MOISTURE AND TEMPERATURE CONDITIONS IN AFFORESTED AREAS IN ABERDEENSHIRE

1. Soil temperature measurements in a forestry plantation at Birkhall,near Ballater, Aberdeenshire, have been maintained from January1952 onwards, and the present paper extends the results alreadypublished (Quart. J. Roy. Met. Soc. lxxxi (1955), 72) with regardto soil temperature profiles, frost occurrence, and the efficiencyof daily maxima and minima of temperature in the estimationof mean weekly temperatures.
2. Results are given for the interceptionof rain by vegetationalcovers of various types and for thedifferences in moisturestatus that occur between soils in anopen ride and under theforest canopy.
3. The amplitudes of diurnaltemperature fluctuations in the rideand under the forest canopyhave been compared. Over the periodAugust 1954 to December1956, the latter average about 60 percent, of the former; thereare, however, large differences betweenthe results for thedry conditions in 1955 and the wet conditionsin the later monthsof 1956, and consideration is given to thefactors contributingto these differences.
4. The mean temperatures in the ride arehigher than those underthe canopy between April and September;the greatest differences,which are of the order of 1? C., occurin the later part ofthe spring and the earlier part of thewinter.