Wter Storge in the Forest Floor of Sublpine Forests of Albert DOUGLAS L. GOLDING Cndin Forestry Service, Edmonton, Albert AND CHARLES R. STANTON Cndin Forestry Service, Ottw, Cnd Received July 5, 1971 GOLDING, D. L., nd STANTON, C. R. 1972. Wter storge in the forest floor of sublpine forests of Albert. Cn. J. Forest Res. 2, 1-6. Wter storge by the forest floor nd its reltion to other chrcteristics of the forest floor were determined for three forest types (spruce-fir (Pice spp. - /Thies spp.) prtilly, cut spruce-fir, nd young lodgepole pine (Pinus contort Dougl.), nd three predominnt spects (north, south, nd est) on Mrmot Creek experimentl wtershed in south western Albert. There ws no significnt difference between uncut nd prtilly-cut spruce-fir forest floor in wterstorge cpcity, depth of Wter held fter drining, wter held per unit thickness of forest floor, or dry weight, lthough forest-floor thickness ws greter under uncut spruce-fir (11.36 cm) thn prtilly cut (9.84 cm). The forest floor verged for cut nd uncut spruce-fir hd greter wterstorge cpcity (1.93) thn under young lodgepole pine (1.35), greter depth of wter held (1.94 cm, 0.85 cm,) greter dry weight (89 506 kg/h, 55 039 kg/h), nd greter thickness (10.60 cm, 4.59 cm). There ws no difference in wter held per unit thickness of forest floor (0.19 cm/cm under spruce-fir, 0.18 cm/cm under pine). The lower vlues for pine thn for spruce-fir re ttributed to n intense fire 30 yers go on the re presently supporting the young pine. Regressions re given of wter held on forest-floor thickness, weight of wter held on dry weight, nd wter-storge cpcity on thickness. GOLDING, D. L., et STANTON, C. R. 1972. Wter storge in the forest floor of sublpine forests of Albert. Cn. J. Forest Res. 2, 1-6. L'entreposge d'eu pr l couverture d'humus et ses reltions ux utres crcteres de l couverture d'humus ont ete determines pour trois types de couvert forestier (epinette-spin, epinette spin eclircie et de jeunes pins de Murry) sur les trois versnts principux (nord, sud, et est) du bssin de dringe experimentl de Mrmot Creek dns le sud-ouest de I'Albert. Aucune difference significtive n' ete trouvee entre les sttions d'epinette-spin non-coupee et eclircie en termer de cpcite d'entreposge d'eu, quntite d'eu retenue pres dringe ou d'eu retenue pr unite d'episseur ou de poids nhydre de l couverture d'humus, meme si l couverture d'humus etit plus episse en-dessous du groupement epinette-spin non coupe (11.36 cm) qu'endessous du groupement epinette-spin eclirci (9.84 cm). En moyenne, l couverture d'humus des groupements epinette-spin non coupe et eclirci vit une plus grnde cpcite d'entreposge d'eu (1.93) que celle sous jeunes pins (1.35) insi qu'une plus grnde quntite d'eu retenue (1.94 cm, 0.85 (cm), un poids nhydre plus eleve (89 506 kg/h, 55 039 kg/h) et une plus grnde episseur (10.60 cm, 4.59 cm). Aucune difference en eu retenue pr unite d'episseur de l couverture d'humus n' ete consttee (0.19 cm/cm pour les groupements epinette-spin, 0.18 cm/cm pour le peuplement de jeunes pins). Les vleurs plus bsses pour le peuplement de jeunes pins sont ttribuees u pssge d'un feu intensif dns l sttion it y 30 ns. Les regressions ont ete clculees entre I'eu retenue et le poids nhydre et entre l cpcite d'entreposge d'eu et l'episseur de l couverture d'humus. Cndin Journl of Forestry Reserch, 2, 1 (1972)
