Possible projects for independent study

These are related to our field work in New Hampshire (opportunities for summer internships!) in Multiple Element Limitation in Northern Hardwood Ecosystems (http://www.esf.edu/melnhe/). We are measuring the response of forests to nutrient limitation, by adding nitrogen, phosphorus, and calcium to 13 northern hardwood stands in Bartlett Experimental Forest, Hubbard Brook Experimental Forest, and Jeffers Brook, all in the White Mountain National Forest.

For research apprenticeships (FOR 298), we can offer a variety of activities in the field and the lab. We will make several weekend trips to New Hampshire to collect leaf litter. Laboratory activities include processing leaf litter, analyzing soil texture, sorting roots from soil, sorting seeds from litter, identifying Neonectria species via microscopy, and entering and managing data. These do not require an independent project and are graded S/U based on hours worked (40 hours/credit).

1. Roots from the soil pits excavated at Hubbard Brook this year can be used to complete a data set of roots collected from soil pits at Bartlett Experimental Forest. The distribution of root biomass is important to predicting forest productivity and nutrient uptake.

2. Are trees producing more leaves in response to fertilization? Which limits leaf production, N or P? Is there more of a response in young stands than old stands or in infertile sites compare to more fertile sites? We are sorting leaf litter by species and weighing them. These can be compared to pre-treatment data to analyze change over time due to nutrient additions. An intern on this project will learn to identify leaves by species, dry and weigh them, and organize and report the data.

3. Soil texture is a master variable that determines water holding capacity and affects nutrient cycling in ecosystems. Some literatures suggest prior to determining soil texture, organic matter must be removed from the soil, but others suggest that it depends on the origin and characteristic of the soil. We have soil samples from all 13 stands, across 3 sites with contrasting parent materials (from granite to amphibolite). We need to determine whether a pre-treatment to remove organic matter (by wet oxidation or dry ashing) is necessary to get accurate results. This project involves soil processing and analysis and data analysis and interpretation.

4. Beech bark disease invaded North America a century ago but the disease is still not entirely understood. So far we know that this disease complex involves the attack of beech trees by either (or both) of two types of beech scale insect, followed by either (or both) of two types of neonectria fungi. An intern on this project will sort photos of diseased beech trees and quantify aspects of the disease on photos of tree bark using ImageJ, a java-based image processing program.

5. In the second year of nutrient treatments, we collected quantitative samples of leaf litter arthropods from all 13 of our sites. Using a dissecting microscope, sorting these arthropods to order (or possibly to family) would help to answer questions about the effect of nutrient additions (N, P, Ca) on the brown food web.

6. Video/photographic documentation of lab procedures: A student interested in environmental interpretation or science communication could help us document many of the lab procedures we find difficult to explain, such as root sorting, leaf sorting, ashing and digestion, ICP, and oxidizing soil organic matter prior to textural determination.

7. Our pre-treatment foliar data set is incomplete! There are archived samples in need of analysis. A student on this project would learn procedures for analyzing tissue chemistry using microwave digestion and inductively coupled plasma emission spectroscopy. Data analysis could include calculation of foliar nutrient resorption in response to our treatments (pre-treatment concentrations being an important covariate in the analysis).

Contact Jenna Zukswert, e mail: jmzukswe@syr.edu for more information.

Title: Phosphorus concentrations in forest streams in response to flow and harvesting

Background:Concentrations of P in streams draining forested catchments are so low (ppb) as to be below the detection limit of analytical techniques used for monitoring P in agricultural settings (ppm). Patterns of P concentration and discharge from streams in forests are therefore poorly known, although P is a limiting nutrient to aquatic organisms.

Project Description: We have a large collection of stream water samples from the Catskill Mountains of NY State and access to similar samples from the White Mountains of New Hampshire. These samples allow questions to be posed concerning the relation of P concentration to discharge (based on samples collected during storm events) and the effects of forest harvest (comparisons of clearcutting, partial cutting, or no cutting). The project would be based in the Soil Fertility Laboratory at SUNY-ESF. The first challenge will be to get the method running again; it used to work for us, but the last person who tried it could not get a good standards curve. Visiting other labs in Syracuse that successfully measure P at ppb concentrations might be an important step.

Title: The Extent and Cause of Regeneration Failure of Sugar Maple

Background: Sugar maple is the most abundant species in the northern hardwood forest, the most widespread forest type in the Northern Forest. Where sugar maple has failed to regenerate in recent years (Jenkins 1997, Beaudet et al. 1999, Didier and Porter 2003), causes have not been fully ascertained. Factors commonly suggested include competition from interfering plants (Hane 2003), herbivory (Didier and Porter 2003, Gardescu 2003), and soil calcium depletion due to acid rain (Jenkins 1997). These causes must yet be evaluated in conjunction with natural factors such as the availability of a seed source and degree of overstory shading.

Project Description: We will assess the current status of sugar maple regeneration across the region, and compare present conditions to those recorded in the past through the USFS Forest Inventory and Analysis (FIA), the North American Maple Project (NAMP), and surveys by the Wilderness Conservation Society (WCS). We will evaluate the importance of factors such as stand age, canopy density, interfering plants (e.g., beech and ferns), deer browsing, landscape position, and soil conditions (e.g., drainage class, acidity, and calcium availability) for explaining spatial patterns in the distribution of sugar maple regeneration. Additionally, we will evaluate the use of sugar maple regeneration as a bio-indicator of soil acidification and associated loss of biodiversity.

Background: This project compares two approaches to modeling nutrient uptake at the root surface: a steady-state approach (Nye and Tinker, Yanai, Smethurst and Comerford), which fails to represent initial conditions, and a time-dependent approach (Barber, Cushman), which makes assumptions about initial conditions and doesn't allow time-varying input. A third model simulates uptake using a finite-difference approach, rather than an analytical solution.

The problem is that the time step of the finite difference model must be very small when the rate of solute flux is large relative to the compartment size. To run the entire model at this time step would be prohibitively slow. The next task, therefore, is to embed the model in a shell that would optimize the time step for each soil compartment as the model runs. Three sets of model parameters have been developed, representing Mg, K, and P uptake by red spruce seedlings. The analytical models have already been run. The comparison of models should be publishable if only the programming problem of optimizing the time step can be solved. The model thus far.

Background: We have data on trace metals in various components of northern hardwood forest ecosystems. These data are generated when samples of plant tissues or soils are analyzed for other purposes, and they represent an untapped source of information about elements that are not much studied. Zinc is a micronutrient that is required in trace amounts by plants, but some species (notably birch species) have high concentrations of Zn, for unknown reasons. We have leaf litter concentrations by species in 13 stands of different ages, along with forest floor concentrations; for 6 of these stands, we will also have soils data. Similarly, manganese is an element that is little studied, though it has been implicated in sugar maple decline.

Other Projects: Please feel free to develop a research topic that would fit your interests and relate to or expand upon our current research.