1. The Role of Citizen Scientists in Monitoring the Hemlock Woolly Adelgid (Adelges tsugae) in New Hampshire
Debra Kimball
M.S. Graduate, Environmental Education
Department of Education
University of New Hampshire

2. The Hemlock Ecosystem
Eastern hemlock is one of the most shade tolerant and long lived tree species in the E. US.
Hemlock is usually located on northern exposures, steep riparian slopes, and edges of wetlands
Provides critical habitat for many plant and animal species
Important in maintaining aquatic habitat, shading streams, regulating stream flow, moderating water temperatures, and shading vernal pools
black throated green and blackburnian warbler, and acadian flycatcher primarily associated with hemlock forests
winter shelter for deer and other mammals
Stream water quality affected as hemlock stands die near riparian areas > increased N leaching

3. Problem
The hemlock woolly adelgid (Adelges tsugae) is a small aphid-like insect that has caused extensive damage to eastern hemlock (Tsuga canadensis) stands from Georgia to Massachusetts.
New Hampshire currently relies on the public to recognize HWA infestation and report it to the county forester, DES Division of Forests and Lands, or UNH Cooperative Extension

4. Range of HWA Infestation

5. Biology of A. tsugae
The hemlock woolly adelgid is parthenogenetic (only females occur)
Produces 2 generations/year
Sistens-9 month cycle, progrediens- 4 month cycle
Together they lay about 200 eggs/year
Best time to see woolly ovisacs between November and June
Feeds during cooler part of year inactive in summer months
injects stylet into xylem ray paremchyma cells, likely injecting a toxic saliva
Reddish brown nymphs can be carried to other trees via wind and animals
Causes rapid desication and foliage discoloration

6. Hemlock Woolly Adelgid - Depletes needle of stored nutrient supplies and photosynthate

7. Field and Lab Measurements
J. Pontius 5/04
Field and Lab Measurements
Hemlock Health
% New Growth
Foliar Transparency
% Dieback
Live Crown Ratio

8. Hemlock Woolly Adelgid Life Cycle

9. Heavy infestation Note grey foliage
Adelgid ovisacs on twig at base of needle

10. Hemlock Decline Productivity Reduced Needles desiccate and drop
Dieback of limbs and entire branches
Mortality typically within 4-6 years
Widespread mortality expected
Once HWA becomes established on hemlock, dramatic declines in new growth production are the first symptoms (Ward et al. 1992). Flushes of new growth then inversely cycle with HWA populations for several years in a density dependent feedback loop (McClure et al. 1996). As nutrient reserves are depleted, defoliation and chlorosis progresses, followed by fine twig and branch dieback. Complete mortality typically occurs within 5-6 years of the initial infestation, although some trees have been known to survive for more than 10 years (McClure 1996, Orwig 2002). Generally, the stands with the highest mortality are those that have had a population of HWA for the longest time (Mayer et al. 1998). However, exceptions to this pattern may occur, depending on environmental conditions (Mayer et al. 1998), and water stress (Onken, 1995).
Most researchers now agree that all hemlock may ultimately be susceptible to HWA (Foster et al. 1999, Orwig and Foster 1998). Large canopy gaps, and in homogeneous stands, entire canopies may be opened. This is expected to reduce plant nutrient and water uptake, and increase light attenuation, soil temperatures, decomposition and nutrient cycling rates (Jenkins et al. 1999, Yorks et al ).
Hemlock mortality can have dramatic effects on nutrient cycling rates. Mortality may result in nutrient leaching from the soil and nutrient loading to stream water (Jenkins et al. 1999). The resulting elevated nutrient leaching could lead to site nutrient capital reduction and in turn, a reduction in forest productivity (Yorks et al. 1999). Because healthy hemlock stands filter rainwater, prevent soil erosion, limit light availability and algal productivity, and have a large effect on soil nutrient cycling, the loss of hemlock in the overstory is likely to be associated with a decline in surface water quality (Yorks et al. 1999). The impact of hemlock mortality on surface water quality is likely to be exacerbated by the tendency of eastern hemlock to grow along streambeds and in ravines (Whitney 1990). This could impact the management of watersheds providing municipal water supplies
In southern New England, HWA has initiated a rapid shift from a coniferous to a deciduous forest, with black birch (Betula lenta L.), red maple (Acer rubrum L.) and various oaks (Quercus spp.) growing up beneath the dying hemlock canopy (Orwig and Foster 1998). Such a dramatic change in forest species composition could be detrimental for the hundreds of avian, mammal, aquatic, amphibious and understory plant species that depend on the unique micro-habitats created within hemlock stands (Evans et al. 1995).
J. Pontius 5/04

11. Hemlock Decline Rating System
J. Pontius 5/04
Hemlock Decline Rating System
Healthy
Pre-visual symptoms
Decline/Recovery Cycle
Final Decline

12. Hypotheses
Citizen scientists will be able to monitor for the presence of hemlock woolly adelgid through out the state of New Hampshire using simple protocols
Student groups can provide reliable ground truth
for hemlock foliar health
Student data will find a relationship between geographic and site location(slope and aspect) of a stand and infestation rates or hemlock health

13. Objectives
Develop training protocols to collect data for a state monitoring system of HWA
monitor stands for the presence or absence of HWA, growth rates, foliar health, and site characteristics
Determine accuracy of plant stress glasses in detecting damaged needles and compare to hyperspectral data
Determine the relationship between geographic and site location(slope and aspect) of a stand and infestation rates or hemlock health

14. Methods
1. Select ten schools/groups to monitor the health of their hemlock stands by determining:
Location, GPS coordinates
Presence of HWA or other pests
(Report any occurrence of HWA to State DES or UNH Extension)
Size and composition of stand
Select 5 trees to monitor overall health (include height, DBH, canopy closure, live crown ratio, % new needle growth, stress glasses results)
Slope and Aspect
2. Acquire Landsat TM satelite datasets and hyperspectral datasets (pre and post infestation)
Have students compare above datasets to yearly ground truth data
3. Develop a Hemlock Health monitoring guide for easier identification of signs of HWA and other hemlock pests
Send out printed copies to selected schools and put on Forest Watch and DES? websites

15. Anticipated results and summary
A citizen scientist monitoring system for the presence of hemlock woolly adelgid and hemlock foliar health through out the state of New Hampshire will assist researchers
Ground truth data for hemlock foliar health will be valid and useful in checking remotely sensed data (Forest Service)
Student data may find a relationship between geographic and site location(slope and aspect) of a stand and infestation rates or hemlock health

16. Websites of Interest
main site
bibliography
Contact # in NH- 603/

17. Pawtuckaway State Park, NH
“Unless an effective biological or chemical control is found that can be released on a massive scale that coincides with the range of HWA, hemlock may be eliminated across broad portions of its range in a few decades” (Orwig and Foster 1999)

18. Timeline Category Fall 04 Winter 05 Spring 05 Sum 05 Fall 05
Lit review
Proposal work
Submit proposal for grant funding
Fieldwork/ school visits
Monitor sites in program
Meet with researchers from USDA forest service, State, UNH
Implement monitoring program
Analyze/report data to State