Clearcut Watershed Research Articles

Macroinvertebrate responses to differing riparian treatments following forest harvest in the headwaters of Trask River watershed

Although it is well-established that macroinvertebrates are an integral part of a healthy stream ecosystem, studies designed to inform forest harvest best management practices for sustainability of macroinvertebrate communities in small streams have been limited. Current riparian management practices for headwater streams generally focus on providing adequate wood supply, reducing debris flows and transport of sediment, and maintaining water quality in larger streams that contain fish. Here we studied the effects of contemporary forest harvest practices on benthic macroinvertebrate density and community composition in 12 small headwater streams as part of the Trask River Watershed Study. To account for seasonal and year-to-year variability in macroinvertebrate densities, we sampled each site at the same time of year for six years before and four years after harvest. Three watersheds were clearcut with variable riparian buffers, three were clearcut with 12 m riparian buffers, and one was thinned with 15 m buffers. Five adjacent watersheds were not treated and were studied as reference sites. All sites had approximately 50 yr old conifer and alder forests, which had revegetated following fires and harvest in prior decades.In these steep mountain streams, benthic macroinvertebrate density and community composition were generally similar across watersheds prior to harvest. Collectors were the most abundant functional feeding group, followed by shredders; scrapers were the least abundant. After harvest, in two of the three clearcut watersheds with variable buffers, the total benthic density and percentage of collectors increased, primarily due to greater numbers of Chironomidae. We also observed more abundant emergence post-harvest at these two watersheds. In the third clearcut watershed with a variable buffer and in the three clearcut watersheds with uniform 12 m riparian buffers, we did not see changes in density or functional feeding groups after harvest. We explored the spatial and temporal aspects of the data using both non-parametric and parametric statistical methods. High variability swamped the treatment effect when watersheds were grouped by riparian treatment for the repeated measure analyses, while NMDS showed a significant shift post-harvest for the watersheds with variable buffers. In the clearcut watersheds with uniform buffers, macroinvertebrates densities and community composition did not shift. At two of the clearcut watersheds with variable buffers, we observed increased density for the first two years after harvest, and chironomids comprised up to 80% of the abundance in samples. In the subsequent years, we documented mixed responses for two watersheds. It was invaluable to have multiple pre- and post-harvest sampling periods in both harvested and reference watersheds in order to better identify site specific responses to treatment and to separate background variability from responses to harvest. We show that retention of riparian vegetation on headwater streams during clearcut harvesting minimized changes in total macroinvertebrate densities and community composition. Small buffers may be key to maintenance of diverse stream invertebrate communities in headwaters.

The long-term case for partial-cutting over clear-cutting in the southern Appalachians USA

Prior to the 1950s, common partial harvesting operations in the southern Appalachians USA involved the removal of logs by ground-skidding and the construction of steep access roads and skid trails along stream channels. Little is known about how these historical practices affected long-term vegetation changes. An experimental watershed in the Coweeta Hydrologic Laboratory was partially harvested in the years 1942–1952 according to these exploitive practices. We compared the partial-cut watershed to a clear-cut watershed and an untreated, reference watershed. Using long-term vegetation surveys, we analyzed patterns in aboveground biomass accumulation, species composition and diversity (Shannon’s index Hʹ and species richness) among watersheds. Contrary to our expectations, the partial-cut watershed recovered to reference levels of aboveground biomass and their species composition was similar over time. The clear-cut watershed had greater abundance of tulip poplar (Liriodendron tulipifera) and black locust (Robinia pseudoacacia) than the other two watersheds. The partial-cut watershed increased in diversity over time, but it remained less diverse than the reference watershed; whereas, the clear-cut watershed had lower diversity than the other two watersheds, and its diversity did not change over time. Distributions of functional groups based on water use and nutrient acquisition traits, and shade tolerance were similar between the partial-cut and the reference watersheds, but differed from the clear-cut watershed. By the 2010s, partial-cut and reference watersheds had similar proportions of diffuse-porous (32% and 33%) and ring-porous (48% and 42%) basal area, while the clear-cut watershed had more diffuse-porous (43%) and less ring-porous (36%) species than the partial-cut or reference watersheds. Tree species associated with arbuscular mycorrhiza were more abundant in the clear-cut watershed than the partial-cut or reference watersheds. Overall, the partial-cut watershed, even with the extreme soil disturbance, did not alter long-term species composition and diversity as dramatically as the clear-cut watershed. These results could help forest managers, conservationists, and hydrologists understand the long-term effects of partial-cutting versus clear-cutting.

