11 research outputs found
Appendix B. Assessment of the relationship between hemlock crown health and understory light availability.
Assessment of the relationship between hemlock crown health and understory light availability
Appendix A. Methodological details: site description, vegetation measurements, hemispherical photography, invasibility, and propagule pressure indices.
Methodological details: site description, vegetation measurements, hemispherical photography, invasibility, and propagule pressure indices
Appendix A. Methodological details: site description, propagule pressure indices, and germination rates.
Methodological details: site description, propagule pressure indices, and germination rates
Appendix B. Summary of exotic plant species cover and density for the 1-m2 monitoring plots of exotic species in 10 hemlock sites in the Delaware Water Gap National Recreation Area (New Jersey and Pennsylvania) in 2003 and 2006.
Summary of exotic plant species cover and density for the 1-m2 monitoring plots of exotic species in 10 hemlock sites in the Delaware Water Gap National Recreation Area (New Jersey and Pennsylvania) in 2003 and 2006
Wason_etal_2017_JApplEcol_data
Datasets on Whiteface Mountain microclimate, tree growth (from permanent plots and tree cores), and plot level basal area and density for dominant tree species
Restoring Soil Calcium Reverses Forest Decline
Forest
decline in the northeastern United States has been linked
to the effects of acid deposition on soil nutrients. To test this
link, we added a calcium silicate mineral to a paired watershed at
the Hubbard Brook Experimental Forest, New Hampshire, in an amount
designed to gradually replace the estimated amount of calcium lost
as a result of human activity in the 20th Century (primarily because
of acid deposition). The experimental restoration resulted in a recovery
of tree biomass increment. The improved calcium nutrition also promoted
higher aboveground net primary production and increased the photosynthetic
surface area in the treated watershed relative to that in the reference
watershed. These results demonstrated that soil acidification accelerated
by acid deposition has contributed to the decline of forest growth
and health on naturally acidic soil in the northeastern United States
and that decline can be reversed by the addition of calcium
Appendix A. Description of treatments, plot data collection, shrub cover and snag recruitment analyses, and tree vulnerability profile development.
Description of treatments, plot data collection, shrub cover and snag recruitment analyses, and tree vulnerability profile development
High Hydroquinone Emissions from Burning Manzanita
California wildfires are becoming
larger and more frequent because
of climate change and historical fire suppression. The 2017 fire season
was record-breaking in terms of monetary damage, area burned, and
human casualties. In addition, roughly 20 million people were exposed
to dense wildfire smoke for days. Understanding the health impacts
of wildfire smoke requires detailed chemical speciation of smoke produced
from different fuels. This study demonstrates the unique chemical
fingerprint observed in smoke from burning manzanita, a common chaparral
and forest understory shrub found in several ecosystems of California.
Burning manzanita during the FIREX Fire Laboratory experiments emitted
hydroquinone (1,4-dihydroxybenzene with an emission factor of 0.4
g/kg) and two sterol/triterpenoid tracer compounds at levels up to
100 times higher than those of the other common wildland fuels in
California such as pine trees, other shrubs, grasses, and duff. Additionally,
these compounds were detected in Berkeley, CA, from smoke produced
during the October 2017 wildfires in northern California, a region
where manzanita grows. In contrast, the identified fingerprint for
manzanita burning emissions was not observed during prescribed fires
of a mixed conifer forest in California’s Sierra Nevada, indicating
negligible amounts of manzanita were burned. As confirmed by shrub
inventory data collected prior to the burns, small amounts of manzanita
remain after prescribed burning, a low-severity forest management
technique, but larger amounts can occur after recovery from high-severity
events like wildfires. Results from this study show that chemical
signatures in smoke can be traced back to specific fuels like manzanita
and that forest management techniques can be used to limit certain
types of wildfire emissions