The Biochemical Oxygen Demand of Finely Divided Logging Debris in Stream Water

Transcription

1 9E. 1, NO. 5 WATER RESOURES RESEAR The Biochemicl Oxygen Demnd of Finely Divided Logging Debris in Strem Wter PLEASE DO NOT REMOVE FROM FILES STANLEY L. PONE' School of Forestry, Oregon Stte University, orvllis, Oregon The impct of Dougls fir needles nd twigs, western hemlock needles, nd red lder leves on dissolved oxygen nd thus on the qulity of mountin strem wter ws exmined. The men OD, 9-d' BUD, nd BOD rte coefficients were, respectively. 454 mg 2/g, 11 mg 2/g, nd.125 for Dougls fir needles, 947 mg 2/g, 11 mg,/g. nd.56 for Dougls fir twigs, 57 mg 2 /g, 2 mg 2 /g. nd.49 for western hemlock needles, nd 882 mg 2/g, 286 mg 2/g, nd.47 for red lder leves. The 9-dy vlues of BOD nd A', for the lef mteril could be estimted ccurtely by tests of nd 6 dys, respectively, for Dougls fir needles, western hemlock needles, nd red lder leves. The BOD of lef mteril exposed to fluctuting temperture exerted 5-dy BOD 4., 2.4, nd 4.2 times greter thn the stndrd temperture BOD, for Dougls fir needles, western henilock needles, nd red lder leves, respectively. Toxicity of lechte extrcted from ech species ws determined on guppies nd steelhed trout fry. The concentrtion of mteril needed to produce toxic effects s s very high, so high. in fct. tht oxygen depletion probbly would be responsible for deth long before the lechte effect. Dt on oxygen depletion obtined in this study will be useful in developing predictive model for wter qulity mngement on forested lnds. The economy of the Pcific Northwest hs been built round wter nd timber resources of the region. Smll strems originting in timbered costl wtersheds serve s prime producers of ndromous slmon nd trout. Growth, development, nd survivl of the young fish produced in these strems re relted to qulity of the qutic environment in which they reside. The qulity of this qutic environment, in turn, is dependent upon the mngement prctices pplied to, nd the condition of, the djcent terrestril environment. The principl timber species of the region is Dougls fir, nd to lesser extent, western hemlock nd red lder. West cost Dougls fir, becuse of its regenertion nd growth chrcteristics, is hrvested by cler-cutting. A common byproduct of cler-cut logging, s well s other timber hrvesting techniques, is slsh, which is composed of limbs, brnches, nd needles or leves of trees. Often this mteril is deposited directly in strem chnnels. In generl, lrge mteril is removed. Finely divided mteril, however, such s needles, leves, nd broken twigs, often remins. This mteril my be responsible for the reduction in dissolved oxygen (DO) concentrtion. Recent field nd lbortory studies indicte tht tree folige is subject to biologicl oxidtion. hse nd Ferrullo [1957] studied the effect of utumn lef fll on oxygen concentrtion in lkes nd strems. They reported tht fter 1 yr, mple leves demnded bout 75 mg 2/g of their initil dry weight, but ok leves nd pine needles required bout 5 mg 2/g of their initil dry weight. The oxygen uptke ws rpid; by dy 1, mple hd chieved bout 7%, nd ok nd pine hd chieved bout 55% of the demnd exerted in 1 yr. Slck nd Feltz [1968] exmined the effect of lef fll on qulity chnges in smll Virgini strem. They reported no significnt chnge in oxygen consumption due to lef fll s the rte incresed from to 2 g/m 2 dy -1. As the rte incresed from 2 to 12 g/m 2 dy-', however, there ws corresponding drop in oxygen concentrtion from 8 to less thn 1 mg/i. Upon ' Now t the Deprtment of Forest Sciences, Uth Stte University, Logn, Uth opyright 1974 by the Americn Geophysicl Union. 