- McGee, Gregory
SUNY College of Environmental Science and Forestry
Forest structural habitat features (SHFs) such as snags, decaying logs, and live, old/large trees are known to provide important habitat for a variety of forest-dwelling organisms in many forest types, and previous research has shown that SHF abundance can be regulated through management decisions. However, in the northern forest region, foresters currently have limited knowledge of how specific silvicultural prescriptions influence SHF abundance and how SHFs affect the abundance and diversity of many forest-dwelling taxa. Many managers seek to modify prescriptions to improve SHF availability while providing for sustainable production of wood products. Our objectives were to quantify SHF abundance in stands with definable and consistently applied silvicultural treatments, assess the role of tree diameter/age on arboreal lichen and invertebrate communities, and incorporate wood decay functions into forest growth simulators in order to predict equilibrium log and snag volumes in modeled stands of varying management prescriptions.
At replicate sites with known and consistently-applied management histories in central and northern New York, and New Hampshire, we sampled: decaying log and snag volumes; cavity tree densities; decayed wood bulk density in relation to known year of cutting (from 3-40 years prior to sampling); and arboreal lichen and mite communities.
Our research conclusions are summarized below.
- – Stands managed under single-tree selection system for 2-3 entries over ~30 years, and even-aged maturing forests that regenerated following clearcutting or fire possessed approximately 50% of the decaying wood volume of unmanaged forests. Most of the difference was due to greater accumulation of large logs (>25 cm diameter) in the old forests.
- – We detected no differences in wood decay rates in even-aged versus uneven-aged managed stands. Approximately 80% of wood mass decays within 20 years. We are modifying a forest growth simulator in order to develop predictive models of equilibrium coarse woody debris volumes under differing management regimes.
- – Large (>55 cm dbh) sugar maples possess nearly twice the total lichen cover of small (15-35 cm dbh) trees. Large and small sugar maples supported different lichen communities. Stand history was less important than tree size in determining lichen abundance and composition, indicating that lichen diversity and abundance can be maintained in even- and uneven-aged managed stands as long as large, residual canopy trees are retained.
- – Arboreal, foliose lichens supported more oribated mites per unit area than bare bark and crustose lichens. In what was the first quantitative assessment of arboreal mites in the northern forest, we found three new, undescribed species in a bark/lichen substrate sample totaling 0.25 m2.