.3

Intermediate thinning

Age Height (m) spacing (m) dbh (cm) vol (m3) Windspeed to overturn (m/s) Windspeed to break stem (m/s)
23 10.3 2.52 14 0.06 12.0 14.2
33 15.8 3.53 22 0.24 12.3 14.2
43 20.5 4.36 29 0.59 12.5 14.4

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Calculate wind speeds for similar trees growing on a podzol
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a.law@macaulay.ac.uk

Last modified: Thu Aug 21 15:53:14 BST 1997