BRIEFER ARTICLES 
GROWTH OF TREES IN SPHAGNUM: 
Data obtained from the Puget Sound region and Alaska indicate that 
trees grow very slowly in sphagnum. In the habitats examined, there 
is no soil in the ordinary sense. The surface of the substratum consists 
of living sphagnum moss, just beneath which is fibrous brown peat. At 
greater depths decay is complete. The observations reported in this 
paper were all made on trees growing at an elevation of less than 750 m. 
Coniferous trees are more common in sphagnum than broad-leaved trees. 
Table I gives growth data for conifers in sphagnum and in other habitats 
in the Puget Sound region. 
TABLE I 
AVERAGE GROWTH OF CONIFERS IN SPHAGNUM AND IN OTHER HABITATS 
SPHAGNUM | OTHER HABITATS 
SrectEs Number of | Ave Number of a neti PERCENTAGE 
specimens nual i increase | examin 
examined in diameter | specimens ™ daaeaee 
Diameter 
Tsuga heterophylla... is I.OI mm. 7 1.56 mm. 64 
Pinus monticola........ 9 0.78 II 1.34 58 
Thuja plicata:. 35.2.5: II 0.60 6 1.15 52 
Pinus OA i) 9 0.78 21 t.57 
Pseudotsuga taxifolia 2I 0.86 16 1.69 40 
Height 
Tsuga heterophylla ..... II 7.37 cm. 7 17.07 cm. 43-1 
Pinu ee ee 9 5.39 II 8.62 62.5 
Thuj a Dee Ir 6.45 6 18.55 34-7 
Peeudotsuga 1 taxifolia. oun 2I 6.32 16 20.93 3.x 
ieee ee 
The percentage for each species in the last column is obtained by 
dividing the number in the second column by that in the fourth, and there- 
fore represents, on a percentage basis, the average amount of growth in 
sphagnum for the specimens examined as compared with the average 
growth on other soils. 
*For more complete data, discussion, and literature, see Jour. Forestry, 15: 
726-739. 1917. 
359] 
[Botanical Gazette, vol. 65 