CANADIAN JOURNAL OF FOREST RESEARCH. VOL. 2, 1972 Introduction The forest floor is n importnt prt of the hydrologic system of forested wtershed. For storms in which the mount of rinfll is less thn the wter-holding cpcity of the forest floor, for the initil period of lrger storms, nd during snowmelt, the hydrologic properties of the forest floor re mjor fctor, determining infiltrtion rte nd overlnd flow. Wter storge by the forest floor my men reduced overlnd flow, decresed erosion, greter loss by evportion, nd with-holding of wter from use by plnts. The forest floor contributes to the development of grnulr soil structure nd incresed biologicl ctivity, orgnic mtter, nd noncpillry pore spce in the soil (Arend 1941), ll of which re conducive to high infiltrtion rtes. This study determines the wter-storge cpcity of the forest floor nd its reltion to other chrcteristics of the forest floor under three min forest types nd three predominnt spects of Mrmot Creek experimentl wtershed. In this study, forest floor includes living moss cover s well s ded orgnic plnt mtter down to minerl soil. Study Are Mrmot Creek experimentl wtershed ws estblished in 1961 on the est slopes of the Rocky Mountins. It is 9.4 km 2 re bout 80 km west of Clgry with elevtion rnging from 1585 to 2805 m bove m.s.l. The bsin is covered minly with glcil deposits (tills nd glciofluvil mterils) nd post-glcil deposits (tlus, scree, nd lluvium) with bedrock outcroppings in the upper prt of the bsin nd long strem chnnels (Stevenson 1967). Beke (1969) clssified the soils s follows, using the terminology of The System of Soil Clssifiction for Cnd (Cn. Dept. Agr. 1970): in the lower prt of the bsin soils re Gry Wooded, with Humo-Ferric Podzol t 1770 to 1920 m, Dystric Brunisol to 2290 m, nd Regosol bove. The re is clssified by Rowe (1959) s the Sublpine Forest Region, Est Slopes Rockies section (S.A.I.). Mture spruce (Pice engelmnni Prry) fir (Abies lsiocrp (Hook.) Nutt.) with n dmixture of lodgepole pine (Pinus contort Dougl.) covers the greter prt of the bsin below tree line (bout 2290 m). The lower prt of the bsin supports young lodgepole pine stnd tht originted fter fire burned over the mture spruce-fir in 1936. Annul precipittion mounts to bout 90 cm, of which 70 to 75% is snow (Storr 1967). Bsin yield mesured s stremflow t the foot of the bsin is pproximtely 47 cm/yer. Description of the nine forest cover-spect combintions is given in Tble 1. Methods Study res were chosen representing the three min forest-cover types nd three predominnt spects of Mrmot bsin. The description of the nine study res is given in Tble 1. In the three described s cutover spruce-fir cover type, prtil cut of merchntble spruce ws mde in 1950. Forest-floor smples were tken t 270 loctions, 30 in ech of the nine combintions of cover type nd spect: spruce-fir, prtilly-cut spruce-fir, nd lodgepole pine on north, south nd est spects of Mrmot Creek experimentl wtershed. Smples were tken 2.74 m prt long line tht ws locted cross the slope in such wy tht the 30 smples could be tken within the designted cover type nd spect. A pruning sw ws used to cut long the edges of 15.24 X 15.24 cm plywood templte nd the smples were removed down to minerl soil nd included not only the ded orgnic plnt mtter but lso living moss cover where it occurred. Smple thickness ws determined by tking the men of the thickness of ech of the four sides. Ech of the smples of the forest floor ws wrpped in cheese cloth, immersed in wter for 48 h, nd then drined for 48 h on ed of snd covered with cheese cloth. TABLE 1. Description of study res Forest cover Aspect Elevtion (m) Slope (%) Stnd height (m) Crown closure (%) Spruce-fir (cut) South 1785 18 20 35 135 54 Spruce-fir South 1845 35 20 85 200 61 Spruce-fir (cut) North 1775 14 20 45 175 74 Spruce-fir North 1800 14 20 45 140 81 Spruce-fir (cut) Est 1785 14 20 45 175 73 Spruce-fir Est 1800 14 20 45 140 78 Lodgepole pine South 1800 24 8 80 30 2 Lodgepole pine North 1785 22 8 80 30 30 Lodgepole pine Est 1835 28 8 80 30 3 Age (yr) Moss cover (%)
