Winter frost

Severe winters with low extreme temperatures over long periods, without snow cover, can lead to catastrophic frost damage (winter frost dam-... 

Table 2.3. Sensitivity of different species of fruit to winter frost.

Only relatively flat sites are suitable for nurseries. On sloping sites there is a risk of erosion because the soil has to be kept bare. In addition, locations where there is a risk of frost (winter frost and late frost) should not be used as nurseries, especially for the propagation of stone fruit and pears on quince rootstocks. Nurseries should preferably be set up on medium-heavy soils. Humus-rich, loamy sand soils or sandy loam soils are especially favourable. A soil index well above 50 is advisable for nurseries. 

For optimum fruit quality, almost all pear varieties need a warm site, rather similar to that required for wine grapes. If these conditions are not present, the fruit very often does not have the desired melting texture and has little flavour in extreme cases the fruit may taste carroty . This applies particularly to late-ripening cultivars. Pear trees are somewhat more sensitive to winter frost than apple trees, and are at severe risk from late frosts because flowering is about 10 days earlier. 

The 2-year-old graft should have 4-6 equal shoots of 40 cm length in 75 cm. These shoots are then used as the framework branches. If Quince A is used as the rootstock, the graft union should not be more than 20 cm above the ground. In the case of Quince C, 2 cm is sufficient, so as to provide better protection against winter frost. 

Mulder on the other hand believes that the East Prussian spruce deaths were caused by the winter frost of 1928-29. 

The texture of blowaway sandy soils and Black Fen soils can be improved by applying 400-750 t/hectare of clay or marl (a lime-rich clay). If the subsoil of the area is clay, it can be dug out of trenches and roughly scattered by a dragline excavator. In other cases, the clay is dug in pits and transported in special lorry spreaders. Rotary cultivators help to spread the clay. If the work is done in late summer or autumn, the winter frosts help to break down the lumps of clay. As a practice, it is no longer considered economical. 

Breeding and selection of cultivars showing an increased resistance to fungal diseases and winter frosts... 

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