983 nturl flushing by storm event the DO responded by climbing to level greter thn 11 mg/i. Hll nd Lntz [1969] reported the effects of logging on hbitt of coho slmon nd cutthrot trout in costl strems of Oregon. Two smll wtersheds were studied, one completely cler-cut nd the other ptch-cut with buffer strips, nd compred with third wtershed tht served s control. Felling on the cler-cut wtershed begn in the spring. Timber ws felled long the strem, nd logs were yrded uphill by cble cross the strem to lndings. This prctice resulted in the ccumultion of considerble quntity of debris, limbs. twigs, needles, nd brk in the chnnel, which restricted flow nd formed pools. The lrge mteril remined in the chnnel throughout the summer. In erly fll the chnnel ws clered of the lrge mteril to permit free flow. A substntil reduction in the DO concentrtion w s observed in surfce nd intrgrvel wters of the cler-cut wtersheds. DO concentrtions from lte spring through most of the summer were too low to support slmon nd trout in one third of the strem vilble to the slmonids; juvenile coho slmon plced in live-boxes there survived less thn 4 min. The lowest oxygen concentrtion reported,.6 mg/1, w s observed in pool resulting from drn composed of debris. During this period, oxygen concentrtion of the control strem nd the strem drining the ptch-cut wtershed remined t levels ner sturtion. Upon removl of lrge debris from the chnnel nd estblishment of free-flowing conditions the DO concentrtion rpidly returned to ner prelogging conditions in the surfce wter. Intrgrvel ox\gen concentrtions, however, remined bout 3. mgil lower thn the prelogging concentrtions for the next 2 yr nd continued to decline over the next 4 yr to levels less thn 2. nig/i t severl loctions. It is pprent tht finely divided logging mteril my be responsible for severe oxygen deficits within smll strem system fter deposition in strem by poor logging prctices. Although such chnges hve been observed, no quntittive informtion describing the potentil for oxygen extrction by decomposition of logging slsh typicl of the Pcific Northwest hs been reported.

2 984 PONE: POLLUTION FROM LOGGING WASTES TABLE 1. Men BOD of Different oncentrtions of Dougls Fir Needles s Percentge of the Men BOD of the 4 Grms per Liter oncentrtion oncentrtion Time, dys The purpose of this study ws to quntify the impct of Dougls fir (Pseudotsug menziesii [Mirb.] Frnco) needles nd twigs, western hemlock (Tsug heterphyll [Rf.] Srg.) needles, nd red lder (Alnus rubr Bong.) leves on dissolved oxygen nd thus on the qulity of mountin strem wter. The study, conducted in the lbortory, consisted of four principl components. First, to define the totl quntity of oxygen required for complete oxidtion, the chemicl oxygen demnd (OD) ws determined for the mteril. Second, n experiment ws performed to determine whether the BOD exerted by Dougls fir needles under stndrd temperture conditions ws relted directly to the mss of vegettion in the smple wter. Third, to quntify the mount of oxygen required by microorgnisms nd the rte t which it ws used, long-term (9-dy) biochemicl oxygen demnd (BOD) ws determined for the mteril. A 5-dy BOD ws lso determined by using simulted strem conditions in which the temperture ws fluctuted dily. Fourth, toxicity of mteril leching from debris into strem wter to guppies (Poccili reticult) nd steelhed trout (Slmo girdneri girdneri) fingerlings ws determined. The toxicity test defined the direct toxicity of the lechte to fish under test conditions. M ETHODS Smpling methods. The strem wter used in this study ws obtined from typicl strem in the Oregon ost Rnge. It ws ssumed tht this wter supported estblished microorgnism popultions tht would consume the test mteril. As result the strem wter served s the sole source of seed in the BOD experiments. The vegettion smpling procedure ws determined experimentlly to eliminte smpling bis becuse of differences in tissue chemistry in leves of different ges from different prts of the tree crown. As result of these preliminry experiments, ll vegettion ws tken from the lower one third of the crown. Dougls fir nd western hemlock needle smples were composed of mixture contining n equl number of needles from north nd south crown spects of