GOLDING AND STANTON: WATER STORAGE IN THE FOREST FLOOR 3 During drining, the smples were covered by inverting the soking tnks over them to reduce vrition in evportion losses. After weighing, smples were dried on rcks with het lmps mintining n ir temperture of 85 C. When selected smples (representing thick, verge, nd thin forest-floor smples) hd reched constnt weight, ll smples were reweighed. Clcultion ws mde of wter-storge cpcity, defined s the rtio of weight of wter held fter drining to the dry weight of the forest-floor smple (i.e., (weight of smple fter drining minus dry weight)/(dry weight)). Wterstorge cpcity differs from the common term wterholding cpcity in tht smples were ir-dried t 85 C rther thn oven-dried. Bulk density ws clculted s dry weight/smple volume, nd wter held fter drining is the weight of wter held fter drining converted to depth. Wter held per unit depth is the rtio of wter held fter drining to forest-floor depth. Anlysis of covrince ws crried out for combintions of the vribles wter-storge cpcity, dry weight nd thickness of forest floor, nd weight nd depth of wter held. Duncn's New Multiple Rnge test (Duncn 1955) ws used to determine the significnce of differences between the mens. Results In the following presenttion of results, by difference is ment sttisticlly significnt differences t the 95% level of probbility. Results re summrized in Tble 2 nd 3. Only for forest-floor thickness ws there significnt difference between uncut nd prtilly-cut spruce-fir, with the uncut hving the greter thickness (11.36 cm, 9.84 cm). The combined uncut nd prtilly-cut spruce-fir hd greter thickness (10.60 cm) nd dry weight (89 506 kg/h) thn did the forest floor under pine (4.59 cm, 55 039 kg/h). Bulk density ws greter for pine (0.14 g/cm 3) thn for spruce-fir forest floor (0.09 g/cm 3). Wter held fter drining ws greter in spruce-fir (1.94 cm) thn in pine (0.85 cm), s ws wter-storge cpcity (1.93, 1.35). There ws no difference in wter held per unit thickness of forest floor, 0.19 cm/cm in spruce-fir nd 0.18 cm/cm in pine. Thickness nd dry weight were gretest on est spect (11.50 cm, 100 231 kg/h) nd lest on south spect (8.70 cm, 80 148 kg/h) in spruce-fir. For pine, est ws lest for both prmeters, but only for dry weight ws the difference significnt (north 69 157 kg/h, south 54 194 kglh, est 41 766 kg/h). Wter-storge cpcity, wter depth held fter drining, nd wter held per unit thickness of forest floor were gretest on est spect in spruce-fir, but no consistent trend ws shown for these prmeters in pine. Wter-storge cpcity (Tble 2) ws strongly relted to the percentge of moss cover on the re (Tble 1) s shown by the following where wter-storge cpcity follows the mount of moss cover: young pine 12%, 1.35; spruce-fir 70%, 1.93; mture pine 87%, 2.31 (mesured under mture lodgepole pine stnd of south spect on Mrmot bsin). Anlysis of covrince on the vribles for the nine species-spect combintions nd for vrious groupings of the nine showed highly significnt reltionships for (1) depth of wter held nd thickness of the forest floor, (2) weight of wter held nd weight of dry mtter, nd (3) wter-storge cpcity nd thickness (Tble 3). Differences between spruce-fir uncut nd prtilly cut, nd between spruce-fir nd pine precluded the use of common regressions for some of these combintions. Discussion The differences in forest-floor chrcteristics between spruce-fir nd pine my be due in prt to the nture of these species nd the stnds they form. However, the differences my be due to the effects of n intense fire tht burned over the re on which the young pine now stnd. Mny studies hve shown tht fire reduces the mount of orgnic mtter in the upper lyers of the forest soil. For exmple, 75% decrese in orgnic mtter in the surfce 2 in. of soil ws mesured fter burning (Austin nd Bisinger 1955), up to 65% reduction in the top 3 in. (Youngberg 1953), 64% reduction in the surfce 2 in. (Dyrness nd Youngberg 1957). The fire on Mrmot bsin not only reduced the quntity of forest floor but in destroying the mture trees gretly lengthened the period required for the forest floor to ttin its preburn condition. Forest floor thickness under mture pine on Mrmot bsin ws 9.44 cm, lmost s thick s under spruce-fir (10.60 cm), nd over twice s thick s under the young pine (4. 59 cm).
