My students

Current:

Andrew Mishler, MS, anticipated completion May 2009
Size of discolored hearts of sugar maple
Dark discolored sugar maple wood is less valuable than the lighter colored sapwood.  Factors leading to the prediction of this characteristic would be very helpful to foresters and timber managers.  Few studies have examined the relationship between dark discoloration size and site or individual tree factors.  We evaluate some of these characteristics (bark type, diameter, slope, aspect, etc.) and present the results.  Future analysis will include stand history and exposure to injury, which is commonly thought to influence dark discoloration in sugar maple.

 

Tim Porter, MPS, anticipated completion December 2008

 

Nick Pitel, MS, anticipated completion May 2010

Health and regeneration dynamics of sugar maple.  We are studying factors that might explain why some stands suffer dieback and mortality following defoliation by forest tent caterpillar, while other stands recover.  We are also interested in the extent and causes of sugar maple regeneration failures; this aspect has not yet been funded.  Both studies will attempt to link soil factors to forest dynamics.

 

Former Students

Dustin Wood, MS, 2008. 
Evaluating the susceptibility of sugar maple stands to defoliation by forest tent caterpillar (Malacosoma disstria Hübner) and the vulnerability to decline.

The recent outbreak of Forest Tent Caterpillar (FTC) in the northeastern U.S. has devastated millions of acres of forestland, resulting in widespread dieback, loss of vigor, and in some cases mortality. However, some forest stands have been more resilient to defoliation stress than others.  The objectives of this study were to 1) determine if dieback, loss of vigor, and mortality in forest stands were greater when the stand was defoliated, and 2) determine the site, stand, or tree characteristics that can be used to predict dieback, loss of vigor, and mortality in forest stands following FTC defoliation, and using regression, incorporate them into a hazard rating model.

Read More:  Two papers are forthcoming from this research.
Where is he now? Research Analyst, SUNY-ESF.

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Paul Lilly, MS, 2007

Cation exchange chemistry and the long-term effects of liming on acidic forest soils in the northeastern United States

I collected samples from four previously established liming experiments in order to characterize the long-term effects of liming on cation exchange properties and test various proposed models for the relationships between pH, base saturation (BS), and cation exchange capacity (CEC). Limed sites generally had higher pH and BS, more organically bound Al and less bound hydrogen, and fewer E horizons. Limed organic horizons had lower organic matter content than controls, and limed mineral horizons had lower effective CEC, suggesting that podzolization may be disrupted or masked in limed soils. Regression analyses testing models of charge development on organic matter suggest that sites binding non-exchangeable Al should be excluded from the pool of potentially dissociable functional groups. Results for models of exchangeable cation equilibria suggest that exchangeable Al does not behave as a base cation, but rather is part of an equilibrium with organically bound Al that buffers pH change.

Where is he now? Working toward PhD, University of Vermont
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Farrah Fatemi, MS, 2007

Aboveground biomass and nutrients in developing northern hardwood stands in New Hampshire, United States

Accurate estimates of biomass and nutrient stocks in young second-growth forests are critical for assessing ecosystem productivity and the contribution of these forests to regional and global nutrient cycles. Forest biomass in northeastern temperate forests is commonly estimated using previously established allometric equations. Most allometric equations for smaller trees (2-12 cm dbh) and corresponding nutrient stock estimations have been developed using smaller trees from older stands (>50 yrs since last cut). To study how the prediction of biomass and nutrients stocks based on tree diameter vary with stand age, we studied six developing stands in and around the Bartlett Experimental Forest, in the White Mountains of New Hampshire. We developed allometric equations for aboveground biomass and nutrients of six northern hardwood species in two young (∼15 yrs old) and two middle-aged stands (∼30 yrs old). We also conducted non-destructive tissue sampling and made measurements to estimate biomass and nutrients in two old stands (>100 yrs old). Results from this study indicate that most allometric equations developed from this study in younger stands are very similar to those developed by other authors for the same species in older stands for total aboveground and wood biomass. However, we suggest that for components such as foliage, bark and branches, site- or age-specific biomass equations should be used in order to accurately assess aboveground biomass. Additionally, some tissue nutrient concentrations (K, P and N) were significantly different in young and old stands, necessitating age-specific nutrient concentrations for accurate estimations of some nutrient stocks.

Read More:  Papers are forthcoming from this research.

Where is she now? Working toward PhD, University of Maine 
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Byung Bae Park. PhD, 2006

Fine root dynamics and tissue chemistry across a calcium gradient in temperate hardwood and softwood forest ecosystems.