three different trees in proportion to their verge number in ech ge clss (H. G. Smith, personl communiction, 197). Red lder leves were tken t rndom from three different trees. Dougls fir twigs were tken from north nd south crown spects of the lower one third of the crown from three different trees. Twigs of different ges were not mixed, but insted, first-, third-, nd fifth-yer ge clsses were formed. Twigs within ech ge clss from different trees were mixed, however. The form of vegettion used in the following experiments ws s follows: whole Dougls fir nd western hemlock needles nd red lder leves cut into 2-cm segments nd qurtered longitudinlly. Anlyticl methods. Vlues for OD were determined by the rpid OD method described by Jeris [1967]. The mss concentrtion dependency of Dougls fir needles ws determined by the Hch mnometric technique [Hch hemicl ompny, 1971]. Proportionl concentrtions of needles were plced in the test continers: The long-term stndrd temperture BOD of the mteril lso ws determined by the Hch mnometric technique. A concentrtion of bout 4 gm/i ws used in the test continers. The test ws run 9 dys for lef mteril nd 45 dys for Dougls fir twigs. To differentite between crbonceous nd nitrogenous BOD in lef mteril, hlf the smples were treted with n equivlent of 1 mg/1 of 2-chloro-6- (trichloromethyl) pyridine to inhibit nitrifiction. The 5-dy fluctuting temperture BOD test with lef mteril ws performed in wter bth in which the wter ws gitted continuously. The vlues for BOD were determined by stndrd dilution technique [Americn Public Helth Assocition, Inc., 1971]. The temperture rnge nd cycle selected were over n 8-hour period, followed by drop from 35. to 12.8 over the next 16 hours. This temperture pttern replicted vlues observed in cler-cut wtersheds of the Oregon ost Rnge [Brown nd Krygier, 197]. Toxicity of the vrious lechtes to guppies nd steelhed trout fry ws determined on the bsis of 24-, 48-, 72-, nd 96-hour tests nd expresed s medin lethl concentrtion. (L5). The 'sttic biossy method,' described by the Americn Public Helth Assocition, Inc. [1971], ws used in these tests. Lechtes used were derived from vegettion plced in wter poisoned with 2. mg He'll s Hg1 2 over 5 dys. He* ws removed from the solution with chelting compound before proceeding with the biossy. Poisoning nd depoisoning procedures followed in this test were developed by Schumburg [1971]. TABLE 2. umultive Stndrd Temperture BOD Exerted in Milligrms of 2 per Grm (Dry Weight) by Dougls Fir, Western Hemlock, nd Red Alder Leves in Strem Wter Bottle No. Time, dys Dougls Fir Needles Men Western Hemlock Needles Men Fed Alder Leves Men ontrols Men

3 PONE: POLLUTION FROM LOGGING WAS1ES 985 RESULTS OD test. The OD test consisted of three replictions for ech mteril. Replictions for ech lef tretment s well s those for the Dougls fir twigs were verged. Men vlues for OD on dry-weight bsis were 454 mg 2/g for Dougls fir needles, 947 mg 2/g for Dougls fir twigs, 57 mg 2/g for western hemlock needles, nd 882 mg 2/g for red lder leves. Mss concentrtion BD test. Results of the mss concentrtion BOD test re presented in Tble 1, which summrizes the men BOD of Dougls fir needles in percent in reltion to the 4.1-g/1 concentrtion used in the stndrd temperture BOD tests. The 2.1-g/1 concentrtion show ed proportionl drop in the BOD, bout one-hlf the BUD of the 4.1-g/I concentrtion from dy 4 to 1. On the other hnd, higher concentrtions did not produce proportionte increse in BOD. Initilly, vlues of BOD for 8.2- nd 16.4-g/1 concentrtions were significntly greter thn BOD for the 4.1-g/I concentrtion, but s time progressed, BOD exerted by the higher concentrtions pproched the vlues for the 4.1-g/I concentrtion. - Although BOD of the 8.2- nd, 16.4-g smples did not remin 2 nd 4 times higher thn BOD of the 4.1-g smple, BOD exerted by the 4.1-g/I concentrtion probbly ws not mss concentrtion dependent. At concentrtions greter thn 4.1 