An example of winter injury to silver beech at moderate altitude
To judge by published records winter injury to native plants in their natural habitats is a rare phenomenon, but it might be nearer the truth to say merely that it is rarely recorded. In either case it seems worthwhile to draw attention to damage recently observed in silver beech on Maungatua near Dunedin since it is our chief timberline species.
The distribution of silver beech on Maungatua is not readily understood. The Range is scarcely 3,000 ft. high and only ten miles from the coast. A survey of rainfall and evaporation rates over the whole mountain has indicated that the entire upland is wet enough for beech forest (Wardle & Mark 1956). But silver beech, which is the only beech species present, is virtually restricted to the seaward face of :the mountain and even there it is almost confined below the 2,000 ft. contour. Its extreme upper limit is however, 2,400 ft. At this altitude there is a small clump of about a dozen trees up to 30 ft. in height. They occupy a steep shallow cleft that faces south-east. It was here that conspicuous winter injury was observed.
In August 1957 when these trees were approached from their southern side their entire canopy appeared brown and desiccated. Only branches within a few feet of the ground were uninjured. Far less damage was apparent when the trees were viewed from their northern side. In due course some of the trees became almost leafless but their buds proved undamaged and were in active growth by December.