The effect of nutrient availability on the chemistry of fine roots and root turnover is important to terrestrial carbon and nutrient cycling, but it is poorly understood. Differences in sensitivity to soil fertility across tree species and developmental stage may influence forest response to environmental change, but these rarely have been compared in the field.

I estimated fine root biomass (FRB), fine root production, and nutrient turnover by coring and minirhizotron technique and aboveground production by allometric equations of hardwoods and softwoods at three Ca gradient sites: Sleepers River, VT; Hubbard Brook, NH; and Cone Pond, NH. I also measured annual growth rates and tissue chemical concentrations among species and growth stages in two contrasting base cation sites at Huntington Forest, NY.

Fine root biomass varied across sites, from 465 g m -2 to 682 g m -2 , but there were no statistically significant differences among sites within forest type. Root biomass density declined with depth; 57 and 66% of FRB for hardwoods and softwoods, respectively, occurred 10 cm above soil. Surprisingly, the ratio of dead to live roots in softwoods increased as a function of depth, but there was no such change in hardwoods. Fine root turnover rates varied from low (0.62-0.71 yr -1 ) to high (1.32-1.86 yr -1 ) as Ca gradient. Fine root production ranged from 1.2 to 3.7 Mg ha -1 yr -1 for hardwood stands and from 0.9 to 2.3 Mg ha -1 yr -1 for softwood stands. Although FRB and leaf litter production were not significantly correlated to soil fertility, fine root production and the ratio of root production to leaf litter production were clearly higher in sites with higher soil fertility.

Root nutrient concentrations were significantly affected by site and root diameter. Calcium and Mg concentrations in live roots were greatest in sites with the highest concentrations of base cations. Calcium concentrations were higher in the larger roots, but P, N, and Al concentrations were higher in the finer root classes. Among sites, I found significant differences of nutrient turnover by fine roots, but not between forest types. Magnitude of differences between sites for each element ranged from 3 times for P and N to 8 times for Ca and Mg, but differences between forest types were less than 2-fold. Root Ca turnover ranged from 3 to 23 kg ha -1 yr -1 increasing exponentially with soil Ca saturation increased. The Ca gradient study suggests that greater nutrient availability leads to greater carbon allocation and nutrient inputs belowground in north temperate forest ecosystems.

In Huntington Forest, sugar maple growth (14.8 cm 2 yr -1 per tree) at the site with higher base cations was much greater than at the other site (8.6 cm 2 yr -1 per tree), but the growth of beech was not different between the two sites. Root and foliar Ca, K, and Al concentrations were positively correlated with soil elements, but Mn concentrations were negatively correlated. Sugar maple differed more than beech between sites in foliar K, Mn, and Zn concentrations. Sugar maple seedlings differed more than mature trees in nutrient concentrations in roots. The sensitivity of sugar maple seedlings to nutrient availability could ultimately contribute to the replacement of sugar maple by American beech in regions of low pH and base cations if base cation leaching by anthropogenic deposition and tree harvesting continues. (Abstract shortened by UMI.)
Read More:

Park, B.B., R.D. Yanai, M.A. Vadeboncoeur, and S.P. Hamburg.  2007. Estimating root biomass in rocky soils using pits, cores and allometric equations. Soil Sci. Soc. Am. J. 71:206-213. PDF

Yanai, R.D., B.B. Park, and S.P. Hamburg.  2006. The vertical and horizontal distribution of roots in northern hardwoods of varying age.  Can. J. For. Res. 36(2): 450-459.     PDF

Park, B.B., R.D. Yanai, J.M. Sahm, D.K. Lee and L.P. Abrahamson.  2004.  Wood ash effects on plant and soil in a willow bioenergy plantation. Biomass and Bioenergy.  28(4):355-365. PDF

Park, B.B., R.D. Yanai, J.M. Sahm, B.D. Ballard, and L.P. Abrahamson.  2004.  Wood ash effects on soil solution and nutrient budgets in a willow bioenergy plantation.  Water, Air, and Soil Pollution 159:209-224. PDF

Effect of Silvicultural Treatments on Carbon Storage of Northern Hardwood Forests Roosevelt Wild Life Station website

Where is he now?  Korea Forest Research Institute (KFRI), Department of Forest Conservation, Dongdaemun-gu, Seoul, South Korea
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Melissa Lucash, PhD, 2006

Methods for measuring nutrient uptake rates of intact roots of seedlings and mature trees

Most studies measuring uptake rates of trees use excised roots, even though excision may lower uptake. In my research I used intact roots to improve estimates of specific uptake rates by seedlings and mature trees.