g/1, however, mss concentrtion dependency my occur nd thus limit the BOD exerted by the mteril per unit time. BOD test. Results of the stndrd temperture BOD test with lef mteril re given in Tble 2. Tble 2 is composed of smples treted with the nitrifiction inhibitor (bottles 3, 4, 8, 9, 13, 14, nd 1) nd smples tht were untreted. It is evident tht there is little difference between BOD exerted by the treted nd untreted smples, n indiction tht nitrifiction either ws not inhibited or did not occur. To determine quntittively whether nitrifiction took plce, ll solutions in test bottles were exmined for nitrtenitrogen by the Brucine method [Americn Public Helth Assocition, Inc., 1971]. In ll instnces the men NO,--N concentrtion of NO,- nitrogen in control bottles 5 nd 15 ws greter thn the concentrtion observed in ny of the smples, whether treted with inhibitor or not. There ws lso little vrition between NO,- nitrogen vlues of different tretments within species. It ws ssumed from these results tht nitrifiction did not occur in ny of the lef smples run t stndrd temperture. Thus results for ech of the four replictions for ech species were combined, nd the men ws clculted for ech time period. Severl trends re pprent upon exmintion of the men vlues given in Tble 2. Dougls fir nd western hemlock needles exert 9-dy oxygen demnd 4 nd 57% less thn tht of red lder leves over the sme period. Within ech TABLE 3. Men umultive Stndrd Temperture BOD Exerted in Milligrms of 2 per Grm (Dry Weight) by First-, Third-, nd Fifth-Yer Dougls Fir Twigs in Strem Wter Twig Age Time, dys First yer Third yer Fifth yer ontrol TABLE 4. Men umultive BOD Exerted in milligrms of 2 per Grm (Dry Weight) by Dougls Fir nd Western Hemlock Needles nd Red Alder Leves Under onditions of Temperture Fluctution Time, dys Vegettion TYPO Dougls fir Western hemlock Red lder ontrols species the men vlues for 5 dys (BOD E) represent only 54, 21, nd 27% of the BOD9 vlues for Dougls fir, western hemlock, nd red lder, respectively. The vlue for BOD.5 within ech species represents bout 9% of the vlue for BOD2o. Results of the BOD test for Dougls fir twigs re given in Tble 3. The first-yer twigs exerted the gretest BOD over 45 dys, slightly more thn 13% of their dry weight. Third- nd fifth-yer twigs followed with BOD,, equl to 9.3 nd 7.8% of their initil dry weight. The BOD, ws equivlent to bout 25% of the BOD., for ll ge clsses, but the vlue for BOD2O ws equivlent to bout 65% of tht for third- nd fifth-yer twigs nd bout 9% of the vlue for first-yer twigs. A test for NO, - in the Dougls fir twig smples ws lso performed. No NO, - nitrogen ws found in either the control or the smple solution. Results of the 5-dy fluctuting temperture BOD test re given in Tble 4. In 5 dys, red lder leves exerted n oxygen demnd equivlent to 23.7% of their initil dry weight, but Dougls fir nd western hemlock needles exerted demnd equivlent to 19. nd 9.7%, respectively, of their initil dry weights. Lechte toxicity. The concentrtion necessry to kill hlf the initil fish popultion (L;) from the lechte of 5-g (fresh weight) smple of vegettion plced in liter of wter ws determined by biossys. Results re given in Tble 5. Guppies generlly were more tolernt to the three lechtes thn trout; the 96-hour L5 for guppies in Dougls fir, western hemlock, nd red lder lechte ws 35, 65, nd 18% by volume, s compred with 26, 7.5, nd 24% by volume for trout. Dougls fir nd western hemlock lechtes in the steelhed trout biossy were not treted with Hg1 2 to exmine the possibility of mercury poisoning (Tble 5). It cn be concluded from these dt tht sufficient mercury ws removed from the lechte of red lder by the chelting compound. Toxicity vlues for Dougls fir nd western hemlock re of the sme order of mgnitude s those for red lder. In ddition, fish in the poisoned lder lechte would hve been killed very quickly if mercury hd been present in sufficient quntities. As Dougls fir nd western hemlock lechtes were not treted with Hg1 2 to inhibit microorgnism decomposition of the leched substnces, the L5 vlues my be high. DISUSSION Results of the mss concentrtion dependency test with Dougls fir needles under stndrd temperture conditions were of prticulr importnce. This test exmined the possibility tht high concentrtions of mteril my inhibit the rte of nutrient trnsfer by diffusion into strem wter or my be toxic to qutic microorgnisms. It ws concluded from the

