J. FURGURSON ET AL.
attention (Shackleton et al., 2011, Kerns et al., 2002, Ticktin,
2004), our research found relatively little literature relating to
their sustainable harvest (Wong, 2000). We did not find any
research recommending guidelines for harvest of bloodroot. In
order to address this gap in the scientific literature, this study
provides plant size and stand density information for nine
stands of protected bloodroot in the Waynesville watershed of
North Carolina. We also analyzed the relationship between
easily observable aboveground plant characteristics and below-
ground biomass, which could contribute to guidelines for sus-
tainable harvest of the resource. In this section, we complement
the analyses with a brief discussion of the distribution and long
term sustainability of bloodroot in western North Carolina to
provide context for comparisons between the protected stands
that we inventoried and nearby harvested stands.
Waynesville Case Study
In the Waynesville watershed, we found that most bloodroot
(eight of the nine stands identified) occurs on northern hard-
wood slopes or poplar coves. Within this habitat type, blood-
root stands have a clumped distribution. Eight stands had simi-
lar characteristics. While the mean density of the ninth stand
was not statistically different at the 15% level, it was much
higher than the other stands in absolute terms. This may be due
to unusual stand characteristics also reflected in its small size.
Bloodroot is known to respond to increased sunlight through
increased clonal growth (Marino et al., 1997), and the stand
was located in a patch of sunlight with little overstory cover,
possibly the result of a treefall gap.
Mean petiole diameter of the bloodroot stands is significantly
negatively correlated with average overstory tree dbh within the
range of conditions where bloodroot was found. It is important
to note that excluding the outlier population, all of the stands
are located within areas where average tree dbh is between
27.38 and 36.17 cm. Bloodroot is not found growing naturally
in large open fields or in very young stands with a low mean
tree dbh and lots of competitive herbaceous cover. Preliminary
literature review and canvassing of possible research sites indi-
cated that bloodroot is not found in young stands or dry sites.
Rather, typical sites for bloodroot are medium-sized hardwood
stands on northern aspects. As the mean dbh of mature stands
increases, bloodroot growth may decline. One explanation for
this is that an older mature overstory of large hardwood trees
allows more light to reach the forest floor and increases the
competition from other understory plants. It is also possible that
increased tree growth results in limited nutrients, which may in
turn lead to a decline in bloodroot growth rates.
Allometric Volume Equations
The relationship between easily recognized aboveground
characteristics (petiole height and petiole diameter) and below-
ground biomass of rhizomes was analyzed to assess the feasibil-
ity of restricting harvest to the largest rhizomes. Regression
analyses based on the 174 harvested rhizomes and their corre-
sponding aboveground plant parts reveal that rhizome biomass
can be predicted fairly accurately with two variables: petiole
height (cm) and petiole diameter (cm) (R2 = 0.77; p < 0.0001).
The regression equations demonstrate that harvesters can
estimate belowground biomass based on the observable above
ground plant characteristics of petiole height and petiole diameter.
Regional Bloodroot Sustainability
In a preliminary reconnaissance made when selecting the
Waynesville study site, four additional forests in Western North
Carolina were visited, including a national forest research site
and private and community forests. This confirmed that rich
cove sites provide excellent habitat for bloodroot.
Field observations and a few sample plots were taken in one
of the sites that had been open to bloodroot harvests and subject
to periodic timber harvests. Bloodroot on these lands was
scarce, even on rich cove sites comparable to those sampled in
the Waynesville watershed. The plants had comparable mean
petiole heights to those on the Waynesville watershed, but stand
densities were notably reduced.
Thus, our inventory may provide an upper bound on blood-
root distribution and abundance, since the Waynesville site is
managed under a conservation easement and not subject to
bloodroot harvest. Based on our canvass of potential sites, the
mean density of harvested stands was less than one plant per
square meter compared to 7.2 plants per square meter in the
Waynesville watershed. If the Waynesville high density stand
outlier is removed, the mean stand density drops to 3.7 plants
per square meter, still significantly larger than the harvested
stands. Due to the similarity in forest types and bloodroot plant
sizes, it is likely that this discrepancy in stand density is due to
harvesting pressure. This in turn suggests that some regulation
of harvest (whether by law or by community norms) and/or
active management such as enrichment plantings will be re-
quired to prevent further decline of bloodroot populations.
According to work on the ecological zones of the Southern
Appalachian Mountains by Simon et al. (2005), 12 percent
(695,000 acres) of the Southern Appalachian Mountains are in
Northern Hardwood or Rich Cove ecological zones. If the
Waynesville watershed can be considered representative of
Southern Appalachia, then we can extrapolate from the occur-
rence of bloodroot in 4.2% of the suitable habitat in Waynes-
ville to estimate that there are 56,000 acres of bloodroot in the
Southern Appalachian Mountains. This represents less than one
percent of the total forest area. If the 1,772,000 acres of Mesic
Oak-Hickory (Simon et al., 2005) are added to the total area of
suitable habitat, the total potential bloodroot area would be
about 197,000 or 3.4 percent of total forest area, although this is
likely an over-estimate, because we found only one bloodroot
stand in this forest type.
Furthermore, anecdotal evidence indicates that bloodroot
may be more common in the Waynesville watershed than in the
region as a whole, suggesting that the total area occupied by
bloodroot in Southern Appalachia is even less than projected
above. Sampling more stands under a variety of ownership and
management types would shed further light on whether the
Waynesville stands are representative and whether diminished
stand density is typical of sites that are open to harvest. Last we
offer a few observations about the natural history of bloodroot
and forest management practices. Bloodroot clearly favors deep
rich soils on north and east facing slopes and rich cove sites, as
well as soils that are not too acidic, which leads to domination
by rhododendron. Most of the Waynesville watershed has this
combination of aspect and soils. Furthermore, though not well
documented, our results suggest that bloodroot thrives under a
certain age, species, and density of forest overstory. Most of the
forest in the Waynesville watershed is about 80 - 85 years old
with a general oak-hickory-poplar forest composition, and a
Copyright © 2012 SciRes. 217