Cedar branch laden with seeds.


Why cedars turn brown over winter


The reasons for this very frequently have to do with dehydration. Cedars, like other evergreens, do not


O


go completely dormant in winter. They continue to photosynthesize, albeit at a much slower rate. This doesn’t mean they are actively growing during this time, but they are “breathing”, expir- ing small amounts of moisture as they do so. To protect moisture as much as possi- ble, evergreen leaves are covered with


16 • Winter 2014


f all the trees in your garden, the one that causes the most grief over winter is the cedar.


a waxy coating and they have tight stomata (the breathing pores on the underside of leaves and needles). But even with these protections, they are vulnerable to moisture loss. Warm sunny days in the latter part of


winter are the days of greatest risk. Dark winter needles absorb the sun’s heat, raising the temperature of the needles higher than the air around them. Inter- nal vapour pressure increases and mois- ture is lost. If this is coupled with wind, then the moisture loss is exaggerated. Cloudy days, even with wind, are far less threatening. The clouds block the


sun’s energy and the wind cools the needles.


The importance of water Water cedars in fall and during


droughty parts of summer. They need to have enough water resources to get through the winter. The tree will store a certain amount of water internally, but on warmer days, it also takes up water from below the frost line under the surface of the soil Remember, soil does not freeze all the way down – the depth of frost will depend on air temperatures and snow cover. If there


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