To determine how uptake varies throughout the year, I measured the temporal variation of nutrient uptake capacity of K + , NH 4 + , NO 3 - , Mg 2+ and Ca +2 in mature loblolly pine trees. I expected net uptake to be positive throughout the year but I observed net efflux of K + , NH 4 + and NO 3 - in July. I also measured uptake at several solution concentrations, expecting uptake to increase with concentration. I observed this pattern in April but not July or October. In October, uptake was constant across concentration; antecedent nutrient concentrations affected the temporal patterns of uptake in July. As expected, I found greater uptake of NH 4 + than NO 3 - . Temporal patterns of uptake capacity are difficult to predict, since experiment duration, antecedent conditions and nutrient solution concentration, affect measured rates of uptake.

I used a sequence of treatments to measure the effect of disturbance during measurements of NO 3 - uptake. First, I measured uptake by loblolly pine seedlings in intact columns of sand using the SUM (soil uptake monitoring) method. Second, I removed the seedlings from the columns and measured their uptake using the hydroponic method. Third, I transferred the plants back into the SUM columns. As predicted, uptake by undisturbed SUM plants was higher than plants which had been excavated and repotted back into SUM columns. In addition, transferring plants from the SUM columns to hydroponics caused a delay in uptake. The SUM column technique holds promise for conducting nutrient uptake studies with minimal disturbance to the root.

I reviewed current techniques suitable for measuring uptake by roots of mature trees. Estimates of uptake obtained using these methods are affected by the sampling scheme, experimental conditions, excision, ion concentrations and the rate of ion efflux. I also discussed two new techniques, the SUM column technique described above, and digital autoradiography. A greater focus on methods development is critical to more accurately measuring uptake of mature tree roots under field conditions.
 Read More: 

Lucash, M.S., R.D. Yanai, and J.D. Joslin.  Nutrient uptake by intact and disturbed roots of loblolly pine seedlings. Environmental and Experimental Botany (in press)

Lucash, M.S., D.M. Eissenstat, J.D. Joslin, K.J. McFarlane and R.D. Yanai. 2007.Estimating nutrient uptake by mature tree roots under field conditions: challenges and opportunities. Trees - Structure and Function 21(6):593-603. PDF

Lucash, M.S., R.D. Yanai, and J.D. Joslin.  2005.  Temporal variation in nutrient uptake capacity by intact roots of mature loblolly pine.  Plant and Soil 272:253-262. PDF

Yanai, R.D., P. Sollins, and M.S. Lucash.  2003.  Ecosystem ecology: in pursuit of principles.  Ecology 84:1640. PDF

Where is she now?  Looking for a tenure-track position.
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Pete Homyak, MS, 2006

Nitrogen immobilization by woodchip application: protecting water quality in a northern hardwood forest.
Forest harvesting can have adverse effects on stream water chemistry by lowering pH, ANC, and increasing nutrient concentrations.  Since forestry best management practices do little to directly address the effects of harvesting on stream chemistry, my research investigated the potential of wood chips derived from logging slash to immobilize inorganic N in a patch cut of northern hardwoods in NY.  Although further research is needed to better quantify the duration of the N immobilization period, surface applied wood-chips have the potential to limit inorganic N input to streams for at least the first year following cutting.  The objective of this project is to provide forest managers with an alternative to limit potential negative impacts on water quality.

Read More: 

Homyak, P.M., R.D. Yanai, D.A. Burns, R.D. Briggs, and R.H. Germain. 2008. Nitrogen immobilization by wood chip application: protecting water quality in a northern hardwood forest.  Forest Ecology and Management 255: 2589-2601.  PDF

Where is he now?  Working toward PhD, UC-Riverside Pete's profile
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Kimberly Bohn, PhD, 2005

Residual spatial structure and implications for sawtimber production in uneven-aged northern hardwoods after selection system silviculture or diameter-limit cutting

Selection system silviculture in uneven-aged stands places more emphasis on residual stand conditions compared to diameter-limit cutting. Differences in stand conditions may affect the ability to sustain sawtimber production as well as non-commodity values over the long-term. Previous work has evaluated the effect of these treatments on stand diameter distributions and growth but not on spatial structure of residual trees. I developed a simulation process for evaluating long-term changes in spatial structure and sawtimber production over a range of initial stand conditions represented on 10 stem maps.I evaluated changes in spatial structure using two methods. Variability of sawtimber spacing was greater after diameter-limit cutting than selection system for each of three cuttings, although differences between treatments decreased during the growth periods between cuttings. No differences were detected in spacing of the poles using variability of basal area as a measure. However, results from the Ripley's K statistic indicated that clumping developed in the pole classes during the growth period following the initial diameter-limit cut. Sawtimber trees were uniformly spaced after selection system and randomly spaced after diameter-limit cutting.

