September 24, 2017 - Rock Tripe

Last week we saw a wide array of fungi, organisms that tend to grow in damp, rich environments - just where you'd expect to find life thriving.  But there are other organisms that somehow defy logic and have adapted to grow in places where they have no right to live.  If you have walked around in some of the darker forests in New Hampshire, particularly near ledges or large boulder fields, you have probably seen this prime example, the Rock Tripe.

Rock Tripe (genus Umbilicaria) growing in the Smyth Conservation Easement

Rock Tripe is a lichen, which are composite organisms made up of at least two, and sometimes three, very different organisms.  One component of lichen is always a fungus, and the second is usually an algae.  The algae lives inside the fungus and the two organisms exchange nutrients - not unlike what a fungus does for a tree. And since algae can photosynthesize using sunlight, CO2, and a few nutrients, [REF: http://allaboutalgae.com/what-are-algae/] it can provide energy to the fungus, which in turn, provides a home for the otherwise structure-less algae.  It's a pretty nice arrangement, and can produce some really large Rock Tripe.

These are nice and green, but in a dry season or on a sunny ledge they can be brown, dry, and stiff.

In case you're ever hungry in the woods, these are edible.  The recommendation is to soften them by boiling, though I can't say I've ever tried it.

We were up in New Brunswick, Canada this week and saw another great example of lichen that grows in an amazing location.

Beard Lichen (Usnea subfloridana)

This is called Beard Lichen, and it's common in the Lakes Region of New Hampshire where I usually see it on the ground after it has been dislodged the tree branches above.  This lichen pulls most of its nutrients right out of the air and it is a great indicator of air quality; it can't live in polluted air, and the better the air quality, the larger it grows.

Beard Lichen on the ground back in Meredith, New Hampshire

Ferns are another plant that often grow on granite, though these use a more conventional approach: they take root in the rotted debris that has collected on the tops of boulders over many years.

They can find the smallest nook to set roots into.

Or they can take over an entire boulder.

Christmas ferns (Polystichum acrostichoides) crowd out all others on this boulder

Christmas ferns got their name because they stay green well into winter, often being seen still bright green when covered with snow.

There are also large plants that manage to take up residence where they have no right to.  White pine and hemlock are both good at this, and all it seems to take is a small crack or depression in the rock which captures both water and a seed, and a tree can take root.

A white pine establishes a toe-hold on Sheep Island in Lake Wicwas

This relationship is more damaging to the host (though even lichen will eventually degrade the rock), as over time, as the root grows, it will slowly pry a granite boulder apart, accelerating the demise of the rock, but helping to create sandy beaches for us (in a few millions years).

Here is a white pine farther along in this process:

This pine has been growing for 10-20 years

During which time it has pried up a large piece of the bedrock

Next is an example of an oak tree that started out trying to grow on top of a boulder, but it didn't work out well for it.  At one point it got toppled over, bringing up some bits of mother earth with it.

But that didn't slow it down much.  It just took a 90 degree turn back up towards the sky and kept right on growing.

Very adaptive in its quest to find the sun

Nature can be both resilient and persistent.  It can also be tolerant.  Take a look at these two trees:

Two different trees with an intimate relationship.  (Credit goes to Jim G. for discovering this.)

The branch of one tree grew right across the trunk of the other, and over the years, the two have grown together.  Even more interesting is that it is an interracial marriage - they are different species. The one on the left with the branch sticking out is an oak, while the receiving tree is a maple. Notice how the oak has grown its bark out, wrapping right around the maple tree.

These trees are in the soon-to-be-conserved extension of the Page Pond Town Forest.  A planned trail will go right by this, so when the property is open I'll provide directions so you can see this natural anomaly for yourself. Until then, be on the outlook for plants growing in unique ways as you travel around the Lakes Region, and let me know what you find growing where it has no right to.