The basin concept: From hydrology to nature management

The main development stages of the basin concept: from landscape hydrology to nature management are considered. It is shown that the river, lake and sea drainage basins are the most widespread natural complexes on and surface, with a high degree of integrity and with clear-cut watershed divides having a powerful integrating factor, the water flow. The substantiation is provided for the concepts of the basis as a geosystem, the runoff-producing complexes and the hydrological functions of landscape as well as for the principles of hydrological, water-resources and water-protection regionalization and zoning. On this basis, a classification of hazardous hydrological processes is developed. The structural patterns of the river network within the framework of structural geography are used for indication of the mean long-term discharge and its mapping, and for a classification of river systems according to their size. It is demonstrated that the integrating properties of the water flow permit the basin to be regarded as an integral system entity not only from the perspective of hydrology but also in terms of geomorphology, biogeocenology, landscape geochemistry as well as in complex physical geography as functionally integral natural complexes thereby creating the natural basis for nature management. On the other hand, many basins are socioeconomic and ethnodemographic entities. Ten principles are formulated for the theoretical justification of the basin concept of nature management where the basin is treated as an integral natural and economic system. It is suggested that such an approach should be used in governance of nature management, especially in international basins, as well as in reforming the system of administrative-territorial division of Russia.

Microsporidian parasitism of crayfish in Canadian shield headwater lakes within forested and clearcut watersheds

Microsporidian parasitism of crayfish in Canadian shield headwater lakes within forested and clearcut watersheds

A Paired Watershed Investigation of Silvicultural Best Management Practices Revisited: B.F. Grant Memorial Forest, Georgia

During the 1970s, a paired watershed study was conducted on adjacent first-order Georgia Piedmont streams. Forestry Best Management Practices (BMP) of that period, including thinned 6-m stream buffers, did not prevent large increases in maximum daily water temperatures and sediment inputs due to clearcut harvest and regeneration. After harvest, peak flows in the clearcut watershed increased substantially relative to reference watershed peaks. This study repeated the earlier study on the same watersheds using 1999 Georgia BMP guidelines after 34 years of loblolly pine regrowth on the treatment watershed. Relative to the original study, the new treatment featured wider streamside management zones, 12–21 m, and better road runoff management. In the original study, much of the increase in treatment sediment load was attributed to soil and brush road crossings on the treatment stream, but these crossings were eliminated after the first study. Implementation of modern BMP eliminated daily maximum water temperature effects. In addition, suspended sediment concentrations appeared unaffected by treatment. However, sediment loads relative to the reference tripled after treatment apparently because changes in treatment watershed hydrology accelerated bank slumping. Suspended sediment yields (560–1,070 kg/ha/year) were small relative to Natural Resources Conservation Service tolerable erosion (1,800–4,400 kg/ha/year) rates.

Positive diversity–stability relationships in forest herb populations during four decades of community assembly

It is suggested that diversity destabilizes individual populations within communities; however, generalizations are problematic because effects of diversity can be confounded by variation attributable to community type, life history or successional stage. We examined these complexities using a 40-year record of reassembly in forest herb communities in two clearcut watersheds in the Andrews Long-term Ecological Research Site (Oregon, USA). Population stability was higher among forest than colonizing species and increased with successional stage. Thus, life history and successional stage may explain some of the variability in diversity-stability relationships found previously. However, population stability was positively related to diversity and this relationship held for different forest communities, for species with contrasting life histories, and for different successional stages. Positive relationships between diversity and population stability can arise if diversity has facilitative effects, or if stability is a precursor, rather than a response, to diversity.

Test of APEX for Nine Forested Watersheds in East Texas

Hydrologic/water quality models are increasingly used to explore management and policy alternatives for managing water quality and quantity from intensive silvicultural practices with best management practices (BMPs) in forested watersheds due to the limited number of and cost of conducting watershed monitoring. The Agricultural Policy/Environmental eXtender (APEX) model was field-tested using 6 yr of data for flow, sediment, nutrient, and herbicide losses collected from nine small (2.58 to 2.74 ha) forested watersheds located in southwest Cherokee County in East Texas. Simulated annual average stream flow for each of the nine watersheds was within +/- 7% of the corresponding observed values; simulated annual average sediment losses were within +/- 8% of measured values for eight out of nine watersheds. Nash-Sutcliffe efficiency (EF) values ranged from 0.68 to 0.94 based on annual stream flow comparison and from 0.60 to 0.99 based on annual sediment comparison. Similar to what was observed, simulated flow, sediment, organic N, and P were significantly increased on clear-cut watersheds compared with the control watersheds. APEX reasonably simulated herbicide losses, with an EF of 0.73 and R(2) of 0.74 for imazapyr, and EF of 0.65 and R(2) of 0.68 for hexazinone based on annual values. Overall, the results show that APEX was able to predict the effects of silvicultural practices with BMPs on water quantity and quality and that the model is a useful tool for simulating a variety of responses to forest conditions.

