Sunday, August 22, 2010

8-20-10 Zealand Pond, Zealand Valley

If last Sunday (8-15-10) was one of the loveliest days I've spent in the mountains this Friday was its twin. I was lucky to have the day off so I could wrap up my cursory explorations of the aquatic habitats of the five ponds and lakes I selected. I wanted to finish this up while the weather was still warm and the day turned out to be nearly perfect. Zealand Pond was different, by comparison, with the previous four lakes I'd investigated and was not what I had expected.

At the half way point to the pond, where last year this beaver dam was causing flooding including water across the Zealand Trail, some enterprising person put in two lengths of stainless steel stove pipe as a top drain to help keep the water at a manageable level. It'll be interesting to see how this works in the winter.

A few feet away the trail leading to Z Bridge was dry again after being flooded most of last fall and winter.

It's clear beavers are back in the valley in force and refurbishing older dams to establish a habitat for themselves that's safe and sustainable (for them) .

The trail was lovely, as it almost always is, including this section through the birches which is my favorite part of the hike and the sunlight early Friday morning was filtered by a thin layer of clouds that gave the trees a silvery sheen.

This small pond beside the trail has been highlighted in this blog before but it is interesting to see how much more the vegetation has fanned out on the southern edge in the past two years and reduced the surface area of the water.

Zealand Pond, part of it, lies behind the overgrown beaver dam in the photo. The pond and the area around the pond has been dissected many times in the past 100 years by beaver dams that may have been designed by the beavers in masterful attempts to change how the water moved up and down the valley. The pond in on a watershed divide and has two outlets that flow to the ocean in two different directions. One flows north into the Zealand River that flows into the Ammonoosuc River 11 miles downstream. The pond's south outlet flows into Whitewall Brook which becomes a branch of the Pemigewasset River in just a few miles at the southern end of Zealand Notch.

This is the south end of the pond. Zealand Falls Hut is located up there on the ridge behind the pond. You can see a bit of the roof left of center of the photo. My plan was to set three 'lines', or 'transects' across the pond: one directly across the pond from this point just to the right of the exposed rock, then north to a small island, and then up to the northwest corner of the pond and back to my starting point. Establishing transects is simply a way to secure "randomness" in a series of measurements, or observations, so those observations can be repeated at a date in the future. Randomness (is there is such a word?) is desired so that the observations won't be biased.

Looking north towards the island I just mentioned and, in the background, an old beaver dam that was built almost 30 years ago (post 1967) and extends entirely across the pond that the beavers used to split and control the flow of water in the lake between the two outlets. Mt. Hale is in the background.

The water was cool, but not cold. I thought I might be able to stay in as long as I wanted. This was my first view upon diving in. It looked eerie. Everythings seemed dead and unattractive in the orange colored water.

I'd seen these plants in the lakes at Carter and Lonesome but not covered with silt and looking half dead.

This, too, was familiar, and it also had a death-like pallor.

A log on the bottom in 6 feet of water near the outlet. The log was not decomposing and was pretty solid. It could probably be lifted out, cut up, dried and still used for something.

This is the bottom in only 4 feet of water and...

This is the bottom in 6 feet of water. That is the deepest water I found and it's in front of the outlet. The outlet, during high water, creates a flow of water and a pretty strong current towards the south and it carves out a six foot-deep trench that's about 40 feet long.

Another log in the vicinity of the outlet.

On the second transect, heading northeast, I found some green plants covered by algae and, whether it was the silt or something else, they didn't look very healthy and it was at this point that my disappointment in Zealand Pond began to hit me. I had hoped for another experience like Lonesome Lake where I would find obvious health in the aquatic system that would mirror the environmental health of Zealand Valley.

On the northeast transect I found this plant in 30 inches of water. They obviously looked much different than other plants I had been observing if only for the green pigment, chlorophyll, but also by their dendritic (branching) form.

They had thick, fleshy stems and looked generally healthy but in this strange light it was difficult not be repelled by them.

For instance, this one looked kind of extraterrestrial and eerie.

When I saw this plant close by I had the sudden thought that I was on Mars.

In the middle of the northeast transect I found this hole and realized, as at Lonesome Lake, that it was a moose's hoof print. It was a dent in the bottom sediments 5 inches deep and it was easy to make out the outline of the hoof.

As I looked around I saw hundreds of them in a diagonal line that ran northwest by southeast and that suggested a moose interstate highway of sorts because it was clear that a lot of moose, or a few particularly anxious moose, had cut across the pond here over a lengthy period of time . From my bushwhacking experiences throughout the Valley particularly on the back side of Whitewall Mountain extending over to the Willey Range I'm aware of the extensive moose "yards" in the area and the traffic across the pond lines up with at least two of the yarding and browsing areas.