Forest cover Aspect Men (cm) TABLE 2. Mens of forest-floor vribles nd significnce of differences between sites Wter held/forest Wter-storge Smple thickness Wter held fter drining floor thickness cpcity Weight of dry mtters Bulk density Significnce Coefficient of of vrition differences (%) Men (cm) Spruce-fir South 8.09 37 1.47 (cut) Spruce-fir South 9.31 39 1.84 Spruce-fir North 9.86 36 1.99 (cut) Spruce-fir North 13.04 35 1.91 Spruce-fir Est 11.26 38 2.11 (cut) Spruce-fir Est 11.73 41 2.30 Pine South 4.83 b 39 0.96 Pine North 4.83 b 30 0.98 Pine Est 4.11 b 25 0.62 Significnce of differences b c c c 'Mens with the sme letter re not significntly different t the 5% level of probbility by the Duncn New Multiple Rnge Test (Duncn 1553). Mens without the sme letter re significntly different. treduced by percentge equl to the proportion of the re in bre soil, rock, live nd ded stems. r) X > Ci > X C Coefficient Significnce Significnce Significnce Coefficient Significnce py of vrition Men of Men of Men of of vrition Men of X (%) (cm/cm) differences (gig) differences (kg/h) differences (%) (g/cm3) differences '''' r o,.4 48 0.18 1.77 c 73,540 b c d 36 0.10..,1 53 54 0.20 0.20 1.84 1.94 b c c 86,755 90,927 c 57 0.15 b 1.98 85,349 c 38 0.07 Pc tri 47 0.19 1.99 98,303 38 0.09 b cn ;1> 60 0.20 2.05 102,159 45 0.09 b 52 0.20 1.45 d 54,194 d 37 0.14 n 37 0.20 1.21 69,157 c d 33 0.17 36 0.15 b 1.41 d 41,766 41 0.11 < C r 40 38 0.10 0.10 0 7:, VI CB.-3
GOLDING AND STANTON: WATER STORAGE IN THE FOREST FLOOR 5 TABLE 3. Sttistics for the regression nd correltion between forest-floor vribles Stndrd Men Men Regression Correltion error of Forest cover X Y Intercept coefficient coefficient estimte Depth of wter in cm (Y)Iforest-floor thickness in cm (X) Spruce-fir, prtil cut 9.84 1.86-0.130 0.202 0.79 0.579 Spruce-fir, uncut 11.36 2.02-0.641 0.234 0.88 0.548 Young pine 4.59 0.85-0.109 0.210 0.83 0.212 Weight of wter in gm (Y)/weight of dry mtter in gm (X) Spruce-fir 225.66 450.08-130.99 2.575 0.94 80.66 Young pine 149.07 198.31 15.85 1.224 0.76 57.34 Wter-storge cpcity (Y)Iforest-floor thickness in cm (X) Spruce-fir 10.60 1.93 1.425 0.048 0.61 0.263 Young pine 4.59 1.35 0.788 0.123 0.54 0.290 Associted with the reduction in orgnic mtter fter fire is reduction in the wterstorge cpcity. Austin nd Bisinger (1955) reported reduction in moisture-holding cpcity in the top i in. of soil of 33.7% fter fire. Rideout (1949) reported tht the wterholding cpcity of soils in British Columbi ws reduced immeditely fter burning, nd required 18-19 yers to completely recover. Dyrness et l. (1957) concluded tht reduction in wter-holding cpcity ws lrgely due to lower mounts of orr. r. q.nic mtter fter fire. Comprison of the spruce-fir, young pine, nd mture pine on Mrmot bsin supports this view. Under mture pine the wter held fter drining nd the wterstorge cpcity were 