Effects of a clearcut on the net rates of nitrification and N mineralization in a northern hardwood forest, Catskill Mountains, New York, USA

The Catskill Mountains of southeastern New York receive among the highest rates of atmospheric nitrogen (N) deposition in eastern North America, and ecosystems in the region may be sensitive to human disturbances that affect the N cycle. We studied the effects of a clearcut in a northern hardwood forest within a 24-ha Catskill watershed on the net rates of N mineralization and nitrification in soil plots during 6 years (1994–1999) that encompassed 3-year pre- and post-harvesting periods. Despite stream NO3− concentrations that increased by more than 1400 μmol l−1 within 5 months after the clearcut, and three measures of NO3− availability in soil that increased 6- to 8-fold during the 1 st year after harvest, the net rates of N mineralization and nitrification as measured by in situ incubation in the soil remained unchanged. The net N-mineralization rate in O-horizon soil was 1– 2 mg N kg−1 day−1 and the net nitrification rate was about 1 mg N kg−1 day−1, and rates in B-horizon soil were only one-fifth to one-tenth those of the O-horizon. These rates were obtained in single 625 m2 plots in the clearcut watershed and reference area, and were confirmed by rate measurements at 6 plots in 1999 that showed little difference in N-mineralization and nitrification rates between the treatment and reference areas. Soil temperature increased 1 ± 0.8 °C in a clearcut study plot relative to a reference plot during the post-harvest period, and soil moisture in the clearcut plot was indistinguishable from that in the reference plot. These results are contrary to the initial hypothesis that the clearcut would cause net rates of these N-cycling processes to increase sharply. The in situ incubation method used in this study isolated the samples from ambient roots and thereby prevented plant N uptake; therefore, the increases in stream NO3− concentrations and export following harvest largely reflect diminished uptake. Changes in temperature and moisture after the clearcut were insufficient to measurably affect the net rates of N mineralization and nitrification in the absence of plant uptake. Soil acidification resulting from the harvest may have acted in part to inhibit the rates of these processes.

Recovery of decomposition and soil microarthropod communities in an Appalachian watershed two decades after a clearcut

We examined decomposition rates of three substrates ( Quercus prinus L., Acer rubrum L., and Cornus florida L.) in a watershed 21 years after it had been clearcut, and compared them to an adjacent control watershed. Previous investigations at these sites had shown that microarthropod populations, important components of the decomposer community, were considerably less dense in the clearcut watershed and that decomposition rates were reduced. Twenty-one years after clearcut decomposition rates in the clearcut watershed had reconverged with the control, and in the case of one substrate ( C. florida) now exceeded the control. Microarthropods maintained denser populations in the clearcut watershed, and oribatid assemblages, the most abundant taxonomic group, were more diverse in that watershed. A contrast of the decomposition of the substrates 8 and 21 years after cable-logging revealed that decomposition was slower in the control watershed in the more recent observations, though this may reflect lower precipitation that year. These results seem to confirm that microarthropod recovery may be indicative of a restored decomposer community functioning, and that this may be reflective of reconverged abiotic conditions at the site.