Closer to the island the diversity of plants increased. There weren't signs of there being more oxygen in the water, or less, but it was difficult to tell because of the silt. I concluded that the silt could be a result of turbulence caused by the moose as they cut across the pond with their hooves churning up the bottom sediments into clouds of silt drifting in the water and finally settling.

At any rate, this photo alone, speaks about eutrophication and the major change in the habitat on the bottom of the pond and in the pond itself. It would be brilliant to study Zooplankton in the pond and establish current population levels for future reference.

Here's the small island approached underwater. Like the small islands in Lonesome Lake it is anchored tenuously by the roots of a few plants.

This is what the island looks like above the surface. This is also a good representative photo of how adaptive larch trees are to these kinds of habitats. The larch tree, and there are several others nearby on the margins of the pond, is a late comer, but offers a better anchor for the other plants and insures the stability of the island for the future. I took several measurements of the area of the island and it will be interesting to observe it over the next decade.

From the island across the southeast quadrant of the pond the water depth diminished to an average of 2 feet and the bottom was covered with this dense mix of plants. There was a current here running south due to a breach of the beaver dam to the north. It's possible that there's more oxygen in the water on this side of the pond due to the current.

As I finished up at Zealand Pond I made generalized comparisons of the four other 'lakes' (Eagle, Lonesome, Lakes of the Clouds, and Carter). It's evident that Zealand Pond and Eagle Lake are the most eutrophied and that succession is moving at a faster pace in these two habitats. I'm not sure why, but at some point the process must reach a critical mass that is determined by oxygen amounts, the pH of the water, and the ability of the water to recharge. The rate of flow must be inversely related to the pace of eutrophication.

As I mentioned the bottom sediments in Zealand Pond were a thick layer that I could extend my hand and arm in as far as my elbow. Normally we consider this sediment layer of particulate organic matter to be a key indicator of a body of water losing its vigor, dying in other words, but only at that stage in succession. Lakes of the Clouds is referred to as a glacial lake, where the glacier scooped out rock that was there and carried it further away. It will probably not go through any further successions for a long, long time and only if there are significant climate changes. It's the most stable of the

Pushing my hand down into the sediments sent up bubbles of gas that smelled faintly of methane, a good measuring stick for eutrophication.

For the moment I've paired Eagle Lake and Zealand Pond of the five bodies of water as the two most likely to proceed to the bog stage before the other three. The other lakes, including Lakes of the Clouds, get "flushed" (recharged) periodically by high flows of water, maybe several times each decade, where Eagle Lake does not. Zealand Pond probably got flushed (by hurricane-sized storms, etc) prior to its dissection by the existing beaver dams. The lakes at Carter probably doesn't get "flushed" extensively but must have a fairly good flow of water moving through it most of the time. Lonesome and Carter are next on the list in terms of eutrophication and succession but not for a long time.

There was evidence of beaver activity in the southeast quadrant of Zealand Pond in the form of sticks and logs that were cut and dragged into the pond by beavers over a long period of time. Some sticks were really old, more than 60-70 years old, and some were more recent.

Because of the shallow water I could just snorkel up to this vacant lodge but I couldn't find the entrance. The resettling of Zealand Valley by at least one family of beavers will be interesting to observe. One has to wonder if the beavers' intent is to stop water flow to the point where euthropication accelerates moving the succession towards dense, fertile soils followed eventually by forest cover.

I often think of plants and soils as being two stages of the same organism that's trying to find equilibrium and I see that beavers, working over long periods of time, help accomplish this. Wolves and buffaloes working together created the astonishingly rich, dense soils of the north central areas of North America. Beavers and moose might be part of that legacy.

This is a beaver lodge anchored to the shore in the very southeast corner of the pond. There are several around and in the pond representing various periods of beaver cultures here. All the lodges, though, exhibit similar architecture and purpose in creating an almost indestructible, safe-from-predators, home for the beavers.

Witherod, or Vibrurnum cassinoides. This is very common in bogs throughout the area and particularly at Zealand.

Golden rod again. How many can there be?

Mesic forest. Again, mesic means somewhere in the middle regarding moisture. Xeric would mean dry like a desert. Hydric is wet and could apply to the bogs we've been looking at. These three terms are generalist ways of defining habitats.

The trail out, back to the road. The Zealand Trail, from Route 3, is really part of the old logging railroad system that crisscrossed the White Mountains. Almost all areas of the "Whites" at one time or another had a railroad extending through them used for hauling out vast amounts of wood (whole trees) from the mountain slopes and valleys.

1 comment:

John Farrell said...

I just came across your detailed post. Marvelous job!