1.20 cm nd 2.31 respectively compred with 1.94 cm nd 1.93 for spruce-fir, nd 0.85 cm nd 1.35 for young pine. This strongly suggests tht the difference between spruce-fir nd young pine is minly the result of fire, nd tht the difference in hydrologic chrcteristics decreses s the pine mtures. Comprisons with other cover types showed tht depth of wter retined by the forest floor ws much higher in spruce-fir nd pine on Mrmot bsin thn in ponderos pine (Pinus ponderos Lws.) (0.23 cm) in Arizon (Clry nd Ffolliott 1969), but closer to the mximum reported by Mder nd Lull (1968) for estern white pine (Pinus strobus L.) (1.12 cm). Field-moisture cpcity determined with tension pltes verged 2.71 cm for mor forest-floor types under western coniferous species in Wshington (Gessel nd Blci 1965). This is greter thn the wter held by the forest floor under either sprucefir or pine on Mrmot. Forest-floor thickness under spruce-fir on Mrmot bsin ws exceeded by western conifers (12.82 cm) (Gessel nd Blci 1965). Pine-floor thickness on Mrmot ws exceeded by the bove noted, by estern white pine (6.35 cm) (Mder nd Lull 1968), nd by both ponderos pine (5.7 cm) nd mixed conifers (5.0 cm) in centrl Wshington (Wooldridge 1970). Other studies hve shown forest-floor thickness of 4.57 cm for oldgrowth fir-hemlock (Abies spp. - Tsug spp.) in Wshington nd Oregon (Willims nd Dyrness 1967), 3.30 cm for ponderos pine in Arizon (Clry nd Ffolliott 1969), 2.79 cm for jckpine (Pinus bnksin Lmb.) plnttion in Michign (Brown 1966), nd 2.03 cm for loblolly pine (Pinus ted L.) plnttion in Mississippi (Williston 1965). In the studies reviewed, forest-floor weight ws less for ll pines except ponderos (73 300 kg/h) (Wooldridge 1970) thn for other conifers. Spruce-fir on Mrmot ws exceeded only by conifer stnds in Wshington (157 884 kg/h) (Gessel nd Blci 1965). Forest floor weights hve been reported for mixed conifers in Wshington, 65 000 kg/h (Wooldridge 1970), nd fir-hemlock in Wshington nd Oregon, 62 768 kg/h (Willims nd Dyrness 1967). Pine on Mrmot bsin hd greter forest-floor weight thn ny of the other pine stnds reported except pond-
6 CANADIAN JOURNAL OF FOREST RESEARCH. VOL. 2, 1972 eros pine in Wshington. Weights reported for other pine stnds re: estern white pine in Msschusetts, 45 955 kg/h (Mder nd Lull 1968), jckpine plnttion in Michign 26 228 kg/h (Brown 1966), lodgepole pine in Colordo 25 331 kg/h (Moir nd Grier 1969), ponderos pine in Arizon 20 848 kg/h (Clry nd Ffolliott 1969), nd loblolly pine plnttion in Mississippi 16 365 kg/h (Williston 1965). It must be noted, however, tht in the studies reported bove, forest floor includes only ded orgnic mtter nd not living moss s in this study, nd wter retention hs been clculted using ovendry weight not ir-dry weight s in this study. AREND, J. L. 1941. Infiltrtion s ffected by the forest floor. Soil Sci. Soc. Amer. Proc. 6, 430-435. AUSTIN, R. C. nd BAISINGER, D. H. 1955. Some effects of burning on forest soils of Western Oregon nd Wshington. J. Forest. 