A MODEL TO SIMULATE THE RESPONSE OF A NORTHERN HARDWOOD FOREST ECOSYSTEM TO CHANGES IN S DEPOSITION

Watershed studies across the northeastern United States have shown that stream losses of SO42− exceed atmospheric sulfur (S) deposition. Understanding the processes responsible for this additional source of S is critical to quantifying ecosystem response to ongoing and potential future controls on SO2 emission. An integrated biogeochemical model, PnET-BGC, was used to investigate inputs and dynamics of S in a northern hardwood forest at the Hubbard Brook Experimental Forest (HBEF), New Hampshire, USA. The changes in soil S pools and stream-water SO42− were simulated to assess the response to both atmospheric S deposition and forest clear-cutting disturbances. Model simulation using the measured dry-to-bulk deposition ratio of 0.21 resulted in an underprediction of soil S pools and stream-water SO42− concentrations in the biogeochemical reference watershed (Watershed 6). However, the depiction of biotic processes (e.g., plant uptake, mineralization) in the model reduced the discrepancy in stream SO42− concentration between measured and model predicted value by ∼50% compared to a previous modeling effort that only considered abiotic processes. Long-term simulations (∼150 yr) indicated that elevated anthropogenic S deposition has increased stream SO42− concentrations and enhanced the incorporation of S in adsorbed SO42− and organic S soil pools. Following the implementation of the 1970 and 1990 Amendments to the Clean Air Act, decreases in S deposition resulted in the net release of S from soil pools, including soil organic S. Model simulation of forest clear-cutting of Watershed 5 at the HBEF showed that NO3− leaching and associated acidification following this disturbance increased adsorption of SO42− to soil. Compared to the reference watershed, stream-water SO42− concentrations were slightly higher, and soil adsorbed SO42− pools were substantially higher in the clear-cut watershed 4–5 yr after disturbance. Simulation of stable S isotopes showed that fractionation associated with the mineralization of soil organic S might explain the depletion in 34S observed between throughfall and stream water in the reference watershed. There is a need for further research on: (1) the rates of dry S deposition and (2) the rate of weathering of various minerals and the isotopic composition of these minerals in order to fully assess the discrepancy (i.e., greater export of S than can be accounted for by atmospheric deposition) in watershed S mass balances. The results of forecasts of the future response to anticipated decreases in S deposition are highly dependent on the nature of this additional source of S to forest watersheds. However, the large size and relatively long turnover time of soil organic S pools compared to adsorbed SO42− pools suggest that a model depicting only abiotic processes will not be suitable for predicting the long-term recovery of stream water from acidification by atmospheric deposition in northern forests.

Organic matter chemistry and dynamics in clear-cut and unmanaged hardwood forest ecosystems

Forest harvesting alters the organic matter cycle by changing litter inputs and the decomposition regime. We hypothesized that these changes would result in differences in organic matter chemistry between clear-cut and uncut watershed ecosystems. We studied the chemistry of soil organic matter (SOM), and dissolved organic carbon (DOC) in soil solutions and stream samples in clear-cut and uncut sites at the Hubbard Brook Experimental Forest in New Hampshire using DOC fractionation techniques and solid-state 13C nuclear magnetic resonance (NMR) spectroscopy. Alkyl-C (aliphatic compounds) and O-alkyl-C (carbohydrates) were the largest C fractions in soil and dissolved organic matter at Hubbard Brook. Alkyl-C ranged from 29–48% of soil C, 25–42% of soil solution C, and 22–42% of streamwater DOC. Carbohydrates comprised 32–49%, 36–43%, and 29–60% of C in soils, solutions, and streamwater, respectively. In both soils and soil solutions, the carbohydrate fraction decreased with increasing soil depth, while the aromaticity of organic matter increased with depth. There were no significant differences in the structural chemistry of SOM between clear-cut and uncut watersheds. The aromatic-C fractions in soil solutions at the clear-cut site ranged from 12–16%, approximately 40% greater than at the uncut site (8.5–11%). Thus, clear-cutting has resulted in the leaching of more highly decomposed organic matter, and depletion of more aliphatic compounds in the soluble organic pool. Because DOC fluxes are small compared to the SOM pool, large differences in soil solution chemistry do not substantially alter the overall composition of SOM. While the organic chemistry of stream DOC varied greatly among 3 sampling dates, there were no obvious clear-cutting effects. Thus, temporal variations in flowpaths and/or in-stream processes appear to be more important than disturbance in regulating the organic carbon chemistry of these streams.

Landscape Modification of DOC Concentration in Boreal Lakes: Implications for UV-B Sensitivity

It has been recently suggested that droughts induced by climate warming reduce the catchment export of colour-forming, and therefore, UV-B protective, DOC to boreal lakes, which in turn may influence the health of resident biota. We determined that the concentration of DOC in 116 Canadian boreal lakes increased in relation to the severity of previous (4–13 yr) catchment forest clearance (reference - buffer strip - wildfire burnt - partial basin clearcut - whole basin clearcut), and was negatively related to water transparency. Removing the landscape influence of catchment drainage ratio showed that lakes within clearcut or burnt watersheds averaged 2 to 3 mg L-1 more DOC than those in reference, undisturbed catchments. Our results suggest the limited possibility that the increased incidence of wildfires coincident with climate warming may partially offset the effects of droughts on catchment export of DOC in the short-term, and thus serve to mitigate the effects of damaging UV-B exposure for selected basins in localized regions.

