| Abstract: | Spring frosts in Thetford Chase cause a major reduction in thegrowth of young Corsican pine and very severe frosts or repeatedfrosting may kill the trees. Records of temperatures taken ona range of sites and in different conditions have shown that(a) spring frosts occur every year at Thetford, but the severefrosts which kill trees outright may only occur once every fewyears, (b) frost damage to plants mainly occurs when the treesare less than 18 in (45 cm) tall, (c) forest clearings largerthan 5 acres (2 ha) do not act as artificial frost hollows,(d) cold air flows down slopes of more than 1° and accumulatesat the bottom, forming a frosty zone. Studies showed that frost damage can be minimized by (a) completecultivation, (b) deep ploughing, (c) underplanting, and (d)strip felling. The benefits of these measures are demonstratedby temperature records and by measurements of tree growth. Methods of reducing frost damage are necessary in areas proneto spring frosts if crops of Corsican pine are to be successfullyestablished at low cost. |
