THROUGHFALL IN FOREST STANDS 129 



Table 2 

 Stemflow in young spruce, 1959. (Means of 20 trees) 



In the present investigation, we have installed resistance units and 

 tensiometers along a random radius of each of six trees. The distances from 

 the stem are respectively, 0%, 40% and 95 % of the radius of the tree crown, 

 as well as halfway across the adjacent opening in the canopy. The depths 

 at each of these points are dependent on the depth to impermeable clay, 

 but the shallowest is at one foot and there are three locations at greater 

 depths. PreHminary results have indicated the presence of a soil moisture 

 pattern corresponding with that of throughfall, which we hope to confirm 

 with further measurements. 



The uneven distribution of soil moisture would be expected to influence 

 evaporation from the forest floor, and this should be borne in mind when 

 measuring evaporation as a factor in the water balance. Drainage might 

 also be affected; it is therefore neither sufficient to take samples for soil 

 moisture measurement, nor to install soil moisture detectors, without tak- 

 ing into account the possibility of local sinks. It would be interesting and 

 important to know whether greater water abstraction by tree roots coin- 

 cides with areas of the woodland floor receiving greater quantities of water. 

 Under some conditions, leaching too might be expected to show a corres- 

 pondingly uneven pattern, with consequent pedological implications. For 

 example, Stewart (i960, unpubHshed) has reported an increasing depth of 

 A2 horizon in a podzol below Scots Pine with increasing distance from the 

 stem. Since the micro-environment of the forest floor is also affected by 

 throughfall distribution patterns, this might underhe certain observed 

 distributions of regeneration and of soil organisms. 