Patterns of nitrate loss from a chronosequence of clear-cut watersheds

Three clear-cuts at the Hubbard Brook Experimental Forest (NH) have resulted in a chronosequence of forest watersheds in close proximity. Following clear-cutting, the stands, now 12, 21, 27, and 78 years old, have different species composition, nutrient capital, and biogeochemistry. In this study, we compared seasonal patterns of NO3− in streamwater, changes in N capital, and N retention in watersheds of differing stand age. All of the watersheds showed elevated losses of NO3−, H+ and nutrient cations (Ca2+, Mg2+, K+) during the first few years following clear-cutting. Increased retention of N occurred during vegetation regrowth compared to the reference watershed (W6). Nitrate concentrations were low during the summer growing season, increased in the late fall and peaked in March during spring snowmelt. Concentrations of NO3− were lower in the regrowing watersheds than in W6 during all months. In W6, there was considerable year-to-year variability in N retention, which was not initially observed in the manipulated watersheds. However, two cut watersheds exhibited higher export of NO3− in 1989 and 1990, corresponding to a 10-year high value in annual NO3− loss in W6. These results demonstrate the importance of land use and cutting history in assessments of N saturation and loss from forest watersheds.

Effect of Timber Harvest Practices on Populations ofCornus floridaand Severity of Dogwood Anthracnose in Western North Carolina

Stand composition and severity of dogwood anthracnose, caused by Discula destructiva, were measured on 39 plots located at the Coweeta Hydrologic Laboratory in western North Carolina. The 0.08-ha plots were selected along transects across watersheds previously clearcut, partially harvested, or not harvested. Basal diameter, percent leaf area with dogwood anthracnose symptoms, and percent branch dieback were estimated for Cornus florida. Dogwood anthracnose was most severe on partially harvested watersheds and least severe on the clearcut watershed. Density of C. florida was greatest on the clearcut watershed, and the number of dogwood stems was inversely correlated (r=-0.31, P=0.05) with disease severity

Effect of site characteristics and 1st- and 2nd-year seedling densities on forest development in a northern hardwood forest

Factors influencing the initial colonization and subsequent (18-year) survivorship of trees were studied in two clear-cut watersheds in the Hubbard Brook Experimental Forest in New Hampshire. Variation in microsite conditions associated with the harvest operations (e.g., soil scarification, slash) and physical gradients within the watershed were particularly important in determining 1st- and 2nd-year densities of pin cherry (Prunuspensylvanica L.) and yellow birch (Betulaalleghaniensis Britt.), whereas factors relating to seed availability and the presence of advance seedlings and sprouts were important in determining 1st- and 2nd-year white ash (Fraxinusamericana L.) density. The 1st- and 2nd-year densities of sugar maple (Acersaccharum Marsh.) and beech (Fagusgrandifolia Ehrh.) were relatively independent of factors measured in this study and were probably related to both seed availability and the presence of advance seedlings and sprouts. Physical site factors immediately following clear-cutting continued to be important in determining the density of pin cherry and yellow birch at stand age 18 years, whereas 2nd-year sugar maple and beech seedling and sprout densities were the most important factors in determining the densities of these species 18 years following clear-cutting.

Emigration and Production of Hatchery Coho Salmon (Oncorhynchus kisutch) Stocked in Streams Draining an Old-growth and a Clear-cut Watershed

Downstream movement of coho salmon fry (Oncorhynchus kisutch) stocked in old-growth and clear-cut watersheds occurred in three phases: (1) a brief period of heavy emigration immediately after stocking, (2) relatively little movement throughout most of the summer, and (3) intermittent heavy emigration during early autumn freshets. Coho emigrated whenever a streamflow change ≥ 3%∙d−1occurred, but movement nearly ceased at flows above a certain level. Temperature changes were less important than discharge in triggering movement. When high densities were stocked, emigrant fry were smaller than residents. When low densities were stocked, emigration after the initial pulse of downstream movement was generally lower and there were no size differences between emigrants and residents. Production in the clear-cut was greater than in the old-growth watershed. Proportionately fewer fish emigrated from the old-growth stream, but when population densities were high, mortality in the old-growth exceeded the clear-cut. Greater emigration from the clear-cut site was possibly related to a scarcity of pools. Although the old-growth stream possessed better rearing habitat, less food may have been available, as suggested by gross photosynthesis rates 50% lower than in the clear-cut stream. Coho production therefore appeared to be most strongly influenced by trophic conditions, while volitional residency was most strongly influenced by habitat quality.