I evaluated sawtimber production and yield on same set of plots used to study spatial structure. Simulated selection system silviculture resulted in consistent sawtimber yields over three cutting periods, with greater than 75% of the volume in medium and large sawtimber. With repeated diameter-limit cutting, sawtimber harvests declined significantly at the second and third entries, and the majority of the volume from these cuttings came from small sawtimber. Comparisons of treatments across individual plots varied by several thousand board-feet, in part because of the large variability in yields from diameter-limit cutting.

Differences in both spacing and the density of trees affected comparisons of sawtimber volume production after selection system or diameter-limit cutting. The greater sawtimber volumes obtained by the simulated selection system treatments may reflect a combination of factors, including more uniform spacing, more optimal densities, and the presence of large residual trees. Further research should evaluate the degree to which these factors influence stand-level production.
Where is she now?  Assistant Professor, University of Florida, West Florida Research and Education Center (WFREC), Milton, FL Kimberly's website
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Karis McFarlane, MS, 2003

Measuring nutrient uptake by roots of sugar maple, red pine, and Norway spruce trees in situ

Freshly excavated intact roots often release nutrients in nutrient uptake experiments, possibly due to disturbance caused during excavation. I tested the effect of four pre-experiment treatments on net uptake of nutrients by sugar maple ( Acer saccharum Marsh.), red pine ( Pinus resinosa Ait.), and Norway spruce ( Picea abies (L.) Karst.) in monospecific plantations in central New York. Roots were (1) "trained" to grow in a sand-soil mixture, (2) excavated and exposed to nutrient solution for two or (3) four days, or (4) freshly excavated. Roots were then exposed sequentially to three concentrations of nutrient solutions for 2 hours each. Net uptake rates increased with concentration for ammonium, nitrate, phosphate, potassium, sodium, and aluminum for all species. Net efflux of calcium increased with increasing concentration. Magnesium was not consistently taken up or released by all species. None of the pre-treatments improved uptake measurements consistently across all combinations of nutrients and species studied.

Read More: 

McFarlane, K.J. and R.D. Yanai. 2006. Measuring nitrogen and phosphorus uptake by intact roots of mature Acer saccharum Marsh., Pinus resinosa Ait., and Picea abies (l.) Karst. Plant and Soil 279(1-2): 163-172. PDF

Where is she now?  Postdoctoral Researcher, Center for Accelerator Mass Spectrometry, Lawrence Livermore National Laboratory Karis' website
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Vincent Giorgio, MPS, 2003
 I completed an MPS while at ESF.  As part of my degree program, I was involved in a research project in Baltimore MD through the Baltimore Ecosystem Study (under the direction of Dr. Katalin Szlavecz at Johns Hopkins University and Dr. Richard Pouyat of the US Forest Service).  The project involved investigating various soil physical, chemical, and biological properties from urban to rural forest patches.  The goal was to determine if an urban-rural gradient could be identified as was described in the literature from studies in the NYC area. 

A total of 52 soil samples were collected and analyzed for bulk density, pH, organic matter content, texture, and nutrient content. Earthworm and macroarthropod samples were also collected at each sampling location.  Significant differences (p <. 0.05) between urban/rural sites were found for bulk density, soil Ca, Mg, and Na with urban sites showing higher values than rural for each. Earthworm density and biomass varied between 10 and 71 ind. m-1 and 3.7 and 75.1 g m-1 respectively. Earthworm biomass showed positive correlation with pH, and negative correlation with soil organic matter content and leaf litter depth. Species composition was a better indicator for site conditions than abundance. Due to the low rainfall that year, microarthropod samples yielded insufficient data to conduct analyses.  Cluster analysis showed that underlying geology was just as important as land use in explaining observed differences between urban/rural sites, indicating that natural phenomenon are likely to be as important and anthropogenic influences.

