Celia A. Evans

Beech Bark Disease: Proceedings of the Beech Bark Disease Symposium

Contains invited papers, short contributions, abstracts, and working group summaries from the Beech Bark Disease Symposium in Saranac Lake, NY, June 16-18, 2004.

Mercury accumulation in transplanted moss and lichens at high elevation sites in Quebec

Mercury deposition was monitored at two mountain sites in Quebec using transplanted lichens and moss. The terricolous lichen species Cladina rangiferina, the epiphytic lichen species Hypogymnia physodes, and the feather moss Pleurozium schreberi were transplanted from a northern Ontario boreal site to the bases and summits of Roundtop Mountain and Mt. Tremblant in southern Quebec. After 12 months, transplants of C. rangiferina sited at the base and summit of Roundtop mountain and the summit of Mt. Tremblant showed a significant increase in mercury concentration over controls (p < 0.05). The largest difference occurred at the summit of Roundtop mountain where mercury concentration was 81.4 ± 10.9 ppb as compared to 45.6 + 10.6 ppb at the control site. No significant increases in mercury concentration in P. schreberi were seen after 12 months at any site althought trends of increase were apparent. After 20 months, further significant increases in Hg content were observed in both the terricolous lichen and the feather moss at both the Roundtop Mountain base and summit sites. A significant increase in Hg content of P. schreberi was also noted at the Mt. Tremblant summit site. Over the length of the study the greatest mercury concentration increases were observed in the feather moss at the Roundtop Mountain summit site (with a 248.3 ± 30.0 ppb mercury concentration as compared to 108.3 ± 30.0 ppb in controls). No significant change in mercury concentration in the epiphyte H. physodes was found during the study. These data indicate that mercury deposition is occurring, especially to higher elevation sites. While mercury inputs at the summits may be increased by the effects of fog, increases in mercury at the base sites cannot be accounted for the same way, but may represent the importance of dry deposition processes.

Inferring controls on the epidemiology of beech bark disease from spatial patterning of disease organisms

1 Spatial pattern in the distribution and abundance of organisms is an emergent property of collective rates of reproduction, survival and movement of individuals in a heterogeneous environment. 2 The form, intensity and scale of spatial patterning can be used to test hypotheses regarding the relative importance of candidate processes to population dynamics. 3 Using 84 plots across eastern North America, we studied populations of two associated plant parasites, the invasive felted beech scale Cryptococcus fagisuga Lind. and the native Neonectria fungi, which together cause beech bark disease (BBD). 4 We evaluated spatial patterns at the scales of trees within stands, stands within the forest and forests within the landscape to examine four hypothetically important factors in the ecology of the disease: (i) local contagion within stands; (ii) regional contagion, or among patch infection–reinfection dynamics; (iii) variation in host susceptibility linked to genetic and/or environmental heterogeneity; and (iv) climate effects on population growth of BBD organisms. 5 Analyses revealed an unexpected lack of spatial aggregation in BBD populations among trees, stands and forests. This implies that propagule pressure is generally sufficiently high throughout the infested region of North America such that neither trees nor stands are spared from the disease by dispersal limitations of the disease agents. Furthermore, variation in tree and stand level susceptibility has minimal impact on BBD dynamics and climate is not a conspicuous driver of abundance within the core range of BBD.

Effect of nitrogen and light on nutrient concentrations and associated physiological responses in birch and fir seedlings

We grew seedlings of two co-occurring high elevation tree species in controlled light and nitrogen (N) environments to examine the effect on foliar N and P concentrations and the resulting correlation with photosynthesis and growth. Foliar N concentrations in both heart-leaf paper birch (Betula cordifolia) and balsam fir (Abies balsamea) seedlings were greater in low light treatments than in high light treatments. P concentrations, however, were lower in birch and fir foliage grown in low light than in high light. N-availability had no effect on foliar N in birch but tended to increase N concentration in fir needles at all but 100% ambient light. N-availability had no effect on P concentration in fir seedlings, but high N decreased foliar P in birch. There was a positive relationship between foliar N-concentration (mg g−1) and mass-based maximum photosynthetic rate (Asat) in birch seedlings and a corresponding growth response to increased N-availability (suggesting N-limitation). Fir photosynthesis exhibited a positive correlation up to 22 mg g−1 – N and a negative correlation above that point, suggesting that high N concentrations may be detrimental to photosynthesis in the fir seedlings. There was no significant effect of N-treatment on growth.

Land use designation and vegetation community structure in the Adirondack uplands (New York, USA)

ABSTRACT Question: Does forest vegetation community structure reflect legislative land use designations? Location: Adirondack Park, New York, USA. Methods: The Adirondack Park, located in northern New York State, is a mixture of public and private lands, with state-owned Forest Preserve lands comprising ca. 42% of the 2.4 million ha, on which timber harvesting and many other forms of anthropogenic disturbance are prohibited. A survey of vegetation communities was conducted in eighteen upland catchments with differing land use history (managed and Forest Preserve), including overstory, understory, and dead wood (snags and downed woody debris) using randomly placed plots. Results: Mean overstory density and basal area were not significantly different between land uses, although mean overstory tree size was greater in Preserve catchments. Sapling densities were greater in managed catchments, while mean herb/shrub coverage was not affected by land use. Densities of 25% of common species were affected by land use, determined by GIS coverages constructed using an Inverse Distance Weighted estimation procedure. Discriminant Analysis of per-plot plant community data correctly classified 89% of both managed and Preserve plots. Conclusion: The success of the Discriminant Analysis in classifying land uses based on vegetation communities indicates its potential utility of this method in comparing forest vegetation to a reference condition in this and other areas. The analysis suggests that at least 85 years is required for Adirondack upland catchments to recover following harvesting. Uncertainty in classification was related to heterogenous management and disturbance patterns within catchments. Nomenclature: PLANTS National Database (www.plants.usda.gov).

Bringing the northern forest to your classroom

In recent years the Forest Service has reemphasized the need for increased environmental literacy among the Nations citizens and has recognized the benefits of addressing that need among school-age children. This publication is a product of an Adirondack Curriculum Project workshop sponsored by the USDA Forest Service, Northeastern Research Station, and Paul Smiths College. The workshop was held at Great Camp Sagamore in Raquette Lake, NY, in June 2005. Great Camp Sagamore is operated by the Sagamore Institute, which is dedicated to the stewardship of the camp and to its use for educational and interpretive purposes. For 2 days, 22 teachers met with resource professionals with expertise in either the Northern Forest or in teaching methods and techniques, or both, and developed the lesson plans in this publication.