The effect of partial and clearcutting on streamflow at Deadhorse Creek, Colorado

Two subalpine forest subdrainages of Deadhorse Creek, Colarado, USA were used to demonstrate the comparable impact on water yield of two tree-harvesting practices. Of the 40 ha North Fork subdrainage 36% was clearcut commercially using five-tree height circular openings. In contrast, 40% of the basal area on the 41 ha Unit 8 was removed by partial cutting in the first step of a three-step shelterwood cut. Annual flow and peak flow from the clearcut watershed were increased significantly. The partial cut resulted in a significant increase in total water equivalent in the winter snowpack and an apparent increase in total annual streamflow that was comparable to the clearcut. The timber harvest on the two subdrainages, however, represented only 10% of the total basal area of the larger Deadhorse Creek Watershed in which they are located. Annual flow at the mainstream gage was not significantly increased as a result of harvest.

Effects of Clearcutting on Rain‐on‐Snow Runoff in Western Oregon: A New Look at Old Studies

Results of updating and reanalyzing streamflow data from studies in two experimental watersheds in western Oregon suggest that clearcut logging has altered snow accumulation and melt enough to have increased the size of peak flows caused by snowmelt during rainfall. In a 96‐ha clearcut watershed in the transient snow zone, peak flows with return periods of roughly 3–8 years were higher than predicted by prelogging data. In a similarly clearcut 10‐ha watershed, sizes of peak flows caused by melting of relatively deep snowpacks during rainfall were also higher after logging. Higher peak flows indicate a higher rate of water delivery to soils, which, in turn, suggests increased potential for both hillslope and channel erosion.

Energy Dynamics of Three Low-Order Southeast Alaska Streams: Allochthonous Processes

ABSTRACT Allochthonous processes of three low-order southeast Alaska streams, exhibiting a range of riparian vegetation and successional stages occurring before and after logging, were compared. Leaf-litter traps were used to estimate annual litter input. Leaf processing rates were measured by confining known amounts of leaf material in litter bags. Instream woody debris and stored and transported organics were also estimated. Annual litter inputs ranged from 52 g AFDW-m−2 on a clearcut watershed to 295 g AFDW.m−2 on a logged and deciduously revegetated watershed. All deciduous species tested (red alder—Alnus rubra, black cottonwood—Populus trichocarpa, salmonberry—Rubrus spectabilis) had fast post-leaching processing rates (k > 0.01), while western hemlock (Tsuqa heterophylla) was processed slowly (k < 0.005). The logged watersheds contained the largest amount of woody debris. Stored particulate organic matter (POM) was generally 2 or more times greater in depositional than erosional areas. Seasonal chan...

Early vegetation recovery and element cycles on a clear-cut watershed in western Oregon

Aboveground biomass and leaf area, net primary production, and nutrient cycling through vegetation were studied for 3 years after clear-cutting (stems only) of a 10.24-ha watershed in the Oregon Cascade Mountains. The riparian zone and four main habitats were analyzed separately. In 3 years, aboveground net primary production increased from 5 to 112 g•m−2•year−1 in the ridgetop habitat; midsummer aboveground biomass increased from 8 to 196 g/m2 in the riparian zone and from 198 to 327 g/m2 on the ridgetop. Other values were intermediate to these. Litter fall of species with perennial aboveground parts averaged 20–27% of standing biomass. Native annuals, especially Araliacalifornica Wats., dominated the riparian zone. Seneciosylvaticus L., an introduced species, dominated most of the rest of the watershed, except for the ridgetop habitat, which was dominated by residual woody shrubs. Uptake of N exceeded losses in streamflow the 1st year and was six times greater in the 2nd; uptake of P and K in that year was 2.5 and 3 times greater than losses. In the 3rd year, total uptake of K (2.5 g•m−2•year−1) equaled the preclear-cutting level, and uptake of N (1.3 g•m−2•year−1) and P (0.3 g•m−2•year−1) was about half that level. No correlation was found between plant uptake and nutrient loss in streamflow. Uptake of all elements exceeded return through leaching and litter fall by 16%, except that of Mg, which exceeded return by 44%. Because of early dominance by species with annuals, the proportion of elements redistributed internally by vegetation was generally low. The amount of nutrients in flux through vegetation, atmosphere, and stream was small in comparison to the amount lost in the removal of tree stems.