4 986 PONE: POLLUTION FROM LOGGING WASTES TABLE 5. Percentge Dilution of Lechte From 5 Grms of Leves per Liter of Wter to Result in LSO for Guppies nd for Steelhed Trout Fry Time, hours Vegettion Type Guppies Dougls fir needles Western hemlock needles Red lder leves Steelhed Trout Fry Dougls fir needles* Western hemlock needles* Red lder leves *These smples were not treted with Hg12. results (Tble 1) tht the 4.1-g/1 concentrtion used in the BOD tests probbly ws not mss concentrtion dependent. In other words, the BOD defined by the long-term tests using the 4.1-g/I concentrtion my be considered to be n ccurte representtion of the mximum BOD tht Dougls fir needles would exert under such conditions. oncentrtions greter thn 4.1 g/1 my be mss concentrtion dependent. The impliction of such condition on the BOD test per unit mss would be lower 9-dy demnd nd lower rection rte coefficient. Vlues for BOD were of primry concern in this study. Initil results were presented erlier (Tble 2). Becuse nitrifiction did not occur in stndrd temperture smples, the four replictions within ech species of the lef smples nd the three replictions within ech ge group of Dougls fir twigs were combined. omposite curves for BOD were constructed through these dt by using lest squres fit. It ws ssumed tht the dt followed first-order process tht my be expressed mthemticlly s y = L(1 - Kit) where y is the oxygen demnd in milligrms per grm t time t, t is the time in dys, K i is the rection rte coefficient (bse e) in liters per dy, nd e is the bse of nturl logrithms ( ). The composite curves for BOD were constructed by using 9 dys of dt nd lso usin g dt for shorter time intervls but extended to 9 dys. The 9-dy BOD ws chosen s the ultimte BOD-exerted vlue L becuse it is representtive of the verge time intervl between spring runoff nd fll freshets. This is the period when logging debris is most likely to ccumulte in smll strems of logged wtersheds in the Pcific Northwest. urves fit through shorter time intervls nd extended to 9 dys serve s prediction of the ultimte BOD. The prediction curves my be considered in much the sme mnner s the 5-dy BOD tht is used to estimte from 6 to 8% of the ultimte demnd for sewge wstes. The rection rte coefficient ws determined by solving (I) for K,: (1) K, = (In L In L t )/1 (2) where L, = L y. Vlues of K, nd L for selected time intervls re summrized in Tble 6. Red lder leves exerted the gretest oxygen demnd over 9 dys, 28.6% of their initil dry weight, ro u ) - O - E o. c w E In. F m o >. pw. o c 4 1 N to > tc O ) $. w (. D 4.4 o O - be =1 '.. ^^ O y 1 Q N V. 4.4c N OD.. r-1 I N M 4 t,41 44 D D n cc.4) err," n c IO o cc c c cc ) O s 1 r- r4 O D O rn.c D t 44 4, O 1 X ) m..1 A M F-4 be X X 44../ N - = o X ro o u ) 1 1 o 6 1 o X X N X D N co cc M + V' ) io 4, 4, 4 E 4,M ;' J w 4, 4, W o. / = ' ul. 41 )- > 3 6' '6' 4., 4, 4, ID ) 4- t. 4. ) '4' , o * +- S W be c

