<html><head></head><body><div class="yahoo-style-wrap" style="font-family:courier new, courier, monaco, monospace, sans-serif;font-size:16px;"><div dir="ltr" data-setdir="false"><div><p class="ydpc57920e1MsoNormal"><span style="font-family:"Calibri",sans-serif"><span> </span>About a week ago a woman I
happened to meet on the Appalachian Trail (AT) and walk with for a few minutes
asked about non-native plants spreading along trails. The day before I had
walked a little used single-track trail I like and this past Saturday was
walking on the AT to the Allentown Shelter from a local road over the mountain.
Then yesterday I walked another stretch of the AT below the Hawk Mountain
Sanctuary which was a mix of trail and logging road. All these trails had the same
pattern with some of their plants – they were transported along the trail then
spread outwards from the trails into the forest. This was very apparent with
the non-native Japanese barberry (<i><span style="color:#202122;background:white">Berberis thunbergii</span></i><span style="color:#202122;background:white">)</span> on the way to the Allentown shelter and the native Eastern Yellow
Stargrass (<i><span style="color:#202122;background:white">Hypoxis hirsuta</span></i><span style="color:#202122;background:white">)</span> on the single-track trail.</span></p>
<p class="ydpc57920e1MsoNormal"><span style="font-family:"Calibri",sans-serif"><span> </span>Over the years I have noticed the
same pattern beginning with grape hyacinth (<i>Muscari armeniacu</i>m<span style="color:#111111;background:white">) </span>and then with the American
Chestnut tree (<i>Castanea dentata</i>). On the loop trail around a local lake,
Blue Marsh, many years ago I saw that <i>M.<span style="color:#111111;background:white"> armeniacum</span></i> was apparently being transported along
a trail from a homestead where it was originally planted along the trail in the
direction most commonly used by mountain bikers and hikers. Several years ago I
realized that <i>C. dentata</i> was seldom found more than 15 yards from a
trail unless it was part of an old stand. This observation made me think about
the differences between open forest versus trails. The difference I saw was the
result of friction. Trails are low friction for birds and mammals when
travelling through a forest. Whereas friction is higher for animals travelling
across the forest. From experience “bushwhacking” from one trail to another is
much harder than traveling on a trail. Basically, it appears that animals preferentially
move on low friction trails as opposed to through high friction open forest.
This preferential movement transports seeds and other propagules first along
trails and then when established into the open forest.</span></p>
<p class="ydpc57920e1MsoNormal"><span style="font-family:"Calibri",sans-serif"><span> </span><i>B. <span style="color:#202122;background:white">thunbergia </span></i><span style="color:#202122;background:white">is an unfortunately outstanding example of first spreading along a trail
then into the forest as I witnessed when walking the AT to the Allentown
shelter. The plants were frequent along this stretch of trail and had not yet
moved into the forest unlike where this stretch of the AT near where it crosses
Hawk Mountain Road. Garlic mustard (<i>Alliaria petiolate</i>) is another
example of this pattern, both as early in this stage of spread and fully
covering a part of the forest as along the AT on Peter’s Mountain. Japanese
stiltgrass (<i>Microstegium viminium</i>) is another excellent example of this
pattern. Yesterday, it appeared that the native American Cancer-root (<i>Conopholis
americana</i>) is doing this on a stretch of the AT I was on below the Hawk
Mountain Sanctuary.</span></span></p>
<div><span style="font-family:"Calibri",sans-serif;color:#202122;background:white"><span> </span>My
suggestion is to monitor the trails and control the non-native invasives as
they migrate along trails before they enter the open forest. Costly remediation
will not be needed if an invasion is dealt with early alongside the trails before
invasive plants penetrate the open forest. This is especially true with aggressively
invasive plants such as <i>B. thunbergii</i>.</span></div></div><div><span style="font-family:"Calibri",sans-serif;color:#202122;background:white"><br></span></div><div dir="ltr" data-setdir="false"><span style="font-family:"Calibri",sans-serif;color:#202122;background:white"> Richard Gardner</span></div><br></div></div></body></html>