53(4), 275-280. BEKE, G. J. 1969. Soils of three experimentl wtersheds in Albert nd their hydrologic significnce. Ph.D. thesis, Dep. Soil Sci., Univ. of Albert. 456 p. BROWN, J. K. 1966. Forest floor fuels in red nd jckpine stnds. U.S. Forest Serv. Res. Note NC-9, 3 p. CAN. DEP. AGR, 1970. The system of soil clssifiction for Cnd. Cn. Dep. Agr., Ottw, 249 p. CLARY, W. P. nd FFOLLIOTT, P. F. 1969. Wter holding cpcity of ponderos pine forest floor lyers, J. Soil nd Wter Conserv. 24(1), 22-23. DUNCAN, D. B. 1955. Multiple rnge nd multiple F tests. Biometrics 11, 1--42. DYRNESS, C. T. nd YOUNGBERG, C. T. 1957. The effect of logging nd slsh burning on soil structure. Soil Sci. Soc. of Amer. Proc. 21(4), 444-447. DYRNESS, C. T., YOUNGBERG, C. T., nd RUTH, R. H. 1957. Some effects of logging nd slsh burning on physicl soil properties in the Corvllis wtershed. U.S. Forest Serv. Pc. N.W. Forest nd Rge Exp.. St. Res. Pp. No. 19. 15 p. GESSEL, S. P. nd BALCI, A. N. 1965. Amount nd composition of forest floors under Wshington coniferous forest. In Forest-soil reltionships in north meric, edited by C. T. Youngberg. Oregon Stte Univ. Press, Corvllis. p. 11-23. MADER, D. L. nd LULL, H. W. 1968. Depth, weight, nd wter storge of the forest floor in white pine stnds in Msschusetts, U.S. Forest Serv. Res. Pp. NE-109. 35 p. MOIR, W. H. nd GRIER, H. 1969. Weight nd nitrogen. phosphorous, potssium, nd clcium content of the forest floor humus of lodgepole pine stnds in Colordo. Soil Sci. Soc. of Amer. Proc. 33(1), 137-140. RIDEOUT, E. F. 1949. A study of slsh burning nd its effects on British Columbi forest soil. M.Sc. thesis, Dep. Agron., Univ. of B.C. 68 p. ROWE, J. S. 1959. Forest regions of Cnd. Cn. Dep. North Aff. Nt. Resour. Forest. Br. Bull. 123. 71 p. STEVENSON, D. R. 1967. Geologicl nd groundwter investigtions in the Mrmot Creek experimentl bsin of southwestern Albert, Cnd. M.Sc. thesis, Dep. Geol., Univ. of Albert. 106 p. S-roRR, D. 1967. Precipittion vritions in smll forested wtershed. Proc. 35th Ann. Western Snow Conf. p. 11-17. WILLIAMS, C. B., JR. nd DYRNESS, C. T. 1967. Some chrcteristics of forest floors nd soils under true fir-hemlock stnds in the Cscde Rnge. U.S. Forest Serv. Res. Pp. PNW-37. 19 p. Witits-roN, H. L. 1965. Forest floor in loblolly pine plnttions s relted to stnd chrcteristics. U. S. Forest Serv. Res. Note SO-26. 3 p. WOOLDRIDGE, D. D. 1970. Chemicl nd physicl properties of forest litter lyers in Centrl Wshington. In Proceedings of the third north mericn forest soils conference, edited by C. T. Youngberg nd C. B. Dvey. North Crolin Stte Univ., Rleigh. Oregon Stte Univ. Press. p. 327-337. YOUNGBERG, C. T. 1953. Slsh burning nd soil orgnic mtter mintennce. J. Forest. 51(3), 202-203.