I also received a Masters in Public Administration (MPA) from Syracuse University’s Maxwell School with a concentration in state and local government.  My program of study included a year-long internship with the USEPA Environmental Finance Center, Region 2, which involved providing technical assistance to local government officials with respect to planning and financing of water and sewer infrastructure upgrades. 
Where is he now?   Since 2003, I have been working as an Associate Project Manager for the NYC Dept of Environmental Protection, Bureau of Water Supply.  My job involves facilitating, planning, coordinating, and implementing capital projects and education/outreach programs associated with the City’s Long-Term Watershed Protection Program, Kensico Reservoir Water Quality Control Program, and East of Hudson Nonpoint Source Management Plan. 

Sarah Kulpa, Honors Thesis, 2002
Calcium and potassium efflux during measurements of nutrient uptake by intact tree roots
Where is she now?  Regulatory Specialist, Devine Tarbell & Associates, Inc, Syracuse.
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Richard Phillips, MS, 1999

The effects of calcium chloride and aluminum chloride additions on rhizosphere soil and suger maple (Acer saccharum Marsh.) fine root chemistry

Calcium chloride (CaCl2) and aluminum chloride (AlCl3) additions were used to induce changes in Ca and Mg availability in eight experimental plots at the Hubbard Brook Experimental Forest, NH. Soils (rhizosphere and bulk) and sugar maple fine roots were sampled in the Oa horizon and the upper 10 cm of the mineral soil. In the Oa horizon of AlCl3 treated plots, exchangeable Al was 42% greater (p < 0.05), exchangeable Mg was 31% lower (p <$0.1) and (Ca + Mg)/Al ratios were 54% lower (p <$0.1) than in control plots. Fine roots in the Oa horizon had 21% less Ca (p < 0.1), 30% less Mg (p < 0.1) and 42% lower (Ca + Mg)/Al ratios (p < 0.05) in AlCl3 treatments than controls. Rhizosphere soil and fine root (Ca + Mg)/Al ratios were strongly correlated (r = 0.84; p < 0.001) irrespective of treatments or horizon. Rhizosphere soils were depleted in Al and organically bound Al (Alo) relative to bulk soil irrespective of treatment or horizon. Rhizosphere soil Alo was negatively correlated with (Ca + Mg)/Al ratios in fine roots (r = 0.85; p < 0.001). These results suggest that (Ca + Mg)/Al ratios in rhizosphere soil may be good indicators of sugar maple fine root nutrition because they account for differences in Al mobilization in the rhizosphere.

Read More: 

Phillips, R.P. and R.D. Yanai.  2004.  The effects of AlCl3 additions on rhizosphere soil and fine root chemistry of sugar maple (Acer saccharum).  Water, Air, and Soil Pollution 159: 339-356. PDF

Yanai, R.D., R.P. Phillips, M.A. Arthur, T.G. Siccama, and E. Hane.  2005.  Spatial and temporal variation in calcium and aluminum in northern hardwood forest floors.  Water, Air, and Soil Pollution. 160: 109-118. PDF

Where is he now?  Assistant Professor, Indiana University, Department of Biology  Rich's website
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David Ray, MS, 1997

Patterns of development in three Adirondack northern hardwood stands following herbicide treatment and shelterwood cutting

A combination of remeasurement and chronosequence techniques were used to examine patterns of early development in three Adirondack northern hardwood stands for a period of 4 to 26 years following shelterwood seed cutting to 35 to 65% canopy cover. Mist blowing and stem injection of herbicide controlled a dense American beech (Fagus grandifolia Ehrh.) understory in these stands, leaving them devoid of advance regeneration. Deer (Odocoileus virginianus borealis Miller) populations had also been reduced by hunting and through natural losses. Both treatments have proven necessary for successful regeneration of diverse and commercially viable stands in the region. Cohort development was described as numbers of stems by size class from time of cutting. Total stems ≥1' tall and ≥ 1" dbh followed distinct patterns of development among stands, while those ≥ 3'and ≥6" tall were more variable. Total stems ≥ 1' tall peaked around 5 years after seed cutting, suggesting most new individuals had arrived and begun to grow by that time. By 10 yrs, stems ≥1' tall were declining substantially, indicating crown closure had led to stratification and competition-induced mortality within the new cohort. By 20 yrs, total stems ≥ 1" dbh were at a maximum. By 25 yrs, the numbers of stems ≥1" dbh had begun to decline. Non-linear regression techniques were used to model the consistent patterns of development observed between the stands. Functions describing the composite behavior of total stems by size class are presented, and a biological rationale for the observed patterns is discussed.