5 PONE: POLLUTION F ROM LOGGING W AS"! FS N co 1 / 7 = DOUGLAS FIR 2 I I 2- DAY FIT 3% ENVELOPE ONTROL Fig. 1. The best-fit BOD curve with 3q envelope fit over 2 dys through the composite dt for Dougls fir needles. followed by western hemlock nd Dougls fir needles, which exerted 16.6 nd 11.% of their initil dry weights, respectively. Dougls fir needles hve the highest rection rte coefficient,.125, which is bout 2. nd 2.5 times greter thn those for western hemlock needles nd red lder leves, respectively. It is evident from Tble 6 tht the 5-dy projected vlues of K, nd L for leves re poor indictors of the ultimte BOD. The ultimte BOD cn be predicted ccurtely, however, from 2-dy fit for Dougls fir nd 6-dy lit for red lder. These reltions re illustrted in Figures I nd 2. BOD curves in Figures I nd 2 re enclosed with 3% envelope for Dougls fir nd 2% envelope for red lder to illustrte the degree of vrition between replictions. It would seem from Tble 6 tht the BOD 9O of western hemlock could he predicted ccurtely by the 45-dy fit. Upon observtion of the dt, however, it is obvious tht one smple (bottle 9, Tble 2) exerted BOD much lower thn tht of the other smples. The BOD of this typicl smple ws nerly stisfied by dy 1 nd completely stisfied by dy 4. As result, different nd probbly more precise estimte of the ultimte BOD for western hemlock ws obtined by using only the first 2 dys of dt to 'construct the composite curve (Figure 3). There ws close greement mong ll four smples during this time period; devition of the fourth smple did not begin until fter dy 1. The composite curve projected from the 2-dy period estimted the BOD 9O s 2 mg 2/g; the three similr smples were included in 1% envelope bout the composite curve. It is evident from Tble 6 tht the 5-dy projected vlues for Dougls fir twigs re poor indictors of the 45-dy predictions of the BOD 9O. The projected BOD vlue for the twigs, however, is similr to the projected 45-dy vlue nd identicl to the 9-dy BOD vlue for Dougls fir needles. The twigs hve much lower vlue.for K 1, n indiction tht their demnd will be exerted over longer time. The composite curve for Dougls fir twigs is illustrted in Figure 4. There is high degree of vrition mong smples; four of the nine smples re not included in the 3% envelope. Seven orrlie nine smples re bunched closely nd dominte the shpe of the curve. The ultimte demnd predicted b y using the 45 dys of dt, however, my he slightly high becuse of the effect of the two high smples. To interpret the long-term BOD tests under stndrd temperture conditions, n ttempt ws mde to define the quntity of sugrs nd polyphenolics leching from the debris over 9 dys. Becuse of fungl intesference the test ws terminted fter 2 dys nd proved of little vlue in explining the BOD results. This test is discussed in detil by Ponce [ Neither the vlues for K, nor those for L were determined for the BOD dt collected under conditions of fluctuting temperture. Some generl conclusions, however, cn be drwn by compring the men vlues for BOD, obtined by using fluctuted temperture with those obtined under stndrd temperture conditions. The stndrd temperture BOD, vlues were tken from the best-fit BOD 9O curve through the composite dt. The men vlues for BOD, of leves exposed to conditions of fluctuted temperture were much greter thn vlues of those exposed to stndrd conditions: 75% higher for Dougls fir, 58% higher for western hemlock, nd 76% higher for red lder. It is pprent from these comprisons tht orgnic debris exposed to conditions of temperture fluctution in comprison with those observed in smll strem exposed to solr rdition by cler-cutting hs much higher oxygen demnd in 5 dys thn the sme vegettion incubted t stndrd temperture. The BOD/OD rtio ws computed to obtin generl estimte of how completely the microorgnisms oxidized the mteril. Specific vlues of BOD for ech species were tken from the best-fit curves through the composite dt, but men vlues for OD were used. The rtios were.24,.29,.32, nd.12 for Dougls fir needles, western hemlock needles, red lder leves, nd Dougls fir twigs, respectively. These rtios indicte tht in ll instnces, less thn one third of the mteril ws oxidized by biologicl gents of decomposition over 9 dys. These reltions provide only generl indiction of the ese with which leves, needles, nd twigs re decomposed by co c co tl RED ALDER MEAN/ 6- DAY F I T 2% ENVELOPE ONTROL Fig. 2. The best-fit 13D curve with 27c envelope tit er 6 dys through the composite dt for red lder le\ es.

