Tuesday, July 22, 2014

Deer Browse Assessment - Nells Rock

Assessing the open space off of Nells Rock Road was a pleasure after having witnessed the stripped forest near Long Hill School.  Hikers are still met with a carpet of greenery in at least some locations along Nells Rock Trail and the Paugussett.  It's not all good news, however.  It looks like deer are having a big impact on the species that make up their favorites foods, such as maples, oaks, maple-leaf viburnum, and Jack-in-the-pulpit, which is changing the composition of the forest.

Assessment plot locations off Nells Rock Road
Six 30' x 30' plots were assessed along an East-West line which began 0.2 mile south of Eklund Garden (see map above).  This line was chosen to avoid swamps and cliffs, which are very common in that area. There isn't much elevation change along the transect - it's a plateau.

Plot #1: Next to a swamp
Plot #1 was located next to a large swamp, and was full of sweet pepperbush, an aggressive shrub that grows along the margins of wetlands. Deer don't care much for it to eat, but a pepperbush thicket can provide good cover and there was a deer path through the thicket and deer droppings in the plot. Only two saplings were found between a height of 12" and 7 ft: One oak and one beech.

Plot #2 - A carpet of maple-leaf viburnum
Plots #2 and #3 had lots of maple-leaf viburnum, but most of it was pretty low.  This is a shrub favored by deer.  It wants to be over 4 feet tall, so you don't expect to see it as a low carpet. Although most of the plants are about 6" tall, there are a few taller plants, and these are the ones showing the most browse damage, especially the ones that are 2-3' high. This was a pattern I saw for the rest of the day.  There is plenty of maple-leaf viburnum off Nells Rock Road, but it's being browsed at a rate that is most likely unsustainable, and will eventually disappear (in contrast, I found only one tiny maple-leaf viburnum in the Long Hill Open Space).  It would be interesting to throw up a deer exclosure here and see what happens to the viburnum over a few years.

Maple-leaf viburnum - browse damage

Maple-leaf viburnum - growing back after being nipped.
Plot #2 had two saplings: A beech and a striped maple (which is unexpected in these parts). Plot #3 was at the top of a low knoll and seemed a bit sparse overall, but it had the largest number of tree saplings of all the plots (an oak, 3 beech, a hickory, 5 black cherry, and one unidentified).
Plot #3: More of the same, but with more tree saplings.
Plot #4 was in a boulder-strewn area and dominated by witch hazel (10'-20' high). Only one sapling was found: a witch hazel.
Plot #4: Sparse vegetation on a boulder field

Plot #5: Rocks and ferns
Plot #5 was poorly drained and had some nice highbush blueberry and cinnamon ferns. Zero saplings in this plot. But heading east of Plot #5, the terrain began to drop to the east and the biodiversity shot up.

Plot #6: A lot more diversity here sprinkled amongst the hayscented ferns
Plot #6 at first glance seems to be all hayscented fern. Deer will not eat the fern, leading to what is sometimes called a "fern desert" where deer numbers are high and the fern takes over. But amongst the fronds there were a large number of plant species, not to mention wood frogs and a land snail. Why was the diversity so much higher here?  Not sure, but one reason is likely that the growing conditions are better as the land begins to slope down to the east, with possibly better soil and more moisture. Plants simply grow faster and can handle more browsing pressure. Another factor may be that the ferns are actually protecting some delicate survivors from the deer. Yet another may be simply the foraging patterns of the local deer, who are creatures of habit and keep foraging along the exact same routes day after day, even when there isn't much to eat there.  Then there is the possibility that there is hunting occurring in the large, vacant property located very close by.

There were 4 saplings observed in this plot: one hickory and 3 ash trees.

Many of the most vulnerable plants, like Jack-in-the-pulpit, were small and not flowering, but hiding in the ferns. Here's a sampling:

Plot #6: Hogpeanut, hayscented fern

Plot #6: False Solomon Seal

Plot #6: Maple-leaf viburnum forming berries

Plot #6: Jack-in-the-Pulpit (small)

Plot #6: Wild geranium, poison ivy, and sensitive fern

Plot #6: Doll's Eye Banebery

Plot #6: Enchanter's Nightshade
Heading back to the car, I noted the vegetation growing along Nells Rock Trail. There were a few Jack-in-the-Pulpit, but all were small and none were flowering (flowering Jack-in-the-Pulpit is sometimes used as an indicator of the deer population).  There were also some asters, but there were all very heavily browsed (see photo below).  This plant should be over a foot tall by now and starting to form flower heads. Instead, these asters have all been cropped low and may not be able to reproduce this year. These is something also very evident at Eklund Garden, where the asters are cropped closely outside the deer fence but proliferate inside the fence.

Nells Rock Trail: White Wood Asters, heavily browsed