Read More: 

Nyland, R.D, Ray, D.G., R.D. Yanai.  2004.  Height Development of upper-canopy trees within even-aged Adirondack northern hardwood stands.  N. J. Appl. For. 21:117-122. PDF

Yanai, R.D., D.G. Ray, and T.G. Siccama.  2004.  Lead reduction and redistribution in the  forest floor in New Hampshire northern hardwoods.  J. Environ. Qual. 33:141-148. PDF

Nyland, R.D., D.G. Ray, R.D. Yanai, R.D. Briggs, L. Zhang, R. Cymbala, and M.J. Twery.  2000.  Early cohort development following even-age reproduction method cuttings in New York northern hardwoods.  Can. J. For. Res. 30:67-75. PDF

Ray, D.G., R.D. Nyland, and R.D. Yanai.  1999.  Patterns of early cohort development following shelterwood cutting in three Adirondack northern hardwood stands.  Forest Ecol. Manag. 119:1-11. PDF

Where is he now?  Forestry Research Scientist, Tall Timbers Research Station and Land Conservancy, Tallahassee, FL Dave's website
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Former Post-Docs

Elizabeth Hane, 2003

Where is she now?  Assistant Professor, RIT, Departments of Biological Sciences and Environmental Sciences  Elizabeth's website

 

Swee-May (Tang) Cripe, 2004

Where is she now? Instructor and Manager, Reproductive, Perinatal & Pediatric Epidemiology Training Program (RPPE), University of Washington
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Tjeerd Bouma, 2004

Read More:

Bouma, T.J., D.M. Eissenstat, R.D. Yanai, U. Hartmond, L. Wang, D. Flores, and A. Elkin.  2001.  Estimating age-dependent costs and benefits of roots with contrasting lifespan: comparing apples and oranges.  New Phytol. 150:685-695.  PDF

Where is he now? Spatial Ecology Researcher,  Netherlands Institute of Ecology Centre for Estuarine and Marine Ecology TJ's webpage

 

Byung Bae Park, 2006-2007

Read More:

Park, B.B., R.D. Yanai, T.J. Fahey, T.G. Siccama, S.W. Bailey, J.B. Shanley, and N.L. Cleavitt. 2008. Fine root dynamics and forest production across a calcium gradient in northern hardwood and conifer ecosystems.  Ecosystems 11(2):325-341 PDF

Where is he now?  see above.
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Others that have worked in our lab

Olga Yakimenko

Dr: Yakimenko (sometimes spelled Iakimenko), Research Assistant, Moscow State University's Faculty of Soil Studies worked with our group spring, 2004, as part of MSU-SUNY Professional Fellows Program. She presented her work and participated in discussions connected with exchanges of biological field work of SUNY and MSU students.

Where is she now? Moscow State University (see also her Fulbright page)

 

Yongkwan Kim

Where is he now? Korea Forest Service

 

David McMillan

Where is he now? President, Owner, and Senior Scientist, Natresco Associates David's website

 

Adam Coates

Adam worked on the first phase of the "Heartwood Project" from 2006-2008.

Where is he now? Staff Pastor, Syracuse Vineyard Church

 

Xing Wang, MS, 2003

Stream water chemistry after a partial cutting in the Neversink River Basin, New York

A paired watershed technique was used to evaluate nutrient losses during the first year after a partial cutting from a small watershed in the Catskill Mountains of southern New York. The lower two third of the 10-ha treatment watershed (Block A) was harvested in February 2002 by a shelterwood method in which 60% of basal area was removed. A nearby 48-ha watershed was left as an uncut reference. Nitrate concentrations started to increase six months after the harvest and reached maximum values (above 100 μmol/L) of ten-fold over pre-harvest levels during the next two months. The concentrations of Ca, Mg and K were lower than pre-harvest values during the first growing season, but higher at high flows during the first dormant season when compared with pre-harvest levels. Total dissolved aluminum (Al to ) increased 4- to 8-fold above pre-harvest concentrations. The concentrations of NO 3 - and Al to remained above the reference concentrations throughout the first winter after cutting. Harvest effects on stream pH were insignificant. The partial cut resulted in measurable changes in stream water chemistry but the changes were much less than those previously observed after clearcutting of a nearby watershed, which demonstrated the role of residual trees in preventing hydrologic nutrient losses, especially during the growing season.

Read More: 

Wang, X., D.A. Burns, R.D. Yanai, R.D. Briggs, R.H. Germain. 2006. Changes in Stream Chemistry and Nutrient Export Following a Partial Harvest in the Catskill Mountains, New York, USA. For. Ecol. Manag. 223:103-112. PDF

Where is he now?  Ph.D. student in Soil and Water Science Department, University of Florida

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