6 988 PONE: POLLUTION FROM LOGGING W ASTES 3 WESTERN HEMLOK 2- DAY FIT 1% ENVELOPE 3 2 t J c 2 m I / 1:$ MEAN to 1 ONTROL \ Fig. 3. The best-fit BOD curve with 1% envelope fit over 2 dys through the composite dt for western hemlock needles Fig. 4. The best-fit BOD curve with 3% envelope fit over 45 dys through the composite dt for Dougls fir twigs. microorgnisms. Mterils contining high concentrtions of cellulose, such s logging debris, often hve highly vrible OD nd thus n inconsistent OD/BOD reltion. SUMMARY Results of this reserch hve provided severl importnt fcts bout OD nd BOD of needles, leves, nd twigs, nture of substnces leching from these mterils, nd toxicity of these lechtes to fish. Men vlues of OD nd 9-dy BOD under stndrd conditions nd ssocited BOD rte coefficients were 454 mg 2/g, I1 mg 2/g, nd.125 for Dougls fir needles, 947 mg 2/g, 11 mg 2/g, nd.56 for Dougls fir twigs, 57 mg 2/g, 2 mg 2/g. nd.49 for hemlock needles, 'nd 882 mg 2/g, 286 mg 2/g, nd.47 for red lder leves. Further nlysis showed tht the 9-dy vlues for BOD nd K, could be estimted ccurtely by tests of shorter durtion: 2 dys for Dougls fir needles, 2 dys for western hemlock needles, nd 6 dys for red lder leves. The stndrd 5-dy BOD ws poor estimtor of the BOD.o nd ssocited K. Nitrifiction did not occur in ny of the stndrd temperture BOD tests, nd the stndrd temperture BOD smples of Dougls fir needles were not mss concentrtion dependent. Lef mteril exposed to conditions of fluctuting temperture exerted 5-dy BOD 4., 2.4, nd 4.2 times greter thn the stndrd temperture BOD, for Dou g ls fir needles, western hemlock needles, nd red lder leves, respectively. Toxicity of lechte extrcted from 5 g (fresh weight)/i of wter of ech species ws determined on guppies nd steelhed trout fry. The concentrtion of lechte needed to produce toxic effects ws very high, so high, in fct, tht demnd for oxygen probbly would be responsible for deth. Results of this study combined with reertion nd debris ccumultion studies re dt essentil to development of n oxygen depletion model tht will enble foresters to predict on-site nd downstrem DO levels with time fter the introduction of known mount of logging slsh. Such model will be useful tool to foresters mking mngement decisions tht my ffect dversely the qulity of the qutic ecosystem. Acknowledgments. This pper is summry of n M.S. thesis cornpleted t Oregon Stte University. The reserch ws supported by U.S. Forest Service grnt P.N.W. 3, 1971, nd is pper 942, School of Forestry, Oregon Stte University, REFERENES Americn Public Helth Assocition, Inc., Stndrd Methods for the Anlysis of Wter nd Wste Wter, 13th ed., 874 pp., Wshington, D.., Brown. G. W., nd J. T. Krygier, Effects of cler-cutting on strem temperture, Wter Resour. Res., 6(4) , 197. hse, E. S., nd A. F. Ferullo, cygen demnd exerted by leves stored under wter, J. N. Engl. Wter l'orlss Ass., 71, , Hch hemicl ompny. Instructions for the Hch Model 2173 Mnometric BOD Apprtus. 13 pp., Ames, Iow, Hll, J. D., nd R. L. Lntz, Effects of logging on the hbitt of coho slmon nd cutthrot trout in costl strems, in Symposium on Slmon nd Trout in Strems, edited by T. G. Northcote, pp , University of British olumbi, Vncouver, B.., Jeris, J. S., A rpid OD test, Wter Wstes Eng., 4, 89-91, Ponce, S. L., The biochemicl oxygen demnd of Dougls-fir needles nd twigs. western hemlock needles, nd red lder leves in strem wtei, M.S. thesis, 141 pp., Oreg. Stte Univ., orvllis, Oreg., Schumburg, F. D., A new concept in smple preservtion Poisoning nd depoisoning, J. Wter Yollut. ontr. Fed., 43(8), , Slck, K., nd H. R. Feltz, Tree lef control on low flow wter qulity in smll Virgini strem, Ent:iron. Sci. Technol., 2(2), , (Received August 9, 1973; revised My 14, 1974.)